ESE's works engine tuner

[TZ350]

<iframe src="http://www.youtube.com/embed/3kaUzQO4i8Y" allowfullscreen="" frameborder="0" height="315" width="420"></iframe>

Kel gave me a hand tonight to try a resistor plug (http://youtu.be/3kaUzQO4i8Y)

Wob had suggested that the high RPM deto could be electrical noise from the old non resistor plug upsetting the Ignitec.

Kel warmed the Beast up and pulled a few runs until we were seeing high rpm deto and backfiring out of the carb at about 13k rpm.

280193

Pulled the old non resistor plug and it looks rich if anything.

280192 280194

I made up a spacer for a 3/4 inch BR10EG resistor plug along the lines suggested by Wob.

There was no real difference, we still had high rpm deto and running on.

We tried advancing the ignition in the over rev area too but no change.

So the answer is not there either.

280191

The curves for the two plugs look about the same. Powers down, over rich is my guess.

Kel points out that when it was running on and he had his thumb on the kill switch he could open and close the throttle, and the induction sound changed but the motor did not respond even though it was auto igniting.

As the motor was auto igniting and running on, when he let the kill switch go, he could open and close the throttle and the motor would respond.

So:-

Ignition off, running on by auto ignition and open/close the throttle = non change.

Ignition on, and running on by auto ignition and open/close the throttle = change.

Whats that about?

[husaberg]

Not really convinced over the Coarse or Fine outputs from a TPS, if it is a potentiometer and you put a potential of 12v on the top , earth at the bottom, then assuming it is a carbon or ceramic track you will get an infinite range of 0 to 12v off the wiper . if it is wirewound with say 100 turns then you will get 100 steps about 1% still not exactly coarse. if it was a switch then you could say it was coarse, even if it had multiple taps.
Not surprised Mike and Neil i didn't really put across clearly what i meant.
What i am suggesting if you have a TPS remote mounted driven by a cable with a slide driven from a cable at the other end i don't believe necessarily 50% of the tps is always going to accurately reflect 50% throttle throw in a TPS that is reading in a rotating arc a likely not designed to truly reflect actual % of throttle position perimeters. What i are suggesting is a likely more accurate way of measuring throttle position is to measure the throttle position at the source and in the direction of the actual motion.
Lastly i don't agree with the 100 steps. But at the end of the day all the Stuff i deal is above 66KV.
The filtering comment was from a PDF(2.1MB) i can't post but was basically a Fly by wire system piggy pack so the throttle response could be tailored based on a PWM circuit.
But yeah that's extreme Overkill esp considering my bike is in two separate Islands and the cylinder is uncast and untested and unfinished.


My TPS, although in cable, was a rotating device ( in fact the very same unit I'm using now ). The first cable went round a rotating quadrant, then a second cable off to the slide throttle ( a lake injector copy ). I had times when the slide would " hook up slightly " but the TPS not. Leeeean off idle but only sometimes untill I caught it in the act one day!! So that was the end of that, no more cable between these two units. I not telling anyone to do as I have done, just saying this is what happened to me.
What he said Mike
Whats the trade deal on one of those custom variable disk housings maybe a with a say of PV gubin thrown and cylinder dome thrown as well.

[Frits Overmars]

Seeing spark plugs and a fork spanner in the same picture makes me shiver. Ring spanners and socket spanners are OK but a fork spanner acts on only two corners of the spark plug's hexagon. That may push the plug body out of round, resulting in leakage inside the plug.

[TZ350]

Seeing spark plugs and a fork spanner in the same picture makes me shiver.

Eeeek yes, no, the fork (open end) spanner was just to prop up the plugs so the plug numbers could be seen in the picture. You can just see part of a proper plug socket and ratchet in one of the other pictures.

[Yow Ling]

Not surprised Mike and Neil i didn't really put across clearly what i meant.
What i am suggesting if you have a TPS remote mounted driven by a cable with a slide driven from a cable at the other end i don't believe necessarily 50% of the tps is always going to accurately reflect 50% throttle throw in a TPS that is reading in a rotating arc a likely not designed to truly reflect actual % of throttle position perimeters. What i are suggesting is a likely more accurate way of measuring throttle position is to measure the throttle position at the source and in the direction of the actual motion.
Lastly i don't agree with the 100 steps. But at the end of the day all the Stuff i deal is above 66KV.
The filtering comment was from a PDF(2.1MB) i can't post but was basically a Fly by wire system piggy pack so the throttle response could be tailored based on a PWM circuit.
But yeah that's extreme Overkill esp considering my bike is in two separate Islands and the cylinder is uncast and untested and unfinished.


What he said Mike
Whats the trade deal on one of those custom variable disk housings maybe a with a say of PV gubin thrown and cylinder dome thrown as well.

OK maybe I follow now, are you concerned the position of pot isnt zero when throttle closed and isnt 100% when fully open. If you are using an ignitech you dont need the full sweep of the pot just a start and end voltage , it sorts out the rest without extra circuitry. I now see what you mean about the 100 steps, in your world thats about 660v per step !!!

[Ocean1]

OK maybe I follow now, are you concerned the position of pot isnt zero when throttle closed and isnt 100% when fully open. If you are using an ignitech you dont need the full sweep of the pot just a start and end voltage , it sorts out the rest without extra circuitry. I now see what you mean about the 100 steps, in your world thats about 660v per step !!!

Also, depending on the mechanical relationship between the throttle shaft and the pot it's quite possible to have zero=zero and 100%=100% but increments inbetween out of step. Is unlikely if the pot's driven directly, (axially coupled) from the throttle spindle, eh?

[speedpro]

None of which matters as the TPS tables map a reading to a value. Who cares if the carb slide and the TPS dont have a perfect relationship. You could have say 30 values mapped over the first 50% of throttle movement and 70 values over the remaining 50%. As long as it never varies it doesn't matter. You may lose some resolution in one area and gain it in another. Unless you lose a LOT of resolution it won't matter.

[Flettner]

The link is the same, you tell the computer idle ( throttle shut ) and then you tell it full throttle, it works out the steps for you. You tell the computer how many steps you want ( up to ten I think ). If you have a problem area you can ( fine fuel control needed like just off idle ) you can zoom in to much higher resolution in the problem area ( fine tune it). This overlay can be done in four separate areas. The problem is when, like with my cable system, the throttle and TPS don't move the same each time, they must work together and the same each time. Solid mounting the TPS to the throttle shaft does achive this. Butterflies are for the garden.
I may have a small order for half ball throttle valves ??

[husaberg]

OK maybe I follow now, are you concerned the position of pot isnt zero when throttle closed and isnt 100% when fully open. If you are using an ignitech you dont need the full sweep of the pot just a start and end voltage , it sorts out the rest without extra circuitry. I now see what you mean about the 100 steps, in your world thats about 660v per step !!!

remember its was for Fuel Injection though,rather than for the ignitech
Yes i am likely over stating as now i think bout it more i doubt half throttle is likely to be half movement slide on a carb anyway.
maybe Neil can add how forgiving the Fuel injection is? i certainly can't, but i are guessing the map for a small 1 cylinder 2 stroke needs to be a hell of a lot more refined than a large capacity 4 cylinder four stroke.

i only threw out the squished shape (to match Robs Port)Slide carb (not butterfly)
<img src="http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=280125&d=1363679839" width="45px"/><img src="http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=280100&stc=1&thumb=1&d=1363598551" width="45px"/>
with a linear TPS as it seems the simplest shortest solution remember.
As i said i liked the throttle slide cum Variable timing better as it even simpler and just as if not more narrow,<img src="http://i1056.photobucket.com/albums/t380/uniflow/0c93ef14.jpg" width="60px"/>

<center><img src="http://images.trademe.co.nz/photoserver/full/257074787.jpg" width="370px"/><img src="http://www.dreamgate.ne.jp/NSR/specs/50_92engine.jpg" width="340px"/><center>

Anyway it seems i just brought a NSR50 or MTX/MTX50 motor for $1.
F5 maybe? not that i have ever seen one.
I must admit i never really had a close look at the pic and just assumed it was a CR80.The tacho drive should have been a bit of a giveaway.
Judging by the water pump grass adornments and the open intake i bet it's real mint inside with our maritime climate and all.:whistle:

[teriks]

Kel points out that when it was running on and he had his thumb on the kill switch he could open and close the throttle, and the induction sound changed but the motor did not respond even though it was auto igniting.

As the motor was auto igniting and running on, when he let the kill switch go, he could open and close the throttle and the motor would respond.

So:-

Ignition off, running on by auto ignition and open/close the throttle = non change.

Ignition on, and running on by auto ignition and open/close the throttle = change.

Whats that about?
This auto ignition was was in gear, clutch out, on the roller at high RPM?
If so, perhaps the auto ignition occurs very late, producing little to no power?

Can you do a test with an all aluminium head?

The cu sheet could act as an catalyst and be part of the problem, especially if you have a hot-spot on it somewhere.

EDIT: I know that copper is a catalyst to at least acetone and methanol, so it's not too far fetched to think that it can lower the auto ignition temperature of gasoline too.

[F5 Dave]

280192 280194

I made up a spacer for a 3/4 inch BR10EG resistor plug along the lines suggested by Wob.



Actually Wob told you to weld it on & he did so for a good reason. You've just made a BR7EG emulator.

[TZ350]

You've just made a BR7EG emulator.

:argh: ...... :facepalm: .... bugger

[wax]

Wob/ frtiz anyone
Have you guys compared wasted spark to a non wasted spark on an engine and what was the result as far as power was concerned

[F5 Dave]

Well I'll chime in under the anyone clause & say a lot of it would depend on the ability of the ign to generate enough juice at high revs.

I do know a chap that had a bunch of issues on a dirty old aircooled bigbore MXr running on Methanol & problems disappeared when they went to a non wasted spark ign. perhaps Meth was igniting, or perhaps see first paragraph.

[wax]

Well I'll chime in under the anyone clause & say a lot of it would depend on the ability of the ign to generate enough juice at high revs.

I do know a chap that had a bunch of issues on a dirty old aircooled bigbore MXr running on Methanol & problems disappeared when they went to a non wasted spark ign. perhaps Meth was igniting, or perhaps see first paragraph.

Yes thats right, Im making a custom flywheel for an msd 4217 ignition for my race bike. Im just wondering one lump or two. Its easy to do one lump but if there were getting a gain with a wasted spark then I will look at making it a two lump flywheel. the other advantage of a two lump flywheel is I can use a spare pickup in case one goes wrong I can simply switch to the other pickup, its an endurace engine

[2T Institute]

Look under the bonnet of any reasonably modern car and do you see individual coils or a single coil?

[wax]

Look under the bonnet of any reasonably modern car and do you see individual coils or a single coil?

I see one coil per cylinder, that doesnt mean they are wasted spark. If you see half the number of coils vesrus cylinder you can be reasaonably sure they are wasted spark. Im not sure if wasted spark made more power on the dyno on a two stroke than a single spark. im not asking about using a distributor ie the single coil.

[F5 Dave]

I can't imagine how they would make more power & in fact give less time to build up charge.

How often to pick up coils go duff? Have to be pretty unlucky & then pretty lucky to work it out & swap it over in time.

[wax]

180 degrees is a fair amount of dwell time. I agree pickups dont give grief often but its a 24 hour race and I just want to have all my bases covered. I was wondering if a wasted sprk system clears the plug better and is less prone to fouling. I mean I didnt think the rsa cylinder with its big square entry to the transfers would make more power. The more you play with these engines the more you realise how finicky they are and even the smallest things make the big difference. I was just hoping to hear from some one who had in fact run it up on a dyno and done the test

[wax]

My ignition system has a full redundant system built into it ready to go. you can just plug it in. 24 hours at 14000 rpm really tests stuff and prior preperation prevent piss poor performance.

Its the stuff you dont do that lets you down

[TZ350]

280279

KX80 single spark per revolution.

280280

KX80 Wasted spark ignition.

Some of our bikes have a wasted spark ignition but we never thought to go to the trouble of trying the ignitions in back to back tests on the dyno.

[wax]

280279

KX80 single spark per revolution.

280280

KX80 Wasted spark ignition.

Some of our bikes have a wasted spark ignition but we never thought to go to the trouble of trying them in back to back tests on the dyno.
Thanks tz Im not sure it will make or not make a difference but it would be worth finding out if its been tested as right now I have the ability to choose

[Flettner]

What do you mean, wasted spark?

[wax]

Wasted spark on a two stroke is when it fires at bdc as well as tdc. Normally its done on a twin cylinder two stroke where they use a single channel ignition system to run both cylinder. On a four stroke its a bit different

[TZ350]

280279

KX80 single spark per revolution.

280280

KX80 Wasted spark ignition.


What do you mean, wasted spark?

Both KX80 flywheels have four poles.

With the first KX80 ignition, both pole pairs charge up the CDI capacitor and the outside trigger coil fires it.

For the second KX80 ignition, both pole pairs charge the CDI capacitor (one pair at a time) and the ignition is triggered by the flux sign change as the magnet pair pass the coil, this happens twice a revolution, so one spark is wasted.

Wax has pointed out some other wasted spark scenarios.

[TZ350]

280282280285

I am very taken with the Ball Throttle Idea.

280283

And I would like to try one in the old plenum setup.

280284

The old plenum suffered from the blars with the short inlet and needed the extension, but the ball throttle may fix that. The other problem with the plenum was fuel dropout puddling in the bottom and affecting the mixture. I fitted a scavenge pump to cure that but never really put any time into it. This time I will use fuel injection and see how that goes.

The plenum was an idea to get around the 24mm carb restriction but 24mm's turned out to be not as much of a restriction as we thought it would be.

But the 24mm will eventually restrict things and I am starting to suspect it plays a part in the over rev deto thing by limiting the crank case filling and case pressure at 13K. My guess is, a Lower case pressure will allow more hot exhaust gas to enter the transfers at high rpm.

280286

Graph of my 24mm taper bored 24mm vis 30mm conventional carb in a back to back test a while ago. The only real difference was in the over rev area which leaves me thinking that the 24 could be contributing to the over rev deto problem. I will try the 30 on the dyno again next week and see what happens with the high rev deto.

[TZ350]

This auto ignition was was in gear, clutch out, on the roller at high RPM?
If so, perhaps the auto ignition occurs very late, producing little to no power?

Can you do a test with an all aluminium head?

The cu sheet could act as an catalyst and be part of the problem, especially if you have a hot-spot on it somewhere.

Another good idea to try out.

[husaberg]

Another good idea to try out.

Why not wack in some cupfuls of Acetone as well as a eggperiment.
It would only take a few minutes.
It woulds be cool is see if it's all, it's cracked up to be.

[TZ350]

280287

I am going to try making another triple exhaust port cylinder. The EngMod 2T simulation, is with the two side ports closed, red line and open, blue line. I can see some sort of power valve arrangement in my life soon.

[bucketracer]

Post a video and dyno run of your daddy's latest abandoned project ...

Whether it works out or not, I am sure there will be something posted about it.

[wax]

I'm guessing no one tried wasted spark on the dunno to see if there was a gain, I had figured maybe it kept the plug cleaner and well know that two strokes love a clean plug

[husaberg]

I'm guessing no one tried wasted spark on the dunno to see if there was a gain, I had figured maybe it kept the plug cleaner and well know that two strokes love a clean plug

Some one would have i seem to think the RDLC was a wasted spark set up, but i am no Yamaha guy.
I struggle to see how you could achieve a HP gain from drawing yet more energy from the engine to power the ignition than is needed to fire the plug though.
But no clue what the loss would be, maybe make a ignition dyno, and run a firing ignition (under load) and see what it draws to power the ignition dyno.
At the end of the day if you plan to run it for reliability, does it matter if it costs you a HP.
If the original ignition was working properly on competition engine the plug shouldn't be dirty should it.

[wax]

Some one would have i seem to think the RDLC was a wasted spark set up, but i am no Yamaha guy.
I struggle to see how you could achieve a HP gain from drawing yet more energy from the engine to power the ignition than is needed to fire the plug though.
But no clue what the loss would be, maybe make a ignition dyno, and run a firing ignition (under load) and see what it draws to power the ignition dyno.
At the end of the day if you plan to run it for reliability, does it matter if it costs you a HP.
If the original ignition was working properly on competition engine the plug shouldn't be dirty should it.
Most of those things I agree with you. Im interested to see if some one has dynoed it and seen a power or loss. As I said I have a choice as to what I do as Im making my own ignition setup for this bike. If some one had dynoed it and found a gain either way then I would be interested in the results. We all know that indexing the spark plug n a two stroke makes a difference and yet you wouldnt think so unless you understand whats causing it. in that case why couldnt a wasted spark system make more or less power

[husaberg]

Most of those things I agree with you. Im interested to see if some one has dynoed it and seen a power or loss. As I said I have a choice as to what I do as Im making my own ignition setup for this bike. If some one had dynoed it and found a gain either way then I would be interested in the results. We all know that indexing the spark plug n a two stroke makes a difference and yet you wouldnt think so unless you understand whats causing it. in that case why couldnt a wasted spark system make more or less power

To tell you the truth i have never seen any definitive back to back testing vs indexed plugs but who can resist the urge to do it.............
All the stuff i have ever seen on it relates to OCD American drag racers running Huge cc clinders with mega cylinder pressures Drag motors on exotic fuels............

[wax]

Its worth 1 mph or about 150 rpm on a 701 yamaha superjet. One of the easiest mods you can do as well.

That doest sound like much but you have to have more power to be pulling that higher rpm of course and 1mph when you drag racing up the start straight is worth heaps

[Flettner]

That's what I understood to be a wasted spark. But this is done for manufacturing convenience of a twin cylinder two stroke more than anything. I doubt it would be of any use on a single. If you need redundancy use a Ingnitec and run both channels into it. I do this but that's only because I have a dual channel Ignitec fitted. Fire them at the same time through one coil. More energy at the plug ( perhaps only 10% but worth having ). Because the F9 runs on E90, I tell any who asks it's E85 from Gull, spark voltage and rise time are important. Two into one helps, never had a fouled plug yet. Sometimes it's been so rich it will hardly run, the joys of tuning EFI.

TZ350, I'd say you are right on the money!

[TZ350]

We all know that indexing the spark plug n a two stroke makes a difference and yet you wouldnt think so unless you understand whats causing it.

I would like to know more about this as I would like to try it on the dyno, which way should the earth strap face?? towards the ex port or the rear boost port or side on to both, or do you have to find out what your own engine likes??

[wax]

aim the open area of the plug at the exhaust port. So the earth strap face it towards the transfer

[Flettner]

Ha, what if you are using a surface fire plug!

[wax]

Ha, what if you are using a surface fire plug! :facepalm:

[TZ350]

aim the open area of the plug at the exhaust port. So the earth strap face it towards the transfer

Ok thanks, I have a collection of indexing washers and will try it.

[TZ350]

280334

Ok. Chambers and I have put our money down on two of these 2-Stroke EFI kits.

From:- http://www.ecotrons.com/2_Stroke_Small_Engine_EFI_kit.html

I asked quite a few questions (that Flettner suggested) before buying it and the supplier always came back with good meaningful information, ie they look like they know what they are talking about.

Giggles has a 4-Stroke version for his new bike and I think its the same as the one Sketchy has on his supercharged 100.

Team ESE have used conventional carbs, then pumper carbs, now fuel injection could be the new thing.

I am not sure, but if we can get them working, these could be the first EFI 2-Stroke Buckets, anyway it will be lots of fun playing with them ....:D

[Moooools]

280334

Ok. I have put my money down on one of these 2-Stroke EFI kits.

From:- http://www.ecotrons.com/2_Stroke_Small_Engine_EFI_kit.html

I asked quite a few questions (that Flettner suggested) before buying it and the supplier always came back with good meaningful information, ie they look like they know what they are talking about.

Giggles has a 4-Stroke version for his new bike and I think its the same as the one Sketchy has on his supercharged 100.

Team ESE have used conventional carbs, then pumper carbs now fuel injection could be the new thing.

I am not sure, but this could be the first EFI 2-Stroke Bucket if I can get it working, anyway it will be lots of fun playing with it.

Looks interesting.

You could make yourself a nice plunger throttle right next to your disk valve for a nice short inlet tract and then inject into the cases. Also means that you aren't putting fuel through the same restrictor as your air. I don't know what atomisation/ dispersion of fuel would be like though...

Also where do you put your map sensor? in the cases? Can you just tune off of tps and rpm alone?

[TZ350]

I don't know what atomisation/ dispersion of fuel would be like though... Also where do you put your map sensor? in the cases? Can you just tune off of tps and rpm alone?

I don't know, but this is where we have fun finding out.

[husaberg]

I don't know, but this is where we have fun finding out.

Team ESE have used conventional carbs, then pumper carbs, now fuel injection could be the new thing.

I am not sure, but if we can get them working, these could be the first EFI 2-Stroke Buckets, anyway it will be lots of fun playing with them ....:D




You tested a EI carb as well too albeit very briefly..........

[TZ350]

You tested a EI carb as well too albeit very briefly..........

Yes, actually two, not enough old style needles available to get the blue one working properly. But Giggles later model one worked well on his FXR.

[Bert]

280334

Ok. Chambers and I have put our money down on two of these 2-Stroke EFI kits.

From:- http://www.ecotrons.com/2_Stroke_Small_Engine_EFI_kit.html

.....

I am not sure, but if we can get them working, these could be the first EFI 2-Stroke Buckets, anyway it will be lots of fun playing with them ....:D

.... could be a race for the first 2-stroke....:innocent:

but you might find some interesting information in here (I think I posted this up a while back):
http://www.125ccsportsbikes.com/forums/index.php?showtopic=63480

[Frits Overmars]

You could make yourself a nice plunger throttle right next to your disk valve for a nice short inlet tract. Like so:

[136kg136ps]

Frits,could that be configured as to change the inlet timing?It would seem that if mounted perpendicular to the crank rotation that one could not only have it as a carb slide but also to change inlet timing.Maybe it was mentioned somewhere and I missed it?

[Frits Overmars]

Frits,could that be configured as to change the inlet timing?It would seem that if mounted perpendicular to the crank rotation that one could not only have it as a carb slide but also to change inlet timing.Maybe it was mentioned somewhere and I missed it?You would have to controll all clearances meticulously, but it could indeed be done.

[Moooools]

. Like so:

More like so:

Only problem is massive amounts of sticktion due to the pressure drop across it. Could be solved with careful implinentation of a little cam.

[wobbly]

So now we will have a GP125 on EFI, with a trick variable computer controlled intake sytem as well, that, oh shit, still detoes in the overev - WTF.
I know that's sarcastic bullshit from me that doesn't help at all, but surely the extra effort needs to be spent sorting the known basic issues, before flying off on another tangent - what happened to the super duper stinger bleed idea for example ,etc etc.

BTW I tried the plug indexing idea on a TM125 engine that won 3 straight kart titles with 50 odd Hp at the sprocket, rotating the bronze insert to any position made no difference, changing plugs saw up to 2 Hp changes.
A crap wasted spark ignition with insufficient burn period or whatever may be a benefit in the big ski engines,as it does in the big 4T engines with horrendously shaped combustion chambers, but with a DC CDI ECU , and a toroid ,all these
negative details go out the widow.
Then if you have some issue like heinously rich allky mixtures,using twin fire CDI / Crane super coils - make all problems regarding ignition power irrelevant.

[bucketracer]

Post a video and dyno run of your daddy's latest abandoned project ...


So now we will have a GP125 on EFI, with a trick variable computer controlled intake sytem as well, that, oh shit, still detoes in the overev - WTF ...

Mocking is easy, and as SS90 has shown, you don't need many smarts to be negative.

[husaberg]

. Like so:
bump Gardner carb

As interesting as this TZ
http://www.raveengineering.com/images/armgardcarbs.jpg
http://2stroker.createforumhosting.com/armstrong-motorcyles-t3382.html

<!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--><!--[if !mso]><object classid="clsid:38481807-CA0E-42D2-BF39-B33AF135CC4D" id=ieooui></object> <style> st1\:*{behavior:url(#ieooui) } </style> <![endif]--><!--[if gte mso 10]> <style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman";} </style> <![endif]-->


Frits,could that be configured as to change the inlet timing?It would seem that if mounted perpendicular to the crank rotation that one could not only have it as a carb slide but also to change inlet timing.Maybe it was mentioned somewhere and I missed it?
couple of pages back
<img src="http://i1056.photobucket.com/albums/t380/uniflow/0c93ef14.jpg" width="240px"/><img src="http://i1056.photobucket.com/albums/t380/uniflow/c0231e31.jpg" width="240px"/>

More like so:

Only problem is massive amounts of sticktion due to the pressure drop across it. Could be solved with careful implinentation of a little cam.
Even with the fuel oil mix?

So now we will have a GP125 on EFI, with a trick variable computer controlled intake sytem as well, that, oh shit, still detoes in the overev - WTF.
I know that's sarcastic bullshit from me that doesn't help at all, but surely the extra effort needs to be spent sorting the known basic issues, before flying off on another tangent - what happened to the super duper stinger bleed idea for example ,etc etc.

BTW I tried the plug indexing idea on a TM125 engine that won 3 straight kart titles with 50 odd Hp at the sprocket, rotating the bronze insert to any position made no difference, changing plugs saw up to 2 Hp changes.
A crap wasted spark ignition with insufficient burn period or whatever may be a benefit in the big ski engines,as it does in the big 4T engines with horrendously shaped combustion chambers, but with a DC CDI ECU , and a toroid ,all these
negative details go out the widow.
Then if you have some issue like heinously rich allky mixtures,using twin fire CDI / Crane super coils - make all problems regarding ignition power irrelevant.


Mocking is easy, and as SS90 has shown, you don't need many smarts to be negative.

I don't think he was mocking, maybe a little blunt but...........................

[Flettner]

http://i1056.photobucket.com/albums/t380/uniflow/c0231e31.jpg
http://i1056.photobucket.com/albums/t380/uniflow/704e15fd.jpg
http://i1056.photobucket.com/albums/t380/uniflow/0c93ef14.jpg

like this?

[Flettner]

http://i1056.photobucket.com/albums/t380/uniflow/IMG_0854_zps8e25f7f2.jpg

YZ 250 barrel

[TZ350]

... oh shit, still detoes in the overev - WTF.

I know that's sarcastic bullshit from me that doesn't help at all, but surely the extra effort needs to be spent sorting the known basic issues, before flying off on another tangent ...

OK, the known basic issue is, that it detos in over rev. A few conventional things have been tried, compression, fuel curve, ignition curve, resistor plug, colder grade of plug, squish clearance, radiused exhaust port, lowered chamber pressure and a few tangents out side of the box, but all to no avail.

But don't sweat Wob, as you are free to suggest the pivotal solution if there is one and save me a lot of time.

Otherwise I will have to figure it out for myself, tangents and all. And at this point I suspect the restriction of a 24mm carb and subsequent lower crankcase filling is playing a part in my over rev deto problems.

If you join the dots of my posts you will be able to see where EFI combined with another tangental idea of mine and the better crankcase filling it will allow fits into things.

[TZ350]

http://i1056.photobucket.com/albums/t380/uniflow/IMG_0854_zps8e25f7f2.jpg

YZ 250 barrel

YZ250 barrel with EFI, this is something clever you are doing, please tell us more.

[speedpro]

There's a Link G4 box in the background.

[Frits Overmars]

YZ250 barrel with EFI, this is something clever you are doing, please tell us more.Here's more:

[Frits Overmars]

So now we will have a GP125 on EFI, with a trick variable computer controlled intake sytem as well, that, oh shit, still detoes in the overev - WTF. I know that's sarcastic bullshit from me that doesn't help at all, but surely the extra effort needs to be spent sorting the known basic issues, before flying off on another tangent - what happened to the super duper stinger bleed idea for example ,etc etc.As I always say, Wob: everybody has to make their own mistakes. You can't say they're not trying! Let them fly off and who knows what they will come up with.
Personally, I must admit that in my younger years I learned as much from blundering as from analytical thinking.

[wobbly]

In no way am I mocking TeeZees efforts, absolutely the opposite.
He is doing all this wrist slashing in public, and I admire the efforts, just trying to suggest concentrating the limited time, we all have, on a fix for the deto issue.
Variable inlet, EFI etc will for sure soak up a heap of R&D time.
I made the same ( negative, sorry ) comment about CVT, but shit, if you think im starting to hold hands with SS90 on here, then I will shut up.

[Flettner]

EFI is not a waste of time and variable valve timing works for me. I'm starting to wonder after reading about so many EFI disasters on two strokes that I've just been lucky, muddling along with just enough knowledge to be dangerous. All I know is when EFI comes into play the design rules change. You can do a lot of things a carb will never do. I certainly won't be using a carb ever again. That Bighorn is running sweet now but it's not been easy.

[Flettner]

Here are all the computers cuddled up under the Bighorn seat. Link Atom G4 and Ignitec ignition.

http://i1056.photobucket.com/albums/t380/uniflow/cb403d3c.jpg

Flywheel and triggers, 12 minus 1 pins.

http://i1056.photobucket.com/albums/t380/uniflow/f02c20e4.jpg

The G4 could do ignition but the Ignitec was already set up and is running the vairable rotary valve housing so I decided to leave well alone.

http://i1056.photobucket.com/albums/t380/uniflow/0f48b25b.jpg

Servo for vairable housing ( R1 ). All very messy but it works, one day maybe I'll clean it all up or not.
After all it is an " Enduro bike " or at least that's what the 1973 advertising says.

[Flettner]

http://i1056.photobucket.com/albums/t380/uniflow/c1d60c9b.jpg

Here is the other end of the R1 servo, this is where the cables attach to the vairable rotary valve housing. 55 degrees valve closing under 4000 rpm then starts moving and at 6500 it's fully open, at 9000 the rev limiter cuts in. Micro switch is to run a light on the handle bars to tell me when the housing is fully open, I didn't trust the mechanism at first.

[Flettner]

Wobbly is right there is a lot more to be had from the "standard" twostroke yet but it is fun having a go at different ideas as well. Especially if you get results.

[Flettner]

Here is a pattern being made up for the next EFI engine, 360cc reverse cylinder, water cooled, power valve, computer controlled rotary valve housing / throttle ( fly by wire or should that be crash by wire )
to fit in a modern YZF 250 frame. Will run on E90 like the Bighorn.

http://i1056.photobucket.com/albums/t380/uniflow/IMG_0843_zps3d5f065b.jpg

http://i1056.photobucket.com/albums/t380/uniflow/IMG_0847_zpsedd4e18a.jpg

[wax]

Thats pretty awesome. Are you drawing it on cad then using a cnc router on it ??

[Frits Overmars]

.....when EFI comes into play the design rules change. You can do a lot of things a carb will never do.Amen to that.

[dinamik2t]

In a spark plug parenthesis, here is an interesting link I came across: http://honda-tech.com/showthread.php?t=3063102

[twotempi]

Before anyone screams - please read the rest of this post.

A pre'72 classic two-stroke is probably stuck with a piston-ported setup. Even a pre'82 Yamaha TZ has this.

What is ( if any) the relationship between inlet timing ( symmetrical ) to exhaust duration/timing ??

For an exhaust duration of say 190 deg is the inlet duration a similiar value , or is any "overlap" between these two functions to be avoided ??

Any guidance would be greatly appreciated.

[cotswold]

Top Scooter 4 cylinder Engine, 2 stroke, 350cc that produces 110 HP ( thats what it said next to the photo )

Just spotted it and thought it was worth an airing

[2T Institute]

Thats pretty awesome. Are you drawing it on cad then using a cnc router on it ??

Flettner uses his favourite coping saw and a selection of wood chisels :lol:

[Haufen]

Before anyone screams - please read the rest of this post.

A pre'72 classic two-stroke is probably stuck with a piston-ported setup. Even a pre'82 Yamaha TZ has this.

What is ( if any) the relationship between inlet timing ( symmetrical ) to exhaust duration/timing ??

For an exhaust duration of say 190 deg is the inlet duration a similiar value , or is any "overlap" between these two functions to be avoided ??

Any guidance would be greatly appreciated.

When Yamaha ran piston ported engines in their GP bikes back in the days, the overlap did not seem to hinder peak horsepower. I forgot the figures, but I think it was in the ballpark of 200 / 200 exhaust and intake port. Of course, jetting becomes more difficult the longer the intake duration on a piston ported engine.

If anyone knows better and / or the exact figures please tell us.

[wobbly]

Here are the Inlet and Ex numbers of what is easily the fastest TZ350 ( 6 port 3G3 ) in the country.
Cylinder is dropped 0.4mm, the inlet ground up, and the Ex ground up further.
There are several hidden tricks in the inlet shape ( see 250G model ), and of course the Ex duct outlet is smaller than the effective port area,but thats secret so dont tell anyone.

[wax]

Top Scooter 4 cylinder Engine, 2 stroke, 350cc that produces 110 HP ( thats what it said next to the photo )

Just spotted it and thought it was worth an airing

There is a video of it running as well on you tube.
I have not seen one of it actually moving under its own power however.
It would be quite the beast I reckon

[RAW]

Judging from the way you wrote that word expand in italic, you have a pretty good idea yourself, Husa. A lower compression ratio before TDC equals a lower expansion ratio after TDC. That means a smaller temperature drop in the burnt gas during expansion, hence a higher exhaust gas temperature, a higher speed of sound in the gas and a higher resonance frequency in the pipe.


Frits, would you share some knowledge ?
The blank Aprilia little end pins, I have installed some, with no other changes.

Recorded weather data and tune up figures appear to no longer be valid, I feel it's now to rich for the same base line data

I surmise that a change to the Hermoltz / frequency side if things has rendered my tuning knowledge / history useless,

Anyone your experiences

[TZ350]

A pre'72 classic two-stroke is probably stuck with a piston-ported setup. Even a pre'82 Yamaha TZ has this.

280418

Out of the box, a 1974 TZ350B's power delivery was like a light switch, all or nothing, after a few mods I got mine to drive very nicely without the abrupt pipeness they were known for.

My final port timing duration’s were:- Ex 200, Primary Transfer 126, Secondary Transfer 130, Inlet 180.

To get this I had to remove 0.75mm from the bottom of the cylinder. And adjusted the squish clearance to 0.025". The pistons just kissed the head, didn't hit but just polished the carbon away in the squish area.

Compression ratio was 15:1, running Av Gas with oil at 16:1 Castrol R, 15% Acetone. Ignition 1.8mm BTDC, Plug N82G gap 0.018". Ring gap 0.012" piston clearance 0.0025", Main Jet 350 left 340 right hand side.

If these things seized, they always seemed to seize on the left side so I ran that side richer and anyway tuning wise you had to treat a TZ as two seperate engines. Std 34mm Mikuni, float 24mm, main jet 320-360, needle 6F9 3rd, needle jet O-2, Slide cutaway 2.5 and pilot jet 70#.

280414

This is a copy of a dwg of the TZ350B pipe I made back in the day. So I am not sure how accurate it is or if the dimensions are from the beginning of the actual pipe or from the piston face. From memory, max RPM for a TZ350B was 10,500 so quite a long pipe.

I see my notes for Pukekohe say, "started shaking with violent weave around the sweeper, had to put weight on the foot pegs each lap to keep control, found broken frame at the front left hand engine mount."

[husaberg]

EFI is not a waste of time and variable valve timing works for me. I'm starting to wonder after reading about so many EFI disasters on two strokes that I've just been lucky, muddling along with just enough knowledge to be dangerous. All I know is when EFI comes into play the design rules change. You can do a lot of things a carb will never do. I certainly won't be using a carb ever again. That Bighorn is running sweet now but it's not been easy.

I must admit i was a bit susceptible but when you think about it.
the Gp racing when at it's almost solely about winning, if the experiments Cagiva etc done didn't achieve almost results they were rejected or neglected. Honda it seems were more interested in the fuel consumption than performance. Dohan and Kokinski weren't interested at all.
Fuel injection software and hardware has also moved on a lot.
It almost reminds me of the 3m post-it story.


Spencer Ferguson Silver is an American chemist who, together with Arthur Fry invented Post-it notes in 1970
I had thought about it, I wouldn't have done the experiment. The literature was full of examples that said you can't do this



In no way am I mocking TeeZees efforts, absolutely the opposite.
He is doing all this wrist slashing in public, and I admire the efforts, just trying to suggest concentrating the limited time, we all have, on a fix for the deto issue.
Variable inlet, EFI etc will for sure soak up a heap of R&D time.
I made the same ( negative, sorry ) comment about CVT, but shit, if you think im starting to hold hands with SS90 on here, then I will shut up. please no more thought of a relationship with SSunamable

[F5 Dave]

. . .. Honda it seems were more interested in the fuel consumption than performance. . . .

Hadn't they achieved the fastest top speed on (erm was it Aoki's) one? Sounds performance based.
[edit I've had to become Husi & had to Google it for completeness, : it was Itoh)

[F5 Dave]

. . .
[edit I've had to become Husi & had to Google it for completeness, :. .

oh Nos, the transformation is complete;

from same NSR site
"Doohan prefers to keep things simple, he wants to win races not develop motorcycles and his tireless efforts at weaning HRC off their high-tech fantasies have been largely responsible for the NSR's success. He only improves things when they need improving.. . . ."

Wob's points compressed?

+
"For '97 Doohan decided he wanted to run a 180-degree motor. HRC didn't like the idea but he was mighty fast during first tests, and when Criville tried the screamer it spat him off at 120mph. Doohan knew he could regain an advantage with the engine, for engine management technology made it more rideable than the old 180-degree V4s and tire technology had caught up too. Plus the screamer sounded so much better".

Well yes it did sound awesome seeing (hearing) him exit out of Lukey Heights & the soundtrack it laid down.

maybe this should be next point of TZ's development? Aural output?...erm input, whatever.

[Flettner]

To be fair, I do wonder that using E90 gives me a little wider fueling range. E90 is not like Methanol where you almost can't be too rich, E90 will certainly blubber when rich and lean, well that's not too desirable! E90 has an unusual feature of requiring more fuel as the engine get's hotter, it will lean out. The EFI has the nice ability to be able to map this and change fueling with temp. Interestingly I haven't damaged a piston since using EFI.

[husaberg]

oh Nos, the transformation is complete;

from same NSR site
"Doohan prefers to keep things simple, he wants to win races not develop motorcycles and his tireless efforts at weaning HRC off their high-tech fantasies have been largely responsible for the NSR's success. He only improves things when they need improving.. . . ."

Wob's points compressed?

+
"For '97 Doohan decided he wanted to run a 180-degree motor. HRC didn't like the idea but he was mighty fast during first tests, and when Criville tried the screamer it spat him off at 120mph. Doohan knew he could regain an advantage with the engine, for engine management technology made it more rideable than the old 180-degree V4s and tire technology had caught up too. Plus the screamer sounded so much better".

Well yes it did sound awesome seeing (hearing) him exit out of Lukey Heights & the soundtrack it laid down.

maybe this should be next point of TZ's development? Aural output?...erm input, whatever.

Aim higher i didn't google it, but it was in a Mag. The injected bike was Itoh the speed differential was simply explained as he was a rather little japanese bloke (plus he wasn't half crippled and he could tuck in tighter.)
Yes your transformation to the dark side is Nearly complete.
But first you have to snog your sister and i get to cut off your hand..
RE the noise why not. the noise of the 2 smokes harassing then passing an Fxr on Yows on bike video on the FXR150 site..... pure music.

Note for the real Anoraks Itoh rode the injected bike for part of the season. But his best result of the year was his one of ride on the injured Doohan bike.
Faster top speed might not necessarily lead to fast laps........ Remember the Gardner San's missile.....
point ot remember is the packaging on a fuel injected bike also offers some other advantages edp on the v4's
Follow the arrows for the attachment

Itailian Friday

Few could deny it is still a beautiful bike.

It was on the cusp of finally living up to its potential.
Finally being developed in a more methodical manner.
A great shame the plug was pulled.

I found this snippet of information whilst looking for Rs125 specs.
It would appear to have come from Shigeru Hattori NSR500 project leader. I am now more confused than ever about how it worked.


Also here some Honda stuff whats the secret HRC

[TZ350]

280419

In no way am I mocking TeeZees efforts, absolutely the opposite.

He is doing all this wrist slashing in public, and I admire the efforts,

just trying to suggest concentrating.

What are you trying to tell me …… :laugh:


280420

The deto in over rev cylinder thats currently on the bike is the 28hp "B" cylinder, with single exhaust port (Green line).

I suspect the real problem with the 28hp cylinder and over rev deto may be insuficent blow down time area, but to increase that, I fear the curve will become more like the Purple 30hp line.

It would be great to get the "B" cylinder working properly if the curve could be kept flat. So Wob if there are any simple suggestions that have been made that I have overlooked trying, I would love to be reminded about them.

The 28hp curve is nice and easy to ride and if its not to hard it would be good to get it working properly, but its not my primary focus, a ridable 30+ hp is.

The real R&D effort is going into improving the bottom end of the tripple exhaust ports 30hp curve, Purple Line.

EngMod2T tells me that I can have both, a much wider flat torqe curve than the 28 and more than 30hp, and I want it all.

<iframe src="http://www.youtube.com/embed/k_8rpGZfsOI" allowfullscreen="" frameborder="0" height="315" width="560"></iframe>

Side exhaust port power valves and better fueling and breathing are the order of the day. In acheving that, the over rev deto problem will probably resolve itself on the way.

[TZ350]

The EFI has the nice ability to ... change fueling with temp. Interestingly I haven't damaged a piston since using EFI.

And crunching numbers on a laptop beats shagging about with jets at $9-$12 a pop and a carb thats a prick to get at (like most bikes) anytime.

There is a lot that is attractive about EFI.

[Frits Overmars]

I suspect the real problem with the 28hp cylinder and over rev deto may be insuficent blow down time area, but to increase that, I fear the curve will become more like the Blue 30hp line.What is there to fear? The blue line is already better everywhere; you just need to gear it 15 % shorter than the red line.

[koba]

What is there to fear? The blue line is already better everywhere; you just need to gear it 15 % shorter than the red line.

And better than most other buckets everywhere too!

[TZ350]

I have been trying to find the posts that talk about pipes and collate and edit them. There is heaps of it and pages 620 630 640 650 660 670 680 690 700 and 730 have un edited collections of raw material. If your interested in expansion chambers they are worth a look. Pages 710 and 720 talk about crankcase volume and inlet length.

P659


Any engine with a case leak will run rich, despite all the head scratching thinking it will suck air and go lean.
A leak will compromise the pumping part of the cycle,and the bigger the leak,the less fuel/air mixture is pumped.
If you jet down seeing a rich plug, it will seize, because then insufficient fuel/oil, is being ingested.
So unless you have pressure tested the whole engine before hitting the dyno, you will not be sure you have an accurate baseline.

If you have the RAD from the dyno runs plus the egt for optimum power then its easy to set up at the track.
BUT - beware, having only the drum inertia will not load the engine sufficiently , for long enough, to simulate the jetting required for roadracing.
For this you need a heap of eddy current load control to slow the acceleration rate in the higher gears of an all gear blast.
Then you can see the egt stabilise when at full noise for long enough, in 6th gear.

Just did this on Saturday at Taupo with one of the RZ400 - F3 racebikes.
The ref egt for max power in 6th on the dyno was 1255.
The RAD at Taupo on the day was 102 so I needed to go up one jet size from what we had at the RAD 99 dyno ref.
The egt max after practice one ( with the longest straight we now run on ) was 1235/1275, so went up one more on the LH side and 2 on the RH.
This gave max recall from the next run of 1197/1204, thus I could see we had full control of the egt and a split of 2 jets.
Ran 4 by 20 minute sessions like that, and from a full noise plug chop at the end, I would now add 1* of timing to the RH side, and go back to a 1 jet split with one size leaner overall.
This then gives us a new baseline at 102 RAD.
Safe as houses, and fast as hell when you have all the info, and good plugs that read both ignition advance and jetting.

P664


thanks the one thing l have changed is the expansion chambers and was ok before . l know the stingers are not the best . bent up years ago so will replace them first


You should be able to get someone to machine up a nice precision nozzle and then just use any old piece of tube to get the exhaust into the muffler. With a bit of thought you could have replaceable inserts of different size. I've tried different nozzles and got interesting results on the dyno.

P671


Any sim you are using to design any part of a 2T engine, and dont take full account of the ignition timing regime - is a waste of time.
I can design a completely shit pipe, and with ignition tricks, make it work 1/2 way reasonable - in a sim and on the dyno.
But its impossible to design a really good pipe that will work well in reality, if you dont define exactly the ignition curve it will see when running.
You can change the temp in the header as seen by the egt probe, from 450 to 650C by simply taking away 4 degrees of timing when in the overev,so the pipe that before had a vertical power drop off
at 13500, now holds 50 + Hp out to 14500.
Same with having the solenoid powerjet scenario,you can easily make a pipe that will spin to 14,000 in the sim, but sadly it has no mid power to speak of at all.
Change the A/F ratio from 12:1 to 14:1 past torque peak, and a MUCH longer pipe, now has a ton of mid, then holds its torque up long enough for that " too long " TL to work at least another 1000 rpm than before,due to
the burning mixture now dumping a huge heat load out the port.


You will spend more time and money friggin round with the old unknown ignition just over a longer period than biting the bullet for a programmable.
I went through this with suspension, spent countless hours rebuilding shocks, buying shims and seal heads. Finaly bought a set, bolted them on set the rebound and have not touched them since. They work 100 times better than my best efforts.

MOTA is a massive compromise especially on the ignition side. However it will provide some useful info on the return wave timing which is what you should concentrate on. As Wob has said probably 100 times and it's worth repeating "big depression/lowest pressure at BDC" and return wave arriving before the exhaust port closes. Get that right then look to get the rpm peak where you want it, finaly jiggle the TL length %'s to what Wob has already posted. Viola no more shit pipe.

P681 to P710 is yet to be farmed for information.


Flowing the wrong way between Transfer Open and BDC is not the result of a too-early returning exhaust pulse, but of insufficient blowdown time.area.

What I meant was the instant just before Transfer Closure. The stuffing pulse from the exhaust should not arrive at the cylinder just yet, but at rpms under the powerband it will, raising the pressure in the cylinder while the transfers are still open.

So the fresh charge gets pushed back into the crankcase, leaving little of it in the cylinder. And on top of that, just after the transfers close, that stuffing pulse reverses sign and direction, and sucks what little charge is left in the cylinder, out...

Loss of heat should be avoided all right, but if you want power, it is more important to avoid detonation. The part of the exhaust duct where washed-through fresh charge temporarily resides, should be kept cool to avoid heating up that charge.

And it is much simpler watercooling an exhaust duct that is part of the cylinder, than cooling a duct that is part of the pipe.....

Deto Sensor.


I have just been putting on my knock gauge on the bucket and when I run her in the drive with the sensitivity set half way, reving the bucket up the gauge went off like a christmas tree and I am wondering what others have there gauges set to?
The gauge is from http://www.knockgauge.eu and the sensor is off a subaru car. It's mounted on a 100cc LC two stroke on a head stud straight onto the head with nothing inbetween if that is any help.


We have one of those but only learning about these things ourselves. And this is how we think it works if that's any help.

Knock rings in the cylinder like a bell.

The ringing has a frequency that depends on the size of the cylinder, bigger the cylinder/combustion chamber the lower the frequency.

The adjustment on the knock gauge selects this frequency much like tuning in a radio station.

The adjustment on the knock gauge is not about adjusting the loudness of the radio station.

To tune the knock gauge in you adjust the knob until you see two strong green lights when accelerating.

We think the two green lights indicate the knock gauge is tuned in properly.

It would worry me if I was seeing the red deto light at this point and start backing the ignition off or richin it up.

On our first dyno runs with the knock gauge we saw perfect green on the pull and red xmas tree lights on the run down so it was detonating badly on run down with a closed throttle.

TeeZee's is set at about a 1/3rd.

We would love to hear more from someone with experience using one of these knock gauges.


If you can get your hands on an oscilloscope it works a treat. We just used one on the UoA dyno with a WR450. Mounted sensor on the side of the cylinder. Knock showed up as huge spikes on the oscilloscope. Well above any other noise. Then again it was on a steady state eddy current dyno. Things might go a bit quicker on one of those inertial thingys. #4StrokebutStillRelated


Been away winning races so will reply now re the deto box.
Calibration is easy, turn it down real low such that the green lights do come on when doing a full throttle run.
Keep turning it up till you get a deto indication somewhere in the powerband, going up on full throttle, or as TeeZee found, when backed off on the overun.
In short - believe what you are seeing, if it shows deto on the overun, then, its got deto in the overun.
This MAY not be an issue when racing as you MAY not damage anything detoing for a short period under these conditions.
But,of course if you have a TPS this means you can use a 3D map, and its easy to pull out a couple of degrees of timing at that point, and the deto will go away - simple.
I found that maximum performance on the dyno meant you had short flickers of deto at nearly all rpm on full throttle,and it lights up when you hit the limiter.
I do several pulls at 1/4, 1/2 and 3/4 throttle,running up against the dyno load, as well as running down on the overun. to generate the TPS driven curve shape.
This enables you to dial up the max advance needed everywhere, then go into the software and back the whole curve down 1 to 2 degrees.
Now you have a good curve shape that the engine actually needs, and any issues on track, can then be taken care of by the box switching the retard input to pull out 2* to prevent unforeseen meltdowns.
I havnt used the deto setup on an aircooled, but I suspect that the deto ringing frequency signal is much bigger amplitude than a watercooled cylinder,meaning you get a much quicker indication of deto approaching.
Means its very sensitive to adjustment, but I say again, if it is flashing deto at one rpm and not at another, then believe what you are seeing, just turning it down so it does nothing, is dumb.


The piezo sensor will easily show the missfire from hitting the limiter, so it will also show a big end knock, as well as the piston hitting the head.
Dont know about excessive piston slap , but probably.
Plenty of "noise" sources in a 2T.

[wax]

And crunching numbers on a laptop beats shagging about with jets at $9-$12 a pop and a carb thats a prick to get at (like most bikes) anytime.

There is a lot that is attractive about EFI.

Does it run a map sensor or some one of measuing air flow. As the pipe changes in temp ie after a long run down the straight the power band is going to come on in a different place due to the gases moving faster in a hot pipe. unless your measuring airflow Im not sure how your going to get around the constant moving goal posts. A carb as crude as it is measures airflow.

[TZ350]

you just need to gear it 15 % shorter.

We tried that at Taumarunui, went up two teeth on the front, from 13 to 15 but still had deto issues at the end of the main straight and badly compromised gearing on other parts of the circuit.

[TZ350]

Does it run a map sensor or some way of measuring air flow.

Yes a map sensor, but to be honest I don't know much about it yet, its a bit of a leap of faith. But I am confident I will be able to figure it out and I am hanging my hat on the fact its all been done before locally with an off road 350 2-Stroke that is regularly run in pretty difficult conditions.

And if it does not work out, there is plan "B" the CVT system, which I am still gathering the parts I need for.

[Frits Overmars]

I suspect the real problem with the 28hp cylinder and over rev deto may be insuficent blow down time area, but to increase that, I fear the curve will become more like the Blue 30hp line.What is there to fear? The blue line is already better everywhere; you just need to gear it 15 % shorter than the green line.

We tried that at Taumarunui, went up two teeth on the front, from 13 to 15 but still had deto issues at the end of the main straight and badly compromised gearing on other parts of the circuit.I think one of us is missing the point. You suspect that increasing the blowdown time.area will lessen the overrev deto. I agree.
Then you fear that by increasing the blowdown time.area your 28 hp curve will change into a 30 hp curve that is shifted 15% higher up the rpm scale.
But your fear is unfounded; the 30 hp curve simply is better. If you plot it over the 28 hp curve, using a 15% smaller rpm-scale for the 30 hp curve, you will see that the 30 hp curve completely encloses the 28 hp curve.
If you use that 30 hp curve and fit a 15% shorter gearing compared to what you used with the 28 hp curve, the bike will behave as before, but with more power everywhere and probably less overrev deto.
BTW: fitting two teeth more up front, from 13 to 15, is gearing it 15% longer, not shorter.

[TZ350]

the 30 hp curve simply is better. If you plot it over the 28 hp curve, using a 15% smaller rpm-scale for the 30 hp curve, you will see that the 30 hp curve completely encloses the 28 hp curve.

30 hp curve completely encloses the 28 hp curve?

280452
28hp-green (actually three different runs overlaied together) 30hp-purple (at first I thought it was drawn in blue)

Are we looking at the same graph? The 28hp deto in the overrev zone cylinder is on the left and the ugly 30hp one on the right.

I thought a big fat torqe curve was the right thing to aim for. And that the 28hp's torqe curve would give better drive out of the corners.

The 30hp one is the one that I thought worth plumping up in the lower rev range with power valves in the side ports. From running EngMod simulations I figured this would give me a much better 30hp torqe curve and get rid of the over rev deto to boot.

[twotempi]

EngMod2T tells me that I can have both, a much wider flat torqe curve than the 28 and more than 30hp, and I want it all

You forgot the next line !!

And I want it now

[wobbly]

What Frits is saying is that if you added 3 teeth to the rear of the 30Hp bike, to give the same terminal speed as the 28Hp setup, then you would
have more power available everywhere.

[Frits Overmars]

30 hp curve completely encloses the 28 hp curve?Yes, if you rescale it 15% to the left.


280452
28hp-green (actually three different runs overlaied together) 30hp-purple (at first I thought it was drawn in blue)
Are we looking at the same graph? The 28hp deto in the overrev zone cylinder is on the left and the ugly 30hp one on the right.
I thought a big fat torqe curve was the right thing to aim for. And that the 28hp's torqe curve would give better drive out of the corners.Torque means nothing without revs. And it's not crankshaft torque but rear wheel torque that makes you accelerate. If you gear that 30 hp curve 15% shorter, rear wheel torque in each gear will be 15% higher at any given crankshaft rpm.
The 30hp one is the one that I thought worth plumping up in the lower rev range with power valves in the side ports. From running EngMod simulations I figured this would give me a much better 30hp torqe curve and get rid of the over rev deto to boot.You can still do that although it will not nearly give you the low down grunt of a trombone pipe. How are those CVT plans coming along? :shifty:


EDIT: I see that while I was struggling with English, Wobbly came up with a much shorter and probably easier to understand answer.

[kel]

What Frits is saying is that if you added 3 teeth to the rear of the 30Hp bike, to give the same terminal speed as the 28Hp setup, then you would
have more power available everywhere.

Ha ha, my suggestion for 2 extra teeth to the back was pretty damn close. Now if I can just figure out how to give usable feed back on suspension and carb set up I'd be the complete test pilot package :lol:

[dinamik2t]

Here is what Frits implied, TZ:
(red being the 30hp curve, moved 1500rpm to the left)

280456

:)

[wax]

How are those CVT plans coming along? :shifty:
.
Ahh the best of all the worlds

[rgvbaz]

Here is what Frits implied, TZ:
(red being the 30hp curve, moved 1500rpm to the left)

280456

:)


To really rescale the graph in terms of changing the graph you need to move the point by the % change in gearing, not just 1500 rpm, so for each rpm point on the 30hp curve times it by say .9 (12.8/14.2) so at the end of the overrev on the 30hp curve 14.2 x .9 = 12.8 rpm

for 15hp occurs at 9400 rpm on the original curve rescaled it would occur at (9400 * .9) = 8460 rpm.

Dave

[TZ350]

Thanks for that, thanks everyone, it wasn't intuitively obvious to me by just looking at the separate graphs.

That red superimposed 30hp curve is way better than I thought, pity I buggered the 30hp cylinder trying to improve it.

Now to find some bigger 58T rear sprockets and start on a new cylinder.

280459

Well look here at what Bucket found in the shed.

[rgvbaz]

I did a graph a while ago showing a KR1S v a RGV. Everyone said the KR1S was better because it had more torque and better drive up the curve. If you change the gearing by .875 then the RGV destroys the KR1S everywhere.


280458

Dave

[Frits Overmars]

Here is what Frits implied, TZ: (red being the 30hp curve, moved 1500rpm to the left)
280456
:)Not quite, Dinamik. Rescaling it 15% to the left is not the same as moving it 1500 rpm to the left.
I'll try to clearify that with some numbers.
8 hp @ 8,000 rpm becomes 8 hp @ 6,800 rpm
18 hp @ 10,000 rpm becomes 18 hp @ 8,500 rpm
30 hp @ 13,300 rpm becomes 30 hp @ 11,305 rpm
26 hp @ 14,000 rpm becomes 26 hp @ 11,900 rpm

EDIT: Damn, first Wobbly, now Rgvbaz; you guys type too fast for me.

[rgvbaz]

Not quite, Dinamik. Rescaling it 15% to the left is not the same as moving it 1500 rpm to the left.
I'll try to clearify that with some numbers.
8 hp @ 8,000 rpm becomes 8 hp @ 6,800 rpm
18 hp @ 10,000 rpm becomes 18 hp @ 8,500 rpm
30 hp @ 13,300 rpm becomes 30 hp @ 11,305 rpm
26 hp @ 14,000 rpm becomes 26 hp @ 11,900 rpm

EDIT: Damn, first Wobbly, now Rgvbaz; you guys type too fast for me.

Sorry, Frits :violin:

[dinamik2t]

Sorry for my misleading post. I understood the pattern now :)

[TZ350]

How are those CVT plans coming along? :shifty:

Good .... but unsure if its best to run the variator off the crank at 13,000rpm or have a reduction from the crank to a jack shaft with the variator on it. Any input about that would be welcome.

280462

I am building a completely new better handling bike based on a MC16 frame.

280461

Similar to FarmerKens that I think will be at least 15kg's lighter than the Beast.

280463 Was 102.6

And for those that like to suggest the rider should lose some to, well I have dropped 10+kg and plan another 5 for a total of 30, bike + rider.

I plan on trying three engines, a CVT system, a version of the Trombone and a conventional layout, I expect in time one will morph into the setup of choice.

Currently I am using the Beast as an engine development platform.

[cotswold]

Tee Zee, with your field being fluid transfer have you considered this , god knows how it works but.........
4: Honda DN-01

ONE of the limits for Yamaha’s hydraulic-drive 2WD bike was the fact the drive system couldn’t carry a huge amount of the engine’s power to the front wheel. Honda’s DN-01 might not have had 2WD, but it showed that hydraulics could be used to carry considerably more power.

The bike’s transmission was a masterpiece, with an angle-drive hydraulic pump that allowed the amount of fluid pumped per revolution to be completely variable – changing the effective gearing as it did so. It was clever stuff.

So it was a shame Honda shackled that transmission to its ancient Deauville V-twin engine and wrapped the whole lot in styling that even its mother couldn’t love. Oh, and then asked crazy-high prices for the finished caboodle. Sales were not high, some dealers joke that DN-01 stands for 'Did Not Order One'. The bike was killed off in short order but may one day be a future classic.



Read more: http://www.visordown.com/motorcycle-top-10s/top-10-least-conventional-production-motorcycles/22440.html#ixzz2Oh2jn3j4

[pete376403]

Tee Zee, with your field being fluid transfer have you considered this , god knows how it works but........

like this...

http://world.honda.com/motorcycle-technology/hondamatic/p3.html#02

Honda first used this transmission concept in the Juno scooter back in the early '60s.

very similar to an automotive air conditioning compressor, except the air con doesn't use variable swash plates

[TZ350]

https://www.youtube.com/watch?v=KubGVzd64rg&feature=player_embedded

Jay Lawrence (was a regular Bucket Racer) riding the Bridgestone ZX10R does the Cliffhanger and smashes the record.

[F5 Dave]

Well unless hes been sneakily coming up to Auckland he hasn't raced buckets for quite some time & his old bucket was in my garage till recently minus a few bits on my 100 now. Used to have some good battles on the 50s here. Good lad too.

[bucketracer]

275392

Fitted the 28hp B cylinder and its all sorted for Taumarunui.
Erm this is far better as far as power delivery goes than the previous (30hp) cylinder.

Forget about the few extra ponies, this is the right direction

TeeZee will probably continue working on his 30+hp cylinder.



the 30 hp curve is simply better. If you plot it over the 28 hp curve, you will see that the 30 hp curve completely encloses the 28 hp curve.

280456

This is what Frits meant. Red being the 30hp curve, moved to the left.

[speedpro]

A really good example of gearing a motor to work at the desired road/track speed can be found in the Harley versus Jap 600 argument. The Harley makes lots of engine torque at 100KmH but a 600 makes a lot less engine torque at the same road/track speed. The 600 is revving a lot higher though so has a higher reduction ratio. Smack them both open at the same lowish speed and the 600 will leap ahead even though it's making a lot less "engine" torque. The rear wheel torque is greater.

It's the same with car advertising. They advertise big torque values for diesels at low engine rpm. Because the reduction ratio between engine and wheels is low the torque is not multiplied as much as say a lower torque, but higher revving, petrol engine. On the road the big torque vehicle be it car or bike ends up being a sluggish heap. R1s and the like are another thing all together.

[koba]

SS90 Blah Blah

The point has been proven many times over; in ways that mean so much more than forum posts on the internet.

Must you persist?

[koba]

Jay Lawrence (was a regular Bucket Racer) riding the Bridgestone ZX10R does the Cliffhanger and smashes the record.

So cool!

Even better once I stopped trying to wipe the bug of my monitor!

[bucketracer]

Good .... but unsure if its best to run the variator off the crank at 13,000rpm or have a reduction from the crank to a jack shaft with the variator on it.

Any input about that would be welcome.

Taken from the link below, Ok nothing about pully speed but V belts are more efficent power transmitters than chain and toothed belts are even better.

http://www.reliableplant.com/(X(1)S(emldn0yrcnjqtm450qij4m45))/Articles/Print/2418

Standard roller chain drives operate at 91 to 94 percent efficiency

V-belt drives transmit power through friction between the belt and pulley. With efficiencies ranging from 95 to 98 percent at installation, these drives use energy more efficiently than roller chain drives, and somewhat less efficiently than synchronous belt drives.

Synchronous belts work on the tooth-grip principle. Round, square or modified curvilinear belt teeth mesh with grooves on sprockets to provide positive power transmission on high-torque applications with high and low speeds.

If drive size is a problem, many synchronous belt drive systems now have have an equivalent capacity to roller chain drives in the same width.

While roller chain requires frequent retensioning and V-belts require periodic retensioning, a synchronous belt typically requires no retensioning for the life of the belt.

Roller chain: A roller chain will elongate approximately 3 inches (or 3 percent) over its life, requiring about 1.5 inches of center distance take-up.

V-belt: A V-belt requires 1.5 to 2.5 inches of center distance take-up over its life, depending on the cross section and belt manufacturer.

Synchronous belt: A synchronous belt typically requires only .04 inches of center distance take-up over its life, depending on the belt type and manufacturer.

Maybe you can figure out the pully/speed info from here:- http://pdf.directindustry.com/pdf/megadyne/complete-catalogue-of-rubber-poly-v-belts/14254-67508-_15.html

[TZ350]

V belts are more efficent power transmitters than chain and toothed belts are even better.

http://www.reliableplant.com/(X(1)S(emldn0yrcnjqtm450qij4m45))/Articles/Print/2418 (http://www.reliableplant.com/(X(1)S(emldn0yrcnjqtm450qij4m45))/Articles/Print/2418)

Thanks for that.

280495

Toothed belts are the best power transmitters, then V belts and chain is the least efficent, who would have thought!!!!!!

[F5 Dave]

Well my lathe has a flat belt drive, perhaps you could try that & while you are at it reduce components by using it as a clutch. You heard it here first. no one else in the history of motorcycling has ever come up with this idea:innocent:.

[Frits Overmars]

Well my lathe has a flat belt drive, perhaps you could try that & while you are at it reduce components by using it as a clutch. You heard it here first. no one else in the history of motorcycling has ever come up with this idea:innocent:.I hate do disappoint you, but the history of motorcycling is a bit older then you are, Dave. Back in the day, before we celebrated a couple of world wars, your novel idea was quite common.

[F5 Dave]

My lathe is a bit older than me too.

Doesn't make me feel any younger in the mornings.

Sorry I was taking the Mick a little.

[Frits Overmars]

Sorry I was taking the Mick a little.Nothing to be sorry about; I welcome every opportunity to do it myself; it makes the world wide web a bit more fun :2thumbsup.

[Ocean1]

I hate do disappoint you, but the history of motorcycling is a bit older then you are, Dave. Back in the day, before we celebrated a couple of world wars, your novel idea was quite common.

My godfather had a Zenith, not sure what year but pre-1st war. It had a variable speed belt, the rear wheel moved backwards to force the pully flanges wider.

Which makes TZ around a century late :nya: And I like the idea of moving the back wheel backwards under acceleration!

[seymour14]

My godfather had a Zenith, not sure what year but pre-1st war. It had a variable speed belt, the rear wheel moved backwards to force the pully flanges wider.

Which makes TZ around a century late :nya: And I like the idea of moving the back wheel backwards under acceleration!

Funny enough we have one of those in our back shed, 1911 production racer Zenith Gradua. As the front pulley was adjusted (like a variable speed drive) the rear wheel had to be extended or retracted to keep the pulley tension and thus keep drive on the rear wheel. Fascinating bikes, and they were banned in there day for being too good!

[Ocean1]

Funny enough we have one of those in our back shed, 1911 production racer Zenith Gradua.

Cool. What sort of nick's it in?

[TZ350]

Sorry I was taking the Mick a little.
Nothing to be sorry about; I welcome every opportunity to do it myself; it makes the world wide web a bit more fun :2thumbsup.

Yep, slowly getting used to how this net humor works ....... :laugh:

[crazy man]

Cool. What sort of nick's it in?not bad for 1911-12 but needs a full restore

[Strokerhaus]

Not certain where it says tooth belt is more efficient than chain, read your data but it only talks about reliability not tranmission efficiency. V belts are not high on efficiency, no problem with that, but not certain about tooth belt v chain. I have just fitted a belt drive to my Enfield but that was more to save weight, I would love to think I gain tractive effort but I have not done the test yet. If you have better data I would love to see it. The article suggested belt and chain can be the same width, but that's not correct I ran a single row primary chain but had to replace it with a 30 mm wide belt, as per Mr Gate's recommendation.

[TerraRoot]

also belts don't like being shoved around tight corners, so both drive cogs have to have a fairly large radius, chains are just easier to get into tight places.

[bucketracer]

Not certain where it says tooth belt is more efficient than chain, read your data but it only talks about reliability not transmission efficiency.

V-BELT DRIVES
V-belt drives transmit power through friction between the belt and pulley. With efficiencies ranging from 95 to 98 percent at installation, these drives use energy more efficiently than roller chain drives, and somewhat less efficiently than synchronous belt drives.
Selecting the right drive system http://www.reliableplant.com/(X(1)S(emldn0yrcnjqtm450qij4m45))/Articles/Print/2418
Taken from a magazine called Reliable Plant and it acknowledges the Gates Corp. ... http://www.reliableplant.com/Magazine/Issue/Reliable Plant/9/2006

Yes you might be right, I checked and it talks about using energy more efficiently, not transmits more efficiently, so is it just syntax or have I miss understood something. http://www.kiwibiker.co.nz/forums/images/smilies/scratch.gif I better Google some more.

[bucketracer]

From what I can make out, it does look like use and transmit are the same thing but V belts may be more efficient than chain when everything is perfect but a V belt can slip further down its efficiency range than a chain and become significantly less efficient at power transmission than chain but a synchronous belt pretty much retains its efficiency for life.

Many efficiency questions deal specifically with the relationship between V belts and synchronous belts. Synchronous belts can offer a slight improvement in efficiency over the standard V belts. http://www.gates.com/facts/documents/Gf000188.pdf

Power transmission efficiency and parasitic idling losses in belt machine elements have been considered for over 50 years. Most references cite efficiencies between 90 and 98 percent for various belts with 95 percent being a typical value http://file.seekpart.com/keywordpdf/2010/12/20/20101220212457984.pdf

From the Gates Corporation http://www.gates.com/australia/brochure.cfm?brochure=7653&location_id=3810

Due to their high efficiency ratings (as high as 99% on a continuous basis in a Poly Chain GT2 drive system), synchronous belt drives can also lower energy costs compared with roller chain drives, which typically operate at 91-94% efficiency, or V-belt drives, which when properly tensioned, operate at 93-95% efficiency.

The complete guide to chain http://chain-guide.com/basics/1-2-1-power-transmission-uses.html

http://www.newenglandbelting.com/GoodyearEagle_TimingBelts.asp Because v-belt and chain drives quickly lose initial tension, they typically run in the lower portion of their efficiency range. Eagle PD™ will continually run at about 98% efficiency.

http://www.grainger.com/tps/power_trans_chainguide.pdf
Chain is the preferred choice for power transmission applications that rely on high power and torque. Chain offers the advantage of working within the widest of temperature ranges, and is highly tolerant of shock loads.

V-belts
are so named for their tapered cross-section. This belt type offers an efficient transfer of power of up to 98%*. Some feature notched inner surfaces that allow them to operate at a reduced radius.

Synchronous belts,
or timing belts, have notches on one or both faces, seating firmly on a meshing pulley surface for as much as 99% efficiency. This option is preferred when input and output shafts must remain synchronized a Belt systems may require more space to operate, and cannot match chain’s reduction power or smaller operating radius.

[bucketracer]

also belts don't like being shoved around tight corners, so both drive cogs have to have a fairly large radius

280508

Bending around a tight corner is a big part of the V belts transmission losses and the reason for these notchy style V belts, it makes them easier to bend.

280509


chains are just easier to get into tight places.

True, and they don't loose as much of their efficiency over time as V belts can and a chain can handle more torqe for its size too.


Good .... but unsure if its best to run the variator off the crank at 13,000rpm or have a reduction from the crank to a jack shaft with the variator on it.

Any input about that would be welcome.

280507

TeeZee, one thing that did come out of all this Googiling was that a V belt can handle a much faster pulley speed than chain but less torque. So a Variator on the crank might be better than a speed reduction (torque amplification) from the crank to a jack shaft with the variator on it and must be why CVT's typically have the gear reduction behind the rear pulley.

[rgvbaz]

I did a quick graph of the 30 hp and 28 hp curve and rescaled the 30 hp curve by .9.

As you can see there isn't much difference between the both of them, the 30hp wins at the top-end where the 28 hp curve is still a little better up the slope. I'd guess, on average, they would both perform about the same.

280510

Dave

[Frits Overmars]

I did a quick graph of the 30 hp and 28 hp curve and rescaled the 30 hp curve by .9.
As you can see there isn't much difference between the both of them, the 30hp wins at the top-end where the 28 hp curve is still a little better up the slope.That is why I suggested rescaling it by 0.85 :whistle:.

[Ocean1]

From the Gates Corporation

Nice work mate. You do have to be a bit careful with comparisons using an interested manufacturer's numbers. Modern belts of all types are very good, and are often a better choice than chain for a given application, but it does get complicated. There's a reason 99.9% of pushbikes, for example use chain, it's transmission efficiency might be arguably smidgeonally lower than a particular selected synchronous belt in the lower torque, higher speed ranges, but that application has to deal with large variations in torque and velocity. Over that range of variables chain remains about the most efficient choice.

If you have a static or narrow rpm and torque variation then selecting a high spec’ modern synchronous belt close to its maximum rated speed using the largest, lightest pulleys you can will produce a slightly more efficient transmission.

For most applications I’m involved with Vee belts are less efficient than both the above, but their use in a cvt system is a straight trade-off between efficiencies gained from optimising engine rpm and the slightly higher transmission losses.

[Frits Overmars]

....For most applications I’m involved with Vee belts are less efficient than both the above, but their use in a cvt system is a straight trade-off between efficiencies gained from optimising engine rpm and the slightly higher transmission losses.From what I've seen on the test bench, first measuring CVTs and then replacing the V-belt set-up with a synchronous belt set-up for more precise measurements ( http://www.hvg-engineering.com/index.php?action=article&group_id=20000002&aid=17&lang=NL ), the V-belt's losses are not just slightly but markedly higher; up to 10%.
Even so, the CVT is unbeatable. Not only because the engine can be kept at max.power rpm all the time; keeping the gas dynamics in the engine going without gear change interrupions is at least as important. In a gearbox engine, after each gear change the engine noise returns immediately, but engine power does not. It can take up to a second before resonance is restored and full power is once more available. But on a tight track chances are that you will have to change gear again within that second, so you will never have the power at your disposal that you saw on the test bench.

[bucketracer]

In a gearbox engine, after each gear change the engine noise returns immediately, but engine power does not. It can take up to a second before resonance is restored and full power is once more available.

TeeZee has often commented, that a lower powered FXR on his flank rounding a corner was able to get its nose in front on the drive out from the apex. That second before resonance is restored realy hurts 2-Strokes. CVT has its appeal.

[Ocean1]

Even so, the CVT is unbeatable. Not only because the engine can be kept at max.power rpm all the time; keeping the gas dynamics in the engine going without gear change interrupions is at least as important.

Not to mention avoiding the not inconsiderable losses through quite so many gears/bearings/bushes. To what extent is the usual trade off between larger pulleys/lighter & more efficient belt and smaller pulleys/lower innertia but less efficient belt dictated by engine rev limits?

And have you encountered steel sectional belts in bike CTV applications?

[husaberg]

Not to mention avoiding the not inconsiderable losses through quite so many gears/bearings/bushes. To what extent is the usual trade off between larger pulleys/lighter & more efficient belt and smaller pulleys/lower innertia but less efficient belt dictated by engine rev limits?

And have you encountered steel sectional belts in bike CTV applications?

I Don't know these have been posted before, the second one is similar to sketchy's supercharger drive

http://www.youtube.com/watch?feature=player_detailpage&v=VmSmv6aiWqghttp://www.youtube.com/watch?feature=player_detailpage&v=MhFK5gfAGpM#t=71s

http://www.youtube.com/watch?feature=player_detailpage&v=hgl7IBmUj8o

[husaberg]

http://www.youtube.com/watch?feature=player_detailpage&v=MhFK5gfAGpM#t=71s
I asked this questiop before but i am not sure wob and frits understood what i meant.
the Aprilia race bike's rsv rsa rsw all ran a servo controlled power valve (2 stage for sealing.)
How is it the servo actuation superior (not the two stages bit i get that) to the simpler solenoid actuation shown here
http://i.ebayimg.com/t/aprilia-rs125-power-valve-solenoid-and-cable-/00/s/MTIwMFgxNjAw/z/VrEAAMXQ~TtRKjLo/$T2eC16NHJHYE9nzpc)CeBRKjLoe7rg~~60_12.JPG
Is it too Fast? it certainly appears faster than a servo?

http://www.youtube.com/watch?feature=player_detailpage&v=3183SOtDEfk

[Flettner]

No, you are all off on a tangent, gearing is still the way. Some industrial variable speed gearboxes run what would be easily explained as a planetary system with the out side ring speed controlled ( normally anchored). 70 HP gearboxes controlled with a five horse electric variable speed motor plugged in the side, controlling the large torque by changing outside gear ring speed. Minimal losses. If it were not for oil pumping losses ( oil through the gears ) then gear drive would be most efficient as the gear teeth are just rolling against each other ( involute ), not rubbing.

[Ocean1]

No, you are all off on a tangent, gearing is still the way. Some industrial variable speed gearboxes run what would be easily explained as a planetary system with the out side ring speed controlled ( normally anchored).

Like an old pushbike hub gearbox? :innocent:


If it were not for oil pumping losses ( oil through the gears ) then gear drive would be most efficient as the gear teeth are just rolling against each other ( involute ), not rubbing.

Aye. Some more commercially derived industry data:

http://www.powertransmission.com/issues/0210/efficiency.pdf

"Gears mesh through a combination of
rolling contact and sliding contact. Spur, helical, and bevel
gears are considered rolling contact gears, because the majority
of the contact is of the rolling type. A typical estimate of
the power loss in rolling contact gearing is 1.5 percent per
stage."

How many stages in a multi-stage epicyclic gearbox?

[Ocean1]

I Don't know these have been posted before, the second one is similar to sketchy's supercharger drive

Little bit, although his isn't variable.

'Er indoors Toyota Blade has one of these lurking somewhere inside: 280575

[rgvbaz]

That is why I suggested rescaling it by 0.85 :whistle:.

I see, Frits!

But then you could rescale the 28 Hp curve by .95 and this would re-align the curves the same, visually, as in the graph I posted before. I chose .9 as it aligned the two curves from the end of the over rev and gives a quick visual comparison of both.

Dave

[Frits Overmars]

To what extent is the usual trade off between larger pulleys/lighter & more efficient belt and smaller pulleys/lower innertia but less efficient belt dictated by engine rev limits?I don't know.
And have you encountered steel sectional belts in bike CTV applications?Only in cars, not in bikes, although I've heard rumours that one large Suzuki scooter is using it.
The problem with a push belt (a Dutch invention, by the way) is that the friction coefficient between the steel belt elements and the heaves is much lower than the friction of a rubber V-belt. Therefore a much larger clamping force is needed, necessitating hydraulics, a pump and a much heavier construction altogether.
For racing I can imagine a heave fitted via a pitch on the input shaft. Advantages: no hydraulics needed and a clamping force that varies with the torque that has to be transmitted.

[Frits Overmars]

I asked this questiop before but i am not sure wob and frits understood what i meant. the Aprilia race bike's rsv rsa rsw all ran a servo controlled power valve (2 stage for sealing.) How is it the servo actuation superior (not the two stages bit i get that) to the simpler solenoid actuation shown here.Is it too Fast? it certainly appears faster than a servo?The Aprilia power valve gradually opens from 10,000 rpm to fully open at 12,000 rpm. A solenoid does not understand the word gradually.

[Frits Overmars]

No, you are all off on a tangent, gearing is still the way. Some industrial variable speed gearboxes run what would be easily explained as a planetary system with the out side ring speed controlled ( normally anchored). 70 HP gearboxes controlled with a five horse electric variable speed motor plugged in the side, controlling the large torque by changing outside gear ring speed. Minimal losses. If it were not for oil pumping losses ( oil through the gears ) then gear drive would be most efficient as the gear teeth are just rolling against each other ( involute ), not rubbing.You have a point regarding efficiency, Flettner. And there have been (and maybe still are) transmissions like you describe, where the electric variable speed motor has been replaced with a small belt variator :p. But if you wish to sell zillions of cheap scooters you have to stick to the KISS principle.

[Haufen]

I think, also taking the gear ratios of TZ's engine into consideration, a plot comparing rear wheel torque through the gears, with both curves geared to the same top speed would be quite handy. That one with the bigger area under the curve, wins.

[Frits Overmars]

I think, also taking the gear ratios of TZ's engine into consideration, a plot comparing rear wheel torque through the gears, with both curves geared to the same top speed would be quite handy. That one with the bigger area under the curve, wins.Sounds good, but it is not completely accurate because top speed is not decisive. In fact top speed is about the most overrated thing in racing. What counts is getting there first, not fastest; the guy or girl with the highest average speed wins and that is true for all forms of motorsport (trial and motoball excepted).

[rgvbaz]

I think, also taking the gear ratios of TZ's engine into consideration, a plot comparing rear wheel torque through the gears, with both curves geared to the same top speed would be quite handy. That one with the bigger area under the curve, wins.

I plotted road force v road speed, mph for both curves, I did use an arbitrary overall gear ratio of 13:1 for the 28 hp curve and 14.4444:1 (13/.9) for the 30 hp curve. For comparison I included power (multiplied by 4 so it's easier to see on the graph) v road speed, mph.

I imagine both curves being used to propel the bike and as I look along the each power curve I try to imagine where each bike would be relative to the other in a straight line. The 28hp bike would set off quicker and go ahead but then the 30hp bike would start to catch up towards the end, not sure if it would pass, i'm guessing it would be close.

280597

Dave

[Haufen]

Sounds good, but it is not completely accurate because top speed is not decisive. In fact top speed is about the most overrated thing in racing. What counts is getting there first, not fastest; the guy or girl with the highest average speed wins and that is true for all forms of motorsport (trial and motoball excepted).

Exactly what I wrote? Gear both to the same top speed, then the potential to get there first = area under the curve(s) of the gear(s).

[Ocean1]

Only in cars, not in bikes, although I've heard rumours that one large Suzuki scooter is using it.
The problem with a push belt (a Dutch invention, by the way) is that the friction coefficient between the steel belt elements and the heaves is much lower than the friction of a rubber V-belt. Therefore a much larger clamping force is needed, necessitating hydraulics, a pump and a much heavier construction altogether.
For racing I can imagine a heave fitted via a pitch on the input shaft. Advantages: no hydraulics needed and a clamping force that varies with the torque that has to be transmitted.

I never understood push belts, for exactly the reason you've given. The belt itself must also be a fair bit heavier to resist bending moments. Simple twin variable sheeves, control on the driver and sprung on the driven is not only much lighter but having a natural negative feedback output from any mechanism makes for simpler and more effective control problem. I take it racing scooter CVTs are torque control only, via radial helical slots/balls or similar?

[Haufen]

I plotted road force v road speed, mph for both curves, I did use an arbitrary overall gear ratio of 13:1 for the 28 hp curve and 14.4444:1 (13/.9) for the 30 hp curve. For comparison I included power (multiplied by 4 so it's easier to see on the graph) v road speed, mph.

I imagine both curves being used to propel the bike and as I look along the each power curve I try to imagine where each bike would be relative to the other in a straight line. The 28hp bike would set off quicker and go ahead but then the 30hp bike would start to catch up towards the end, not sure if it would pass, i'm guessing it would be close.

280597

Dave
Looks like they'd be pretty close to each other, indeed. The 30hp curve should be easier to drive, because it's torque rises more softly

If we knew the gear ratios of TZ's engine, we could even better relate that to real world driving, and, as a bonus, it would give us optimum shift rpm for each upshift. It would look like this:

http://www.mintelonline.de/Dokumente/Technik/Diagramme/ZugkraftdiagrammLC4.jpg

[Flettner]

You have a point regarding efficiency, Flettner. And there have been (and maybe still are) transmissions like you describe, where the electric variable speed motor has been replaced with a small belt variator :p. But if you wish to sell zillions of cheap scooters you have to stick to the KISS principle.

There is that KISS again! Thankfully we are not interested in selling zillions of scooters:yes:. I absolutely agree that a variable speed gearbox is the way forward and have given it much thought, but not built anything yet. I'm still looking at engine variability.

[TZ350]

If we knew the gear ratios of TZ's engine, we could even better relate that to real world driving, and, as a bonus, it would give us optimum shift rpm for each upshift.

The Beast was fitted with a 1974-76 five speed TS125 Transmission gear set to get away from the ugly gap between 2nd and 3rd in the GP box. I will see if I can find the ratios.

[jasonu]

The Beast was fitted with a 1974-76 five speed TS125 Transmission gear set to get away from the ugly gap between 2nd and 3rd in the GP box. I will see if I can find the ratios.

In my opinion having just 5 gears is a major problem. Are you sure you can't get the
TS100/125 six speeder to fit?

[TZ350]

In my opinion having just 5 gears is a major problem. Are you sure you can't get the TS100/125 six speeder to fit?

We have had a good look at that, its not impossible but the shafts are 12mm longer and it would be a bit of a tricky welding and machining job on both halves of the cases.

Graphed with Combustion efficancy set to 83%
280614
3ex PV in side ports, basic RS pipe.

An easier option may be keeping the 5 speed and making a cylinder with tripple exhaust ports and power valves in the side ports or a CVT system.


For those interested in such things, its not the top gear ratios that make the GP gearbox difficult but the lower ratios. 1st and 2nd are to low for an already geared down bike on a tight track.

An early 5 speed TS gear box can be modified to fit a GP by shortening the clutch input shaft and modifying the GP gear selectors buy building two of them up on the outside of the forks to fit the sliding dogs and opening up the ID of the other to clear its dog.

273987

Red Line is the standard Suzuki GP125 gear box.
Blue Line is the standard Suzuki TS125 gear box.
Purple line is the TS Box with modified gears, the different size gears can be made to fit by modifying the shape of the teeth.

A std TS gearbox suits a GP very nicely on a long track and a modified one works well on a short track.

OK I found an old Team ESE post about the gear ratios with a GP to TS conversion. The graph was done by TwoTempi.


You can see from the photo that the shaft from the donor TS125 is longer and fatter than the GP125 one.
This is a pain in the butt as it necessitates some engineering, which means ....

On Cotswolds thread he is converting a set of 5 speed TS gears for his GP

[Yow Ling]

While not bucket related, a little has been written about this engine here, here is a little extra information

http://www.vincelewis.net/bigengine.html

[bucketracer]

TeeZee if your getting into fuel injection there is a whole new language and concepts to learn.

Like “Speed Density” and “Alpha-N”, VE Volumetric Efficiency Table, AEM’s, IAT’s, TPS, VTA and how to use Excel spread sheets for smoothing 3D plots in CSV format.

Something below I scraped of the net to give you the idea……

Speed Density. So after much thinking about how to explain what true Speed Density is vs what we do here for instance, how AEM's are often setup, etc. I came up with the following idea, just explain what everything is and remove doubt.

MAF - if you dont know this one its a volume sensor. Thats it. Ours have IAT and a baro comp to make it more accurate but it simply measures volume entering the engine. If there are boost leaks its inaccurate, doesnt like VTA (letting metered air leave without pulling fuel), all the stuff we know.

Alpha-N - TPS x RPM. That is all that is with no VE compensation (i.e. boost). If I tell it that at 100% throttle and 6000 rpm it does it at all boost levels independent of air volume.

Speed density - estimates air mass by pressure vs temp. Then applies this to a 3D map. The "3D" we already have, its Load (pressure or volume) x RPM with a set value in each cell. Every point can be fine tuned so this is really Alpha N with compensation. Any VE changes needs a retune, doesnt matter the system. It only knows pressure and rpm not what the true mass of the air is (it has a trim table and most get ignored above certain levels).

I use the fuel temp sensor to mimic an IAT since its already in the car. The IAT reads gross temp not average. It can heat soak, be subject to a meth jet to close, all sorts of little issues. The actual trim table in the Evo ECU really isnt setup for IAT trim anyway. It has an algorithm that allows for minor alterations to fueling since its set for a MAF, and then trims timing vs air temp.

Fuel temp is more or less constant. The fuel heatsoaks going thru the rail hits the tank and then is sent forward again. It takes 15 minutes to get full heat into the fuel system (ask anyone with an A1000). It is a rough average of engine bay temp which is what the MAF does factory. I have done exhaustive testing and see no more than 5-6* variation from fuel temp as a source to what the MAF would read in the corner of the engine bay.

Now for the term everyone has been waiting for, Boost Comp. This is what MAFs do, most SD setups (AEM, Motec, Autronic, Vipec, etc.) do for fueling. It assumes VE is more or less constant until you hit backpressure in the turbine housing, head flow, cam size, and VE starts to drop off again.

I set the fueling at 16psi and in our maps this is 180% load or so. The values are constant out to 38psi. Hyper Boost Compensation is the proper name. Retuning is as easy as altering either the max boost portion of the MAPVE table to allow more or less fuel vs pressure, and in some cases the tip in portion of the MAPVE (121kpa column).

There is no such thing as true speed density. I havent seen any AEM ever do this or any other standalone. GM is the closest to True SD and its because tada they use a MAF as well to judge volume vs pressure.

There is also Alpha-N with Boost Comp. This is more or less what we do EXCEPT IT HAS NO TEMP input. It is solely rpm x TPS x pressure. Since we aren't doing fueling by TPS vs RPM at any point other than accel enrichment it is not accurate to call the SD we normally do on Evos Alpha N or N-Alpha or Alpha-Omega or whatever. Alpha N is different and is normally something reserved for ITB cars or quads (single cylinders) that have really non specific fueling and just need fuel vs tps x rpm.

Often we deal with the question, "Which is better speed density (SD) or mass air flow (MAF)". As with most things in life there are advantages and disadvantages for both. Its better to understand each strategy so as to make the most informed decision.

Mass Air Flow

Mass air flow sensor equipped cars fuel either directly from or by a blended model of both mass air flow and speed density calculations. The MAF sensor is located somewhere in the intake stream typically away from sharp bends and typically at least 8-10 inches away from the throttle body however these rules are not always followed. There are several different types of MAF sensors but for most GM applications it is a frequency biased "cold-wire" sensor that generates a signal between 0 and 15k Hz. MAF sensors read not just airspeed but the relative mass of the air which eliminates pressure and temperature as variables. They are usually positioned to sample from the middle of the intake tubing which should give the best average reading.

Since the MAF sensor samples from a specific spot in the inlet tubing changing the airflow in or around the sensor requires recalibration of the MAF sensor. Changing the airflow around a MAF sensor can be caused by a change in size of the intake plumbing, bends before or after the MAF sensor, and changes to the MAF housing.

Several applications that use MAF biased strategies also use Speed Density as a backup or for a blended fuel calculation. They also use Speed Density as a sanity check for MAF readings.

Advantages

Typically more forgiving and easier to tune
If the MAF sensor has been calibrated typically fueling remains consistent as modifications change. It can be said that the MAF equipped cars are a little more forgiving to new modifications
Since the MAF sensor measures air mass directly it can be said that a MAF equipped car might stay in calibration as the engine wears or in extreme environment changes (however this is not normally a concern for well tuned speed density applications).

Disadvantages

Sensitive to changes to the intake plumbing
Can be fouled by becoming dirty. Once fouled MAF calibration is skewed
Sensitive to cam reversion on large cammed cars. The MAF sensor isn't directional so air pulsing back and forth can affect repeatability and reliability.
Limits on performance. Most systems can not read at higher horsepower levels.

Speed Density

Speed density systems calculate the density of the air first by measuring the temperature of the inlet air and manifold pressure. With the density of air known the engine controller then looks up how much air it expects to be moving at a specific engine speed and manifold pressure. This is done in the Volumetric Efficiency table or VE table. Traditionally the VE table is 3D and has two axes Engine Speed (RPM) and Manifold Pressure or % Load. A engine that is 100% efficient moves exactly its displacement every two rotations in 4-cycle engines.

Advantages

Less restriction in the intake tract
More freedom in the intake tract
Able to measure air consumption on very high horsepower builds where a MAF sensor might be limited.
Able to read boost if equipped with a greater than 1 Bar map sensor
Free from errors encountered in MAF fouling.
Works better with large cams where reversion affects reliability.

Disadvantages

Is a little more difficult to tune
Relies on a well tuned Volumetric Efficiency Table
Less forgiving to new modifications to the engine
Might have errors in large weather changes however a proper tune makes this minimal if any error.

There are several vehicles that come with MAF sensors from the factory and there are several vehicles that come speed density from the factory. Really which fueling strategy you should go with on a aftermarket application is up to your modifications goals and expectations. If you are not the one to be tuning your setup please consult with your tuner for what he or she recommends.

Speed-Density is a method of estimating airflow into an engine in order to supply an appropriate amount of fuel and adequate spark timing. First, vocabulary:

ECM, ECU, Engine computer : used interchangeably to mean the computer operating the fuel injectors and running the engine
RPM : Revolutions Per Minute – how fast the motor is spinning
MAP : Manifold Absolute Pressure – (usually) the pressure of air entering the motor
ECT : Engine Coolant Temperature sensor – sensor used to measure the temperature of coolant circulating through a motor. Sometimes called different things by different manufacturers. I will use ECT here
IAT : Intake Air Temperature sensor – sensor used to measure the temperature of air entering the motor. Sometimes called different things by different manufacturers. I will use IAT here.
Displacement : the volume swept by a piston descending from the top to the bottom of the cylinder bore. More here.
AFR : Air Fuel Ratio – the ratio of air to fuel present in a combustible mixture. Usually stated as a ratio, i.e. 14.7:1 for the stoichiometric AFR for gasoline. Stoichiometric AFR varies from fuel to fuel.
Lambda : similar to AFR, except usually expressed as a number where 1.0 represents a stoichiometric mixture for all fuels. Lambda and AFR are the same concept expressed in different units.
Stoichiometric : a mixture containing the precise amount of oxidants required for complete combustion of all fuel present. See here or here for more information on chemistry involved.
Ideal Gas Law : PV= nRT (Pressure times Volume equals moles of gas times ideal gas constant times temperature) More to be read about this here.
Moles : a measure of how many atoms are present. See here.
Induction stoke : the part of a 4-stroke engine’s cycle in which air is drawn into the cylinder by the piston. See here for more information if you are not familiar with a 4 stroke engine’s operation.

Basic Goals and Method

The goal of Speed-Density is to accurately predict the amount of air ingested by an engine during the induction stroke. This information is then used to calculate how much fuel needs to be provided and may also be used for determining an appropriate amount of ignition advance.

The theoretical basis for this is the Ideal Gaw Law (more here.) rearranged to solve for “n” (the number of moles of gas present :

n = PV / RT

In order to use n = PV / RT to calculate the amount of air a motor ingests during the induction stroke we would need:

P is pressure in the cylinder immediately after the intake valves close.
V is volume, which we know from engine displacement.
R we know (it’s the Ideal Gas Constant see here for more)
T is the temperature of the gas in the cylinder immediately after the intake valves close.

Many of the things required to calculate the amount of air the engine ingests using the ideal gas law are missing, unavailable or at least incomplete. Some notable points where reality is less than ideal:

Our MAP sensor measures the pressure differential caused by the downward stroke of the piston in the intake manifold, not pressure in the cylinder as the intake valves initially close.
We are assuming that there is no residual exhaust left in the chamber to contribute to “poisoning” of the intake charge.
Camshaft overlap (i.e. when both intake an exhaust valve are open simultaneously – see here) makes fluid flow modeling considerably more complicated.
T that we need is the temperature of the gas in the cylinder. This is not usually MEASURED – instead it is ESTIMATED from the temperature of air in the manifold (IAT), the temperature of the cylinder heads (ECT) and other factors. “RT” is often referred to as the “density correction term” as it tries to account for how air density varies with temperature. Density correction is arguably one of the biggest problems with speed-density. (more on this later)

Speed-Density introduces the concept of Volumetric Efficiency (VE) to account for the differences between what it can observe and what is really going on. (mostly problems 1-3 above) Roughly speaking, VE is the ratio between the amount of air actually present in the cylinder and the amount of air we predict would be in the cylinder using MANIFOLD pressure (MAP) instead of cylinder pressure for our “P” Pressure term, REVOLUTIONS Per Minute (RPM) times Displacement (Volume / REVOLUTION) for our “V” term and an air temperature value estimated from some combination of ECT and IAT for our “T” term.

A motor said to be operating with 100% VE has the same amount of air actually in the cylinder as predicted by n = PV / RT. Most engines operate at considerably less than 100% VE in most operating conditions. The difference between actual airflow and theoretical maximum airflow is termed “pumping loss.” Some engines (most notably Honda engines :) ) can achieve slightly greater than 100% VE in certain conditions. Most engines operating under forced induction can be thought of to have a VE greater than 100% in some conditions.

Speed Density ECMs generally have one or more VOLUMETRIC EFFICIENCY (VE) tables that are a critical item to be adjusted. These tables allow predicted airflow values to be more closely adjusted to observed reality.

Strengths of Speed-Density

Speed-Density has many things going for it:

Pressure sensors do not pose any restriction to the flow of air into the engine, unlike a MAF sensor.
MAP sensors respond to changing conditions very quickly, enabling it to have fairly good transient response especially compared to Mass-Air-Flow
Compared to a carburetor, it allows much more control over the mixture at different engine loads
Simplicity: all the sensors required are extremely reliable.

Weaknesses of Speed-Density

Speed-Density is known for having several notable issues:

Density correction, density correction, density correction. You might not think that temperature is that big of a deal, but trust me it is! Seasonal changes can wreak havoc on speed-density systems. Superchargers or turbochargers that compress air and raise its temperature from adiabatic heating cause significant changes in density that must be accounted for. Altitude can also be really problematic. Many systems incorporate Barometric Pressure sensors to try to address this, but it’s an imperfect correction.
Large camshafts with extremely low vacuum due to high overlap close to idle. Camshafts that have low or pulsing vacuum close to idle present a challenge for Speed-Density. MAP sensor averaging can help. Alpha-N blending can help. It is still very tricky to use speed density to predict airflow with a pressure sensor with camshafts that do not build an appreciable amount of vacuum.
Volumetric Efficiency tables can be very time consuming to tune.
Engine modifications generally produce volumetric efficiency changes requiring re-tuning.
Quite a lot of math is required to do Speed-Density “by the book.” Because of this, most manufacturers implement something kind of like theoretical speed-density and cut corners or combine math operations in order to allow faster execution on puny computing hardware. (Remember, most ECUs made prior to 2000 have a slower processor than the average inexpensive cellphone circa 2010)

Sanity Checking a Speed-Density Tune

There are a few rules that transcend particular manufacturer implementations:

Volumetric efficiency rarely changes suddenly. VE tables should almost always have very gradual changes.
VE usually DECREASES as pressure DECREASES (i.e. more vacuum = less VE)
VE usually maxes out at an RPM close to peak engine torque at maximum observed load, which is usually where peak cylinder filling occurs.
Remember that VE tables are not the only thing that controls fueling. Temperature correction tables (ECT, IAT) are often implemented as multiplier/divider tables. Don’t forget about injector battery tables either! (see the separate article on Injector Tuning for more on this)

Alpha-N

An Alpha/N table allows the ECU to calculate some sort of output based on any combination of how much the throttle is open (Alpha), and how fast the engine is spinning (N). The Alpha term can range from 0% (closed throttle) to 100% (wide open throttle). The term "N" corresponds to engine RPM.

The two main Alpha/N tables are used to determine ignition advance and fuel injector pulse width. An Alpha/N ignition table would use throttle position and RPM to calculate what spark advance it should be using. Similarly, an Alpha/N fuel table would use throttle position and RPM to decide how long the fuel injectors should stay open.

Throttle Angle

The throttle angle term was tougher to figure out. While the RPM rows were spread out evenly across the operating range, the throttle angle columns were not. There is a good reason though. If you think about it for a minute, a difference in throttle angle is not a simple linear change like RPM. For example, changing the throttle angle from 1% open to 2% open is a huge difference (100%, in fact). Compare that to changing the throttle angle from 90% open to 91% open, which is only about a 1.1% difference. What this really means is that the effects of throttle changes are concentrated mostly in the range of small throttle openings. In contrast, at large throttle angles, the same small changes are almost meaningless. Therefore, the throttle angle, or 'Alpha' part of the table is strongly stacked towards providing lots of information at the end of the scale where the throttle is barely open, and has much less information about situations where the throttle is open fairly wide. This also makes sense when you consider that much of what a rider considers as 'driveability' issues occur when cruising down the road with the throttle barely open. Giving the ECU extra information about part-throttle situations makes for better driveability.

Alpha-N uses the throttle position (alpha) and RPM (N) to calculate the amount of fuel to inject as opposed to using the manifold absolute pressure (MAP) and RPM to calculate the amount of fuel to inject. Alpha-N is useful for long duration cams where the resolution of manifold air pressure (map) would be small.

Manifold Absolute Pressure, then, is just what it says: The absolute pressure which exists in the inlet manifold, usually measured in the plenum (if one exists). The MAP in an engine which is not running is equal to atmospheric pressure. If, on a "standard day", an engine is idling at a measured manifold "vacuum" of 14 inches,, the MAP is actually 15.92 "HG (29.92 - 14 = 15.92).

1 atmosphere = 760 mmHg = 29.92 inHg = 14.7 lb/in2 = 101.3 KPa

[husaberg]

That's a big post, A lot to take on board, who would of thought that.

[Moooools]

[B]TeeZee if your getting into fuel injection there is a whole new language and concepts to learn.

Like “Speed Density” and “Alpha-N”, VE Volumetric Efficiency Table, AEM’s, IAT’s, TPS, VTA and how to use Excel spread sheets for smoothing 3D plots in CSV format.

Wank wank wank.

I think you would be pretty game to try anything other than an 'Alpha-N' setup. Pulsing on a single cylinder will make the engine hunt and low rpm. And MAF will restrict your inlet and is heavy as balls.

And download matlab instead of excel. Much better at dealing with large matrices.

[TZ350]

Thanks Bucket and Mooools

To get started, most of the info for VE, Speed Density and Alpha-N maps can be gleaned from the EngMod2T simulations.

Because of the pulsing in the inlet tract that Mooools talked about and which is particularly bad in a 2-Stroke, the Fuel injection system we are getting has a Speed Density map for low RPM and uses Alpha-N for the high RPM end.

I have been told that as an optional add on, it can also have a mixture adjustment with exhaust temperature option. I am not sure how that works but hopefully it means we can give it a target ET and it will maintain it just like Wobbly has talked about for maintaining optimum AFR with changes in conditions during the day.

I am not sure how the injection timing works but the system triggers from the existing ignition pickup. Because I want to inject into the transfers while the are open and flowing, I guess it will be easy enough to fit a dedicated trigger at some other point to get the injection timing right.

Anyway hopefully Chambers and I will have our kits by the end of the week.

[Moooools]

Thanks Bucket and Mooools

To get started, most of the info for VE, Speed Density and Alpha-N maps can be gleaned from the EngMod2T simulations.

Because of the pulsing in the inlet tract that Mooools talked about and which is particularly bad in a 2-Stroke, the Fuel injection system we are getting has a Speed Density map for low RPM and uses Alpha-N for the high RPM end.

I have been told that as an optional add on, it can also have a mixture adjustment with exhaust temperature option. I am not sure how that works but hopefully it means we can give it a target ET and it will maintain it just like Wobbly has talked about for maintaining optimum AFR with changes in conditions during the day.

I am not sure how the injection timing works but the system triggers from the existing ignition pickup. Because I want to inject into the transfers while the are open and flowing, I guess it will be easy enough to fit a dedicated trigger at some other point to get the injection timing right.

Anyway hopefully Chambers and I will have our kits by the end of the week.

I am quite surprised the fuel map control isn't around the other way. With tps at low rpm and MAP at high.

Does it not have adjustable injection timing?

[Frits Overmars]

....I have been told that as an optional add on, it can also have a mixture adjustment with exhaust temperature option. I am not sure how that works but hopefully it means we can give it a target ET and it will maintain it... So if your exhaust gas temperature is lower than it should be, the mixture is made leaner, right?
Fine, except that EGT drops when the engine starts to detonate. Need I paint the rest of the picture?

[TZ350]

I am quite surprised the fuel map control isn't around the other way.

Maybe it is, know more when I get may hands on it.


Does it not have adjustable injection timing?

I will post more as we get to know how it works.


So if your exhaust gas temperature is lower than it should be, the mixture is made leaner, right?
Fine, except that EGT drops when the engine starts to detonate. Need I paint the rest of the picture?

Hmmmm I see you point, hopefully they have this covered as it also has a cylinder head temp sensor. But I don't realy know, or even know if I properly understood what they were trying to tell me.

I guess I will find out in due course if we have a lemon or a peach.

[bucketracer]

Mountain Thunder- Methven Street Race 2013- Buckets- Race 3


<iframe src="http://www.youtube.com/embed/uutU3xytSdo" allowfullscreen="" frameborder="0" height="315" width="420"></iframe>

There are so many really cool Bucket race meetings.

[bucketracer]

I am quite surprised the fuel map control isn't around the other way. With tps at low rpm and MAP at high.

From what I can make out from the documentation downloaded off the net for TeeZees EFI, the makers intend using MAP for low rpm and TPS for the high end.

280665

[Flettner]

TZ don't be too concerned, there will always be doubters,I have running proof that EFI works well on a twostroke. Although I only understand the Link computer, much of this has already been done by Link all you have to do is choose the options you want.
Frits you can run the deto sensor back into the computer, it will adjust, retard and rich. The Link will do this.

[rgvbaz]

I think, also taking the gear ratios of TZ's engine into consideration, a plot comparing rear wheel torque through the gears, with both curves geared to the same top speed would be quite handy. That one with the bigger area under the curve, wins[/SIZE].

Not to sure if the area will tell you the winner?

If you plotted force by distance this would give you the total work the curve could do, but we are really after the rate of doing work (power) so we would need to consider time.

I know that power = force*velocity, which is what we would get from the force v speed graphs but the scale on the speed axis would be wrong; it has a liner scale but change in velocity is a square relationship.

Dave.

[bucketracer]

TZ don't be too concerned, I have running proof that EFI works well on a twostroke.

Also the same EFI as TeeZee is getting is used on 2-Stroke powered Para Gliders

280667

Engines used are almost exclusively small two-stroke types, between 80cc and 350cc, that burn mixed gasoline and oil. These engines are favored for their high output power and light weight. For years, these engines used carburetors because of small volumes of production. Now with our low cost and simple 2-stroke fuel injection kits, it is the first time its commercially viable to convert them to the fuel-injection.

Certainly these engines can take all advantages of fuel injection, namely, better fuel efficiency, more power, easy to start, compensations to temperature / weather changes, and self-adaptations to altitude changes, etc.

We have customers successfully installing our EFI kit to their ParaMotor engines already. Some earlier adopters have flown with our EFI kits. The simplicity of our 2-stroke EFI kit makes the conversion comparatively easy for ParaMotor applications.


<iframe src="http://www.youtube.com/embed/UBhtiAgES2s" allowfullscreen="" frameborder="0" height="315" width="560"></iframe>

[Frits Overmars]

....Frits you can run the deto sensor back into the computer, it will adjust, retard and rich.I am all for using that deto sensor signal as you describe, Neil. I just wanted to warn TZ about the risk in using an EGT signal for EFI purposes.
BTW: this is starting to look like German: they cram their sentences with abbrevs (and still manage to build sentences twice as long as the English).

[fatbastd]

Haleijulia!! It's taken me since before Christmas, but I've finally managed to get to the end...

I thought I had a rough handle on how things worked, but am nothing but a festerer compared to what I've read here...good effort. I have a garage full of two strokes and shall be nicking good stuff from here to make them faster, safer.

Just a couple of thoughts: Wob's comments regarding selection and sticking to the aim (more than 30RWHP) sticks out like dog's when you read stright through all the last 745 pages and we all want to see the end result and how it's done. Against that ideal, I know TZ350's view - it's all good fun, so a few diversions are OK, and that's the real benefit.

Just thinking about big TZ's posted recently - may be 100 pages back..the engine from Trev Discombe's Nicco 750 that Stu Avant rode to a win at Pukekohe in the Marlboro series is back in it's own frame in Aucklland and regularly ridden (if not that often). The motor in that bike is quite stock, and alwys was - as Avant said when quizzed as to how he pulled off the win 'I just hung my arse out a bit'. There was also a mention of there being 9 TZ750's in NZ - a little pessimistic - I know of 13 at the last count IIRC (2 recent arrivals in Invergiggle), with 5 living within 50m of each other! One was shipped overseas a couple of years ago, to the USA. In the late 70's there were 5 new monoshocks in boxes in Auckland that went directly overseas again -someone I know was taken to see them at the time. The ex-Hawera bike (now sold) rated a mention here as being a very original bike - not so: the frame was by Ken McIntosh (I had the original frame that I believe TD wrote off- now recontructed and in a bike in Brisbane), the forks in the bike when Scotty rode it were RZ500 (and crap for the job) and the motor has a set of replacement crankcases. I believe the new owner is keen to drag it out for whizz around.

Anyway, enough big two-stroke crap: it's looking like a kid of mine is keen to ride and buckets are a favoured jumping-off point (pardon the pun). It might have to be a four-stroke to get things going (ease of riding, stock - min maintenance), but greduating to a proper two-stroke would be a development plan. Might have to swing my fat leg over one too, though it's have to weight about 35kg to give me a competitive power to mass ratio!

I know some of you buggers in the flesh, so I'll be looking over your shoulders soon, prolly at Mt Wellington..

Cheers

FB

[husaberg]

Haleijulia!! It's taken me since before Christmas, but I've finally managed to get to the end...

I thought I had a rough handle on how things worked, but am nothing but a fester compared to what I've read here...good effort. I have a garage full of two strokes and shall be nicking good stuff from here to make them faster, safer.

Just a couple of thoughts: Wob's comments regarding selection and sticking to the aim (more than 30RWHP) sticks out like dog's when you read straight through all the last 745 pages and we all want to see the end result and how it's done. Against that ideal, I know TZ350's view - it's all good fun, so a few diversions are OK, and that's the real benefit.

Just thinking about big TZ's posted recently - may be 100 pages back..the engine from Trev Discombe's Nicco 750 that Stu Avant rode to a win at Pukekohe in the Marlboro series is back in it's own frame in Auckland and regularly ridden (if not that often). The motor in that bike is quite stock, and alwys was - as Avant said when quizzed as to how he pulled off the win 'I just hung my arse out a bit'. There was also a mention of there being 9 TZ750's in NZ - a little pessimistic - I know of 13 at the last count IIRC (2 recent arrivals in Invergiggle), with 5 living within 50m of each other! One was shipped overseas a couple of years ago, to the USA. In the late 70's there were 5 new monoshocks in boxes in Auckland that went directly overseas again -someone I know was taken to see them at the time. The ex-Hawera bike (now sold) rated a mention here as being a very original bike - not so: the frame was by Ken McIntosh (I had the original frame that I believe TD wrote off- now reconstructed and in a bike in Brisbane), the forks in the bike when Scotty rode it were RZ500 (and crap for the job) and the motor has a set of replacement crankcases. I believe the new owner is keen to drag it out for whizz around.

Anyway, enough big two-stroke crap: it's looking like a kid of mine is keen to ride and buckets are a favoured jumping-off point (pardon the pun). It might have to be a four-stroke to get things going (ease of riding, stock - min maintenance), but graduating to a proper two-stroke would be a development plan. Might have to swing my fat leg over one too, though it's have to weight about 35kg to give me a competitive power to mass ratio!

I know some of you buggers in the flesh, so I'll be looking over your shoulders soon, prolly at Mt Wellington..

Cheers

FB

Great post,Now if you can pm me those address's for all those TZ's.. :innocent:
I can't let that last bit go though 4 stroke for lower maintenance? i am guessing your son hasn't done mx then.
Those 4 stroke things have far to many whirling bit's that wear out and have the propensity go pop in a expensive way at any time.
Two stroke's on the other hand are the paragon of reliability....:whistle:


<img src="http://www.mantismail.com.au/database/account-75/coming-soon_1.jpg" height="123px"/><img src="http://www.dreamstime.com/while-stocks-last-thumb18040977.jpg" height="123px"/>

As people have, i guess sussed out already. I will be very soon to make a few, Well very Aprilia like cylinders (With more than a lot of help from Neil ie Fletner)
These cylinder's and heads have been modeled on the RSV. As beautifully detailed in the engine drawings from Frits( ie triple ex and 5 transfers and a 2 stage blade pv.)
So if everyone thinks it is the most, illegal, underhand, dastardly, or not in the spirit of Buckets etc please speak now or for ever hold your piece.
If not those that want one let me know.
In the spirit of bucket racing the cylinders will be sold as un-machined castings. (In an effort to keep costs down)
The buckets will be a strictly a negligible profit sideline as the intention is to sell them mainly to people who have RGV250's and NSR250's the likes as a bolt on road kit up to around 300cc

<img src="http://topmoto.www5.50megs.com/images/aprilia2501.jpg" height="223px"/><img src="http://www.motorcyclespecs.co.za/Gallery/Aprilia%20RS250%2094.jpg" height="223px"/><img src="http://www.suzukicycles.org/photos/RGV/RGV250-Gamma/1990_RGV250L_blwhite_475.jpg" height="223px"/>

Hopefully maybe Neil sorting out the PV and Head domes and machining and Mr Wob the pipes and so forth....
It would be kind of neat to sell Aprilia copy cylinder kits into Europe for people with Aprilia bikes with Suzuki engines.

[bucketracer]

Hey TeeZee I cam across this thread where Flettner talks about fuel injecting his Kawasaki 350, hopefully he won't mind it being re posted here.

http://twostrokemotocross.com/forum/general-two-stroke-talk/cycle-world-two-stroke-article/

I use a Link Atom computer on my MX twostroke. Rear transfer port injection, by staging the injection, fuel wastage is reduced, more power, wider power spread. Enough oil deposit on the transfer runs down to the crankcase to service the bigend. It's been running for about eight months now.

This bike has a vairable rotary valve housing operated by the Ignitec ignition. From 55 degrees valve closing at low speed to 78 Degrees at full throttle.

Fueling changes. Link EFI has the ability to change the fueling as the head temp changes. With Ethanol the fuel requirement changes above 70 degrees C, more fuel required. This can be changed on a graph that uses TPS and Temp. This information is overlaid the main fuel map. Very handy with an air cooled engine.

The rotary valve still organizes the air into the crankcase, just has no fuel with it. Oil is still deposited from the injected fuel around the crank case and rotary valve via deposits in the transfer ports. One of the problems with the Link computer is some it's twostroke injection timing software is not operational yet. I can change the start of injection timing to a given point with the "on time" moving away from this point. I'm injecting approx over 180 degrees at full throttle (180 degrees injector on time ), so I have to set the start at approx 20 degrees after TDC ( quite a way before transfers open) so that at full throttle there is no injection still happening after transfer closes. If injection occurs after transfer port shut the fuel mixture on the next cycle is not so accurate ( power loss ). This I have found. Best it to have a fixed shut time ( approx 30 degrees before transfers shut ) and have the injection start vary. This will bring max injector start time to about 30 degrees ATDC at full throttle. This is what is needed, as up to about one third throttle is happening as the transfer is occurring. This I have found gives best bottom end power. Clear as mud?

In a nutshell, the injection timing is important. I can see why it's probably a good idea to use a small and a large injector, staged. The Link software is not able to do this in " twostroke mode" . Also there is an option to nail down the injector finish time and adjust the start time, or a center and adjust either way from that point. Also not available in twostroke mode. These options are available in fourstroke mode. So next step is to call the bike a fourstroke twin, 360 degree firing ( I don't need to use the ignition as this is done with a separate unit), This will use two drivers ( switches ) in the Link unit to run each cylinder ( if it were a twin ). Both drivers can be hooked together to run my pair of injectors each 360 degree cycle. This requires a cam sensor, I'll use a circuit called a flip flop connected to the ignition trigger ( single pulse per rev ). This circuit ( flip flop ) will only allow every second pulse to be seen by the Link computer, as far as the computer is concerned, a cam sensor. This will trick the computer in doing what I need it to do. Now all these options will be available. New Link soft wear will be available in eight months. I can't wait that long, I want it now. That's a big nutshell.

Yes I did think of using wobbly's ignitech unit. Cost a little more than the Link. I've used quite a few link units in the past on the Subaru powered gyro copters we build and have a good working relationship with the guys at link. But I was a little disappointed that the Atom unit I was sold did not have the suitable soft wear activated even though I was told that it was when I bought it. No problem, as it will be available in the next soft wear release. At the moment I'm "tricking" the computer into doing what I want. To be fair not a lot of after market computer makers have had a lot to do with transfer port injection where timing is so important. It is interesting to note that the default setup for injector timing is batch fire every 180 crank degrees ( fourstroke car engine ), this timing is random every time the engine is started. Once started it stays constant, but next time you start it will locate somewhere else. You can imagine the issues this caused, trying to tune this type of setup was impossible and it took a while to sort it out. I ended up making a device to strobe the injectors on and off points. Link's experience with twostroke injection has only been with snowmobile engines injecting into the intake ( an electronic carburetor ) where injection timing seems to be less important. You can appreciate I've put a lot of time and thought into this project.

How hard was it nail down tuning? Well it's still happening, some of the problem has been the computer setup as stated above and some the ethanol fuel I'm running ( too many new things at once ). Ethanol has the odd requirement for more fuel above 70 / 80 degrees C ( engine temp ). Water cooled engine you would never notice. Air cooled, at 120 degrees it becomes very lean so more fuel is needed. This is were the computer is soo good as it can easily be setup for this. This was always the problem with the MFI system I had previous. Very rich cold and early in the race only to come right at about two laps in, very frustrating! Now we can fuel it so the engine never sees 120 C.

[136kg136ps]

What increase in air volume will there be with the fuel being injected downstream of the 24mm restriction and how much power does ENGMOD2 suggest it will add ? EFI seems a win win given that restriction.

[TZ350]

What increase in air volume will there be with the fuel being injected downstream of the 24mm restriction and how much power does ENGMOD2 suggest it will add ? EFI seems a win win given that restriction.

Good question and I am sure EngMod2T can amswer it, but so far I have not gone to much effort to compare simulated differences between a carb and down stream fuel injection, but I have looked at the effects of bigger carbs and plenums.

Sure, by reving to the moon, there are engines that make big hp with a 24 carb. But EngMod2T shows there are better gains and mechanical safety to be had by fattening the torque curve at lower rev's and this requires more airflow, ie a bigger carb or something clever.

Also, although I should check this on the dyno by trying the 30mm carb in another back to back test. I believe the 24mm carbs restriction is contributing to my over rev deto problem.

I had fuel dropout problems and lubricating doubts before when I first tried the plenum. But now I see EFI allowing me to re visit the plenum idea as a way to negate any restrictive effects of the 24mm carb and increase the air flow through the inlet system.

[TZ350]

I will see if I can find some video of the plenum and carburettor.

<iframe src="http://www.youtube.com/embed/YxiEo8cgopg" allowfullscreen="" frameborder="0" height="315" width="420"></iframe>

First ever Startup.

<iframe src="http://www.youtube.com/embed/p4ef-WUO1Qs" allowfullscreen="" frameborder="0" height="315" width="420"></iframe>

A quick blits, not to far as its a bit dangerus going fast past the other units.

We ran it at the track but in the end shelved the idea as it suffered from a lot of fuel dropout leaving a cupful or so of very oily fuel behind in the plenum and this made us worry about whether enough oil was getting to the engine.

EFI could allow us to look at the plenum again.

280684

The new plan, is to run the 24mm carb dry, run a ball inlet and TPS inside the plenum and fuel inject directly into the transfer ports.

[bucketracer]

EFI could allow us to look at the plenum again.

280684

The new plan, is to run the 24mm carb dry, run a ball inlet and TPS inside the plenum and fuel inject directly into the transfer ports.

I can understand keeping the old 24 carb, 24 carb equivalent and all that, but why run it dry? you could use it to run water for a bit of charge cooling, the surplus water would collect in the bottom of the plenum and could be drained to a catch bottle.

280696280697

The Ball and TPS looks like it could do what you tried to achieve with the Vtec flap arrangement when you had problems with inlet resonance (the blaars) in the plenum before.


if we try the plenum again it will be with a short inlet and the VeTec inlet butterfly thing for changing the inlet resonance.

280700

[koba]

So if everyone thinks it is the most, illegal, underhand, dastardly, or not in the spirit of Buckets etc please speak now or for ever hold your piece.
If not those that want one let me know.

I think its a bit stink.

"for ever hold your piece." :facepalm:

[bucketracer]

I think its a bit stink. "for ever hold your piece." http://www.kiwibiker.co.nz/forums/images/smilies/facepalm.gif

Whats stink, Husas spelling/grammer?

[koba]

Whats stink, Husas spelling/grammer?

Yes, that's obvious.

The home cast barrel is starting to depart from a non competition engine base.

Yeah, I know it's long been held that homebuilt = OK but is it? how far is too far?

Modifying a GP 125 barrel to replicate RSA porting is without a doubt OK but to cast a cylinder up based on factory race parts; too far?

My gut feeling says yes, it is.

It is around here that the inevitably blurry line between a modified non-competition engine and a specifically competition designed unit lies.

I've thought about making one and have dismissed it as illegal or at best just "too damn grey to go there".

[husaberg]

I think its a bit stink.

"for ever hold your piece." :facepalm:


Whats stink, Husas spelling/grammer?

Oh, i agree my grammer is real bad, but my smelling is beyond reproach:innocent:


Yes, that's obvious.

The home cast barrel is starting to depart from a non competition engine base.

Yeah, I know it's long been held that homebuilt = OK but is it? how far is too far?

Modifying a GP 125 barrel to replicate RSA porting is without a doubt OK but to cast a cylinder up based on factory race parts; too far?

My gut feeling says yes, it is.

It is around here that the inevitably blurry line between a modified non-competition engine and a specifically competition designed unit lies.

I've thought about making one and have dismissed it as illegal or at best just "too damn grey to go there".


Modifying a GP 125 barrel to replicate RSA porting is without a doubt OK
but to cast a cylinder up based on factory race p̶a̶r̶t̶s̶;̶ design too far?

Malcolm I have tidied up that bit so people don't get the wrong idea.
Grey is drab. Rules unfortunately are not always black and white.

It should be noted that home built cylinders and engines have run at Bucket GP's before. So the precedent had already been set long long ago.
So it isn't starting to depart from the non competition engine, More the the horse she haft done long departed, meet a nice stallion retired to a farm and had some foals. Then was sent to a glue factory and made into kebabs.
Or to use your analogy the ship has long since sailed.

Personally i don't see it as against the rules but it would be a very boring world (not to mention very unlikely;))
if everyone agreed with me.

With regard to design.
All two stroke porting is indeed based on race designs, mostly originating the from original work done by MZ IFA and DKW. Racing improves the breed and all that.

It just so happens in this case the work done by Mr Thiel and Mr Overmars and other, made freely available on the internet is more worth copying.

[Grumph]

If you're still using what started out as road crankcases then arguably it's still based on a road motor...

The Westoby bucket, pics of which were posted here on the chassis thread, has a barrel reputed to be a spare from the C3 built by the late Jim Cashman, which defeated the reigning world champion in the support class for the marlboro series....which predates many of the people posting on here.

Those barrels were cast in Dunedin I believe by Jim himself.

[husaberg]

Is this it with the right cylinders
<img src="http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=253954&d=1325147433" height="320px"/><img src="http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=253955&d=1325147433" height="320px"/><img src="http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=253953&d=1325147433" height="320px"/>

<img src="http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=253958&d=1325147515" height="270px"/><img src="http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=253957&d=1325147515" height="270px"/><img src="http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=253960&d=1325147797" height="270px"/>
<img src="http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=253959&d=1325147797" height="340px"/><img src="http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=253956&d=1325147433" height="340px"/>
To tell you the truth i never knew it was a bucket. I thought it was a 125 and i posted the pics (you had sent them to me though for the chassis thread)
stilll think in this case the spine was to compromised with the reed engine, Neat bike though, who has it now?
Neat rear disk well before they were common on the tidlers.


And as far as rules go, the official word from the MNZ Road Race commissioner is it was the INTENT of the rules blah blah blah and they also suggested that the Bucket community needs to be self policing :gob:

Heres a copy of the reply from MNZ, some on here have already seen a copy of this. :innocent:


Subject: Re: MNZ rule clarification or rule change required
Date: Tue, 18 Oct 2011 23:09:19 +1300

Hi again Gavin

The rule reads pretty clearly from where I'm looking - the use of competition engines and gearboxes is specifically disallowed ....... the ORIGINAL wording from 25 odd years ago is probably better, but what we have now is fine.

If we take your suggestion to its full extent, you have a major can of worms - for instance, there are several KT100 parts in an AG100 engine. There is the odd early RM part in a TF125. and so on etc etc.

As one who was building and racing buckets from the first day they escaped the Airforce, I can tell you the intent of the original rules was to encourage the building of performance, not simply the buying of horsepower in the guise of factory race parts. So the rules specifically excluded the use of these .... and there was no such thing as RS125 framed MB100 cylindered MB50's either. But centre-hub steered G4TR's with watercooled RG cylinders grafted on were rightly applauded. Homemade alloy monocoques with VT250 headed CB125 engines were cool, and LEGAL

The Bucket community needs to be self-policing to an extent - if people are building bikes with illegal parts, suggest you do something about it by putting pressure on the guilty parties yourselves

Hope this helps ??????

Cheers
Peter R

This was my original email asking for clarification ...

2010_MoMS_Chapter_24_Road_Racing_Miniature.

24.2.4 Engines must be derived from non-competition motorcycles. Motocross, Road Racing,
Enduro and Go Kart motors and transmission parts are not permitted

Seeking clarification on this rule. The extra S added after Go Kart motor above has led a lot of confusion over the wording.
Some people read this rule to mean while its clear on competition transmission parts, its not clear on competition motor parts.
As its worded, some interpret that a complete motor is not allowed, but interpret by some logic that they are allowed to use competition motor PARTS.
No I would not agree putting in race parts is the same in effect as using the whole engine.
These would be excluded if it were to read Go Kart motor and transmission parts, but with the extra S added to motor, it seems some read this that its only a complete motor that is not permitted.
A point to be looked at, but I think (motor"s") was to cover off all motors of what ever brand and not as you have interpreted it.

Has this been raised in discussion in before? Not to my knowledge Was the extra S added as a typo? It seems to me that is a typo, as why would you ban transmission PARTS but not motor PARTS?
It has come to light that some people seem to think it is in the rules to use Go Kart parts in some engines in "Bucket racing".
A notice on the MNZ web site should clarify this for all competitors.

Can you confirm the intention of this rule? And is it possible to have the wording changed if it has been a typo all these years?

The items in red were a reply from Paul Stewart part of MNZ.
Shame he wasnt able to add in some comma's in his first line, as it is, Im not sure if he agrees or disagrees :facepalm:

So after all that, I think they missed the point of my original query ..... oh well .....
Can't be long before two stroke bucket bikes will be banned, due to their carbon footprint anyway is it?
Oh and sorry for the thread hijack, but welcome to the Bucket forum, you'll get use to it. :yes:

http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=263658&d=1336905185
http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=263654&d=1336897776

[Bert]

Grey is drab. Rules unfortunately are not always black and white.

It should be noted that home built cylinders and engines have run at Bucket GP's before. So the precedent had already been set long long ago.
So it isn't starting to depart from the non competition engine, More the the horse she haft done long departed, meet a nice stallion retired to a farm and had some foals.
Or to use your analogy the ship has long since sailed.

Personally i don't see it as against the rules but it would be a very boring world (not to mention very unlikely;))
if everyone agreed with me.

With regard to design.
All two stroke porting is indeed based on race designs, mostly originating the from original work done by MZ. Racing improves the breed and all that.

It just so happens in this case the work done by Mr Thiel and Mr Overmars and other, made freely available on the internet is more worth copying.

It would/will be interesting to see what some of the silver-backs (Enter Mr Speedpro & Mr F5Dave) think of this.
but since 1995 (I'm late starter so not a sliver-back) I've seen some really interesting backyard engineering and that is what makes this class so interesting.
But maybe that why some people are pushing for the name change to moto4 rather than formula 4 (and slowly removing the ability for those that can; to actually build stuff. like all the other boring classes i.e. superbikes).

I have to say I'm sitting on Husa's side of the fence on this one; this is in the spirit of the rules (and well within the actual boundaries of the written rules).
This concept is no different than someone using a motoGP (more likely a 600cc) grind on their new blank four-stroke cams....
I'm not sure why there has to be a line between modifying your barrel to this spec or casting a new one to the spec.
Each process requires skill that is hard learnt; and not forgetting the fact that these are not being produced as 125cc cylinders so they are still going to be a compromise...

The issue (real grey area) may be if they are being produced as an aftermarket offering... but this again maybe no different than the derbi kit....:corn:

[crazy man]

l like it to ! its what buckets is about . l just don't like the idea of using gp rolling frames . maybe a % of one would be better but if its in the rules well can't do much about it

[TZ350]

Yeah, I know it's long been held that homebuilt = OK but is it? how far is too far?

How clever is too clever??

I am watching this with interest..... :)

[seymour14]

How clever is too clever??

I am watching this with interest..... :)

I'm also with Bert and Co., if the individual is clever enough to build reproduction parts that are along the lines of fully fledged GP machines, I would still applaude the skill required to pull it off.

Granted, CNC machines have made the impossible attainable, but there is still a sense of pioneering spirit in working through any part on a bike and pulling off the build. Remember, it is not only the build that is at stake, the end product must suit the intended rider, and this is always the other critical part of the equation.

Buckets should remain a class of "inventors", this and the knowledge we all gain from exploring new possibilities is half the fun of the Class. You get a hell of a lot more pride out of doing the hard yards then just the "lets just chuck money at the problem". Crazyman's a good example, he is really chuffed with the outcomes for his bikes, the development time to finished bike was truly stunning to me. This goes the same for the majority of the bikes in the F4 and F5 classes, how many times are we doing corrections/rebuilds/developments at the track? Ask a Superbike rider to adjust his machine and he would probably stare blankly back at you!

We have our Class just right, and I think we can police ourselves pretty well in general.

[Flettner]

Huseberg, just melt down your old barrels to recast to new ones. Same old barrel just reshaped, a bit like reshaping it with a die grinder. Yes? I see no problem with that.

[husaberg]

Huseberg, just melt down your old barrels to recast to new ones. Same old barrel just reshaped, a bit like reshaping it with a die grinder. Yes? I see no problem with that.

The foundry would be stoked, Maybe an old Triumph or Harley crankcase... or a wok
Maybe non competition alloy.
I have to admit i would like to use old Cat pistons ala Bert (he stopped using the ford Y ones earlier)
But i think the new ones are steel.
I love f4 for there freedom.
I actually see it more in the spirit to make them available to competitors rather than just for myself or a select few.
Certainly don't expect to gain a fortune from them:weep:

Do you have any pics of the chassis of the uniflow 100 Neil? Home brewed or modded?

[TZ350]

280727

This is where I have got to with my simulations for the EFI map data.

These start at 500rpm but I have not displayed the bit below 5,000 rpm because its pretty much all the same and a bit boring. And who would have thought that the engine would rev further on smaller throttle openings.

Because the gaps are getting bigger, when I have finished this series I will have to go back and do some in between ones for the lower throttle settings.

[Haufen]

Not to sure if the area will tell you the winner?

If you plotted force by distance this would give you the total work the curve could do, but we are really after the rate of doing work (power) so we would need to consider time.

I know that power = force*velocity, which is what we would get from the force v speed graphs but the scale on the speed axis would be wrong; it has a liner scale but change in velocity is a square relationship.

Dave.

I am under the impression that you are overcomplicating things in your thinking.

If you plot rear wheel driving force against speed, then it will show you which engine setup will accelerate faster at a given speed (because in our assumption, we are talking about the same bike with the same rider (weight) in the same riding position with the same tire pressure riding in the same wind conditions etc.)


280727

This is where I have got to with my simulations for the EFI map data.

These start at 500rpm but I have not displayed the bit below 5,000 rpm because its pretty much all the same and a bit boring. And who would have thought that the engine would rev further on smaller throttle openings.

Because the gaps are getting bigger, when I have finished this series I will have to go back and do some in between ones for the lower throttle settings.

Which data will you take from the sims to feed the ecu with?

[TZ350]

Power Curves

280732


Which data will you take from the sims to feed the ecu with?

280730

RPM, TPS VE and Fuel ...

280731

Here is Fuel vis RPM and TPS.

There is a lot of good information to be gleened from the EngMod2T simulations that will be usefull in prepairing the initial Maps for the EFI.

[Grumph]

Is this it with the right cylinders
To tell you the truth i never knew it was a bucket. I thought it was a 125 and i posted the pics (you had sent them to me though for the chassis thread)
stilll think in this case the spine was to compromised with the reed engine, Neat bike though, who has it now?
Neat rear disk well before they were common on the tidlers.


In fact the barrel in the pics is a w/c Ag100 one - the current owner needs a YB100 piston to get it running with the right barrel. It's piston port too - not reed. Ports appear to be based on TD/TR layout.

Amusingly (to me) the frame is one of 3 built by the Westoby's - the other 2 had Rotax 125's in and ran in the NZ champs. You could therefore say they used a genuine race frame.....well predating the RS125 framed buckets.

All this shows really is that whatever you can think of doing in buckets in NZ, someone's probably done it before....

[rgvbaz]

I am under the impression that you are overcomplicating things in your thinking.



Quite possibly :yes:

Dave

[TZ350]

280822

Chambers and my EFI stuff turned up today, only 4 days delivery time and it was Easter, how good is that! real good!

280823

All the bits.

280820

RF Shielded CPU

280824

We checked and yes, the light you can see through the throttle body is equivalent to a 24mm carb.

280821

Here are all the bits connected up on the wiring loom, real simple, real easy.

280828

As an optional extra we got a wide band O2 kit to help with tuning on the dyno.

[chrisc]

As an optional extra we got a wide band O2 kit for tuning on the dyno.

:woohoo:

This is awesome. Changing all those jets, the needle and inlet trumpets the other night on the dyno was such a hassle! When you can sit next to the bike with a laptop and change the fueling without anything mechanical... what are you going to do with all that time saved!?

[speedpro]

As an optional extra we got a wide band O2 kit to help with tuning on the dyno.

I'd check how that's going to last on a 2 stroke before using it.

[TZ350]

I have been told that as an optional add on, it can also have a mixture adjustment with exhaust temperature option. I am not sure how that works but hopefully it means we can give it a target ET and it will maintain it.

So if your exhaust gas temperature is lower than it should be, the mixture is made leaner, right?
Fine, except that EGT drops when the engine starts to detonate. Need I paint the rest of the picture?


The EFI unit turned up today and I am starting to get my head around how it works. Turns out, you give it a max exhaust temp and if its exceeded then the EFI self richens. There was no mention of a lower set point. Still won't react to deto and the subsequent drop in exhaust temp, but at least having an upper exhaust temperature set point is going to be much better than nothing.

[TZ350]

I'd check how that's going to last on a 2 stroke before using it.

I plan on looking in Pick-a-Part to see if there are any compatible ones to act as crash test dummys.

[Frits Overmars]

The EFI unit turned up today and I am starting to get my head around how it works. Turns out, you give it a max exhaust temp and if its exceeded then the EFI self richens. There was no mention of a lower set point. Still won't react to deto and the subsequent drop in exhaust temp, but at least having an upper exhaust temperature set point is going to be much better than nothing.Enrichening when the EGT exceeds a certain level, is fine, as long as the base setting is rich enough without this EGT-enrichening and as long as the EGT-signal does not work in the opposite direction, i.e. leaning the mixture when the EGT drops below a certain level.

[rgvbaz]

I think, also taking the gear ratios of TZ's engine into consideration, a plot comparing rear wheel torque through the gears, with both curves geared to the same top speed would be quite handy. That one with the bigger area under the curve, wins.

Ok, I was a bit confused too so I did some maths (if your American that's: math). The pic below has two curves on a Driving force v road speed graph. I guess you would never have anything like that in reality but to show the point... Both the areas under each curve (well straight lines) are 18 grid boxes in area yet curve A can accelerate the imaginary vehicle to 35 Km/hr in 2.22 secs Vs curve B which takes 4.17 secs.

I used the equations out of John Bradleys book for most of my spreadsheet.

280864


Dave

Edit: Cum time = cumulative time not...

[TerraRoot]

can't wait to hear all about how this efi kit works for you TZ, i've had it to the back teeth with ordering and changing jets

[TZ350]

280865

Yep, that is a super sticky Hoosier, Chambers is building a sidecar and has been thinking about the dark side and CVT.

[chrisc]

I used the equations out of John Bradleys book for most of my spreadsheet.

Damn good book! I'm half way through now.

[Haufen]

Ok, I was a bit confused too so I did some maths (if your American that's: math). The pic below has two curves on a Driving force v road speed graph. I guess you would never have anything like that in reality but to show the point... Both the areas under each curve (well straight lines) are 18 grid boxes in area yet curve A can accelerate the imaginary vehicle to 35 Km/hr in 2.22 secs Vs curve B which takes 4.17 secs.

I used the equations out of John Bradleys book for most of my spreadsheet.

280864


Dave

Edit: Cum time = cumulative time not...

Thanks for that, Dave. I think I missed something. I will think that through. What happens if you take an acceleration vs speed graph with the same area instead?

[F5 Dave]

. . . (if your American that's: math). ...
If you are English that is 'You're'. Oh you are? How embarrassing:innocent:.

[TZ350]

Some more lovely odds and ends that are in the kit.

[rgvbaz]

If you are English that is 'You're'. Oh you are? How embarrassing:innocent:.

Bugger that's embarrassing. :angry2:

Dave

[Sketchy_Racer]

The EFI kits are great, mine worked straight out of the box.

The only problem I have encountered is it is VERY sensitive when you are burning a new map to the ECU, if it for any reason faults and wont start or will start but run funny, re burn the map to the ECU. Make sure you also earth everything well, I had issues with a crank trigger playing funnies because of poor earthing. Matt from Ecotrons seems very helpful and knowledgeable.

Cheers,

-Sketchy

[koba]

Ok, I was a bit confused too so I did some maths (if your American that's: math). The pic below has two curves on a Driving force v road speed graph. I guess you would never have anything like that in reality but to show the point... Both the areas under each curve (well straight lines) are 18 grid boxes in area yet curve A can accelerate the imaginary vehicle to 35 Km/hr in 2.22 secs Vs curve B which takes 4.17 secs.

I used the equations out of John Bradleys book for most of my spreadsheet.

280864


Dave

Edit: Cum time = cumulative time not...

I've got a simpler method, it involves a stop-watch.

[koba]

I've been playing about with some workings out again.
From looking at other engines and results I've decided a really rough guide for inlet area on an engine of the type and power output we are looking at is around 190 to 200 sec/metre x 1000 @ 12000rpm.

Mine is likely around 110 in it's current state.
A Reed inlet seems infinitely more difficult to calculate and predict than a disk valve.
I think I can get mine to around 135 @ 12K in the same size reed cavity but that is all a guess and still woefully inadequate.

This is all from MOTA working out the effective area based on reed lift and all that, the max area for mine will be going from 12CM2 to 18.4CM2, still well short of the 26CM2 I think I may need.

This is crazy, madness made worse by my partial understanding.
Still I know I need to work on making what I have flow as much as possible for as long as possible.
I see where Frits got into the 24/7 idea.

More time, more numbers more thinks...

[TZ350]

The EFI kits are great, mine worked straight out of the box.

The only problem I have encountered is it is VERY sensitive when you are burning a new map to the ECU, if it for any reason faults and wont start or will start but run funny, re burn the map to the ECU. Make sure you also earth everything well, I had issues with a crank trigger playing funnies because of poor earthing.

Thanks for the heads up.

We have not heard anything for a while, how is your project going?


Matt from Ecotrons seems very helpful and knowledgeable.

Yes I have talked with Matt a few times by email, and even sent him a link to this thread in case he wants to check out what we are saying about his EFI kit.

[rgvbaz]

I've been playing about with some workings out again.
From looking at other engines and results I've decided a really rough guide for inlet area on an engine of the type and power output we are looking at is around 190 to 200 sec/metre x 1000 @ 12000rpm.

Mine is likely around 110 in it's current state.
A Reed inlet seems infinitely more difficult to calculate and predict than a disk valve.
I think I can get mine to around 135 @ 12K in the same size reed cavity but that is all a guess and still woefully inadequate.

This is all from MOTA working out the effective area based on reed lift and all that, the max area for mine will be going from 12CM2 to 18.4CM2, still well short of the 26CM2 I think I may need.

This is crazy, madness made worse by my partial understanding.
Still I know I need to work on making what I have flow as much as possible for as long as possible.
I see where Frits got into the 24/7 idea.

More time, more numbers more thinks...

I've got a simpler method, it involves a dyno.:yes:

[F5 Dave]

The EFI kits are great, mine worked straight out of the box.

The only problem I have encountered is it is VERY sensitive when you are burning a new map to the ECU, if it for any reason faults and wont start or will start but run funny, re burn the map to the ECU. Make sure you also earth everything well, I had issues with a crank trigger playing funnies because of poor earthing. Matt from Ecotrons seems very helpful and knowledgeable.

Cheers,

-Sketchy

Hey you've got a week to make it raceable (if that's a word). There's a Bucketing tradition.

Oh yeah I must drop your stator back.

[rgvbaz]

Thanks for that, Dave. I think I missed something. I will think that through. What happens if you take an acceleration vs speed graph with the same area instead?

Not sure?? I've melted my brain :( I will have a think/look if I get some time.

Cheers

Dave

[TZ350]

Posted because someone asked about the fuel pump details.

I think it is 25l/hr at 3bar and draws 2.5A, but it would pay to check the exact details and price with Matt.

Matt of Ecotrons info@ecotrons.com

[Sketchy_Racer]

Thanks for the heads up.

We have not heard anything for a while, how is your project going?



It's sitting waiting at the moment, I have finished the final-final design of the supercharger but in my interest to start machining prototype parts I decided to start my own company on the side and purchase a CNC mill and Lathe to setup making small custom components.

Soon there will be a cheap and easily available facility for custom cnc parts to be made for buckets :banana:


Hey you've got a week to make it raceable (if that's a word). There's a Bucketing tradition.

Oh yeah I must drop your stator back.

HAHA! Yeah it aint going to happen sorry mate, I've got the business above keeping me out of trouble at the moment and the Superbike is also keeping me broke and busy. Maybe a couple months time I will be able to get back into the bucket!


Cheers,

-Sketchy

[Frits Overmars]

I was a bit confused too so I did some maths (if your American that's: math). The pic below has two curves on a Driving force v road speed graph. I guess you would never have anything like that in reality but to show the point... Both the areas under each curve (well straight lines) are 18 grid boxes in area yet curve A can accelerate the imaginary vehicle to 35 Km/hr in 2.22 secs Vs curve B which takes 4.17 secs.Let me add a bit to your confusion,Dave :devil2:
280961

The red curve B in your picture shows an initial power of zero HP at 5 km/h with a matching acceleration of zero m/s².
You claim a time of 4.17 s for the acceleration from 5 km/h to 35 km/h in. I claim that you will never reach 35 km/h because with zero acceleration at 5 km/h you will never get away from that first point of the power curve.

Have I got a different apoproach? Well....yes, but I published it on a restricted forum and it would be a deadly sin to bring anything at all from that forum into the open.
But what the heck, it was my own lecture and I hope they won't kick me out for publishing it here as well. So here is the full text (gimme a minute to prepare it for you folks. I'll be back).

[rgvbaz]

Let me add a bit to your confusion,Dave :devil2:
280961

The red curve B in your picture shows an initial power of zero HP at 5 km/h with a matching acceleration of zero m/s².
You claim a time of 4.17 s for the acceleration from 5 km/h to 35 km/h in. I claim that you will never reach 35 km/h because with zero acceleration at 5 km/h you will never get away from that first point of the power curve.

Have I got a different apoproach? Well....yes, but I published it on a restricted forum and it would be a deadly sin the bring anything at all from that forum into the open.
But what the heck, it was my own lecture and I hope they won't kick me out for publishing it here as well. So here is the full text (gimme a minute to prepare it for you folks. I'll be back).
I look forward to it
I'm sure if it's your work no one will mind:niceone:

[Frits Overmars]

I decided to write this little story about power curve comparison after reading the following posts from fellow members AAAA and BBBB.

A 2000 rpm wide powerband at 5000 rpm is the same width as a 4000 rpm powerband at 10000 rpm once the gearing has been corrected to give them both the same performance.

If the rpm ratio is the same and the average power within the range is the same, the two powerbands would be "functionally equivalent". That is, a change to the overall gear ratio would make them perform the same...... The same average power over a given rpm range will produce the same average acceleration. It does not matter what the "shape" of the powerband is -- sloping upward, sloping downward, or flat.I could not agree more, BBBB. But it requires a fundamental definition of 'average power'. And that is not 'the area under the power curve'.
Another one, also from BBBB:

Although we can narrow the powerband down to the absolute limit and have it show excellent results in a simulation like Dynabike, I'd want to have more margin than that for any application except maybe drag racing or bench racing. It is one thing to operate out front at "full speed" on the track, but traffic can cause you to operate in an undesirable part of the powerband. Similarly, recovering from a mistake (missed shift, forgetting how many downshifts a particular corner requires, etc.) is another reason we need a broader powerband.Once again I fully agree and I would add that this could only come frome someone with actual competition experience. Any engine builder who thinks he can base his powerbands on the ratios of a gearbox, is not going to make his riders very happy - in fact he is not going to keep them very long.

Peak power alone does not say much about the usefulness of an engine. The combination of power curve and transmission, the sort of application the engine will be used for, and the abilities of the rider, together define which is the optimum engine character.

An example: a 125 cc road race engine can always be kept between 10.000 and 14.000 rpm thanks to its six-speed gearbox. Wether this engine produces 2 hp or 20 hp at 6000 rpm, is unimportant.
But a kart engine with direct drive without a gearbox has trouble staying above 5000 rpm in slow corners; it only can manage to do so by means of a very short gearing that forces the engine to rev over 17.000 rpm on the straightaway. For such a kart it is imperative that acceleration out of slow corners does not cost too much time. There may be only one such corner on the whole circuit, but time lost there cannot be made up by a higher top speed on the straight.
Therefore a sensible tuner will not concentrate on peak power; he will make sure that the power is never really bad in the whole range from 5000 to 17.000 rpm (in this kart-example).

I prefer to work not with a powerband but with a power range, which I define as the highest rpm of a power curve, divided by its lowest rpm.
Experience has taught what kind of power range is needed for a certain application. Road racing calls for a range of about 1.4 . When a CVT is involved, I imagine 1.2 over even less might be enough (though I'm only guessing here as I have next to no experience with these things). Motocross calls for something like 2. A touring bike needs at least 3 to be comfortable. And the direct-drive kart in the above-mentioned example needs about 3.4 (17.000/5000).

Let us asume we have a measured power curve from 7000 to 14000 rpm. That gives a power range of 2.
Within this power curve all possible range values are investigated, from range=1.00; range=1.01; range=1.02; etc, up to range=2.
For each of these range values the whole power curve is examined in order to find which lower and upper rpm values yield the highest average power.
For range=1.5 for instance, we start with calculating the average power between 7000 and 10.500 rpm. Then we proceed with 7010--10.515; then with 7020--10.530; and so on, until the final possibility of 9333--14.000 rpm. And the highest value found is stored as THE average power for range 1.5, together with its corresponding lower and upper rpm limits.

All stored values for average power are displayed in range graphs. So when you are preparing an engine that will need a range of 1.6 , you can see at a single glance which engine delivers the best average power at range 1.6 . Furthermore you can see between which rpm values this engine is most effective. And you don't need to fall into the trap that ALL engine builders have fallen into at some time: attaching too much importance to peak power.

Maybe you are used to comparing the acceleration times of different engines on an inertial dyno. But that only makes sense if these engines are all run between the same initial rpm and the same final rpm, AND all with the same gearing.
The range concept does not suffer from any of these limitations; it functions under all circumstances. And because you can compare the range graphs of all your engines, you'll be able to distinguish much quicker which range is best for a specific application. That is an experience you would otherwise only gather after years of trial and error.

Suppose you are preparing an engine for an application that requires a power range of 1.5. Then which of the two power curves below should you pick? Hard to say, isn't it? But when you look at the power range curves on the right, it is clear as day: the yellow curve wins.
280962280963

Two more power curves. The yellow curve does not look very useful. But maybe it could work with a CVT.... The power range curve on the right tells us what we need to know. If the CVT can keep within a 1.2 rpm range, the yellow curve is OK. And if the CVT can keep within a 1.1 rpm range, the yellow curve is a winner!
280964280965

Another advantage of the power range curve: it can show you the rpm limits you should operate between. At range 1.2 the yellow power curve works best between 9970 rpm (the blue curve) and 11.964 rpm (the white curve).
280966

[Frits Overmars]

Earlier I claimed that average power is NOT the area under the power curve. A claim like this calls for an explanation, so here goes.
280967
Take a look at the power curve above. It is a peculiar curve where at rpm-point E the power totally collapses, but then comes back. The reason I drew it like this will become clear in a minute.
We can look at the red area under the curve and convert that to a rectangle. The yellow rectangle in the picture below has the same area as the red areas under the original power curve. So you could say the average power between rpm-point A and rpm-point B has a magnitude equal to the height A--D. Or could you?
280968
Let us put the engine with the peculiar red power curve in a vehicle and start accelerating, from rpm-point A to rpm-point B. How long will that take? It will take forever because the power at rpm-point E is zero, so acceleration at point E is zero; we will never get past that point. Acceleration from A to B will take an eternity which means that average power between A and B is zero!

Admittedly you won't encounter a power curve like the one in the first red picture very often. But the acceleration versus area argument holds for any power curve. Let's take a look at a 'normal' curve without a zero-power point. The curve below is split up into 9 equal rectangles, each with a horizontal dimension A--B that represents rpm, and a vertical dimension A--G that represents power.
280969
When you convert the sum area of those 9 rectangles into a single rectangle with the same rpm spread A--F, it will have a height A--H that is 1.8 * A--G. Assuming A--G equals 1 HP, then the average power A--H would be 1.8 HP (picture below).
280971
Now let us look at the same power curve and determine the average power via the acceleration approach. We will assume that acceleration from A to B with the available power A--G takes 1 second.
Between B and C the power is twice as much, so acceleration from B to C will take ½ second. And so on.
Total acceleration from A to F takes 20/6 s. If this acceleration were to have a constant value, it would take 1/5 * 20/6 = 4/6 s from A to B. This would require a constant power of 6/4 * A--G. Assuming again that A--G equals 1 HP, then the average power would be 1.5 HP instead of the 1.8 HP that came out of the area-approach...
280972

[emess]

Frits, many many thanks for a great artical ( and the previous 300 odd posts)

I have learned more in the last year reading posts from you, Wobbly and others than I have in the previous 50 years of 'playing' with two strokes.

I do not have much to offer to the discussion (apart from more questions!) but some may find this useful. Rather than use the site search which usually fails, use Google so to search this site use an ordinary search phrase and after it add

site:www.kiwibiker.co.nz

for example

Frits priceless site:www.kiwibiker.co.nz
or
Frits pisa site:www.kiwibiker.co.nz

the same will work for other sites with the appropriate site address

Mick

[Frits Overmars]

.... Rather than use the site search which usually fails, use Google so to search this site use an ordinary search phrase and after it add site:www.kiwibiker.co.nz (http://www.kiwibiker.co.nz)
for example
Frits priceless site:www.kiwibiker.co.nz (http://www.kiwibiker.co.nz) or Frits pisa site:www.kiwibiker.co.nz (http://www.kiwibiker.co.nz)
the same will work for other sites with the appropriate site address
MickJust what I needed, Mick. Site searches usually fail, not just on Kiwibiker, but on any forum I visit. Your approach really works. Thanks very much for the tip.

[dinamik2t]

Frits, I've just returned home and admittedly I haven't given it much thought. The thing that came into my mind while reading your power average explanation is using a deviation factor (like std deviation in statistics or the ripple factor in electronics) to give more info about such irregularly variating quantities, eg a power curve.

I believe it could be simpler to understand and make use of. Still won't cover a zero acceleration condition, but what do you think?

[Frits Overmars]

Frits, I've just returned home and admittedly I haven't given it much thought. The thing that came into my mind while reading your power average explanation is using a deviation factor (like std deviation in statistics or the ripple factor in electronics) to give more info about such irregularly variating quantities, eg a power curve.

I believe it could be simpler to understand and make use of. Still won't cover a zero acceleration condition, but what do you think?I don't think it will yield the same outcome; it must be able to handle zero acceleration conditions.

[jasonu]

.

Soon there will be a cheap and easily available facility for custom cnc parts to be made for buckets :banana:

Cheers,

-Sketchy

Bucket racers are a notoriously stingy pack of tight arses, I hope you are not planning on getting rich quick from this scheme...

[F5 Dave]

He's well aware being one himself, but good luck Glen, hope it works out well 'cause you have the skills to make some good kit.

[136kg136ps]

So Frits,is the zero acceleration phase due to gearshifts and/or the associated cessation of the pipes effect on engine power?Please forgive my questions if they are repetitive,I have a hard time wrapping my mind around the dynamics of two strokes as all my engineering background is electrical and gas turbines both far simpler than these motors apparently.

[Sketchy_Racer]

Bucket racers are a notoriously stingy pack of tight arses, I hope you are not planning on getting rich quick from this scheme...

No money to be made from bucket parts, I have some specialist contracts that are there to make the money ;) Bucket parts are for fun.

[Frits Overmars]

So Frits, is the zero acceleration phase due to gearshifts and/or the associated cessation of the pipes effect on engine power?Please forgive my questions if they are repetitive,I have a hard time wrapping my mind around the dynamics of two strokes as all my engineering background is electrical and gas turbines both far simpler than these motors apparently.There can certainly be zero acceleration phases in the occurences that you mention, but that is not the issue when converting power graphs into power range graphs.
The power to range conversion algorithm must be able to handle zero acceleration situations. Nothing to do with engine dynamics in this case, just math.
By the way, if you really want to grasp the difference between the 'area under the curve'-approach and the acceleration approach, put another 97 yellow rectangles on top of the 3 rectangles between C an D in the picture below, and repeat the area-calculation and the acceleration-calculation of average power.
281014

[136kg136ps]

I think I get it,the added blocks just reduce that segment to 1/100 sec vs. 1/3 sec.Even if it was instantaneous it wouldn't alter the time but by the original 1/3 sec?Having nearly negligible effect on average power.
One could use this calculation and datalogging to determine the best gear ratios and final ratio for each track.

[jasonu]

No money to be made from bucket parts, I have some specialist contracts that are there to make the money ;) Bucket parts are for fun.

Nice one mate. I wish there was access to affordable services like you are offering when I was raceing. Good luck with your venture.

[Frits Overmars]

I think I get it, the added blocks just reduce that segment to 1/100 sec vs. 1/3 sec. Even if it was instantaneous it wouldn't alter the time but by the original 1/3 sec? Having nearly negligible effect on average power.You got it http://www.kiwibiker.co.nz/forums/images/icons/icon14.png.
The above suggests that effort is better spent filling dips in the powerband rather than trying to move the peak a little higher; the weakest link is always decisive.

Here is a story I use to make young riders understand:
"We are on a circuit, 2 km long. You ride the first kilometer with a speed of 100 km/h and the second kilometer with a speed of 0 km/h. Then what will be your average speed over one lap?"
About ten out of ten answers will be: "50 km/h". But of course you guys won't fall into that trap, will you?
This time next year you will still be standing halfway round that circuit, because with 0 km/h you won't get any further. So the average speed will be zero.
The lesson to my young riders is: racing is not about being fast. It is about not being slow anywhere.

There is also a second lesson:
Working on your engine may improve your lap times a couple of tenths. Working on your tires and suspension may be ten times more effective.

[Flettner]

TZ, box turned up today. Interesting.

[TZ350]

I am looking forward to hearing what you think can be done.

I was in at work this afternoon thanks for the cylinders and I see the F81 has been collected. I hope you saw the EFI stuff on the bench, I would be interested in what you think of it.

I am getting some bigger injectors, 650cc/min and a bigger 45L/hr pump. The plan is to use a 650cc injector paired with a 460 and 25L pump paired with a 45 that is switched on by the Ignitec at WOT above 10K rpm or there about.

I am keen to follow your advice and inject into the transfers while the transfer ports are open. And that means there is only 1/3 of the time (120 deg duration) to complete the fuel injection cycle.

So I need much bigger pumps and injectors compared to injecting into the inlet as the inlet is open for 2/3 of the time (230 deg duration) or the crankcase for possibly up to 100% of the time (360 deg duration) where a 25L pump and a smaller injector would do.

[Frits Overmars]

I am getting some bigger injectors, 650cc/min and a bigger 45L/hr pump. The plan is to use a 650cc injector paired with a 460 and 25L pump paired with a 45 that is switched on by the Ignitec at WOT above 10K rpm or there about.A carburetted engine will need about 0.35 liter per wheel-HP per hour; it may be even less with injection.

I am keen to follow your advice and inject into the transfers while the transfer ports are open. And that means there is only 1/3 of the time (120 deg duration) to complete the fuel injection cycle. So I need much bigger pumps and injectors compared to injecting into the inlet as the inlet is open for 2/3 of the time.Bigger injectors yes, but why a bigger pump? (I assume one pump will suffice). It will run continuously anyway; you will only need an airspring-loaded buffer volume between pump and injectors.

[Yow Ling]

I am looking forward to hearing what you think can be done.

I was in at work this afternoon thanks for the cylinders and I see the F81 has been collected. I hope you saw the EFI stuff on the bench, I would be interested in what you think of it.

I am getting some bigger injectors, 650cc/min and a bigger 45L/hr pump. The plan is to use a 650cc injector paired with a 460 and 25L pump paired with a 45 that is switched on by the Ignitec at WOT above 10K rpm or there about.

I am keen to follow your advice and inject into the transfers while the transfer ports are open. And that means there is only 1/3 of the time (120 deg duration) to complete the fuel injection cycle.

So I need much bigger pumps and injectors compared to injecting into the inlet as the inlet is open for 2/3 of the time (230 deg duration) or the crankcase for possibly up to 100% of the time (360 deg duration) where a 25L pump and a smaller injector would do.

How are you going to oil the big end?

[TZ350]

Page 750 links list

Rather than use the site search which usually fails, use Google so to search this site use an ordinary search phrase and after it add

site:www.kiwibiker.co.nz (http://www.kiwibiker.co.nz)

for example

Frits priceless site:www.kiwibiker.co.nz (http://www.kiwibiker.co.nz)
or
Frits pisa site:www.kiwibiker.co.nz (http://www.kiwibiker.co.nz)

the same will work for other sites with the appropriate site address

Mick
Pipes

268048

A handy little tool put together by Bucket for checking the BMEP of different Engines.

You change the values in the yellow squares and the answers appear in the green ones. Its a great tool for compairing different bikes and what development potential they may have left and who's telling porkies.
P217

Case com is a very complex subject but a few rules of thumb apply.
The higher the bmep of an engine then the higher the delivery ratio, thus a larger case can store the higher volume of ingested air at a higher pressure and this is then available to the transfer ducts.
But the quality of the duct and port geometry also affects the case com required.
The smaller the case vol (higher ratio) the greater the pressure rise in the case as the piston drops - this suits compromised transfer ducts with little or no inner wall shape, as it helps force the flow around thru the ducts quicker.
Good duct/port geometry allows the use of a bigger case as they don’t need a large pressure ratio across the port to initiate good flow.
Lastly is the effect of the pipe geometry, the diffuser sucks like hell on the Ex port around BDC, pulling flow thru the transfers, and it is important to match the pipe diameter ( and thus the diffuser included angles) to the transfer port/duct geometry.

Suck too hard on crap transfers and they loose directional control - giving greater short-circuiting out the Exhaust port.

Thus you have a Catch22 in that you need a small case to speed up the flow, but this limits the available stored mixture, and you want to suck on the transfers as much as possible, but no so much as to loose the control of the flow direction - or to speed up the loop velocity excessively thus reducing the trapping efficiency..

One myth that needs busting here is that the bulk of the flow thru the transfers is initiated by the piston dropping. This happens in lawn mowers, not racing engines.

Pipe diffuser suction when the piston is around BDC forces the bulk of the flow volume, NOT the pressure in the case forcing flow up the ducts.
When the transfers open there is more pressure in the cylinder than in the case.
Thus we get flow reversal at the initial transfer opening point.
This also means that the transfer port that opens first - flows last, as it has the greatest flow reversal affect, down the duct.

In general, high bmep engines that by default will have good port/duct geometry, will like a case com down near 1.3:1, lower performance engines with crap transfer/duct geometry will perform best with the ratio higher, up near 1.4:1.
Thus as you develop an engine, increasing its efficiency with better porting, then this will allow the use of a bigger case, and bigger pipe diameter/vol, to work with that - the two go hand in hand.
Page 470 its worth a look at the original post.

The big thing to come out of the last ten pages seems to be that insufficient blow down time area can lead to over heating by having excessive hot exhaust gas entering the transfer ports and over heating the engine.

On the original post Husa has now placed a spread sheet with rod dimensions.

There are other link/post collections on most other decade pages ......


Basic 2 stroke Tuning
by Eric Gorr Changing the power band of your dirt bike engine is simple when you know the basics. A myriad of different aftermarket accessories is available for you to custom tune your bike to better suit your needs. The most common mistake is to choose the wrong combination of engine components, making the engine run worse than stock. Use this as a guide to inform yourself on how changes in engine components can alter the powerband of bike's engine. Use the guide at the end of the chapter to map out your strategy for changing engine components to create the perfect power band.

TWO-STROKE PRINCIPLES
Although a two-stroke engine has less moving parts than a four-stroke engine, a two-stroke is a complex engine because it relies on gas dynamics. There are different phases taking place in the crankcase and in the cylinder bore at the same time. That is how a two-stroke engine completes a power cycle in only 360 degrees of crankshaft rotation compared to a four-stroke engine which requires 720 degrees of crankshaft rotation to complete one power cycle. These four drawings give an explanation of how a two-stroke engine works.
1) Starting with the piston at top dead center (TDC 0 degrees) ignition has occurred and the gasses in the combustion chamber are expanding and pushing down the piston. This pressurizes the crankcase causing the reed valve to close. At about 90 degrees after TDC the exhaust port opens ending the power stroke. A pressure wave of hot expanding gasses flows down the exhaust pipe. The blow-down phase has started and will end when the transfer ports open. The pressure in the cylinder must blow-down to below the pressure in the crankcase in order for the unburned mixture gasses to flow out the transfer ports during the scavenging phase.
2) Now the transfer ports are uncovered at about 120 degrees after TDC. The scavenging phase has begun. Meaning that the unburned mixture gasses are flowing out of the transfers and merging together to form a loop. The gasses travel up the back side of the cylinder and loops around in the cylinder head to scavenge out the burnt mixture gasses from the previous power stroke. It is critical that the burnt gasses are scavenged from the combustion chamber, in order to make room for as much unburned gasses as possible. That is the key to making more power in a two-stroke engine. The more unburned gasses you can squeeze into the combustion chamber, the more the engine will produce. Now the loop of unburned mixture gasses have traveled into the exhaust pipe's header section. The gasses aren't lost because a compression pressure wave has reflected from the end of the exhaust pipe, to pack the unburned gasses back into the cylinder before the piston closes off the port. This is the unique super-charging effect of two-stroke engines. The main advantage of two-stroke engines is that they can combust more volume of fuel/air mixture than the swept volume of the engine. Example: A 125cc four-stroke engine combusts about 110cc of F/A gasses but a 125cc two-stroke engine combusts about 180cc of F/A gasses.
3) Now the crankshaft has rotated past bottom dead center (BDC 180 degrees) and the piston is on the upstroke. The compression wave reflected from the exhaust pipe is packing the unburned gasses back in through the exhaust port as the piston closes off the port the start the compression phase. In the crankcase the pressure is below atmospheric producing a vacuum and a fresh charge of unburned mixture gasses is flowing through the reed valve into the crankcase.
4) The unburned mixture gasses are compresses and just before the piston reaches TDC, the ignition system discharges a spark causing the gasses to ignite and start the process all over again.

CYLINDER PORTING
The cylinder ports are designed to produce a certain power characteristic over a fairly narrow rpm band. Porting or tuning is a metal machining process performed to the cylinder ports (exhaust & transfers) that alters the timing, area size, and angles of the ports in order to adjust the power band to better suit the rider's demands. For example, a veteran trail rider riding an RM250 in the Rocky mountain region of the USA will need to adjust the power band for more low end power because of the steep hill climbs and the lower air density of higher altitudes. The only way to determine what changes will be needed to the engine is by measuring and calculating the stock engine's specifications. The most critical measurement is termed port-time-area. This term is a calculation of a port's size area and timing in relation to the displacement of the engine and the rpm. Experienced tuners know what the port-time-area values of the exhaust and transfer ports should be for an engine used for a particular purpose. In general, if a tuner wants to adjust the engine's power band for more low to mid range he would do the following things. Turn down the cylinder base on a lathe to increase the effective stroke (distance from TDC to exhaust port opening). This also retards the exhaust port timing and shortens the duration and increases the compression ratio. Next the transfer ports should be narrowed and re-angled with epoxy to reduce the port-time-area for an rpm peak of 7,000 rpm. The rear transfer ports need to be re-angled so they oppose each other rather than pointing forward to the exhaust port. This changes the loop scavenging flow pattern of the transfer ports to improve scavenging efficiency at low to mid rpm (2,000 to 5,000 rpm). An expert rider racing mx in England would want to adjust the power band of an RM250 for more mid to top end power. The cylinder would need to be tuned radically different than for trail riding.
Here is an example. The exhaust port would have to be raised and widened to change the port-time-area peak for a higher rpm (9,000 rpm). For either of these cylinder modifications to be effective, other engine components would also need to be changed to get the desired tuning effect.

CYLINDER HEAD
Cylinder heads can be reshaped to change the power band. Generally speaking, a cylinder head with a small diameter and deep combustion chamber, and a wide squish band (60% of the bore area). Combined with a compression ratio of 9 to 1 is ideally suited for low to mid range power. A cylinder head with a wide shallow chamber and a narrow squish band (35-45% of bore area) and a compression ratio of 8 to 1, is ideally suited for high rpm power.
There are many reasons why a particular head design works for certain types of racing. For example; a head with a wide squish band and a high compression ratio will generate high turbulence in the combustion chamber. This turbulence is termed Maximum Squish Velocity, MSV is rated in meters per second (m/s). A cylinder head designed for supercross should have an MSV rating of 28m/s. Computer design software is used to calculate the MSV for head designs. In the model tuning tips chapters of this book, all the head specs quoted have MSV ratings designed for the intended power band changes.

CRANKSHAFT
There are two popular mods hop-up companies are doing to crankshafts; stroking and turbo-vaning. Stroking means to increase the distance from the crank center to the big end pin center. There are two techniques for stroking crankshafts; weld old hole and re-drill a new big end pin hole, or by installing an off-set big end pin. The method of weld and re-drilling is labor intensive. The off-set pin system is cheap, non-permanent, and can be changed quickly. In general, increasing the stroke of a crankshaft boosts the mid range power but decreases the engine's rpm peak.
The term "Turbo-Crank" refers to a modification to the crankshaft of a two-stroke engine, whereby scoops are fastened to the crank in order to improve the volumetric efficiency of the engine. Every decade some hop-up shop revives this old idea and gives it a trendy name with product promises that it can't live up to. These crank modifications cause oil to be directed away from the connecting rod and often times the vanes will detach from the crank at high rpm, causing catastrophic engine damage. My advice, don't waste the $750!

CARBURETOR
In general a small diameter carburetor will have high velocity and a good flow characteristic for a low to mid rpm power band. A large diameter carburetor works better for high rpm power bands. For 125 cc engines a 34mm carburetor works well for supercross and enduro and a 36 or 338 mm carburetor works best for fast mx tracks. For 250 cc engines a 36 mm carburetor works best for low to mid power bands and a 39.5 mm carburetor works best for top end power bands. Recently there has been a trend in the use of air-foils and rifle-boring for carbs. These innovations are designed to improve air flow at low throttle openings. Some companies sell carb inserts, to change the diameter of a carb. Typically a set of inserts is sold with a service of over boring the carb. For example; a carb for a 250cc bike (38mm) will be bored to 39.5mm and two inserts will be supplied. The carb can then be restricted to a diameter of 36 or 38mm.

REED VALVE
Think of a reed valve like a carburetor, bigger valves with large flow-areas work best for high rpm power bands. In general, reed valves with six or more petals are used for high rpm engines. Reed valves with four petals are used for dirt bikes that need strong low end and mid range power. There are three other factors to consider when choosing a reed valve. The angle of the reed valve, the type of reed material, and the petal thickness. The two common reed valve angles are 30 and 45 degrees. A 30-degree valve is designed for low to mid rpm and a 45 degree valve is designed for high rpm. There are two types of reed petal materials commonly used, carbon fiber and fiberglass. Carbon fiber reeds are lightweight but relatively stiff (spring tension) and designed to resist fluttering at high rpm. Fiberglass reeds have relatively low spring tension so they instantly respond to pressure that changes in the crankcase, however the low spring tension makes them flutter at high rpm thereby limiting the amount of power. Fiberglass reed petals are good for low to mid power bands and carbon fiber reeds are better for high rpm engines.
Boyesen Dual Stage reeds have a large thick base reed with a smaller thinner reed mounted on top. This setup widens the rpm range where the reed valve flows best. The thin reeds respond to low rpm and low frequency pressure pulses. The thick reeds respond to higher-pressure pulses and resist fluttering at high rpm. A Boyesen RAD valve is different than a traditional reed valve. Bikes with single rear shocks have off-set carbs. The RAD valve is designed to redistribute the gas flow to the crankcases evenly. A RAD valve will give an overall improvement to the power band. Polini of Italy makes a reed valve called the Supervalve. It features several mini sets of reeds positioned vertically instead of horizontally like conventional reed valves. These valves are excellent for enduro riding because of improved throttle response. In tests on an inertia chassis dyno show the Supervalve to be superior when power shifting. However these valves don't generate greater peak power than conventional reed valves. Supervalves are imported to America and sold by Moto Italia in Maine.

EXHAUST PIPE
The exhaust pipe of a two-stroke engine attempts to harness the energy of the pressure waves from combustion. The diameter and length of the five main sections of a pipe, are critical to producing the desired power band. The five sections of the pipe are the head pipe, diffuser cone, dwell, baffle cone, and the stinger. In general, after market exhaust pipes shift the power band up the rpm scale. Most pipes are designed for original cylinders not tuned cylinders. Companies like MOTOWERKS custom computer design and fabricate pipes based on the cylinder specifications and the type of power band targeted.

SILENCER
Silencers come in all sorts of shapes and sizes. A long silencer with a small diameter enhance the low to mid power because it increases the bleed-down pressure in the pipe. A silencer with a short length and a large core diameter provides the best bleed-down pressure for a high rpm engine. Too much pressure in the pipe at high rpm will radically increase the temperature of the piston crown and could cause the piston to seize in the cylinder.

FLYWHEEL WEIGHTS
The flywheel is weighted to improve the engine's tractability at low to mid rpms. There are two different types of flywheel weights, weld-on and thread-on. A-Loop performs the weld-on flywheel weight service. Steahly makes thread-on flywheel weights. This product threads onto the fine left-hand threads that are on the center hub of most Japanese magneto rotors. normally the threads are used for the flywheel remover tool. Thread-on flywheel weights can only be used if the threads on the flywheel are in perfect condition. The advantage to weld-on weights is they can't possibly come off.
External rotor flywheels have a larger diameter than internal rotor flywheels so they have greater flywheel inertia. Internal rotor flywheels give quicker throttle response.

AFFECTS OF THE IGNITION TIMING
Here is how changes in the static ignition timing affects the power band of a Japanese dirt bike. Advancing the timing will make the power band hit harder in the mid range but fall flat on top end. Advancing the timing gives the flame front in the combustion chamber, adequate time to travel across the chamber to form a great pressure rise. The rapid pressure rise contributes to a power band's "Hit". In some cases the pressure rise can be so great that it causes an audible pinging noise from the engine. As the engine rpm increases, the pressure in the cylinder becomes so great that pumping losses occur to the piston. That is why engines with too much spark advance or too high of a compression ratio, run flat at high rpm.
Retarding the timing will make the power band smoother in the mid-range and give more top end over rev. When the spark fires closer to TDC, the pressure rise in the cylinder isn't as great. The emphasis is on gaining more degrees of retard at high rpm. This causes a shift of the heat from the cylinder to the pipe. This can prevent the piston from melting at high rpm, but the biggest benefit is how the heat affects the tuning in the pipe. When the temperature rises, the velocity of the waves in the pipe increases. At high rpm this can cause a closer synchronization between the returning compression wave and the piston speed. This effectively extends the rpm peak of the pipe.

HOW TO ADJUST THE TIMING
Rotating the stator plate relative to the crankcases changes the timing. Most manufacturers stamp the stator plate with three marks, near the plate's mounting holes. The center mark is the standard timing. If you loosen the plate mounting bolts and rotate the stator plate clockwise to the flywheel's rotation, that will advance the ignition timing. If you rotate the stator plate counterclockwise to the flywheel's rotation, that will retard the ignition timing. Never rotate the stator plate more than .028in/.7mm past the original standard timing mark. Kawasaki and Yamaha stator plates are marked. Honda stators have a sheet metal plate riveted to one of the mount holes. This plate insures that the stator can only be installed in one position. If you want to adjust the ignition timing on a Honda CR, you'll have to file the sheet metal plate, with a 1/4in rat-tail file.

AFTERMARKET IGNITIONS
The latest innovation in ignition systems is an internal rotor with bolt-on discs that function as flywheel weights. PVL of Germany makes these ignitions for modern Japanese dirt bikes. Another advantage to the PVL ignition is that they make a variety of disc weights so you can tune the flywheel inertia to suit racetrack conditions.
MSD is an aftermarket ignition component manufacturer. They are making ignition systems for CR and RM 125 and 250. MSD's ignition system features the ability to control the number of degrees of advance and retard. These aftermarket ignition systems sell for less than the OEM equivalent.

TIPS FOR BIG BORING CYLINDERS
In the mid nineties, European electro-plating companies started service centers in America. This made it possible to over bore cylinders and electro-plate them to precise tolerances. This process is used by tuners to push an engine's displacement to the limit of the racing class rules, or make the engine legal for a different class.
When you change the displacement of the cylinder, there are so many factors to consider. Factors like; port-time-area, compression ratio, exhaust valves, carb jetting, silencer, and ignition timing. Here is an explanation of what you need to do when planning to over bore a cylinder.
Port-Time-Area - This is the size and opening timing of the exhaust and intake ports, versus the size of the cylinder and the rpm. When increasing the displacement of the cylinder, the cylinder has to be bored to a larger diameter. The ports enter the cylinder at angles of approximately 15 degrees. When the cylinder is bore is made larger, the transfer ports drop in height and retard the timing and duration of those ports. The exhaust port gets narrower. If you just over bored and plated a cylinder, it would have much more low end power than stock. Normally tuners have to adjust the ports to suit the demands of the larger engine displacement. Those exact dimension changes can be determined with TSR's Time-Area computer program.
Cylinder Head - The head's dimensions must be changed to suit the larger piston. The bore must be enlarged to the finished bore size. Then the squish band deck height must be set to the proper installed squish clearance. The larger bore size will increase the squish turbulence so the head's squish band may have to be narrowed. The volume of the head must be increased to suit the change in cylinder displacement. Otherwise the engine will run flat at high rpm or ping in the mid range from detonation.
Exhaust Valves - When the bore size is increased, the exhaust valve to piston clearance must be checked and adjusted. This pertains to the types of exhaust valves that operate within close proximity of the piston. If the exhaust valves aren't modified, the piston could strike the valves and cause serious engine damage.
Carb - The piston diameter and carb bore diameter are closely related. The larger the ratio between the piston size and the carb size, the higher the intake velocity. That makes the jetting richer. Figure on leaning the jetting after an engine is over bored.
Ignition Timing - The timing can be retarded to improve the over rev. Normally over bored engines tend to run flat on top end.
Pipe and Silencer - Because only the bore size is changed, you won't need a longer pipe only one with a larger center section. FMF's line of Fatty pipes work great on engines with larger displacement. Some riders use silencers that are shorter with larger outlets to adjust the back-pressure in the pipe for the larger engine displacement.

[TZ350]

How are you going to oil the big end?

That has been on my mind. Flettner says enough oil finds its way around to lubricate everything. But I will nead to ask him more about that.

I can see how oil can dribble down the transfer port walls to lubricate the main brgs. But the big end??? its not intuitively obvious.... :scratch:

If Flettners engine has an oil slinger on a main brg that feeds oil to the big end then I will need to think of something like that my self, there is room for one, may be a good idea any way.

[husaberg]

My guess is reversion and gravity. The heavier components should drop off under pressure.
At the end of the day it will be suck and see.
If it doesn't work there is always a set up to direct a small injector at the big end or maybe the set up used on compressed air tools?
Fletners set up does seem to be very oily though even on Alcohol.

[Bert]

My guess is reversion and gravity. The heavier components should drop off under pressure.
At the end of the day it will be suck and see.
If it doesn't work there is always a set up to direct a small injector at the big end or maybe the set up used on compressed air tools?
Fletners set up does seem to be very oily though even on Alcohol.

It is something that I've been thinking about as well...
I was looking at putting the oil pump back on and hoping that the right parts would get enough oil.:weep:

Will the fuel injection system actually handle pre-mixed fuel? (I should have asked that originally)...

650cc injectors; right time for a re-think....:weep:

[Yow Ling]

Suzuki gt 750 used to supply oil directly to the mains and big end, this was done with a 2t oil pump and a galley in the crank 4t style , i think this was their posiforce system, they may have used it on tiddlers too , hard to remember as Im only 50

[husaberg]

Suzuki gt 750 used to supply oil directly to the mains and big end, this was done with a 2t oil pump and a galley in the crank 4t style , i think this was their posiforce system, they may have used it on tiddlers too , hard to remember as Im only 50

Yamaha also had some fiendishly complex auto lube systems on the 60's multi GP bikes.
<img src="http://lh6.ggpht.com/_qTkqdg18azg/S7xpbUwk_CI/AAAAAAAABS8/SaGyKazL_3o/s400/yamaha%20125%20v4.jpg" height="440px"/><img src="http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=258589&d=1330253931" height="440px"/>
<img src="http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=258590&d=1330253950" height="340px"/><img src="http://www.yamaha-classic-racingteam.nl/site2/index.php?page=125cc_ra31a_pub" height="340px"/><img src="http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=281050&d=1365283639" height="340px"/>

Honda's approach on the MB was ingenious in its simplicity.

Yes looking at the engine diagram for the V4 it does look like it had pressure feed big ends but it reved to over 17000......
<img src="http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=258585&d=1330252520" height="440px"/>

I think the wolf/stinger may have pressure feed the big ends as well?
But i are not yet 40 so not sure.

[TerraRoot]

how are these big pumps getting powered? gonna need a fair amount of amps..

[Ocean1]

Suzuki gt 750 used to supply oil directly to the mains and big end, this was done with a 2t oil pump and a galley in the crank 4t style , i think this was their posiforce system, they may have used it on tiddlers too , hard to remember as Im only 50

They also used it on TS185s, and I suspect TS125s. Would be an easy solution.

[TZ350]

They also used it on TS185s, and I suspect TS125s. Would be an easy solution.

281051

Posi Force lubrication is the fall back position.

When I raced a Suzuki TR250R it had pre mix and a Posi Force pump wired 30% open.

281052

Geoff Perrys TR500R had the same setup.

To start with I intend copying Flettners layout of injectors in the rear transfer port.


how are these big pumps getting powered? gonna need a fair amount of amps..

Big battery supplemented with a small generator, a semi total loss system. And the big pump wont run all the time, it will switch on as demand requires.

[Flettner]

http://mob1056.photobucket.com/albums/t380/uniflow/1f6c55fd.jpg

I guess I've been lucky, I put my injectors here to hide them. As it happened this was the right compromise. These two 720 cc injectors flow enough fuel on E90 to be fully fueling at about 180 degrees timing. I fire these injectors at 60 degrees after TDC so there is a time when transfers are not open but fuel is waiting at the transfer catchment ready to go. Because this is the back transfer it seems enough oil is feed down to the bigend. It's done fifty hours now with no bigend or main bearing problems.

[husaberg]

TZ bet me to the pic:niceone:

<img src="http://www.dansmc.com/suzuki_tc-ts90_oil.JPG" height="540px"/><img src="http://www.oldjapanesebikes.com/mraxl_GT_Resource/manuals/t250_t350service/image/Suzuki_T250_T350_Service_Manual_1969_12b.jpg" height="540px"/>
As Neil said i think it may be a solution to a problem that hasn't occurred as of yet.

Actually would the GP125 be set up like this as standard?

[Moooools]

You got it http://www.kiwibiker.co.nz/forums/images/icons/icon14.png.

There is also a second lesson:
Working on your engine may improve your lap times a couple of tenths. Working on your tires and suspension may be ten times more effective.

I am quite curious as to whether top level teams go to the expense of getting their tyres tested and acquiring proper tyre data.

It would be a damn useful thing to have, but most data is held onto very tightly by those who commission it. Probably due to the price tag of the testing.

[TZ350]

As Neil said i think it may be a solution to a problem that hasn't occurred as of yet.


Yes ....


Actually would the GP125 be set up like this as standard?

No ....

[Grumph]

Around 50 years ago when EFI wasn't even a dot on the horizon, Irving suggested constant flow injection via the big end. Hilborn injection was pretty much state of the art then with Lucas and Bosch just getting progress on mechanical injecion.
It's still a viable scheme - just vary the pump output to suit.