ESE's works engine tuner [Archive] - Page 12

TZ350

30th September 2010, 18:03

Thomas and Bucket are making a good job of assembling the engine.

Thomas explained the soft closing idea to me and it sounds like it has merit.

This is a little something towards understanding compression ratios that I found on the net..........

As the boys are going to have to set the compression ratio later by skimming the head and measuring the volume of the combustion chamber as they go along to achieve the ratio they think is best for this engine.

There are basically two commonly utilised methods of stating a given engine's compression ratio:

The "Uncorrected Method" (sometimes referred to as the Geometric or European method) which compares the volume above the piston at Bottom Dead Centre (BDC) to the volume above the piston at exact Top Dead Centre (TDC). This method is often criticised because it does not reflect the dynamics that occur during the engine's actual running conditions, but, as with steady state flow techniques used on a flow bench (which also do not duplicate actual running circumstances) it has a very useful place in the planning of an engine's tuning and application.

The "Corrected Method" (sometimes referred to as the Trapped or Japanese method) which compares the volume above the piston at the point on the upstroke that the exhaust port roof is fully closed (on a two stroke, exhaust valve closed on a four stroke) to the volume above the piston at exact Top Dead Centre (TDC). This at first seems to be the most sensible way of looking at the situation since how could we really begin compressing fuel/air mixture before all "leaks" are shut off, right? Well, not really...

At elevated engine speeds (rpm), the piston is moving so quickly that it will actually "outrun" the fuel/air mixture to the "leak" and "trap" a much larger volume of fuel/air in the upper cylinder than just the static volume above the exhaust port. This "trapping efficiency" improves with more rpm's.

The rest can be read here:- http://www.sacoriver.net/~red/uccr.html (http://www.sacoriver.net/%7Ered/uccr.html)

F5 Dave

1st October 2010, 10:37

well that in itself isn't the issue. At higher speeds you are also entering the tuned freq of the engine. At the start he is saying some fairly shaky things, but redeems himself further down. . . . Then I lost interest in what is obviously designed as marketing material.

The real situation is that it is always a compromise & it is up to your to find the best compromise for your engine & power you want. That means testing & if you go down a different path (say smaller stinger/steeper baffle vs lower compression & altered ignition) you should really rip up & start again. However not many have that much time or money to test pure results every time.

SS90

1st October 2010, 12:42

All silliness aside, it's actually not a bad link.... But let's just be clear, while is has some well written factual information with-in, I would say about 30% is either wrong or dubious.

Such is the Internet.

TZ350

1st October 2010, 17:21

. . . . Then I lost interest in what is obviously designed as marketing material.

The real situation is that it is always a compromise & it is up to your to find the best compromise for your engine & power you want.......

Hi Dave

Marketing material? must have gone over my head, I completely missed that.

What I saw was a good description of the difference between corrected and uncorrected methods of measuring compression ratios and how you need to be aware that dynamics affects things and that trying for an 8:1 or 9:1 corrected compression ratio might well put you outside of what is workable when calculated as an uncorrected ratio and that some sort of compromise may be needed.

Its topical for us, because when the boys set the new engine up to get their chosen corrected ratio they will need to keep an eye on the uncorrected ratio too.

I posted it because I thought the descriptive part explained what I wanted to say and was written better than I could manage myself (and quicker too).

I think the general public aren't all clowns and can be trusted to appreciate the meat of the message and to ignore whatever commercial aspect there might be if that doesn't interest them.

And I agree, it is up to the tuner to find the best compromise for their engine and its almost always a compromise.

bucketracer

2nd October 2010, 12:14

220227

By sliding a feeler gauge around the edge of the piston you can tell if the rod is bent as the feeler gauge will be tight on one side and not the other. With the tip of the feeler gauge you can also tell if the top ring is broken. Checking for broken top rings maybe more applicable to 4-strokes, but still it's a good trick to know.

220223

Using a feeler gauge to check the deck height, and as this is a flat top piston and the head is also flat the static squish clearance (0.8mm) will also be the same as the deck height on this engine. Its anyones guess what the dynamic squish will be, what with rod strech and all that. Possible dynamic affects are something to keep in mind.

220224

The best tool known to man for pulling lock tabs up tight and removing frost plugs from car engine blocks.

Go on, tell me it can't be done, I thought it was a load of old cobblers to untill I saw how Thomas uses one of these to pull frost plugs and it's real easy.

For me to show you, it will cost two chocolat fish.

220225

After inserting the Cir-Clips, push them a quarter turn to ensure they are properly seated in the grove. If they are not in properly they will snap in and snug down as you turn them. (helpfull engine building tips from Thomas).

220226

A tool made from a couple of handle bar clamps and pipe to hold the crank so the primary gear nut can be done up tight.

Well I have finally figured it out, KiwiBiker loads the pictures according to file size and not how I select them, is there an option to change that?

jasonu

2nd October 2010, 16:37

Buckets4Me

2nd October 2010, 18:07

In the picture showing installing the piston clips I notice the cutouts behind the transfer cutouts appear not at all symetrical, in fact not even similar. Is it the photo angle, an optical illusion, or some sort of 'trick' grind?

220251

I belive they have been playing around with flow benches and trying to get even flow across the piston
also nothing is square in the gp engine the transfers are on an angle

TZ350

2nd October 2010, 18:55

There are basically two commonly utilised methods of stating a given engine's compression ratio:

The "Uncorrected Method" (sometimes referred to as the Geometric or European method)

The "Corrected Method" (sometimes referred to as the Trapped or Japanese method)

At elevated engine speeds (rpm), the piston is moving so quickly that it will actually "outrun" the fuel/air mixture to the "leak" and "trap" a much larger volume of fuel/air in the upper cylinder than just the static volume above the exhaust port. This "trapping efficiency" improves with more rpm's.

And of course, when the bike is up on the pipe, the leak is being plugged (the 2-stroke supercharging effect) with a high pressure pulse from the expansion chamber.

So the final compression pressure is much higher than the "Corrected" compression ratio would suggest.

bucketracer

3rd October 2010, 10:09

Starting to really come together now

220264

Increased size of the boost port, we could have covered the old gash port but decided we would try enlarging it and drawing from the crankcase and under the piston together.

220265

Plenum extension so the cover is not too close to the inlets bell-mouth.

220268

Oil sucker. hopefully this will cure the oiling problem by sucking up the oil that collects at the bottom of the plenum.

220266

Wrong ring gap, brand new piston kit, if we hadn't checked the ring gap (0.004" per inch of bore dia) we wouldn't have found that a std ring had been shipped with a 0.5 os Wiesco piston.

220267

A view of the primary inlet tract from the plenum to the crankcase. This needs to be the correct length, or at least long enough, we found that if it was too short, we got a mid-range Blarrr problem.

There is a relationship between inside diameter, length and the inlet closing point that's important.

After retarding the inlet closing point without success to cure the mid-range Blarr problem, it was found that having the inlet too short for its ID was the real cause of the Blarrrs. Probably took TeeZee a couple of nights to figure it out, or at least the time it took to try several rotary valves with shorter timings.

bucketracer

3rd October 2010, 10:57

Copper Cooling Fins..........

.220275

Copper block placed so as to pick up the heat entering the cooling system from the exhaust port and dissipate it through the extra copper fining.

TeeZee has the idea that there is a lot of heat here that comes from the exhaust gases spraying directly down onto the port floor from the port window as the piston just cracks the port open.

220274

The copper block and how it presses onto the copper cooling fin for heat transfer can be seen here.

220276

And here......

220272

The start of the cylinder cooling fin.

220273

Drilling a center for the combustion chamber, the stud and screw holes for holding the fin onto the head for ease of handling.

bucketracer

3rd October 2010, 11:08

Cutting out the combustion chamber..........

220278

We used a hole saw for cutting out the combustion chamber.

220280

To get a good finish to the hole its important to use a guide pin (clutch push rod from a GP125 fits) and not a drill bit as the flutes of the drill will chew out the guide hole and the finish of the hole being cut will be sloppy.

220277

Start the cut but don't cut right through.

220279

So there is not a lot of burring, I finished the cut from the other side.

220281

Then I Cleaned the finished cut up with some emery and a battery drill.

Spearfish

3rd October 2010, 14:16

Just a thought, would some CPU heatsink grease between the block on the port and fins help increase the contact patch?

Spearfish

3rd October 2010, 14:17

doubled up

TZ350

3rd October 2010, 14:54

Just a thought, would some CPU heatsink grease between the block on the port and fins help increase the contact patch?

Bucket used copper coat, (plenty of that around work) but I think your right CPU grease would probably have been better.

bucketracer

3rd October 2010, 19:23

Setting the compression ratio.

From what I can see the corrected compression ratio ranges from 7-9:1, 7-8:1 for air-cooled 125 engines and 8-9:1 for high performance water-cooled ones.

Its tempting to go for the highest possible, but aside from problems with the bike going flat on top and not revving out Graham Bell in his book, Two Stroke Performance Tuning, Table 2.2 lists his ideas of permissible uncorrected compression ratios. For a 125 running 100 Octane he lists 14.3:1 and for 100/130 Avgas 15:1 as the upper limits.

Its easier to get a corrected compression ratio of 8:1 from a motor whose exhaust opens 96 degrees after TDC than one that opens 81 degrees ATDC and stay within the limits suggested by Bell. Because 96 has more volume above the exhaust port and requires a bigger head volume than 81 does.

Thomas and I chose a cylinder head volume of 9.5cc for a corrected ratio of 7.3:1 and uncorrected ratio of 14.2:1.

220412

A quick calculation of the volume in the squish area and copper head fin leaves 6cc for the head. Pouring 6cc into the head gave us an idea of how much needed skimming from the head as a first cut.

220413

Then it was all assembled up and measured with syringes filled with anti freeze solution. Anti freeze wont rust the engine and is easy to see, the syringes we used were a plastic 5cc and two 3cc units purchased from the local Chemist, they were only $2-3 each.

220415

Several cuts later we got the 9.5 cc we wanted, in checking the head volume we filled the chamber until the first thread of the spark plug hole was almost covered. The top of the piston and head joint were sealed with a smear of grease.

As an added benefit, because the copper fin takes heat from the squish area and distributes it twice as quickly as the alloy head can by itself, with copper the outer fins can pull more of their weight dissipating heat.

As the heat path is longer to the outer fins, the outer fins wouldn't normally do as much work as the inner fins but with the extra copper fin, the copper carry's heat out to them as well as being a heat radiating surface itself.

220414

Having sorted the head we made a cushion for the plenums blow off valve by gluing silicon on the cover and lightly screwing the plate to it, when the glue has set we should have a soft, flat sealing surface.

Of course non of this is the last word in 2-stroke tuning but for what its worth, its what we are up to at Team ESE.

Dad, NedKelly and Chambers have had me make plenty of parts for them before, but with Thomas's help I have been really enjoying working on my first complete motor.

Now to get this sucker fitted into TeeZee's FZR frame and see how it goes.

SS90

4th October 2010, 06:03

[QUOTE=bucketracer;1129874434]

Increased size of the boost port, we could have covered the old gash port but decided we would try enlarging it and drawing from the crankcase and under the piston together.

The picture of the boost port looks much better, feeding from the crankcase as well should see some real gains.

Have you tried this boost port set up with a standard induction set up? It would be interesting to find out what the results are from no other mods other than that.

On the GP Hundy of chambers if that has not been done, I believe there would be good gains there too.

Also, try 65 degrees on the boost port top edge.

F5 Dave

4th October 2010, 09:28

220224

The best tool known to man for pulling lock tabs up tight and removing frost plugs from car engine blocks.

Where do you keep your tools? outside in a fish bin? Or was that one salvaged from Auckland Harbour?:innocent:

TZ350

4th October 2010, 11:58

Where do you keep your tools? outside in a fish bin? Or was that one salvaged from Auckland Harbour?:innocent:
Yes it looks pretty ugly, I shuddered when I saw Buckets picture, the boys often have to work on site with some nasty corossive materials, tools will rust like that overnight after being out on a job the day before. They have found it pays to let the tools dry out completly before CRCing them again.

Chambers

11th October 2010, 07:14

.

Whats this TZ?

220985

F5 Dave

11th October 2010, 08:55

um, an RG50 with Simon's old tail-peice & my old swingarm?

& probably rear sprocket, which I don't think I ever got paid for. Bloody Si.

Buckets4Me

11th October 2010, 17:45

um, an RG50 with Simon's old tail-peice & my old swingarm?

& probably rear sprocket, which I don't think I ever got paid for. Bloody Si.

na it was TZ making sure he stayed in second place in the points ahead of CHAMBERS

even if it did mean that he was passed on the OUTSIDE by a GIRL trying to lap him

TZ350 76 points and second
CHAMBERS 62 points and thirds

Dutchee

11th October 2010, 18:33

Umm, not sure he wasn't undertaking me, and it wasn't practice? Either that or lining up 43 and 44???
I don't recall overtaking anyone (and definitely not lapping), but then again, I do suffer alzheimers/dimentia, so better stories always appreciated hehehe

bucketracer

13th October 2010, 21:48

Getting there, but it's going to be a close call being ready for Hampton Downs on the 17th.

221171

Skimming the outside of a KX125 stator plate to fit the GP engine.

221169

Boring the inside so the stator plate clears crank seal housing.

221168

All fits very nicely and the trigger coil sits nicely in the housing.

221166

Chambers has made some very nice looking engine plates for TeeZee.

221167

The motor slots right in and my pipe fits too.

221170

Looks the part......now to see if we can get it to go..........

kel

14th October 2010, 12:27

Certainly does look the part! Dont forget the air filter.

Buckets4Me

14th October 2010, 17:42

Certainly does look the part! Dont forget the air filter.

The air filter it's at the bottom of the rubbish bin. How can you call it a majic vacume cleaner if it has a filter on the frount

Buddha#81

15th October 2010, 07:17

The air filter it's at the bottom of the rubbish bin. How can you call it a majic vacume cleaner if it has a filter on the frount

Hot slicks and rolling into the pits after practice, left hand turn a fist full of pea gravel into the carb and you might rethink its name? It looks great and after riding the same framed FXR powered bikes down here good choice for the likes of HD and Taupo.

F5 Dave

15th October 2010, 08:07

pea gravel? where do you think he is? Ruapuna?

Buddha#81

15th October 2010, 10:50

pea gravel? where do you think he is? Ruapuna?

Thats right you dont have to grit the track for snow in the Norf!:blink:

TZ350

15th October 2010, 11:26

.

221249

Ok.... a filter it is then..........

Buddha#81

15th October 2010, 12:30

.

221249

Ok.... a filter it is then..........

you cant trick us.......different pipe!!!! tell us your scared now?

TZ350

15th October 2010, 17:55

you cant trick us.......different pipe!!!! tell us your scared now?

Good spotting............you can read me like a book.........:shifty:

TZ350

15th October 2010, 22:12

Spent an interesting evening with a fellow F5 rider at a motorcycle shop watching the mechanic run my F5 buddys RG50 up. Best couple of hundy he has ever spent my friend recons.....

It was informative to watch a bike that felt like it ran ok at the track, being tuned on the dyno.

Retarding the ignition about 12 degrees and dropping two jet sizes found another hp and fattend the curve up.

221292

The dyno guy said, over advanced and over rich to compensate is a common problem with bikes tuned by the seat-of-the-pants method.

been there, done that myself .........:doh:

ac3_snow

16th October 2010, 07:31

shucks you could buy a new project for a couple hundy! hard to argue with those improvements tho.
I'm taking a guess that you need a fancy pants ignition/coil to adjust timing? or is there some mechanical way to do so.
(it is far too early for me to attempt figuring out such enigmas)

speedpro

16th October 2010, 08:14

Looks like a lot of runs, good improvement though. That gain on the upslope will be real noticeable. Retarding the timing puts heat in the pipe in the higher revs effectively shortening it with the result you see - it keeps making power. 12 degrees is heaps, you should have been able to hear that at the track, it would have sounded flat and not revved freely.

SS90

16th October 2010, 08:20

Good spotting............you can read me like a book.........:shifty:

yes, what is that off... An early RS125?

TZ350

16th October 2010, 08:43

........hard to argue with those improvements tho.
I'm taking a guess that you need a fancy pants ignition/coil to adjust timing?.....

No its not a digital programable, just an old 80's YZ125 ignition, it may have some built in retard but I don't know for sure.

Its an example of how seat of the pants can fool you.........

TZ350

16th October 2010, 08:45

.......12 degrees is heaps, you should have been able to hear that at the track, it would have sounded flat and not revved freely.

12 degrees is our gestimate, it felt like it revved ok but you did mention to D that it did not sound pipey enough, so you were right.........

TZ350

16th October 2010, 17:35

221310.

OK..... got my FZR-GP125 going, runs up and down the drive OK, just have to hope it holds together tommorow at Hampton Downs.

TZ350

17th October 2010, 05:32

Feeling a little nervous, it has to meet big bike rules, will it pass scrutineering? Will it hold together, Have I guessed the right main jet, gearing Etc...... I hate these last minuet rushes where the bike is only ready the night before.

And my last real ride on a big track was a year ago, and more recently on a 50 at Mt Welly where I fought Dutchee tooth and nail for last place and won, actually I won handsomly.

Finishing, and beating a Super-Light or a Street-Stock would be fun, anyway just finishing with an unproven bike will be something too………….:niceone:

Bert

17th October 2010, 08:25

F5 Dave

18th October 2010, 08:32

well clearly it is for a GP125. I mean a bike shop listing that & not even saying what it fits? Sheesh. Probably one of 4 required for an RG500 & got slipped in a box of reeds by mistake.

SS90

18th October 2010, 08:45

well clearly it is for a GP125. I mean a bike shop listing that & not even saying what it fits? Sheesh. Probably one of 4 required for an RG500 & got slipped in a box of reeds by mistake.

I was thinking something similar... It looks like it could fit my Trabant too.

TZ350

18th October 2010, 16:35

Good Luck TZ. nothing worse than racing a last minute finished bike...

stumbled across this (though it might be up your ally)
http://www.trademe.co.nz/Trade-Me-Motors/Motorbikes/Parts-for-sale/Performance/auction-324144345.htm

not sure if it is within the rules.. reeds and the like has always been a bit vague...

Thanks for the link, I looked it up and its an after market valve for a Sea-Doo, nothing available for a GP125 of course but seeing the cabon rotary valve gives me the idea we could make our own oversized covers for larger carbs and have bigger diameter rotary valves lazer cut from carbon fiber sheet for them and that would be within the rules.

There can be problems when a steel valve is rubbed hard on the outer alloy valve cover by the crankcase compression as alloy and steel often stick even with hard anodised covers this might be a problem, but the carbon valve should be ok.

How is your own F4 TZR100 project going Bert? I still have a bit of titivating to do on mine.

speedpro

18th October 2010, 18:08

221310.

OK..... got my FZR-GP125 going, runs up and down the drive OK, just have to hope it holds together tommorow at Hampton Downs.

and . . . . . . .

TZ350

18th October 2010, 18:18

and . . . . . . .

I got out in the second race for 2-3 laps before the heavens opened up again, my impression is, that the bike has legs, great breaks and will handle well, but still a little polishing to do to get it running perfectly, but you get that with a new bike.

The rough condition of the pits was a shock, but the cafe and loos were great. It cost me $60 a lap but I got enough track time to fall in love with the place and the organisers are keen to run a good show.

And extra full marks to those like Rick, Chambers, Gavin and Damion to name a few, who kept going on slicks in the very wet conditions of the last race. Damion is the hard man of the day as he rode eveything with slicks no matter how wet it was out there.

And congrats to Gavin for winning the first race and Woody the last one.

Kickaha

18th October 2010, 19:31

And full marks to those who kept going on slicks in the wet.

Slicks in the wet work well better than most people think they should (on Buckets anyway)

Buckets4Me

18th October 2010, 20:40

Slicks in the wet work well better than most people think they should (on Buckets anyway)

they travel a bit faster up this way
that and he forgot his bright yellow rain coat
but he didn't forget how far up the bank he fired the rg50 with slicks on. Or how much fun it was riding it another 3 laps with no brakes

Yow Ling

19th October 2010, 05:27

. Or how much fun it was riding it another 3 laps with no brakes

Ahh so you have started preparing the 2011 BOB bikes then. Always something to fall off

k14

19th October 2010, 12:27

they travel a bit faster up this way
Obviously you have never ridden down here :facepalm:

jasonu

19th October 2010, 12:57

Quote There can be problems when a steel valve is rubbed hard on the outer alloy valve cover by the crankcase compression as alloy and steel often stick even with hard anodised covers this might be a problem, but the carbon valve should be ok.

I think you are looking for trouble where there is none.

jasonu

19th October 2010, 12:58

Slicks in the wet work well better than most people think they should (on Buckets anyway)

Except at Mt Wellington!

TZ350

19th October 2010, 20:23

For those who just have to search for something special.

Dimensions and part numbers, find what you want then look up the part number to see what its off.

Piston Dimensions

http://stores.ebay.co.uk/Janets-Bike-Parts/Piston-Measurements-page-1.html

http://stores.ebay.co.uk/Janets-Bike-Parts/Piston-Measurements-page-2.html

http://stores.ebay.co.uk/Janets-Bike-Parts/Piston-Measurements-page-3.html

ConRod Dimensions

http://stores.ebay.co.uk/Janets-Bike-Parts/Con-Rod-kit-Dimensions.html

http://stores.ebay.co.uk/Janets-Bike-Parts/Con-rod-dimensions-2.html

Rear Sprocket Dimensions

http://stores.ebay.co.uk/Janets-Bike-Parts/Rear-Sprocket-Dimensions.html

Front Sprocket Dimensions

http://stores.ebay.co.uk/Janets-Bike-Parts/Front-Sprocket-Dimensions-Type-2.html

TZ350

20th October 2010, 19:18

Compairing The Plenum with some of the more applicable Dyno Charts that have been posted here.

221752221751

The first thing I noticed was that if you use the DIN way of representing HP you get a higher figure than using SAE.

Not having customers to impress we prefer the more conservative SAE method ourselves but as other charts are in DIN we will have to display ours that way too so as to compare apples with apples.

And its worth while following the quotes back to their original posts, as there is a lot of interesting stuff there.

221755

If anyone tries to tell me that the transfers are too small (from the pictures), then they are right, they are only 10% bigger than the pics to give the results in the graph.....makes you think about transfer port area .....

221754

I can't claim responsibility for this engine, but (so far) the highest power I have seen from this capacity with a 24mm Carb is this series of runs.
The red line was a different exhaust

221753

This one is the Plenum (blue line) compaired with a conventional side carb (red line) and both running with Buckets first ever chamber designed by himself, maybe not spectacular but not a bad effort either.

221756

Attached is a pretty old dyno chart. Ignore the red line that was a dodgy experiment. The line going to 13,500 was the old MB100 sidecar. That engine only had the original 2-petal reed block and a 28mm Keihin. The other line is my old piston port only TS100. 200deg timing on both intake and exhaust. I have no idea why it made such good power. Both peaked at 19.9rwhp.

motorbyclist

21st October 2010, 04:15

ok, searching this thread looks a bit daunting so I'll have to ask:

why is the intake plenum placed downstream of the carby, as opposed to upstream of the carby? (ie, why have it wet rather than dry?)

what advantage does this arrangement give and how?

(I'm somewhat qualified so please don't dumb it down)

TZ350

21st October 2010, 05:15

why is the intake plenum placed downstream of the carby, as opposed to upstream of the carby? (ie, why have it wet rather than dry?)

what advantage does this arrangement give and how?

This class of racing (F4) limits 125 2-strokes to a 24mm carb and air cooling.

The hoped for advantage, was that the motor sucking air/fuel from the plenum through an internal inlet tract larger than 24mm would allow it to make more power than it could by sucking directly through the restrictive 24mm carb.

To make power the carb needs to be bigger, or at least the inlet tract needs to be bigger and pass more air.

The idea is the motor only sucks from the plenum when the inlet valve is open and thats for only 50% of the time more or less, but the restricive 24mm carb at WOT gets to fill the plenum for a 100% of the time.

Using the plenum in theory allowes the 24mm carb to flow much more air than it would have if it was attached to the motor in the conventional way.

It works but still needs some development, the problem is oil/fuel dropout within the plenum, the plenum has potential but currently we are making more power from this motor in other ways and will take another look at the plenum later, and probably do something along the lines that Yow Ling has sugested to me.

The picture is of the Plenum (blue line) and conventional setup (red line) both with Buckets own first ever pipe design.

bucketracer

22nd October 2010, 16:36

.

An interesting take on needle/jet http://www.youtube.com/watch?v=h0Rj_yvDo8Q

An idea so obvious, why it has'nt been done before..........

F5 Dave

22nd October 2010, 16:40

Ahh fer heavens sake I tried to watch it & it was taking him 15 min to take the lid off the carb.

What was it, the drilled parallel hollow needle? They've been trying to pump that since the 90s. Never took off, obviously not the be all & end all.

TZ350

22nd October 2010, 16:58

What was it, the drilled parallel hollow needle? They've been trying to pump that since the 90s. Never took off, obviously not the be all & end all.

New to us.............. :blink:

motorbyclist

22nd October 2010, 19:41

This class of racing (F4) limits 125 2-strokes to a 24mm carb and air cooling.

The hoped for advantage, was that the motor sucking air/fuel from the plenum through an internal inlet tract larger than 24mm would allow it to make more power than it could by sucking directly through the restrictive 24mm carb.

To make power the carb needs to be bigger, or at least the inlet tract needs to be bigger and pass more air.

The idea is the motor only sucks from the plenum when the inlet valve is open and thats for only 50% of the time more or less, but the restricive 24mm carb at WOT gets to fill the plenum for a 100% of the time.

Using the plenum in theory allowes the 24mm carb to flow much more air than it would have if it was attached to the motor in the conventional way.

It works but still needs some development, the problem is oil/fuel dropout within the plenum, the plenum has potential but currently we are making more power from this motor in other ways and will take another look at the plenum later, and probably do something along the lines that Yow Ling has sugested to me.

The picture is of the Plenum (blue line) and conventional setup (red line) both with Buckets own first ever pipe design.

right, so why not put the plenum on the dry side, like a conventional airbox/intake tube? How is pushing the air any different than pulling it? If the carb was that close to the intake that the air was not at a near constant velocity then why not just space it out appropriately and use an airbox/plenum to force air to the reeds where it won't fill with fuel?

I'm well aware of the bucket rules and how the plenum works, but I'd like to know the reasoning behind your design decision. Trying to smooth the air flow with an accumulator and assumedly with resonance for a boost just seems like a good way to slow engine response and cause issues with flooding.

got any drawings/pictures of what it looks like (don't worry I won't be stealing your ideas)

TZ350

22nd October 2010, 20:59

got any drawings/pictures of what it looks like (don't worry I won't be stealing your ideas)

A drawing...........

http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=215565&d=1281168712

And a picture............

http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=215564&d=1281168712

221889

And the dyno graph, plenum blue line, conventional carb red line, no other changes, back to back tests.

There is over a 1,000 pictures on this thread, and there are a few of the plenum. If you use "Thread Tools" near the top of the page then "View Thread Images" you can find all sorts of interesting pictures and related posts that people have put here, looking through the pictures to find related posts is easier than trawling the thread for info........

motorbyclist

24th October 2010, 22:42

And the dyno graph, plenum blue line, conventional carb red line, no other changes, back to back tests.

There is over a 1,000 pictures on this thread, and there are a few of the plenum. If you use "Thread Tools" near the top of the page then "View Thread Images" you can find all sorts of interesting pictures and related posts that people have put here, looking through the pictures to find related posts is easier than trawling the thread for info........

cheers for that - I never knew that feature existed!

I don't doubt it makes power, I just reckon putting it on the dry side would be easier. Of course now I see how you've done it perhaps an external plenum would be more difficult to build...

I do like the simple way in which you've done it - and what's with the head? extra cooling?

TZ350

25th October 2010, 21:55

- and what's with the head? extra cooling?

An air-cooled head typicaly runs between 125 to an upper limit of around 350 degrees C. Water cooled performance 2-stroke engines typically run around 50-80 degrees C. The higher temperature of the combustion chamber limits the amount of power that can be made and sustained in an air cooled engine.

222125

Combustion Chamber C2 runs hotter than C1 because of the longer thermal path to the fin. To keep the combustion chamber cool the thermal path needs to be as short as possible.

222130

I think its this necessity to keep the thermal path to the radiating surface (fin) as short as possible that we see the splayed head design like this high powerd kart engine where the roots of all of the fins are as close as possible to the combustion chamber shell. Unlike the Suzuki GP head which has a much longer thermal path to the outer fin tips.

222126

The copper forms the squish band and with coppers better thermal properties it conducts heat away from the squish band area better than aluminium would have and I think the squish should run cooler with the copper there.

222127

Copper transfers heat twice as fast as aluminium, in the picture below you can see the head has a large flat area machined on it. And the copper is used to transfer heat from the combustion chamber area towards the outer fins, in that way the chamber runs cooler as the outer fins get to dissipate more of the waste heat load.

222128

And if you are playing with all of this copper it makes sense to me to extend it out into an extra fin. By in large my engine runs cooler than other air-cooled 2-strokes I have been able to measure. But best of all, it seems much less prone to fading during a race.

motorbyclist

26th October 2010, 03:58

wow that's a pretty novel way to cool the motor and resist detonation all in the same package.... bloody brilliant! are the copper fins measurably hotter than the aluminium ones?

motorbyclist

26th October 2010, 04:05

The higher temperature of the combustion chamber limits the amount of power that can be made.

isn't it moreso the fact that we can't extract waste heat fast enough, thus limiting power by the material properties of the motor (ie melting of aluminium)? IIRC hotter engines are more efficient right up until the motor siezes and/or melts or the fuel auto-ignites (which makes your copper squish band a very good idea)

ie, given stronger cooling, we can handle the extra heat from higher power output

SS90

26th October 2010, 06:17

IIRC hotter engines are more efficient right up until the motor siezes and/or melts or the fuel auto-ignites (which makes your copper squish band a very good idea)

ie, given stronger cooling, we can handle the extra heat from higher power output

Am I reading that right?

"Hotter engines are more efficient right up to when they seize"?

I wouldn't subscribe to that at all.

TZ350

26th October 2010, 16:55

.......hotter engines are more efficient.......

Depends on what kind of efficiency you are talking about, maximum work extracted from minimum fuel used (like, lean burn) or maximum power achieved from an engine and air consumed (as in, rich best power).

Taken from “Physics in an Automotive Engine” a big read but worth the effort and even interesting and amusing in places........

By increasing the temperature of the thermostat, in other words, reducing the effectiveness of the cooling system and making the engine run hotter, a SLIGHT improvement in fuel economy is achieved. However, the hotter engine tends to heat incoming air up which REDUCES the air density and therefore reduces the power produced by the engine. Now you know WHY the engine seems to have more power if you replace the modern 195°F thermostat with a 165°F one, but the engine creates more pollution due to poorer burning and it also has worse gas mileage.

The full text can be read here.... http://mb-soft.com/public2/engine.html

In searching the net for the good stuff, I am more impressed by items like this one where the author uses maths to explain his point of view and provides credible references that can be followed up..........

motorbyclist

26th October 2010, 20:13

Am I reading that right?

"Hotter engines are more efficient right up to when they seize"?

I wouldn't subscribe to that at all.



Material properties are one of our limiting factors for power output. A cool chamber sucks heat (ie, energy) out of the combustion gases - this heat is driving the pressure we use to extract work.

A hot chamber doesn't suck up so much energy from the hot gas. However, our materials (and manufacturing tolerances) dont allow us to exceed certain temperatures before things get too big and lock up (ie, seizes) or the parts weaken too much and fail. Another way to look at it is if we used a strong insulator for the motor instead of metal; this way no heat is added to the intake charge, and no heat is lost during power stroke (wiki "otto cycle" and "carnot cycle"). The only heat lost is through the exhaust gas.

Watercooling is better than air cooling because we can extract more heat; This allows us to release more heat and extract more power without material failure, even though we're shedding most of the energy through the radiator and not the rear wheel.

the motor being cooler is not the reason it's better - it's the ability to remove all the waste heat. In theory a hot engine will get more power from a given amount of fuel, but to trump a watercooled system the thing would need to be made of silicon or a composite like what they use for turbos (I forget the name of it)

motorbyclist

26th October 2010, 20:26

Depends on what kind of efficiency you are talking about, maximum work extracted from minimum fuel used (like, lean burn) or maximum power achieved from an engine and air consumed (as in, rich best power).

well seeing as improvement to intake volumetric efficiency is a primary way to improve power, I run on per unit fuel. My point was that while and air-cooled motor is more efficient than water, we can get away with stuffing more fuel into the watercooled motor without melting it and extract more power overall. The temperature of the cylinder isn't the reason it's better.

Have you seen the new direct-injected petrol motors? They can run ultra-lean by just injecting a little pocket of fuel around the spark plug and using the rest of the intake air to insulate the piston from the heat. This gives a great boost to efficiency by using the heat to pressurise the gas, rather than heating the coolant.

EGR is another technique that can theoretically improve fuel efficiency by charging the cylinder with inert gas that allows the same pressure at a lower temperature. However, this is used to reduce NOx emission usually at a cost rather than a benefit.

TZ350

26th October 2010, 21:20

..........A cool chamber sucks heat (ie, energy) out of the combustion gases.........A hot chamber doesn't suck up so much energy from the hot gas.........Watercooling is better than air cooling because we can extract more heat; This allows us to release more heat and extract more power......... even though we're shedding most of the energy through the radiator and not the rear wheel.......the motor being cooler is not the reason it's better - it's the ability to remove all the waste heat.......

Yes these things make sense to me........

And I can see what you mean now, that the temperature of the water cooled cylinder isn't the big reason it's better, it is an ability to shed waste heat that makes a cooling system better.

But in the interests of running a hot engine for the sake of thermal efficiency there must be a point where a hot cylinder and head along with the heating effect of compressing the incoming fuel charge during the compression stroke results in overheating of the fresh mixture and causes spontaneous ignition throughout the fuel charge.

Surely this inevitability of detonation must be the limit to how hot surfaces within an engine can be run.

And from previous investigations into ways of keeping the thermal energy from combustion out of the cooling system we looked at insulating materials like ceramic coatings and in a high performance engine they don't make sense, because of their inability to pass waste heat to the cooling system. Making insulators or low conductive materials regardless of their thermal strength prone to overheating at their surfaces.

But I can see them being useful in compression ignition engines and low powered IC units looking for fuel efficiency, particularly ones running on fuels with a high latent heat of evaporation like alcohol where you don't want the evaporating fuel to over cool the engine, or too much of the combustion heat to be lost to the cooling system.

Now that you have explained it to me, direct injection petrol engines look interesting, making less combustion heat but getting more power at the wheels because less energy is lost to the cooling system through the thick blanket of un-combusted air, now there is a good idea.

I had always thought in terms of ingesting as much air as possible and burning up every molecule of oxygen, but yours looks at making less waste heat.

......... hmm....... darn, now you have got me thinking about what could be done......:scratch:

I have been finding out, how hard it is converting a good idea into something that works, like using a plenum to get around the restriction of a 24mm carb.

Well we might have to find out, direct injection may be the project for next year, after Taupo........

Spearfish

27th October 2010, 05:12

Yes these things make sense to me........

Direct injection petrol engines look interesting for the reason you have given but I doubt my ability to make one .......... hmm....... darn, now you have got me thinking about what could be done......:scratch:.......and would it work???

.....well we might have to find out, it may be the project for next year, after Taupo....

That would be an easy project....start with a diesel engine and convert it to petrol...:yes::blink::facepalm:

Buckets4Me

27th October 2010, 06:04

That would be an easy project....start with a diesel engine and convert it to petrol...:yes::blink::facepalm:

so how many 125 2 stroke air cooled diesels are out there ?

bucketracer

27th October 2010, 06:35

.

Ok....just because you asked........

SS90

27th October 2010, 08:37

.

Ok....just because you asked........

I am confused, does the plenum work or not?

Buckets4Me

27th October 2010, 12:04

I am confused, does the plenum work or not?

what you cant read ???

did you not see the graph ?

where have you been ?

what happened to your other posts ?

This one is the Plenum (blue line) compaired with a conventional side carb (red line) and both running with Buckets first ever chamber designed by himself, maybe not spectacular but not a bad effort either.

222242

TZ350

27th October 2010, 15:37

I am confused, does the plenum work or not?Not confused, asleep....... it was all published a page or two back.................

....I earn my living from developing.... AIR COOLED, TWO STROKE 125 (AND 140) CC CYLINDERS..... Buckets efforts with Thomas's help compaires very well with your own work tuning 24mm carb, rotary valve, 125 air cooled 2-strokes.

The Plenum idea works but it's not finished, I think we can do better than 20rwhp..........

TZ350

27th October 2010, 20:49

The race is on to find a small capacity 2-stroke air-cooled diesel motorcycle engine........

Not a motorcycle engine but close:- The Junkers Jumo 205 aircraft engine was the most famous of a series of diesel engines that were ... http://www.enginehistory.org/Diesels/CH4.pdf

SS90

27th October 2010, 20:54

TZ350

27th October 2010, 21:25

Breadth for Mt Welly or Power for Taupo, roll-up...roll-up and takes yours pick..half a chance this has been covered before...:zzzz:

SS90

27th October 2010, 21:32

breadth for Mt Welly or power for Taupo, takes yours pick.........

No, what I mean is you seemingly had more power without the Plenum previously.....3 horsepower more it would seem.

I was wondering what the difference was, because from your previous posts, you showed a "how to" of getting 17 horsepower, with an old RG250 pipe, no porting, and just raising the compression and using an original piston and cylinder head.

this engine is considerably ported, thin single ring piston, squish head and so on, and with no plenum produces the same as an engine with essentially no engine work.

Thats what I don't understand.

TZ350

27th October 2010, 21:39

Maybe hp doesn’t tell the whole story.......you have always been very interested in the torque curve.....

Certainly the shape of Buckets plenum torque curve is better than the ones in your graphs for driving around Mt Welly......

Or has something changed with your thinking now????

SS90

27th October 2010, 21:47

No, nothing has changed in that respect, I am trying to follow this development process, and actually encourage you to see the Plenum through (believe it or not)

And, in all seriousness, I cannot see why you have actually lost 3 hp, after viewing the images of the cylinder that your son posted, and then seeing a massive power loss on the power curve you posted, compared to previous figures you have quoted, it seems to me that something is wrong.

That new cylinder should clearly be able to, at the very least, match the old cylinder for power. The exhaust you posted pictures of, according to you, with the plenum, makes 20hp, but with-out makes 17.

That is a head scratcher for me.

Do you have any clues as to why?

TZ350

28th October 2010, 03:58

The exhaust you posted pictures of, according to you, with the plenum, makes 20hp, but with-out makes 17.

That is a head scratcher for me.

Do you have any clues as to why?

222276

"The exhaust you posted pictures of, according to you, with the plenum, makes 20hp, but with-out makes 17."

Actually it's 20 and 18, ...... still a lie repeated often enough I suppose........

"That is a head scratcher for me. Do you have any clues as to why?"

Could it be, 20 with the Plenum, means it's working ....... :facepalm:

There is always someone who needs it spelt out for them.........

Buckets4Me

28th October 2010, 06:22

All very interesting.

Try not to take offense here TeeZee, but the confusing thing for me is, previously you tell us you had 21 Horsepower WITHOUT the Plenum, now you have 20 with, and, what is it, 17 without?

Why is that?

222276

"The exhaust you posted pictures of, according to you, with the plenum, makes 20hp, but with-out makes 17."

Actually 18 and 20

"That is a head scratcher for me. Do you have any clues as to why?"

Could it be the Plenum.... :facepalm:

or the fact that you are choking it with a 24mm carb ?

come on and wake up will ya

Spearfish

28th October 2010, 07:51

or the fact that you are choking it with a 24mm carb ?

come on and wake up will ya

Is 24 the largest allowed?

Is there any restriction on injection?

F5 Dave

28th October 2010, 11:34

equiv to 24mm. Read the rules,there's plenty of links about or just MNZ site.

bucketracer

28th October 2010, 17:02

Is 24 the largest allowed?

Is there any restriction on injection?

 Section 24.2.4 of the MNZ rule book.

F4 2 stroke engines over 104 cc are restricted to carburetion equivalent to a single 24mm carburettor.

Definatly 24mm carb and do the words "restricted to carburetion" really mean to exclude fuel injection?

Slingshot

28th October 2010, 18:23

Section 24.2.4 of the MNZ rule book.

F4 2 stroke engines over 104 cc are restricted to carburetion equivalent to a single 24mm carburettor.

Definatly 24mm carb and do the words "restricted to carburetion" really mean to exclude fuel injection?

The important bit is "equivalent" - so you'd be pushing shit uphill if you tried to use a 30mm throttle body.

speedpro

28th October 2010, 18:32

I drafted that rule and fuel injection was not considered at the time. The wording does inadvertantly exclude fuel injection.

bucketracer

28th October 2010, 18:57

...........have you thought about putting a clear cover over the plenum chamber and seeing if you can see any interesting fuel/air movements inside the chamber? Could give some real insight as to how the air is moving around inside there and I assume you would be able to see it as the air will be mixed with fuel which will give it a misty look? -Sketchy

In a couple of weeks we are going to have another go at this, and will try this idea and one or two others suggested to Dad by Yow Ling and Speedpro.

Old Youtube vids of the plenum engine in action........

Very easy startup http://www.youtube.com/watch?v=YxiEo8cgopg

Power Run up the drive http://www.youtube.com/watch?v=p4ef-WUO1Qs

Not exactly the same setup as the vids, (different pipe) but a dyno graph of the engine with ordinary carb setup giving 18rwhp and with the plenum like in the vid's and that gave 20rwhp in back to back tests showing the plenum idea definitely works and probably has much more potential yet for TeeZee to wring out of it.

222347

The engine was running a pipe I designed myself and I am grateful to Dad and the rest of the Team for letting me have a go and paying for the dyno time to test it.

Its one of those funny things, the pipe isn't a keeper but it's still a success in it's own way and will be joining the karate suit and acoustic guitar in the cupboard as mementos of the times I am most proud of.

My chamber and plenum, dyno graph is especially pleasing to have, to hang over my bed, as on my very first try I was able to equal Bavaria's best, or the best we have seen anyway, and I have the proof.

Totally chuffed, and will always be reminded of my success whenever I hear talk of karate suits and acoustic guitars and probably be inspired to show my graph off again.......... actually I might just show it of from time to time just for the heck of it anyway......:D

Thanks TeeZee and the Team.

bucketracer

28th October 2010, 19:10

The important bit is "equivalent" - so you'd be pushing shit uphill if you tried to use a 30mm throttle body.

Yes, good point, and I agree, sorry, I should have made it clear I was thinking of an equivalent 24mm throttle body.......

SS90

28th October 2010, 20:55

Its one of those funny things, the pipe isn't a keeper but still a success and will be joining the karate suit and acoustic guitar in the cupboard as mementos of the times I am most proud of.

My chamber with the plenum, dyno graph is especially pleasing to have and hang over my bed, as on my very first try I was able to equal the Bavarian best and have the proof.

Totally chuffed, and will always be reminded of my success whenever I hear talk of karate suits and acoustic guitars and happily show my graph off ..........

.

Im flattered to be your idol Bucketracer.

Any chance of a video of that pipe on the dyno?

I am glad your are proud of your work.

Are you able to explain why the old cylinder and exhaust made more power with out the Plenum than the new cylinder and pipe with the plenum, but 2 HP less with out?

Easier to follow... Using TeeZees data

Standard cylinder, piston, head, just raise compression, and RG250 chamber

17 HP

Modified ex. Port,squish head,single ring piston,A.G. Bell Pipe
21HP

same as above, with Plenum (Hard to decipher Teezees data), but I think....

20hp

Cylinder by Thomass and you, your pipe, Plenum, various precious metals...

21HP

same as above, no Plenum

18HP

See what I mean?

The new cylinder makes less power (2hp) than the old with out the Plenum, but it makes essentially the same, with the Plenum.

That makes no sense.

I can't work out why, or how that would be.

It's your work, so best to ask you I suppose.

if you want to try and run with the Baverians, then I will ask the same questions they would ask you if you presented this data to them.

I am sitting in a room with 3 Baverians, and these questions are being asked by them, just so you know.

bucketracer

28th October 2010, 21:13

I am glad your are proud of your work.

Yes I am proud of my work.

The rest of your post is a bit rambily, it would be smarter if you could explain how TeeZee's plenum idea tops your best efforts to date........

SS90

28th October 2010, 21:16

Yes I am proud of my work. The rest of your post is a bit rambily but maybe you can explain how TeeZee's plenum idea tops your best efforts to date........

Don't change the subject.

Buckets4Me

28th October 2010, 21:16

Im flattered to be your idol Bucketracer.
.

I dont think he was saying you where his Idol :p

Buckets4Me

28th October 2010, 21:18

Don't change the subject.

why not your good at it

bucketracer

28th October 2010, 21:23

Don't change the subject.

No...... your the one that keeps talking about the plenum and dyno graphs

Here is yours and mine to help you,......... now why is the plenum better than the graph of your best efforts?

I think we will be ignoring you again until you can say something sensible.

SS90

28th October 2010, 21:26

No...... your the one talking about the plenum and dyno graphs

Here is yours and mine to help you,......... now why is the plenum better than your graph?

What, 4 years ago, on a cylinder I made myself, running through a 4 speed gear box, that currently makes over 27 PS?

You really are making me look good. Thanks!

now, stop your all too familiar desent into childishness, before the moderators close this thread down!

My question is simply do you know why the cylinder you and Thomas did makes less power than a cylinder with essesntially a standard cylinder, with just the exhaust time area increased?
I am interested to know why.

gav

28th October 2010, 22:03

Yes I am proud of my work.

The rest of your post is a bit rambily, it would be smarter if you could explain how TeeZee's plenum idea tops your best efforts to date........

Seriously, you two are as bad as each other, but SS90 does raise some valid points.
Have you got any dyno runs of the various set ups to compare. Could be as simple as different weather conditions etc on the day of the runs or maybe the later curves make less peak power but over a broader range? It wouldnt do any harm to pull your head in now and again and try and answer a quite reasonable question.

SS90

29th October 2010, 06:49

or the fact it has a new pipe on it

why answer someone that is just trying to cause trouble ??
did you not read the posts he has deleted ?

where where the reasonable questions in calling bucketracer names

What the hell are you talking about?

What names?

You paranoid boy.

This is a public forum, and as such, like it or not, debate and discussion is permitted.

I don't think it unfair to discuss the fact that current "set up" seems to make less power than last.

Its topical. Very much so.

We can take the different dynes into account, fair enough, but the point I am trying to make is that, from the data provided, the old cylinder, with no plenum, makes more power than the new cylinder with a Plenum.

This is going by your Fathers data.

I was hoping someone would have data from all the available set ups you have been posting.

Apples with apples and such things.

Are there any runs of the same engine with the several other exhaust options your Father has available?

If I was trying to draw a conclusion for the highest power engine, going by the data your Father has provides, it would seem that the old cylinder, with the new exhaust, and the Plenum would make well in advance of 21 hp ( Because if the new cylinder makes LESS power WITH the Plenum than the old cylinder made WITHOUT.... It would stand to reason that (going by TeeZees data) that to achieve the most power (peak and spread) you need the new pipe, the old cylinder , and the Plenum.

This is, of course, assuming that all data presented has been honestly applied to each example.

It seems really odd to me, that's all.

Going by the data provided that is.

kel

29th October 2010, 12:24

The simple fact is that the ESE motors have had serious development time and thought poured into them and the results show not only in the quality (and volume) of work but in the performance on the track. The GP125's are producing seriously useable power and a top end to envy. So it’s great to compare Dyno runs but let’s face facts it is on the track that real performance is measured. The level of racing at Mt Wellington is fierce, Avalon (on an ESE bike) was in third place in the points race before retiring with a non motor related mechanical issue, there's your proof on performance!:bye:
Teezee, I look forward to your continuing experiments, development and results.

SS90

29th October 2010, 21:31

.

I would be impressed by a videoed 27 PS at the rear wheel dyno run of a 24mm carbed rotary valve air cooled 125cc 2-stroke engine with more than a 2000 rpm power spread that you built yourself, any chance of a vid and graph?......:)

This is Buckets first dyno graph.

Ok, I will post a video of one of my engines on the dyno, 125cc air cooled, 28mm carb reed valve piston inlet induction 28 mm D slide Dellorto..... And I have already posted a graph.... Last year As soon as you post a video of either the plenumed bike riding a lap or 2 , or running on a dyno.

fair enough?

SS90

29th October 2010, 21:39

Its the only dyno graph I have, and SS90 has been told many times that the plenum works, and even seen vids of it, TeeZee has been more than reasonable, and yet SS90 goes on trying to undermine his achievements.

"He raises some valid points", well I don't think so. Whether or not my engine makes more or less power than other ESE bikes is irrelevant. Its the comparison on the same engine, with and without the plenum fitted that matters and indicates it's potential.

This time we had my graph showing a proper apples with apples comparison between the two setups and it was my pleasure to point out it equals or betters the best yet seen from Bavaria. So.....make a habit out of mocking my Karate suit and acoustic guitar at your peril.

And if the Bavarian s haven't been able to see the potential by now they probably couldn't understand the answer anyway, that is, unless they are onto it and SS90 as their front man is being deliberately obtuse.

What a load of cobblers, I posted a graph of a 20 hp 24mm carbed disc valves engine 12 months ago... In fact, Teezee reposted it a couple of pages back.... That engine was built almost 6 years ago.

All your waffle about people not understanding BMP is ridiculous.... Thus is what some of us do for a living, you simply google things then list them here, and get your back up when I question your data.

If you don't like it, yiu would just have a wee private forum jerk circle so you can tell each other how good you are.

This is a public forum, and debate and discussion is permitted.

If you don't like it, write a book.

SS90

29th October 2010, 21:45

And, for the record, using your data, so far, the evidence is that the Plenum does not work.

The old engine WITHOUT the Plenum made more power than the new engine WITH the Plenum.

that's a FAIL.

SS90

29th October 2010, 22:10

My first try with the plenum is as good as that, people who claim they do it for a living should be ashamed of themselves.... got anything more up to date, didn't think so, so do we have to mark your efforts as a fail????????

And you didn't show much understanding of BMEP on page 2683 when TeeZee was trying to explain it to you..... you should Google more and expand your education ....

This is a public forum, and debate and discussion is permitted.

If you don't like it, write a book.

BMP is quite new to you, as you have demonstrated, as are time areas, scavenge patterns, squish heads, primary compression, and so on.

TeeZees continual insistence on trying any mathematical formula to "smoke and mirror" observers into believing that this engine may make less power, but if we look at this portion of the the graph, we see a gain, so this makes it an all round better engine.

Its good that your dad tells you how good you are, it's important for a teenager to hear these things... But let us not lose sight of that fact that encouragement needs to be tempered with reality.

If you want to run with the big boys, and spend the last year criticizing my writings, you have to be prepared for the consequences.:violin:

It was only a year ago that Team ESE claimed that the key to power was exhaust port duration, and that the engine made so much power that it was over heating..... We all know the out come of that theory....eh!

But, I will concede that if you can somehow manage to read this thread from post to post (hard work), you have been able to demonstrate that the way to learn, is to actually listen to what others say, and not follow the net blindly, and act like you knew it all the while time.

gav

29th October 2010, 22:30

:facepalm:

Yow Ling

30th October 2010, 09:02

:facepalm:

Yea that showed em Gav !!

bucketracer

30th October 2010, 11:02

from the data provided, the old cylinder, with no plenum, makes more power than the new cylinder with a Plenum.

Apples with apples and such things.

Comparing the old engine, which is now in Chambers bike (72) with TeeZee’s new one (14) is not, Apples with apples and such things.

To get an idea if the plenum concept works, you have to test the same engine, with and without the plenum…

SS90 does raise some valid points. It wouldn’t do any harm to pull your head in now and again and try and answer a quite reasonable question.

I don’t think they are valid points, you know, apples with apples and such things, and as for pulling my head in and answering a reasonable question, I would if it was also honest and intelligent ……..

And, for the record, using your data, so far, the evidence is that the Plenum does not work. The old engine WITHOUT the Plenum made more power than the new engine WITH the Plenum. that's a FAIL.

Mt Welly is more about drivability than power. When your not being childish you do sometimes make sense and ironically I was trying some of your ideas, Dad said they wouldn’t work, but I was pleased he gave me a free hand to try.

I will leave my graph with the plenum so others can see for themselves if the plenum works, when compared, back to back on the same engine, you know, Apples with apples and such things and a graph of your best work so they can compare my efforts plus the plenum with you own.

That way they can make up their own minds. If you have a more up to date graph, please post it.

SS90

30th October 2010, 11:29

Comparing the old engine, which is now in Chambers bike (72) with TeeZee’s new one (14) is not, Apples with apples and such things.

To get an idea if the plenum concept works, you have to test the same engine, with and without the plenum…

I don’t think they are valid points, you know, apples with apples and such things, and as for pulling my head in and answering a reasonable question, I would if it was also honest and intelligent ……..

Mt Welly is more about drivability than power. When your not being childish you do sometimes make sense and ironically I was trying some of your ideas, Dad said they wouldn’t work, but I was pleased he gave me a free hand to try.

I will leave my graph with the plenum so others can see for themselves if the plenum works, when compared, back to back on the same engine, you know, Apples with apples and such things and a graph of your best work so they can compare my efforts plus the plenum with you own.

That way they can make up their own minds. If you have a more up to date graph, please post it.

Erm, Im not trying to make this a competition.

It's late, and I have been at work since 8:00 am...... But, ok, let's rock.

Ignoring the other graphs I posted, let's concentrate on this one.

My engine produces 20 PS at just over 7500 rpm

Yours less than 7ps at the same rpm....

Mine 19 NM at 7250

Yours.... A shade over 13NM at 9700

Which is more driveable?

Would you like to discuss BMEP now?

You know, if you stopped trying discredit me, and compete, just realise you are young and have a lot to learn.... And you might actually start.

Here is some really good advise.

If you want to be a tuner, other than showing some respect, a great idea would be to get hold of an AX100 (you can buy 125 cylinder kits for them), fit a 24 mm carb to be in the rules, and develop a high horsepower engine with the restrictions of a 4 speed gear box..... When everyone around you has the same limitations (no possibility of 5 speeds), the level of competition goes through the roof.

Trust me, 125cc, 4 speed, 23 PS is achievable....albeit peaky power...... And difficult to keep in the power.

TZ350

30th October 2010, 20:15

.

Changing tack slightly......... we have been troubled by carb flooding in the past, with old carbs, the problem was traced to the "O" ring around the needle seat. It shrinks over time and leaks allowing the carb to flood. Its not a common size but we were able to get them from seal imports...............

jasonu

31st October 2010, 04:44

...If you want to be a tuner, other than showing some respect, a great idea would be to get hold of an AX100 (you can buy 125 cylinder kits for them), fit a 24 mm carb to be in the rules, and develop a high horsepower engine with the restrictions of a 4 speed gear box..... When everyone around you has the same limitations (no possibility of 5 speeds), the level of competition goes through the roof.

Trust me, 125cc, 4 speed, 23 PS is achievable....albeit peaky power...... And difficult to keep in the power.

It would be like riding a can of spagetti and maybe a bit dangerous with the AX running gear.

TZ350

31st October 2010, 13:20

It would be like riding a can of spagetti and maybe a bit dangerous with the AX running gear.

Something like riding our old GP's...............

TZ350

31st October 2010, 13:31

Ok.... a revisit of the three times past the main jet thing ..............

No one that disagreed with me has yet told us what happens to the induction wave when it slams up against the inlet when it shuts.........

Now, we know, at that point it becomes a reversion wave............

But those that say, that the inducted inlet mixture does not pass the main jet at least three times have not yet explained what happens to the inlet charge that is turned back as a reversion wave when the port closes......... and what happens when the inlet port opens again.

What do they think it's doing, sitting around having a picnic?

Anyone can see that the mixture won't be just lamely waiting around to be sucked in on the next induction cycle, as it's dynamic and will be heading of somewhere, and quickly............

I would like to know more, and could reaserch it and maybe find an interesting link to post, but this is something that a person who endlessly tells us they make their living tuning 2-strokes, so knows what they are talking about could probably explain in a more interesting way.

Now, what I think happens.... is the induction mixture resonates in the inlet tract, and some, if not all passes the main jet at some point, at least three times.......

If you think I am wrong.... try explaining what you believe actually happens.....

Moooools

31st October 2010, 17:36

Two dyno graphs scaled-alike. Enjoy.

(Team ESE wins in my opinion):yes:

speedpro

31st October 2010, 20:58

SS90

31st October 2010, 21:51

Two dyno graphs scaled-alike. Enjoy.

(Team ESE wins in my opinion):yes:

Hhahahahaha,
So you are trying to tell us that an engine that produces DRAMATICALLY less torque at DRAMATICALLY higher RPM is a better engine?

Bwahahahahahah!

:scooter:

SS90

31st October 2010, 22:05

I'm no scientist but I have observed a fog of fuel and air outside a carburetor opening at certain rpm on the dyno. We all agree air entering a carburetor on it's way to the engine collects fuel as it passes through the carb. It "may" not collect any fuel as it bounces out and the fog I have observed "may" be the air mixed with fuel it collected on the way in. When that air/fuel fog reenters the carb once the intake cycle restarts it will collect more fuel as per the first time it entered. At the least the air entering a carb that is bounced back out once the intake port closes will collect two loads of fuel. I personally think there will be fuel collected by the air every time it passes through the carb.

Easy check would be to put a carb on the test bench with airflow reversed and see if any fuel is mixed with the air as it flows in the reverse direction.

Ignoring TeeZess intentionally antagonistic post, I will reply to yours Speedpro.

"fogging" or "standoff" is more prevalent depending on set up of an engine.... The higher state of tune ( high exhaust time area,blowdown time, expansion chamber baffle angle and so on), anyone that has run a 125GP bike with out an air box can relate to this.

When the bike comes on the pipe, and the inlet tract comes into to resonance, standoff will occur, certainly, I don't disagree.

But, to say that this causes the main jet to be drawn from "a minimum of three times" as far as I am concerned in nonsense.

I see it as a similar effect to the plugging effect of an expansion chamber on an exhaust port.

The returning wave meets an incoming wave, and the result is a mixing of the incoming air and fuel, meeting the returning air/fuel.

If this "three times past the main jet" theory was accurate, power jets would be redundant.....

TZ350

31st October 2010, 22:17

Would you like to discuss BMEP ........

Trust me, 125cc, 4 speed, 23 PS is achievable....albeit peaky power...... And difficult to keep in the power.

I am always interested in BMEP.......
Could you please give me the calculated results for those figures you quoted, the answer in psi or bar is ok...

Ours from memory (original plenum run) when we couldn't get a graph from Johns dyno, were 115psi for 20hp at 9,500 and 125psi for 19hp at 8,500 rpm.

And have you actually acheved that... 23PS, 125cc with a 24mm carb, ......

I am interested in a little more info if you have it, was it rotary valve and air cooled, 23PS at what rpm and how wide was the power spread? as measured from peak torque to peak hp ...

And do you (hopefully) have a dynograph of this 23PS engine, .....or was it just a theory?

I ask because I am interested in these things ........

SS90

31st October 2010, 22:25

I am always interested in BMEP.......
Could you please give me the calculated results for those figures you quoted, the answer in psi or bar is ok...

Ours from memory (original plenum run) when we couldn't get a graph from Johns dyno, were 115psi for 20hp at 9,500 and 125psi for 19hp at 8,500 rpm.

And have you actually acheved that... 23PS, 125cc with a 24mm carb, ......

I am interested in a little more info if you have it, was it rotary valve and air cooled, 23PS at what rpm and how wide was the power spread? as measured from peak torque to peak hp ...

And do you (hopefully) have a dynograph of this 23PS engine, .....or was it just a theory?

I ask because I am interested in these things ........

I certainly do have a dyno graph, and I will print it our and date it too.... Even post it on here.

On one condition.

You supply a video of either the Plenumed bike being ridden down the road (or on track).... And by ridden, I mean a complete set of gear changes, or being run on a dyno.

Prove to us all it works.

in return, I will post a video of a 23 ps, 24mm carbed 125cc air-cooled 4 speed engine being run on a dyno.

fair?

TZ350

31st October 2010, 22:29

When the bike comes on the pipe, and the inlet tract comes into to resonance, standoff will occur, certainly, I don't disagree.

But, to say that this causes the main jet to be drawn from "a minimum of three times" as far as I am concerned in nonsense.....

Now if we take one of those molecules of fuel from the standoff at the bellmouth.

We have to ask, did it get added to the fuel as the air mixture was moving into the carb (first pass)

or did it get added as the mixture reversion moved back out to the carbs Bellmouth (second pass as ventures work in both directions)

and will another molecule be added when this fog is sucked back in (third pass) just asking……..

TZ350

31st October 2010, 22:38

I certainly do have a dyno graph, and I will print it our and date it too.... Even post it on here.

On one condition.

You supply a video of either the Plenumed bike being ridden down the road (or on track).... And by ridden, I mean a complete set of gear changes, or being run on a dyno.

Prove to us all it works.

in return, I will post a video of a 23 ps, 24mm carbed 125cc air-cooled 4 speed engine being run on a dyno.

fair?

The plenum has worked well enough for Bucket to match your best so far and that the concept works.....

Do you have a dyno graph or not, it's a fair question, if you have post it.....

We know the plenum concept works, Bucket proved that and as the plenum hopfully progresses to something practical it's progress will be posted up, you can count on it.

You asked for a dyno graph of the plenum and expresed an interest in back to back tests with an ordinary carb, we gave it to you.

I wouldn't say your full of it but..........now its your turn.......

SS90

31st October 2010, 22:42

Now if we take one of those molecules of fuel from the standoff at the bellmouth.

and will another molecule be added when this fog is sucked back in (third pass) just asking……..

Interesting, but, like I say, if the returing air/fuel passes over the main jet, just as an expansion chamber "plugs" an open exhaust port, does the same not happen for a main jet, and, if not, why.....?

If this was a valid theory, would we not have electronically controlled man jets that acted in place of an electronically controlled power jet?

And when you think about it, when you use a power jet, you use a smaller main jet, equal to approximately the differential between the main jet and the original power jet.

In your theory, power jets are redundant, because (in your theory), this occurs naturally.

TZ350

31st October 2010, 22:46

Interesting, but, like I say, if the returing air/fuel passes over the main jet, just as an expansion chamber "plugs" an open exhaust port, does the same not happen for a main jet, and, if not, why.....?

If this was a valid theory, would we not have electronically controlled man jets that acted in place of an electronically controlled power jet?

And when you think about it, when you use a power jet, you use a smaller main jet, equal to approximately the differential between the main jet and the original power jet.

In your theory, power jets are redundant, because (in your theory), this occurs naturally.

You are wiffiling again.......... if there is a standoff, on which pass did that molecule come from....... before replying again take some time to think about it....... there may be another answer......

SS90

31st October 2010, 22:48

The plenum has worked well enough for Bucket to match your best so far and that the concept works.....

I wouldn't say your full of it but.....

Do you have a dyno graph or not, it's a fair question, if you have post it.....

We know the plenum concept works, Bucket proved that and as the plenum hopfully progresses to something practical it's progress will be posted up, you can count on it.

You asked for a dyno graph of the plenum and expresed an interest in back to back tests with an ordinary carb, we gave it to you now its your turn.......

Would you and your offspring stop turning this into a pissing contest TeeZee?

In any event, you have not matched diddly squat.

I beat you on your precious BMeP, by a long shot.

19 NM at 7400 rpm?

What do you have?

Not even close.

I will happily supply all the graphs and video you need, just as soon as you out your money where your mouth is.

Again, you say it works, I say "prove it".... You have never supplied an independent witness to say it works, a six month old video of a single gear run up your mums driveway proves nothing.

What do you have to lose?

Do it, and I will stop posting on your thread.

just oust a video of you plenum bike doing an all gear run up the road, or even better, and all gear run on a dyno.

I heard a wee birdie from Hampton downs recently........ I'm confident you cannot prove this thing works yet.....

TZ350

31st October 2010, 22:58

Do it, and I will stop posting on your thread.

You have already used that line up when you told us, that if we posted a dyno graph of the plenum you would stop posting on the thread........

Its becoming ever apparent you word's not worth much .......

We have shown you the plenum graph you asked for, now you owe us.........

So go on post your graph and tell us how wide the power spread is.........

SS90

31st October 2010, 23:05

You said that if we posted a dyno graph of the plenum you would stop posting on the thread........

you word's not worth much .......

We have shown you the plenum graph you asked for now You owe us.........

So go on tell us how wide the power spread is then.........

The offer was time dependent TeeZee.

The word from Hampton downs is not giving you any credibility.........

Come on man, stop dribbling, and come up with the goods....... Your starting to sound like your plenum.... I think it went....... Bkahhrgggghhhhh. Bbblllaghhhhh.....

TZ350

31st October 2010, 23:13

The word from Hampton downs is not giving you any credibility.........
Come on man, stop dribbling, and come up with the goods....... Your starting to sound like your plenum.... I think it went....... Bkahhrgggghhhhh. Bbblllaghhhhh.....

The person who embarks on personal attacks is the one who does not want to defend the facts........

Why can't you answer reasonable questions? Like why did Buckets engine equal your best efforts when he used the plenum?

Put up your new dyno graph if you have one and add something to your own credibility or go home.........

SS90

31st October 2010, 23:22

The person who embarks on personal attacks is the one who does not want to defend the facts........

Why can't you answer reasonable questions? Like why did Buckets engine equal your best efforts when he used the plenum?

Put up your new dyno graph if you have one or go home.........

But it has not equalled my 2 year old engine.... Your confused...... How does your engine match mine?

Mine 19NM at 7400
Yours 14NM at 9500..... WTF?

the modified graph that Moooools posted says it all. (thanks for that Mooools!)

And, stop with the smoke and mirrors will you?...... You have not been able to explain why the new engine, with the Plenum produces less power than the old one with out a Plenum.

I am not making personal attacks TeeZee, not even close, you keep saying it works, onlookers at Hampton Downs say it did not.

TZ350

1st November 2010, 05:34

But it has not equalled my 2 year old engine.... Your confused...... How does your engine match mine?

Please post the up to date dyno graph of your rotary valve, air cooled, 125cc engine with the 24mm carb and I will show you how my engine match's it..........

The person who embarks on personal attacks is the one who does not want to defend the facts........

Why can't you answer reasonable questions? Like why did Buckets engine equal your best efforts when he used the plenum?

Put up your new dyno graph if you have one and add something to your own credibility or go home.........

Like I said before, why can't you answer a reasonable question? Like why did Buckets engine equal your best efforts when he used the plenum?

SS90

1st November 2010, 05:57

Please post the up to date dyno graph of your rotary valve, air cooled, 125cc engine with the 24mm carb and I will show you how my engine match's it..........

Like I said it before, why can't you answer a reasonable question? Like why did Buckets engine equal your best efforts when he used the plenum?

But it doesn't TeeZee. None of your engines match mine in any way.Your efforts to fustrate me, are amateur at best.

I'll give ya wee tip. Your exhaust designs where the power is lacking .... Ditch the computer programmes...... Get your own dyno (I think one of your previous plans was to build one ) and spend a few months with some sheet metal, a good EGT, and a sheet metal roller (clip joints are amazing here) and see what you come up with. The expansion chamber is the key.

Move the Karate suit, acoustic guitar, train set, and drum kit to the side...and make space for your latest incomplete project.

Moooools

1st November 2010, 06:35

Hhahahahaha,
So you are trying to tell us that an engine that produces DRAMATICALLY less torque at DRAMATICALLY higher RPM is a better engine?

Bwahahahahahah!

:scooter:

Who said anything about engines?!
Team ESE wins by default because they don't come across as ego stroking jackasses in every post.:innocent:

TZ350

1st November 2010, 14:56

But it doesn't TeeZee. None of your engines match mine in any way.Your efforts to fustrate me, are amateur at best.

Move the Karate suit, acoustic guitar, train set, and drum kit to the side...and make space for your latest incomplete project.

As I said before.......

The person who embarks on personal attacks is the one who does not want to defend the facts........

Why can't you answer reasonable questions? Like why did Buckets engine equal your best efforts when he used the plenum?

Put up your new dyno graph if you have one and add something to your own credibility or go home.........

Why can't you answer a reasonable questions?

Like why did Buckets engine equal your best efforts when he used the plenum?

Why won't you put up a dynograph of your up to date engine?

Thats the real head scratcher...... :scratch: it's not an unreasonable question.....

TZ350

1st November 2010, 15:35

No, what I mean is you seemingly had more power without the Plenum previously.....3 horsepower more it would seem.

I was wondering what the difference was, Thats what I don't understand.

I think Bucket has already answered that.......

Comparing the old engine, which is now in Chambers bike (72) with TeeZee’s new one (14) is not, Apples with apples and such things.

To get an idea if the plenum concept works, you have to test the same engine, with and without the plenum…

Mt Welly is more about drivability than power. When your not being childish you do sometimes make sense and ironically I was trying some of your ideas, Dad said they wouldn’t work, but I was pleased he gave me a free hand to try.

That's it test the same engine with and without the plenum and it does not take a genius to work out that he wasn't looking for power but spread and drivability. In real terms maybe it wasn't great but at least with the plenum it was the equal of SS90's own peaky graph......

To ask why it didn't make as much as mine was not unreasonable, but to keep harping on after being told the answer, thats when it become unreasonable........

Hands up anyone else who thinks that SS90 has wasted enough of our time.......

I would have liked this to be worthwhile but it takes two, so moving on......

Leed

1st November 2010, 15:50

.
.
your all havin me on right...

I started at Page 1 of this thread, read 70% bore

and jumped forward and saved myself 193 pages of dribbling non-sense

havent reliable two strokes (road bikes included) have had 80% bore ratios for over twenty years?

so tell me what page do I need to skip back to, to make some power before I fit my 39mm carbs to my 125cc cylinder??

Anyone want my new Vforce3 reeds for a Banshee (see advert on Bike Trader page of forum) or a spare pair of PWK 39mm if interested
.
.

TZ350

1st November 2010, 18:16

Leed

1st November 2010, 19:24

In this class of racing F4, 125cc 2-strokes are limited to a 24mm carb and air cooling ......

Use "thread tools" near the top of the page then "view thread images", helps cut through the boring bits......

Inspite of the dribble various people have posted some good stuff, looking through the pictures is a better way of finding it........

sweet thanks for the tips there - this forum has things a bit more complex in navigating and finding like minded topic is tricky - I saw several here had RG50 and assumed in general you were also talking water cooled motors...

I wont comment on the pages I read on what is a balance factor etc because
if you dont have to relocate a web pin (stroke), change rod length, compensate for lighter or heavier pistons, crank phasing or use other parts in place of parts no longer available, you need never worry about getting a PHD on the subject and would just run what was on the bike originally

speedpro

1st November 2010, 19:34

....I wont comment on the pages I read on what is a balance factor etc etc because if you dont have to relocate a web pin (stroke), change rod length, compensate for lighter or heavier pistons or use other parts in place of parts no longer available you need never worry about getting the degree on the subject

Unless . . . you are revving it a lot more than it was designed for.

FYI - I've reduced the stroke, have a longer rod, different piston, removed the counter-balance shaft, and rev it heaps higher. Apart from that it's just like when Mr honda built it.:beer:

richban

1st November 2010, 19:41

Leed

1st November 2010, 19:58

someone is bound to have a Helmholtz arithmatic sum lying around they no longer have use for

:shutup:

does a bucket stop being a bucket once the cylinder is of a certain capacity

or just when you stop needing an arc welder?

TZ350

1st November 2010, 22:28

Have you guys looked at a conventional plenum in front of the carb. I was wanting to make an adjustable one to tune on the dyno but never did. I read somewhere that with a properly resonating airbox/plenum you can achieve 130% intake efficiency. That way you could get rid of the pod filter you were going to run. I have a large dislike for pod filters. Just a thought.

Yes I think your right, that there are gains to be made and if you have a programmable ignition that can control a power valve stepping motor you could use that to make a resonating airbox that's resonant frequency was adjusted to match the rev's.

But you would still be stuck with the problem that only so much air can be forced through 24mm. At a certain velocity (mach number) the carb chokes and no amount of increased pressure can force any more through any faster.

The idea behind our plenum is that the engine gets to suck air/fuel from a large volume through a larger 30'ishmm inlet and as the motor only sucks for half the time the 24mm carb at WOT has all the time to re-fill the plenum and ineffect could flow twice the air to the engine than a conventional 24mm side carb can.

Of course, twice as much = twice the power, well it doesn't quite work out like that in reality but Buckets dyno graph showed that the plenum added some useful gains and lifted the torque curve of his motor. It makes sense that a longer flatter torque curve is much more drivable than a peaky one......

I can see a variable resonating air box being an interesting idea, now that could be plan "B" or the next project after we get the plenum sorted...........thanks for the idea.

Leed

2nd November 2010, 07:07

what is that diagram trying to say...

the airbox has a 250cc volume?
its the motor that is 250cc?
the engine is sucking from dia34mm?

TZ350

2nd November 2010, 11:15

what is that diagram trying to say...

the airbox has a 250cc volume?
its the motor that is 250cc?
the engine is sucking from dia34mm?

Class regulation, restrictive 24mm carb feeding 250cc plenum, 125cc motor sucking from plenum through 34mm inlet tract. In theory motor is not restricted by 24mm carb........

Brilliant huh..... and the first working example was seen here, in NZ, the world center of 2-stroke innovation......:laugh:

Leed

2nd November 2010, 11:26

I congratulate you on YOUR invention

maybe you could call it Boost Bottle 2k10

TZ350

2nd November 2010, 17:55

As we know, a torque curve like the Matterhorn, however high, makes for a peaky engine and difficult to ride and that a flater wider torque curve makes for a more drivable engine and of course, flat, wide and higher is better still.

Looking at buckets graph showing the back to back trace of a conventionally mounted 24mm carb vis the plenum with its 34mm internal inlet.

You can see that if both torque curves could be combined in some way the power spread could be nearly 3,000 rpm wide, an extra 50%, making for a much more drivable engine.

As the only real difference between the curves is, that one is of a 24mm inlet tract and the other a 34mm one.

Now we are not talking about changing the length here for some resonant gain, but varying the effective diameter of the inlet as the rev's change.

This works, because reducing the inlet diameter as the rev's drop keeps the kinetic energy of the gas stream up for better crankcase stuffing at lower rpm and the larger inlet tract allows better crankcase filling at higher rpm.

So logic would tell us, that if we could have an inlet that varies in diameter from 24 to 34mm as the rpm increases then we would get the combined benefit of both curves.

But how to do that........... :scratch:

richban

2nd November 2010, 19:11

So logic would tell us, that if we could have an inlet that varies in diameter from 24 to 34mm as the rpm increases then we would get the combined benefit of both curves.

But how to do that........... :scratch:

You could rob the aperture ring out of a camera lense for resting on the dyno. Some very old lenses had very manual aperture controls. You would need maybe an 85 mm lens then just rig a cable to the aperture and throttle job done. Easy you may need a swiss army knife in your tool kit for this job.
222666

Yow Ling

2nd November 2010, 19:24

You could rob the aperture ring out of a camera lense for resting on the dyno. Some very old lenses had very manual aperture controls. You would need maybe an 85 mm lens then just rig a cable to the aperture and throttle job done. Easy you may need a swiss army knife in your tool kit for this job.
222666

that might cause alot of turbulence when maybe you want laminar flow.
maybe a piece of rubberish tube with ally ends if you wound up one end the rubber tube could constrict, could use a ypvs servo to do the twisting , they start coming on at 6 or 7 k, all in by 9500

bucketracer

2nd November 2010, 20:22

You could rob the aperture ring out of a camera lense......
222666

That looks good.......

.......maybe a piece of rubberish tube with ally ends if you wound up one end the rubber tube could constrict, could use a ypvs servo to do the twisting.....

Hadn't thought of that........ but it looks very good too........

222673

I dug around in Dad's junk box and found a tuning capacitor. I had in mind that if he made a whole lot of leaves like the capacitor has and put a 34mm hole through them, then when the leaves are rotated, the hole that forms the inlet would be opened or closed and when fully open it could be quite smooth inside.

bucketracer

2nd November 2010, 20:59

......maybe a piece of rubberish tube with ally ends if you wound up one end the rubber tube could constrict, could use a ypvs servo to do the twisting , they start coming on at 6 or 7 k, all in by 9500

Actually what about just flattening the tube, reducing its cross sectional area for lower rpm and opening it again for high rpm........

Buckets4Me

2nd November 2010, 21:18

So logic would tell us, that if we could have an inlet that varies in diameter from 24 to 34mm as the rpm increases then we would get the combined benefit of both curves.

So logic should tell you this is going to be long and costly and you had better put it out of your mind till after Taupo

bucketracer

2nd November 2010, 21:35

I congratulate you on YOUR invention

maybe you could call it Boost Bottle 2k10

Actually that's a good idea, a snappy name for TeeZee's plenum, but Boost-Bottle is not right as a boost bottle is a resonant chamber and TeeZee's plenum is a space where fuel/air mixture is stored waiting for the engine to snap it up.............

Maybe it should be called 2K10-Red-Shed where every engine gets a bargain.........

SS90

2nd November 2010, 22:46

Actually that's a good idea, a snappy name for TeeZee's plenum, but Boost-Bottle is not right as a boost bottle is a resonant chamber and TeeZee's plenum is a space where fuel/air mixture is stored waiting for the engine to snap it up.............

Maybe it should be called 2K10-Red-Shed where every engine gets a bargain.........

Huh?

Its the same thing, a boost bottle is a resonant chamber, and so is the plenum.

Leed

3rd November 2010, 07:56

So logic would tell us, that if we could have an inlet that varies in diameter from 24 to 34mm as the rpm increases then we would get the combined benefit of both curves.

yep... its call a carburetor

the works teams only used inlet tracts as short as possible... but you want to add volume...
...but they had the choice to run as bigger carbs as they liked.

the ideal lengths for inlet and exhaust are way longer than practical on a motorcycle hence tuning to lower orders of resonance.
what about upstream of the carb that also affects its flow... variable length trumpets (as done on the R1), stacks with proper/full return radius's
controlled by a powervalve servo
...but not that practical if the carb is at the front of the engine

bucketracer

3rd November 2010, 14:07

Huh?

Its the same thing, a boost bottle is a resonant chamber, and so is the plenum.

And TeeZee would call it a resonant chamber too, if that was the primary reason it is there .......

But unlike the resonant boost bottle, the plenum has a bigger purpose ......

F5 Dave

3rd November 2010, 16:52

I have to pop in to say making that sort of power at such pedestrian revs is pretty impressive. Now presumably the restrictions of poxy scooter parts, 4 gears & perhaps fixed gearing mean keeping to those sort of revs. Give that sucker some revs & I don't think the 'shape' of the torque curve would be a discussion point.

bucketracer

3rd November 2010, 17:44

SS90

3rd November 2010, 22:29

Just roll back a years worth of posts, you will see several other curves, all revving to 10,000 or so, some quite impressive, some a little more amateur.

For us, it come down to rideability.

I like my road engines to be like that, and my favorite race engine actually only makes 18 ps, but is so easy to ride fast, particularly on the karts tracks in Europe (although, generally speaking, they are somewhat more open than NZ Kart tracks)

Just to reaffirm where scooter engines are at, remember, we have been getting more tha 27 ps and 22 NM for some years now, it is nothing new (34mm carbs).

But the trend for many of us now is to have the most torque at the least RPM.

Its easier than you think to achieve

Plenty of us are getting 22 to 23 ps with 24 mm carbs, 4 speed gearboxes, and so on.

The 24 mm carb is more about "how much can I get" rather than being a rule like buckets (no carb size limit it most of the classes), although there is a "control class" for certain a model of cylinder, certain manifold, and certain carb, but the top 3 bikes are dyno tested at the end of the days racing, and anyone with more than 13ps is disqualified (unless theybare wiling to have their engine pulled down to check..... No one ever has been willing, funnily enough)

The rules are different though, in the class you now can run up to 140cc, but not that many people do, the reality is, in a short wheel based oddball set up as these things, you only really need, like I say 20 ps and 20 nm, and you have a good chance of getting on the podium. That and the fact that you don't need to rebuild you engine every 3 meetings.

the guys running the maximum capacity, easily break 30ps and 24nm (at about 11,500 rpm)

There is a guy in Saarbruken that has recently achieved 38ps, but it is water cooled,and 140cc.

It will be for quarter miles, of that I am certain.
It appears a Small frame Vespa crank can only handle more than 25 ps for only so long.... New ones are only €34, so not a big worry, unless of course you had cut them like me, then you have some hoers prep work.

TZ350

4th November 2010, 05:49

Just roll back a years worth of posts, you will see several other curves, all revving to 10,000 or so, some quite impressive, some a little more amateur.

Plenty of us are getting 22 to 23 ps with 24 mm carbs, 4 speed gearboxes, and so on.

Thank you for the wright up, yes your right, it's not always about hp, and we think, being easy to ride is where the FXR's have got it over us at Mt Welly.

Looking at the shape of the curves is where we are getting to now ourselves. The last year has turned out being more about building new chassis than engine development.

Building up new bikes takes longer than anyone would think and we feel we are runing out of time (again) to be ready for Taupo.

I will see if I can find the earlier graphs, and I am trying to get some graphs of different FXR's for comparison.

Because they relate to our own work any graphs of your 22 to 23 ps engines with 24 mm carbs would be most welcome.

SS90

4th November 2010, 07:08

The first one from the same series of runs, (different exhaust), same carb, same head, but had a very high primary compression

All early runs I have saved are from screen shots, because at the time
of all this work, we had a printer compatibilty problem, and I had to save screen shots of everything, everything from the end of summer 08 can be printed.

The second run, (believe it or not), is exactly the same cylinder as the first run we have been comparing to bucketracers cylinder (20.1PS), and I mean EXACTLY, and we fitted the same exhaust as the first graph..... I assure you, the cylinder is the same 100%...... only the primary compression is more suitable to the set up.

The "hole" at 5,500 rpm, with some effort can be tuned out, its not easy, but it can be done (Baffle angle).... this cylinder and exhaust set up, if optimised, will see 23PS with 24 mm carb, and, if you have the energy (and a 34mm carb, or bigger) I have seen 27PS....... it is worth noting, 23PS is where the clutches start needing "a little work"

F5 Dave

4th November 2010, 10:13

. . .
The "hole" at 5,500 rpm, with some effort can be tuned out, its not easy, but it can be done (Baffle angle).... . . .

Do you think? Odd. Typically if the baffle angle is too steep the hole is considerably closer to peak power & the peak power is pretty peaky. Dual stage baffles are supposed to provide an extended over but are harder to get right than single cone. I would have thought that dip would have been an inlet compromise. A symptom of loading up perhaps. What was the inlet method? Over enthusiasm on the throttle on the dyno & a rich needle?

SS90

4th November 2010, 11:08

Do you think? Odd. Typically if the baffle angle is too steep the hole is considerably closer to peak power & the peak power is pretty peaky. Dual stage baffles are supposed to provide an extended over but are harder to get right than single cone. I would have thought that dip would have been an inlet compromise. A symptom of loading up perhaps. What was the inlet method? Over enthusiasm on the throttle on the dyno & a rich needle?

The dip at 5,500 is a really well known thing here, and is due to the exhaust... (Shallow long baffle angle) many people in the scooter scene have battled that for years (before my time), and indeed to you can tune it out with some carb set up, but it is never perfect (although it shows up much more on the dyno than on the road)

If you scroll back to about February or march, I posted a picture of the baffle angle of an exhaust.... It's the same design as the power graph.

the problem is more pronounced depending on which reeds you use in my experience... And the best ones for these types of exhausts, weirdly enough come from Polini, but they don't make them anymore! I will post a picture in the morning.

I used NSR250 reed blocks (which are pretty damned generic anyway), and one day on eBay I saw this weird reed block, from the early nineties, it cost €10 incl. Shipping, so I brought it, it took me ages to get round to testing it, but it cleaned the curves up massively...... The problem seems to be the with the high "scavenging suction" this exhaust design provides, the top reeds just stay open too much, causing a flooding of the inlet (boost bottle anyone?) when it "comes on the pipe"

When you see the reed valve you will see why it is effective in this area.

I am sure you are aware Dave, computer program designed pipes only get you so far.... Clip joints and A dyno.... That's how you learn, and the truth is every person I know who spends the time with clip joints comes away with a more powerful expansion chamber than the one they started with designed on a computer program .

TZ350

4th November 2010, 18:40

I am sure you are aware Dave, computer program designed pipes only get you so far.... Clip joints and A dyno.... That's how you learn, and the truth is every person I know who spends the time with clip joints comes away with a more powerful expansion chamber than the one they started with designed on a computer program .

The computer programe was usefull for getting us started on the right track, and now we are planning on a bit of chamber development of our own after Taupo, the plan is to make several sets of straight pipes with slip joint in the middle and try them on a dyno.

But for now we have to concentrate on getting the best out of what we already have.

I am very interested in these two curves and how the power spread was extended by retarding the ignition.

222744

Fixed ignition blue, retarded green, usefull power spread looks like it could be from 8,500 to 11,500, for 3,000 rpm.

The boys have fitted a programmable ignition to Ned Kellys bike and are figuring out how to set it up and programe in a curve, dyno time is expensive but it will be interesting to see what can be done.....

222745

The Ignitech ignition can also control water injection, green line, who knows if we can make that work but if it does and we can broaden the useable power by another 500 rpm then we would have a 3,500 rpm wide power spread and that has to be good.

But wait, there is more, and if we can make any of those ideas from Richban, Yow Ling, or Bucket for changing the plenums internal inlet tracts diameter work, then we could have a power spread over 4,000 rpm wide and that would be seriously good.

222746

Red line 24mm carb, Blue line 34mm inlet tract. If the inlet tract inside the plenum could be varied from say 22 to 34 then the power spread would be a lot wider, maybe by as much as a 1,000 rpm.

222748

Although making more power is nice, going for a wider power spread, like this graph would be better........

So at the moment we don't need much more power, we only need to concentrate on extending the power spread as wide as possible as we see that as the way to compete with the FXR's at Mt Welly, that and good handling bikes ........

222750

SS90

4th November 2010, 21:29

Haha, yea, I relate to all that... Never tried water injection myself, thought about it many times though.

Honestly, have a look at your baffle angle and stinger length, if you could get the boys to make a up a clip section just for baffle angles and stinger lengths, you will be pleasantly surprised.

Do you remember the home built dyno, that used recorded sound?

The guys that invented it are not too far from me, they have a roller set up, it works really well, and accurate too... Would be a good project for Bucketracer.

I am of the opinion many shops in NZ charge too much for Dyno time.

F5 Dave

5th November 2010, 14:46

SS90

6th November 2010, 01:14

From what I've seen it is hard to make money out of a dyno in NZ.

I've made rudimentary joints for testing cones with clamps & thick foil tape. It lasts only a short time & you have to be prepared to check it after the run to confirm it was a valid one & clearly you need to have muffler totally self supporting.

It's sort of true in Europe too (making Money from a dyno), there are some very specialized manufactures over here, that make cutting edge dynes for top companies, and they replace them every year, so you can lease last years hitech best for €150 per month... If you can't pull that in a month you should shut up shop I say.....

The best clip system I have seen to date was Graham Harris's Honda RS125 set up, of course it very bulky, and like you say, sealing it is the pain in the arse.

Spearfish

6th November 2010, 22:16

It's sort of true in Europe too (making Money from a dyno), there are some very specialized manufactures over here, that make cutting edge dynes for top companies, and they replace them every year, so you can lease last years hitech best for €150 per month... If you can't pull that in a month you should shut up shop I say.....

The best clip system I have seen to date was Graham Harris's Honda RS125 set up, of course it very bulky, and like you say, sealing it is the pain in the arse.

Is it possible to make a half decent dyno at home?

I knew someone who was building his own with an old commercial exercise bike connected by chain to an old set of electricians cable rollers. From memory the bike computer can load up the effort needed with some measurement of energy expended with revs etc?
He was interested if tinkering made improvements from his own datum rather than knowing accurately the hp.
It was going to be used to tune a kt100 cart engine his son was racing but I think it was a short lived interest and never finished.

bucketracer

7th November 2010, 22:10

.

I came across these photos of where it all began for Team ESE. NedKelly's barn fresh bike and a few photos of Ned and Tim punting the old GP's around Mt Welly.........

SS90

8th November 2010, 06:48

Is it possible to make a half decent dyno at home?

I knew someone who was building his own with an old commercial exercise bike connected by chain to an old set of electricians cable rollers. From memory the bike computer can load up the effort needed with some measurement of energy expended with revs etc?
He was interested if tinkering made improvements from his own datum rather than knowing accurately the hp.
It was going to be used to tune a kt100 cart engine his son was racing but I think it was a short lived interest and never finished.

Very possible, the hard stuff is the data box to calculate the correction factor. (atmospheric conditions)

There are plenty of home built dynos that have no correction factor, and you can buy pre made windows based programs very cheaply all over the place.

If you wanted one for a commercial venture, data boxes are critical (even then, top end stuff is about €5,000) but for "home", a basic programe, a pick up to count the roller speed, and you are away.

koba

9th November 2010, 17:39

Very possible, the hard stuff is the data box to calculate the correction factor. (atmospheric conditions)

There are plenty of home built dynos that have no correction factor, and you can buy pre made windows based programs very cheaply all over the place.

If you wanted one for a commercial venture, data boxes are critical (even then, top end stuff is about €5,000) but for "home", a basic programe, a pick up to count the roller speed, and you are away.

I have a few ideas on all this but its not going to be high on the project list for a great number of years yet!

Leed

10th November 2010, 13:31

...I have observed a fog of fuel and air outside a carburetor opening at certain rpm on the dyno...

probably just water vapour in the air condensing at the bellmouth in the same way as can be seen on Aircraft carrier jets throttling up - rather than carb coughing up any fuel mixture

I cant find anything decent (photo/video) of exactly what I mean but have a look at 3minutes 30seconds...
http://www.youtube.com/watch?v=QprQcfr45fk
observe how the intake flashes briefly white when the water condenses - better seen stationary or at takeoff
the same thing can sometimes happens on a plane (seen when landing) etc the air on top of the wing has to speed up to match the air below... pressure drops, water condenses

there is a velocity profile across the Bellmouth/Velocity stack, Mach 0 outside, maybe Mach 0.23 in the throat
at some point the air accelerates enough that the vapour pressure is sufficiently low for the water to condense

http://www.richard-seaman.com/Aircraft/AirShows/Oceana2005/Tomcats/RetroF14WithVapor8oClock.jpg

F5 Dave

10th November 2010, 14:18

Interesting, but why would this happen at some revs yet not occur, typically, when the engine is running at it's most efficient range?

koba

10th November 2010, 16:43

probably just water vapour in the air condensing at the bellmouth in the same way as can be seen on Aircraft carrier jets throttling up - rather than carb coughing up any fuel mixture

I cant find anything decent (photo/video) of exactly what I mean but have a look at 3minutes 30seconds...
http://www.youtube.com/watch?v=QprQcfr45fk
observe how the intake flashes briefly white when the water condenses - better seen stationary or at takeoff
the same thing can sometimes happens on a plane (seen when landing) etc the air on top of the wing has to speed up to match the air below... pressure drops, water condenses

there is a velocity profile across the Bellmouth/Velocity stack, Mach 0 outside, maybe Mach 0.23 in the throat
at some point the air accelerates enough that the vapour pressure is sufficiently low for the water to condense

http://www.richard-seaman.com/Aircraft/AirShows/Oceana2005/Tomcats/RetroF14WithVapor8oClock.jpg

What the hell?

I think fuel standoff outside a carb is a well established phenomenon.

Even just google it.

You see it accounted for in the design of airfilters and the like.

speedpro

10th November 2010, 18:22

I can see his point. Pressure drops in certain circumstances can definitely produce visible condensation. You would see it on 4 strokes as well if that was the cause of what we've observed. I think someone should try holding a lit gas torch up to the carb intake. That should answer the question.

I'd like to video the results, just out of scientific curiosity of course

Henk

10th November 2010, 18:48

I thought I saw something that could have been standoff on the FXR when I was running it without the pod and with the cam timing out. Not going to try and repeat in the interests of science because I don't want to rebuild my engine (again)

TZ350

10th November 2010, 20:50

.

Ok this is where we are now at with the plenum.

When I started this the thinking was, that if the regulation 24mm carb restricted the power output of a 125cc then find a way for the engine to breath without the 24mm restriction by letting the motor breath through a 34mm inlet tract from a plenum.

But as always, getting a good idea to actually work is not that simple .........

223152

Buckets Pipe with Side Carb (green) and Plenum (red) compaired to one of the old 21rwhp GP's with an RM style pipe (blue).

Bucket with his chamber and plenum was looking for a more low down and broader spread of power.

223153

RS Pipe/Plenum (red) compaired to the old GP (blue)

The RS (red) and Buckets (green) Pipe and Plenum setups are running on a cylinder with the exhaust opening 86 Deg ATDC and the old GP with the RM spec pipes exhaust opens 79 Deg ATDC.

The old 24mm carb GP setup has more exhaust port-time-area than the plenums setup.

Looking at the graphs, I think there is a functional missmatch between the rev range the larger plenum 34mm inlet want's to work at and the exhaust port-time-area of the plenums cylinder and the smaller size of the exhaust port is holding the plenum back.

I think the exhaust is running out of go just as the plenums 34mm inlet tract is getting into its stride and the plenum setup may be more suited to the old style GP engine with it's greater exhaust port-time-area.

It also might be time to look at cutting exhaust side ports into the plenum cylinder to get more exhaust port-time-area.

The next step when I get time is to try the plenum with the old style GP cylinder and RM pipe modified to fit my bike.

More $$$ and another trip to the dyno..........223154

And next year the plan is to make a set of test pipes with slip joints....for testing when the dyno $$$'s allow......

TZ350

10th November 2010, 22:05

.

While I was waiting for my turn on the dyno, they were running up a Honda RS125 that was turning out 40+ rwhp at 12,500 rpm.

Now I have an old RS pipe (maybe a 37'ish rwhp one) and a plenum that flows a very impressive amount of air, nearly as much as an old RS carb.

So why can't I make high 20's hp........... exhaust port-time-area and scavinging flow patterns is all I can see missing..........

With some development 27-28 rwhp must be possible with a reasionable spread of power from my 125 engine.... :scratch:

Spearfish

10th November 2010, 23:37

.

While I was waiting for my turn on the dyno, they were running up a Honda RS125 that was turning out 40+ rwhp at 12,500 rpm.

Now I have an old RS pipe (maybe a 37'ish rwhp one) and a plenum that flows a very impressive amount of air, nearly as much as an old RS carb.

So why can't I make high 20's hp........... exhaust port-time-area and scavenging flow patterns is all I can see missing..........

With some development 27-28 rwhp must be possible with a reasonable spread of power from my 125 engine.... :scratch:

40hp! ? Meh, yours will be there in no time you haven't reached 200 pages yet.

richban

11th November 2010, 17:32

.

While I was waiting for my turn on the dyno, they were running up a Honda RS125 that was turning out 40+ rwhp at 12,500 rpm.

Nice 320hp per litre yes please. Best I have got so far on the FXR is 155. I want 175 but that is hard from on a 4 stroke single.

speedpro

11th November 2010, 17:52

Nice 320hp per litre yes please. Best I have got so far on the FXR is 155. I want 175 but that is hard from on a 4 stroke single.
Over 20hp isn't to be sneered at, mind you being a pussy 4-stroke it is allowed to be half as big again as a real race engine.

bucketracer

11th November 2010, 19:53

.

I got the job of setting up NedKellys IgniTech programmable Ignition.

If your not lucky enough to have a bike that Igni make a drop on ignition for then you have to setup one for yourself.

This is how we went about it with one of Team ESE's bikes and Mt Eden Motorcycles dyno. Chambers is friendly with Mike and was able to get a bit of a deal on some dyno time.

223239

First step is to find TDC.

223240

Mark TDC and the Advance you want, we chose 15 degrees BTDC. and marked them on the fly wheel, the flywheel turns ant-clock wise so the advance is marked to the left of the TDC mark.

This does not have to be that accurate as its only needed as guide so you can see that the ignition is firing somewhere near the right place. The ignition will be optimized on the dyno later.

223236

The next move is to find the base advance.

223238

Ours was about 10 Degrees.

223237

The base advance is entered into one of those little box's in the program and initially the real advance is setup as a straight line in the curve part of the IgniTech program.

223242

With the ignition programed and the spark plug out, (but plugged into the HT lead and resting on the head) you can then use the Dyno's starter to spin the engine over. Then with the motor spinning over you can use a timing light see if you have got the initial advance more or less where you want it.

If the advance lines dont line up, you simply adjust the base advance setting and cylinder correction until they do.

<object width="480" height="385">

<embed src="http://www.youtube.com/v/JKt9OWnYdsQ?fs=1&hl=en_US" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="480" height="385"></object>

With the initial advance setup more or less where you want it, you are ready to rock and roll on the dyno optimizing the ignition curve.

The IgniTech software is very clever as changes to the ignition curve can be made on the fly and the Ignition itself re-programed while the engine is still running............

richban

11th November 2010, 19:56

Over 20hp isn't to be sneered at, mind you being a pussy 4-stroke it is allowed to be half as big again as a real race engine.

Now Now speaking of big check out the size of this carb. Testing the new head. Flowing 118cfm223248

koba

11th November 2010, 20:55

Now Now speaking of big check out the size of this carb. Testing the new head. Flowing 118cfm223248

Is that a ring of Knead it around the carb mouth?

bucketracer

11th November 2010, 21:04

.

Something to cheer the 4-Stroke boys up, some naughty valve float porn Vid

There is some juicy spring oscillation here.....
<object width="480" height="385">

<embed src="http://www.youtube.com/v/i_NpzU4pGjc?fs=1&hl=en_US" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="480" height="385"></object>

richban

12th November 2010, 05:54

Is that a ring of Knead it around the carb mouth?

Yep playing with bell shapes. Added 4 more cfm. Ended up just liking a small radius bell, nothing fancy.

koba

12th November 2010, 06:42

Yep playing with bell shapes. Added 4 more cfm. Ended up just liking a small radius bell, nothing fancy.

Love your method!

bucketracer

12th November 2010, 19:39

Running up NedKellys RS/GP125 on the dyno

<object width="480" height="385">

<embed src="http://www.youtube.com/v/NlOGxzs2iM8?fs=1&hl=en_US" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="480" height="385"></object>

This has port duration’s of, inlet 225, transfers 132, exhaust 202 degrees and an RM copy chamber.

<object width="480" height="385">

<embed src="http://www.youtube.com/v/NyTNk_LTfLE?fs=1&hl=en_US" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="480" height="385"></object>

Had some fun playing with ignition curves………

There was enough time between runs to be able to make a change to the curve and re-program the ignition before the next pull..........

TZ350

12th November 2010, 20:38

Now Now speaking of big check out the size of this carb. Testing the new head. Flowing 118cfm223248

I am very impressed with your setup and the dial gauges for checking flow at different valve lifts.........:niceone:

TZ350

12th November 2010, 20:55

.

The boys have been busy dynoing Neds bike so that we have a base line to work too.

We know we can make hp like Neds, but we realy need power spread to be able to compete with the FXR's and bikes like this South Island one........

<object width="480" height="385">

<embed src="http://www.youtube.com/v/PsEFKYULNDc?fs=1&hl=en_GB" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="480" height="385"></object>

And the new light weight frame, from memory I think the whole thing is around 80kg's...

223284

Marsheng kindly sent me his dyno graph too.........

223277

I would love to see some other 4-stroke graphs, just to see what we are up against.............

We have been a bit distracted before chasing hp, power spread is the way forward for us at Mt Welly I recon.......

richban

13th November 2010, 00:25

I am very impressed with your setup and the dial gauges for checking flow at different valve lifts.........:niceone:

Yep big brothers workshop is wonderland for petrol heads. That engine will be stroked 1.5 up and runs a standard piston size takes it to 156. Hoping to gain some toque over the other engine. Also finished the megaphone that I tested at BOB. It sounds rather angry and added some nice mid and top end power on the track. Needs a dyno comparison to make sure I wasn't just dreaming. Then the ignition and we are ready to take on you 2 stroke lads.

Yow Ling

13th November 2010, 07:04

Bert

13th November 2010, 07:35

Is increasing the stroke to allow 156cc within the rules ?
the way the rules are written the capacity limit is 150cc with allowance for overboring.

Stroking and overboring are different fish

Is this mod within the rules , or just outside?

I realise plenty of people run +2.0mm pistons as that is a bit of an oversight in the rules, be interesting to hear others take on it

One would suggest at as long as the maximum capacity isn't breached then all good.
Technically you could argue that Rich has stroked his motor (sleeve down the bore then gone out to the second/third rebore; that happens to be the same size as the original)....
There is nothing in the rules that state that a motor has to stay the same spec's as it was first constructed.

Plenty of us have gone the other way and de-stroked two stroke motors to run larger pistons and stay'ed within the 104 limit.

Maybe Speedpro could comment on this?
(or read http://www.kiwibiker.co.nz/forums/showthread.php/68694-6/page21)

The biggest issue I see is that fact that us poor suffering 100cc two stroke riders are really constrained by the 104 limit; 106-108 would open up plenty of very cheap piston options (i.e. Kart pistons; ~$45-$55) without the need for serious stroke changes (would still require significant engine work but)...
and really would it make any real extra power??? Surely <1HP max... but it would bring the cost down; anyone brought a RG400 piston lately?:sick:

Maybe a rule change could be no more than 8cc oversize for all F4 motors that would be fair wouldn't it?
especially given the fact that 150cc to-158cc is nearly 10% of our entire motor size!!!

TZ350

13th November 2010, 07:54

It sounds rather angry and added some nice mid and top end power on the track. Needs a dyno comparison to make sure I wasn't just dreaming. Then the ignition and we are ready to take on you 2 stroke lads.

Take on us 2-stroke lads....... what..... we are already running, trying to catch you 4-stroke guys up......:facepalm:

Maybe a rule change could be no more than 8cc oversize for all F4 motors that would be fair wouldn't it?
especially given the fact that 150cc to-158cc is nearly 10% of our entire motor size!!!

I agree, 8cc would put more inexpensive piston options within reach, like the KT100 cart piston for 106cc on a GP100.

Spreedpro uses an offset bigend pin in his MB100 engine thats running a KT100 piston to keep within the capacity limit...

SS90

13th November 2010, 08:02

richban

13th November 2010, 08:04

richban

13th November 2010, 08:11

I don't think it will be too long before the two strokers disappear from the diesels, but like Burt writes, an issue is cost..... Piston selection for the current displacement limits things somewhat, its not so much the dispacement that is the issue, but rather the production of suitable pistons for the bore/stroke ratios.

Just make it 110cc and open carb... And 133cc 24 mm carb...problem solved.

Well if Speedpro is making 29.2hp within the rules then you 2 smokers can stay where you are. I am heading to the US to live soon and the loacal rules in Porland are 105cc water Cooled 2 stroke...Unlimited Mods 210cc air cooled 4 stroke ....Unlimited Mods 150cc water cooled 4 stroke ....Unlimited Mods They don't even have an air cooled option from what I se they are running dirt bike engines in everything. KX CRF ect

Bert

13th November 2010, 09:43

....I am heading to the US to live soon and the loacal rules in Porland are 105cc water Cooled 2 stroke...Unlimited Mods 210cc air cooled 4 stroke ....Unlimited Mods 150cc water cooled 4 stroke ....Unlimited Mods They don't even have an air cooled option from what I se they are running dirt bike engines in everything. KX CRF ect

the two strokers are mainly based on 85cc MX motors taken out to 100cc ish.. Almost the same rules as Australia..
one has to remember that there was not a lot of little Japanese road bikes imported into the US to make an aircooled rule with...

Maybe 85cc are the way of the future of F4 (my annual rant that will shot down again for the sixth year running:facepalm:)

SS90

13th November 2010, 10:02

Well if Speedpro is making 29.2hp within the rules then you 2 smokers can stay where you are.

Im really not doubting this but, I have to say that 29 ps from 100cc is VERY impressive, by anyones standards.

Is there a dyno graph of this?

Totally feasible for sure, but still impressive.

Looking at the pipe design from the images he has posted, I am surprised.

ajturbo

13th November 2010, 10:08

Maybe 85cc are the way of the future of F4 (my annual rant that will shot down again for the sixth year running:facepalm:)

bert,... you paint your own target on yourself.... and i know where to get a paintball gun from.........

in saying that.. can i bore the poor old RG50 out to 85cc???:corn:

ajturbo

13th November 2010, 10:12

hey guys... i sooon will be living up your way... i will have to pop around one day... with the mighty GT...

oh and i have a FXR (?) frame that just could hold a GT125 engine in it one day..........

.

The boys have been busy dynoing Neds bike so that we have a base line to work too.

We know we can make hp like Neds, but we realy need power spread to be able to compete with the FXR's and bikes like this South Island one........

And the new light weight frame, from memory I think the whole thing is around 80kg's...

223284

Marsheng kindly sent me his dyno graph too.........

223277

I would love to see some other 4-stroke graphs, just to see what we are up against.............

We have been a bit distracted before chasing hp, power spread is the way forward for us at Mt Welly I recon.......

richban

13th November 2010, 10:21

.

Is there a dyno graph of this?

.

He was tricking.

Bert

13th November 2010, 10:35

bert,... you paint your own target on yourself.... and i know where to get a paintball gun from.........

in saying that.. can i bore the poor old RG50 out to 85cc???:corn:

1. yeayea i know (paint balls at 10 yards); but change will never happen unless someone sticks there hand up...

2. no, but I believe a early water-cooled RM80 barrel will fit the studs.,.
or
have a look at this:
http://www.cokerraceproducts.com/tuning.htm :yes:

Kickaha

13th November 2010, 12:14

I don't see a problem with the stroke.

I do, which is what Yow Ling was pointing out

24.2.1 Solo motorcycles shall have two engine capacity classes:
F4 2 stroke 55-100cc
2 stroke 55-125cc air cooled
4 stroke 55-150cc
F5 2 stroke 0-50cc
4 stroke 0-100cc air cooled

So F4 has a capacity limit of 150cc

24.2.3 The maximum capacity for rebored engines shall be:
F4 2 stroke 55-100cc - 104cc
2 stroke 55-125cc air cooled - 130.5cc
4 stroke 55-150cc – 158.09cc
F5 2 stroke 0-50cc - 53cc
4 stroke 0-100cc - 104cc

The key word is rebored there is no allowance for going over the 150cc limit with stroking

ajturbo

13th November 2010, 12:54

yeah.. have seen that already.. but as i have not blown the thing up yet (not from lack of trying!!!) i'll still be punting it around, giving some of the 100cc+ bikes a run for their money....

nothing like a stock std bike to get people pissed off with me...:woohoo:

1. yeayea i know (paint balls at 10 yards); but change will never happen unless someone sticks there hand up...

2. no, but I believe a early water-cooled RM80 barrel will fit the studs.,.
or
have a look at this:
http://www.cokerraceproducts.com/tuning.htm :yes:

richban

13th November 2010, 14:30

I do, which is what Yow Ling was pointing out

24.2.1 Solo motorcycles shall have two engine capacity classes:
F4 2 stroke 55-100cc
2 stroke 55-125cc air cooled
4 stroke 55-150cc
F5 2 stroke 0-50cc
4 stroke 0-100cc air cooled

So F4 has a capacity limit of 150cc

24.2.3 The maximum capacity for rebored engines shall be:
F4 2 stroke 55-100cc - 104cc
2 stroke 55-125cc air cooled - 130.5cc
4 stroke 55-150cc – 158.09cc
F5 2 stroke 0-50cc - 53cc
4 stroke 0-100cc - 104cc

The key word is rebored there is no allowance for going over the 150cc limit with stroking

Ok to shut you all up or maybe start more discussion. Engine was running a 64mm piston. I changed the stroke. That made it 169. Purchased a new sleeve REBOED IT to 62mm. Now 156 rebored. Totally within the rules.

Kickaha

13th November 2010, 14:40

Purchased a new sleeve REBOrED IT to 62mm. Now 156 rebored. Totally within the rules.

62mm is stock bore size, so the capacity increase isn't as a result of being overbored, it's a result of a longer stroke with a stock bore

richban

13th November 2010, 14:51

62mm is stock bore size, so the capacity increase isn't as a result of being overbored, it's a result of a longer stroke with a stock bore

Shut up. 64mm was what I had. So are you saying you are not allowed to change you crank config or stroke in buckets? Coz plenty of people have and calculated the change back to within the cc ratings.

TZ350

13th November 2010, 15:22

.

Sure, legalisticly the extra capacity is to allow over boring but I am comfortable with people using better pistons than the std ones and then de-stroking to get back within the capacity limit.

I personally have an RG50 thats over bored for a better piston and de-stroked 3mm for 49.9cc....and thats legal.

And I was expecting when the time came for a re-bore that I could use the extra capacity limit allowed to 50's for re-bores......... I hadn't realised some might think thats a grey area........ it's a curly one.. ;) ... and I hadn't realy thought about it.....

I know my F5 motor with a standard brand x piston is < 50cc

So I suppose I could argue that my RG50 motor with a "standard piston" is < 50cc therefore oversize rebores and the little extra cc is within the rules as they are.

Yow Ling

13th November 2010, 15:39

Ok to shut you all up or maybe start more discussion. Engine was running a 64mm piston. I changed the stroke. That made it 169. Purchased a new sleeve REBOED IT to 62mm. Now 156 rebored. Totally within the rules.

When you purchased the new sleeve you bored it not rebored it
to rebore is "•Removing of the worn or damaged interior surface of a cylinder to create a new working surface.

Would be interesting to find out what the rules actually mean , otherwise they may as well scrap the 150cc capacity limit and replace it with the 158cc

If there was no benifit to be had by stroking the engine and returning to 156cc why would you bother?

jasonu

13th November 2010, 17:28

[QUOTE=richban;1129907168]Well if Speedpro is making 29.2hp within the rules...

29.2hp Yeah Right...

jasonu

13th November 2010, 17:30

Well if Speedpro is making 29.2hp within the rules then you 2 smokers can stay where you are. I am heading to the US to live soon and the loacal rules in Porland are 105cc water Cooled 2 stroke...Unlimited Mods 210cc air cooled 4 stroke ....Unlimited Mods 150cc water cooled 4 stroke ....Unlimited Mods They don't even have an air cooled option from what I se they are running dirt bike engines in everything. KX CRF ect

Where abouts in the States is this? Details please

richban

13th November 2010, 17:46

Would be interesting to find out what the rules actually mean , otherwise they may as well scrap the 150cc capacity limit and replace it with the 158cc

If there was no benifit to be had by stroking the engine and returning to 156cc why would you bother?

Yeh! Its all in the way you read them. All I see is a capacity limit. I have a modifiyed engine it is under the max capacity limit. Job done. There is no mention of crank mods in the rules. But yet lots of people mod them. Unless there is a big appendix out there with all the definitions listed. Its up for interpretation. If you feel really strong about it then maybe you should petition the rule makers.

Why bother. In the interests of development. To try and go faster. Why else

richban

13th November 2010, 17:51

Where abouts in the States is this? Details please

Not far from you. Portland. http://www.oregonsuperbikers.com/classes Maybe I might see you there next year some time. The tracks look good.

speedpro

13th November 2010, 18:53

The way I read the rules is you can change the stroke because it doesn't say you can't. However if the engine is over the stated capacity of 150cc for example then it has to be rebored to be legal as the maximum capacity is for "rebored" engines. Whether the stock liner is rebored in the case of a short stroke engine or a new liner is rebored it doesn't matter, it just has to be "rebored". As stated by Yow Ling it does say "re"bored not just bored.
Using the same logic it is illegal to use KT100 piston pin circlips which is why I only ever use stock MB clips.
It's academic, nobody is going to protest about it, we're al too tight.

Kickaha

13th November 2010, 19:04

Yeh! Its all in the way you read them. All I see is a capacity limit.

Which is 150cc

I have a modifiyed engine it is under the max capacity limit. Job done. There is no mention of crank mods in the rules. But yet lots of people mod them.

How many is lots? how many have used a longer stroke to gain capacity?

Unless there is a big appendix out there with all the definitions listed. Its up for interpretation.

Up for interpretation? Not really, it states quite clearly it is for rebored engines

Can you show me where it says you can gain that capacity over the class limit (150cc)by stroking?

TZ350

13th November 2010, 19:04

TZ350

14th November 2010, 19:12

Well that was this years 2-hour, and Team ESE didn't exactly cover itself in glory.

My bike promptly suffered a lockup in practice, I have not investigated yet but suspect a meltdown from too much top end retard. No real problem as we had a spare bike.

But my teammate was out in B grade trying out his 50 and was knocked off in the sweeper by someone putting on the moves and trying to be a hero. Result knocked out, broken collarbone and a trip to Hospital in the ambo.

In the 2-hour itself, Pumber did the suicide thing, flinging himself up the road in grand style and skittling our star rider. Chambers got going again, although he was in some pain, he and Ned put up a real good showing until about the 1 hour 30 mark. Then a mystery electrical ailment brought it all to a stop, funny thing, it could be restarted, run for a bit and then the fire would go out again.

So that was Team ESE’s day, a meltdown, a ride in the ambo and a mystery electrical gremlin, but enjoyable all the same.

Still it could have been worse, Henk did the clasic thing and lent his spare bike to a couple of young guys who then beat him in the 2-hour.

Not being able to be out there myself, gave me the chance to watch some really good riding as Kel, Rick, Fixer to name a few were really flying…….

And as always, the people were great and it was a stunning day, near perfect conditions....

Buckets4Me

14th November 2010, 19:43

223480 before having a small off at the fastest part of the track

223479 NedKelly catching #69

223478 Chambers before being skittled

SS90

14th November 2010, 23:25

...My bike promptly suffered a lockup in practice, I have not investigated yet but suspect a meltdown from too much top end retard.

If too much top end retard was the cause, you should expect to see erosion on the exhaust side of the piston crown (caused by the over heating of the exhaust port).

From your other posts I would be surprised, based on your exhaust port width (limited by no bridge) and data you have posted regarding ignition timing.

My experience is that terminal problems caused by too much top end retard is only applicible with ultra wide bridged exhaust ports, narrow unbridged ports simply do not have the width to allow enough hot exhaust gasses through fast enough to heat the piston crown terminally.

I would be very interested to see a picture of your piston!

koba

15th November 2010, 06:31

If too much top end retard was the cause, you should expect to see erosion on the exhaust side of the piston crown (caused by the over heating of the exhaust port).

From your other posts I would be surprised, based on your exhaust port width (limited by no bridge) and data you have posted regarding ignition timing.

My experience is that terminal problems caused by too much top end retard is only applicible with ultra wide bridged exhaust ports, narrow unbridged ports simply do not have the width to allow enough hot exhaust gasses through fast enough to heat the piston crown terminally.

Just like an RGV I Borrowed for a hillclimb once... *Sigh*

TZ350

15th November 2010, 15:57

.

My FZR/GP125 that nipped up after an hour or two on the dyno, Hampton Downs and 3 laps of practice for the 2-Hour.

When it nipped up at the 2-Hour I thought it might have been given too much "retard" and overheated.

223504

Green line fixed ignition (that was used at Hamton Downs), blue line after playing with the programable ignition retard.

I could move the green line up to the blue line just by playing with the retard curve.

So much retard after peak power at 9k and how hot the motor got frightened me so I settled for the red line.

223506

Ignition curve for the red line. With the retard thing this motor sure gets hot.

223500

Top of the piston.

223501

Piston ring locating pin is missing or worn away allowing the ring to turn.

223502

The ring turned and the ends caught in the exhaust port.

223503

Cylinder bore damage.

I think that the ring has been working against the locating pin and dislodged it or worn it away.

And with the exhaust port at 75% of the bore, obviously extra care and thought is needed in shaping the exhaust port so that it does not abruptly push the ring back and hammer one end of the ring against the locating pin.

Years at 70% without any problems, and now at 75% this has happened twice recently.........:scratch:

ac3_snow

15th November 2010, 19:45

The ring turned and the ends caught in the exhaust port.

ouch!! glad your day still ended up alright.
will you be needing to start again with a new barrel now or are you able to bore that one out and clean up the damage? at least you had some luck, having the spare bike there :scooter:

TZ350

15th November 2010, 20:12

ouch!! glad your day still ended up alright.
will you be needing to start again with a new barrel now or are you able to bore that one out and clean up the damage? at least you had some luck, having the spare bike there :scooter:

Thanks for your interest.

I may be able to save the barrel, it interests me because it has an exhaust port opening 86 deg ATDC and large transfers. I will keep it untill after Taupo when I hope to make some straight pipes with slip joints for testing. There are some ideas that others have suggested, that I would like to try out.

I have another barrell with similar large transfers and an exhaust port opening 80 deg ATDC for more port-time-area that I will try with my old RM copy pipe. That would be the same setup as NedKellys 23rwhp engine but with more transfer area and wider ex port. Unfortunatly it is also a 75% ex-port-width barrel just like the one that I have just broken.

Buckets4Me

15th November 2010, 20:14

ouch!! glad your day still ended up alright.
will you be needing to start again with a new barrel now or are you able to bore that one out and clean up the damage? at least you had some luck, having the spare bike there :scooter:

you taking the piss or what :p

luck he say, luck. It's not luck when your partner gets knocked of the race before and is carted off to hospital
and the other team get a bif in the first few laps into the 2 hour and hurt as well (I think there are some scared people that payed a few dollars to stop them this year)

Yow Ling

15th November 2010, 20:26

you taking the piss or what :p

luck he say, luck. It's not luck when your partner gets knocked of the race before and is carted off to hospital
and the other team get a bif in the first few laps into the 2 hour and hurt as well (I think there are some scared people that payed a few dollars to stop them this year)

Sounds like if you didnt have bad luck you wouldnt have any luck that day

TZ350

15th November 2010, 20:50

ouch!! glad your day still ended up alright. :scooter:

I know the names, captn_soup, mooools and ac3_snow but can't place who was who that got to ride Henks spare bike. If that was you, you guys did pretty well, if not, did you ride the 2-hour too? and did you enjoy it?

Henk

15th November 2010, 20:55

Capn Soup and AC3_snow rode the spare bike and yes they did bloody well for a couple of guys that haven't been racing long and hadn't ridden the bike until Sunday morning. They beat us :brick:

TZ350

15th November 2010, 20:59

Sounds like if you didnt have bad luck you wouldnt have any luck that day

Hi Yow Ling, yep Chambers and I on a good day are to fast for B grade and too slow for A so have pretty much decided to ride F5 as there arn't that many F5 bikes at Mt Welly and run the F4's at long tracks like Hampton and Taupo where we get a bit more elbow room. And occasionaly lend the 125's to someone like Av or David M who can do them justice at Mt Welly......

The 2-Hour was won by a Team riding a 2-Stroker and it's very interesting to see some realy good riders like Rick and Kel who are keen as to build Strokers too, with any good luck, next year could see the return of 2-Strokes to the pointy end of "A" grade.

TZ350

15th November 2010, 21:04

Capn Soup and AC3_snow rode the spare bike and yes they did bloody well for a couple of guys that haven't been racing long and hadn't ridden the bike until Sunday morning. They beat us :brick:

They beat us too........ buy a country mile.....:laugh:

Henk

15th November 2010, 21:16

They beat us too........ buy a country mile.....:laugh:

Same here 6 laps x 400m = 2.4km, about a country mile.

Buckets4Me

15th November 2010, 21:37

Same here 6 laps x 400m = 2.4km, about a country mile.

so whats 200+ laps x 400m =

speedpro

15th November 2010, 21:47

If too much top end retard was the cause, you should expect to see erosion on the exhaust side of the piston crown (caused by the over heating of the exhaust port).

From your other posts I would be surprised, based on your exhaust port width (limited by no bridge) and data you have posted regarding ignition timing.

My experience is that terminal problems caused by too much top end retard is only applicible with ultra wide bridged exhaust ports, narrow unbridged ports simply do not have the width to allow enough hot exhaust gasses through fast enough to heat the piston crown terminally.

I would be very interested to see a picture of your piston!

I've had TS100 pistons fizzled right down to the ring across the exhaust port.

CM2005

15th November 2010, 22:20

so whats 200+ laps x 400m =

we did 168 laps, which was 67km lol epic considering the bike was in bits 2 hours before the race with oil everywhere, broken cases, no pipe or bodywork.. hah
4th to last in the race,and i binned it twice!! Crashtastic! Need more ground clearance!!

Moooools

16th November 2010, 06:21

Would have been a quick trip up there if it was me.:yes:

Bert

16th November 2010, 06:50

.

223503

Cylinder bore damage.
.......

Years at 70% without any problems, and now at 75% this has happened twice recently.........:scratch:

lunched piston hummm, I've seen this before. is gap set correctly for the temperature you are running at?
Interesting that only one side of bore has worn the brunt of the damage (melted piston). mine (TF) use to do this; the port (through its lead up shape and port face shape) directed slightly more gas to one side of the port (and around the piston into the transfer:facepalm:); so i assumed that this was heating up the piston unevenly?? i attempted to slightly reshaped the entire port length (though i can't confirm that it made any difference)..
I also noted that your port on that side of the bore looks rather square cut (might be the photo, though looking back it seems to show up in other older photos). is this putting uneven pressure on the ring? resulting in ring stress and hammering that you are seeing..

your piston, lunched :gob: (not nicked) i bet you that sounded funny when it happened... I hope you didn't do to much damage to the roof of your exhaust port?

as for your retard curve, I would have thought that is wasn't retarding enough (resulting in extra heat), I would have though that 8-10 degrees would be a mark to aim for (as seen with MX's & RS125s systems). but in saying that I haven't had any of my bikes on a dyno for years to see how well my CDI works..

TZ350

16th November 2010, 08:39

GP125 18+ rwhp: skim the barrel 1.5mm and “o” ring it, thin alloy spacer plate under the barrel and Suzuki RG250 pipe. Ex opens 86 deg ATDC and Trans opens 114 ATDC, std head , inlet timing 145/55 and carb mj 95.

GP125 20+ rwhp: skim the barrel 1.5mm and “o” ring it, thin alloy Spacer plate under the barrel and Suzuki RG250 pipe modified to RM125 specs, KX80 ignition. Raise the exhaust to open 83 deg ATDC, and widen to 70% of the bore, cut 30 deg from the closing point of the rotary disk, so inlet opens 145 BTDC and closes 85 ATDC. Set the mj 105 and ignition timing, 26-28 BTDC using a dyno.

Pipe dimensions Suzuki RM125 B/C page 82 Bell http://www.kreidler.nl/artikelen/performance-tuning-graham-bell/performance-tuning-graham-bell.pdf

Save the stuffing around and go buy one of these digital, programmable ignitions
http://www.ignitech.cz/english/aindex.htm originally posted by K14

The engine........

223678

To fit an RG250 pipe all that is needed is to cut the header flange off, modify it to fit the GP cylinder, bolt it back onto the cylinder and weld the pipe back in place at the right angle and fit a new back mount on the chamber some place, real simple.

223675

It turns out that the front of an RG pipe is the same dimensions as the RM chamber we want for the 20+ option.

The old 18 rwhp RG250 pipe with the front section cut off.........

223676

The new 20+rwhp RM copy chamber made from part of the old RG250 one compared to an original RG250 pipe.

223679

A dyno graph of the 20+ rwhp option, red line fixed KX80 ignition blue line IgniTech programmable ignition.

223677

The above mods will pull 20+ rwhp from a GP125, Ned's manages 23 after these simple changes.

The key is being able to get some dyno time to set it all up.

Bucket and Thomas managed to get some Dyno Vids of Ned's bike which is pretty much the above specs, with maybe a little more exhaust duration.

The Vids can be seen here............

Running up NedKellys RS/GP125 on the dyno

TZ350

16th November 2010, 08:42

Sure, good chambers are developed on dynos by people with lots of experiance...blar blar blar.....

But most of us don't have a dyno and have to start some place........

This is my XL spreadsheet for the basic design of an expansion chamber, based on work by someone who undoubtably knows their stuff......... this is a good place to start and then develop from there if you have the $$$$ and time........

The spread sheet......

223667

And the Maths...........

223669
223666
223665
223664
223668

bucketracer

16th November 2010, 11:55

.

Bert has a very extensive links list........... http://www.kiwibiker.co.nz/forums/group.php?do=discuss&discussionid=1489

Some links from this thread:-

Port/Time/Area Jennings page 81-82 http://www.vintagesleds.com/library/manuals/misc/Two-stroke%20Tuner%27s%20Handbook.pdf

Pipe dimensions Suzuki RM125 B/C page 82 Bell. http://www.kreidler.nl/artikelen/performance-tuning-graham-bell/performance-tuning-graham-bell.pdf

If you want to plan your ports using Jennings or Blairs methodology then this very good and inexpensive software is just the ticket. http://www.porting-programs.com/ makes it very easy to get the true total and mean port areas of the transfers.

We see that the flow bends upwards and forward towards the exhaust port as the cycle proceeds and the piston rises to shut the port.
Abstract taken from http://www.lortim.demon.co.uk/vsih/pistons.htm

Prof Blair on the design of an intake bell mouth:- http://www.profblairandassociates.com/pdfs/RET_Bellmouth_Sept.pdf

IgniTech programmable ignitions for race bikes
For 2-strokes get the SPARKER DC-CDI-P2 race http://www.ignitech.cz/english/aindex.htm because it is has all the bells and whistles

KartWeb Tech Articles
www.kartweb.com/TechArt/2Stroke/chapter1.doc (http://www.kartweb.com/TechArt/2Stroke/chapter1.doc)
www.kartweb.com/TechArt/2Stroke/chapter2.doc (http://www.kartweb.com/TechArt/2Stroke/chapter2.doc)
www.kartweb.com/TechArt/2Stroke/chapter3.doc (http://www.kartweb.com/TechArt/2Stroke/chapter3.doc)
http://www.kartweb.com/TechArt/2Stroke/chapter1-2-3.swf
http://www.kartweb.com/TechArt/2Stroke/2_stroke_technology.htm

24mm carb for 30+ hp go-cart engines
Carb-01 http://www.out2win.com/catalog/images/ibeal5.jpg
Carb-02 http://www.out2win.com/catalog/ibea.html
Carb-03 http://www.j3competition.com/downloads/technical/L6_Homologation.pdf

http://www.tz350.net/tz250page.htm portmap for the TZ250 from 1976 to 1984.

Some interesting info on hydroformed expansion chambers from Bert.
I though it might be useful; if it hasn't been posted before.
http://ypvsbox.free.fr/pipedesigner_en.html
and this
http://www.gifford.ca/hydroform.html

The specs of Avalons Team ESE's BOB Suzuki GP125 20 rwhp engine:

Skim the barrel 1.5mm and “o” ring it, no head gasket, thin alloy spacer plate under the barrel and Suzuki RG250 pipe modified to RM125 specs, KX80 ignition. Raise the exhaust to open 83 deg ATDC, and widen to 70% of the bore, cut 30 deg from the closing point of the rotary disk, so inlet opens 145 BTDC and closes 85 ATDC. Champher the inlet side of the crank at 45 deg to aid inlet flow. Set the mj about 102.5 105 107.5 and ignition timing, 26-28 BTDC using a dyno. A link to Bells book and the RM pipe specs can be found on page 100 of this thread.

Cheap easy effective mods that most anybody can do and get 20+ rwhp from a Suzuki GP125.

Forced convection and micro bubbles........
Check it out here:- http://www.liquidcooledairpower.com/lc-ridofheat.shtml

Plenty of links to other interesting items to read on pages 80-90-100-110-120-130, 140 Etc..

TZ350

16th November 2010, 15:35

A bit of info from Yamaha on Transfer Port Shapes.........

TZ350

16th November 2010, 16:08

223683.

Chambers is back from the Doc's and Team ESE now have 2 broken collar bones after the 2-hour.............

We were out to ride a clean race so are very pissed off.........

Henk

16th November 2010, 16:20

Short word, starts with F

SS90

16th November 2010, 21:26

lunched piston hummm, I've seen this before. is gap set correctly for the temperature you are running at?
Interesting that only one side of bore has worn the brunt of the damage (melted piston). mine (TF) use to do this; the port (through its lead up shape and port face shape) directed slightly more gas to one side of the port (and around the piston into the transfer:facepalm:); so i assumed that this was heating up the piston unevenly?? i attempted to slightly reshaped the entire port length (though i can't confirm that it made any difference)..
I also noted that your port on that side of the bore looks rather square cut (might be the photo, though looking back it seems to show up in other older photos). is this putting uneven pressure on the ring? resulting in ring stress and hammering that you are seeing..

your piston, lunched :gob: (not nicked) i bet you that sounded funny when it happened... I hope you didn't do to much damage to the roof of your exhaust port?

as for your retard curve, I would have thought that is wasn't retarding enough (resulting in extra heat), I would have though that 8-10 degrees would be a mark to aim for (as seen with MX's & RS125s systems). but in saying that I haven't had any of my bikes on a dyno for years to see how well my CDI works..

I agree 100% Bert, my opinion is that the square exhaust port that the standard GP125 is cursed with my well be the other limiting factor in the design (the first being the odd crowded rear transfer arrangement.)

Still, more that 22 PS from one is respectable, by any standards, it would just seem that the time area is now limited by the width you can go, meaning the only option is more duration (bummer)

Perhaps the best option in the quest for power would be to machine out the cast in liner on a lathe, and make you own liner to suit.

Not as hard as it sounds, and you can be very certain your scavenge patterns are what you want before fitting.

Bert

16th November 2010, 21:35

Bert has a very extensive links list..........

some stolen from Team ESE and Mr SS90...

bucketracer

16th November 2010, 21:47

some stolen from Team ESE and Mr SS90...

I think TeeZee is pleased you have grabbed the better ones and added them to your collection and that you have made it open for all to read.

Yes the square GP port is a problem, 70% did not allow much rounding of the window, 75% was as much about improving the shape as increasing port time area.

TeeZee and Chambers are talking about drilling in little side exhaust ports, the feasibility of it has been the topic of conversation around the lunch room table lately.

SS90

16th November 2010, 22:07

TeeZee and Chambers are talking about drilling in little side exhaust ports, the feasibility of it has been the topic of conversation around the lunch room table lately.

I have seen a guy here try that a few years back, on a cast iron cylinder, but I am unsure that it really worked as hoped, I cant see you ruining a cylinder if it doesn't have a real effect...... I say go for it.

How much time area would you gain by having a 70% port, and auxillery exhaust ports as big as the space allows? That would be the answer to if it worked or not.

I have had some concepts about auxillery exhaust ports explained to me, and the crux of it was that not all calculated auxillery exhaust port time area is applicible, and the main advantage is not time area as such, but rather improvement of scavenging of the exhaust port when the piston is halted at BDC... better for touring engines than racing engines.

But for sure, auxillery exhaust ports increase time area, just not as much as you wold expect. (remembering that 80% of the exhaust gasses escape as soon as the exhaust port cracks open, rather than exiting in a controlled orderly linear fashion in response to opening time.)