ESE's works engine tuner

[RMS eng]

With all the talk about wanting to utilize only a couple of gear changes per lap, I would have thought that the solenoid powerjet was a gift from heaven.
A late model well tuned RS125 will rev to around 12400 if the PJ is disabled,turn the PJ function back on and it will go to 13800+.
Its so simple and you retain exactly the same lower rev power,but with easily another 1000rpm to work with you have the choice of adding teeth on the back, getting better acceleration from torque multiplication, or keeping the same gears - but increasing the terminal speed.
And from the dyno curves I have seen, most of the 100 buckets with short stroke lengths, arent even beginning to stress the bottom ends - with less peak rpm than the 54.5mm stroke 125 bikes or karts that will easily run to 13000 all day.

or you could get a PJ carb off an old IT175

[Buckets4Me]

or you could get a PJ carb off an old IT175
240858 just taking a look for one

[Yow Ling]

or you could get a PJ carb off an old IT175

Does it have a solenoid to turn it off ? Needs to be able to be controlled by ignition

[ajturbo]

That last crash when I almost ran you over was quite spectacular...

Almost..ALMOST... is not good enough!!!:mad::lol:

[bucketracer]

I would have thought that the solenoid powerjet was a gift from heaven. A late model well tuned RS125 will rev to around 12400 if the PJ is disabled,turn the PJ function back on and it will go to 13800+.

240865

Fitting an electric PJ carb won't happen over night but it will happen, as they say .......... an elec PJ carb is waiting its turn in the que of development ideas scheduled to be tried on TeeZee's bike.

[F5 Dave]

. . .
And from the dyno curves I have seen, most of the 100 buckets with short stroke lengths, arent even beginning to stress the bottom ends - with less peak rpm than the 54.5mm stroke 125 bikes or karts that will easily run to 13000 all day.
Sounds good, but often buckets are made from old beaters that have been lying around. That being said we used to rebuild our RG50 cranks every year, with std parts they were reliable to 12,500 over rev for ages, but take them to 13 regularly & they'd let go. Commuter parts. obviously some engines are better suited for revs than others. An MB will out survive a TS at revs.

[wobbly]

Most of the issues with the old cranks will be the cage construction of the big end bearing.
The "new" design has a flat outer shape, with no indented rib to support the rollers.
The flat design has no stress raiser corners, and this technology is what allows todays 2T engines to rev reliably to the mechanical limit of the parts - not the cage flying to bits..
The short strokers would be reliable to over 15000rpm as long as the rod is physically well designed using the good cage design.
Todays engines dont "wear out" the crank pin, the rollers ,or the rod big end, its the cage that rubs on the rod bore and eventually fails.
I have done 1500Km of racing miles on a pair of rods in a Rotax Superkart engine, and done this 3 times, just changing the big end assy with no discernable wear on the hardened parts.

[husaberg]

TZ mentioned how the Honda RS pipe inlet is larger than the GP exhaust port outlet, while this is common place on 4 strokes for the purpose of AR I wasnt aware it was used on 2 strokes but on reviewing RSA photos I came across this
239992
239993
Jan Thiel "One wants the pressure wave coming back into the cilinder but NOT the burned gases that are hot and can cause detonation!"
Makes sense.

as above found this on Honda rs125
Space bar now working again

[Kickaha]

I have done 1500Km of racing miles on a pair of rods in a Rotax Superkart engine, and done this 3 times, just changing the big end assy with no discernable wear on the hardened parts.


With that one sentence you've just made me doubt everything you've ever posted
(providing you're talking about the 256)

I find it extremely hard to believe a Rotax could complete one meeting with out exploding and requiring a total rebuild requiring incredibly expensive parts which take months to acquire :whistle:

[bucketracer]

The latest 8 round F4 series is over. Finishing order of the bikes by engine type ......... new season starts in a few weeks.

RS80 (overbored Derbi 50 2-stroke)
CB150T (overbored CB125T)
RS80 (overbored Derbi 50 2-stroke)
FXR150
FXR150
FXR150
FXR150
FXR150
CB150T (overbored CB125T)
FXR150
CB150T (overbored CB125T)
FXR150
FXR150
FXR150
GP125 (2-stroke) highest finishing Team ESE bike.
FXR150
FXR150
FXR150
FXR150
TS125 (2-stroke)
FXR150
GL145
FXR150
Derbi 70 (2-stroke)
MB100 (2-stroke)
FXR150
FXR150
CB125T
CB125T
MB100 (2-stroke)
GP125 (2-stroke)
FXR150
FXR150
FXR150
FXR150
CB125
FXR150
CB125T
FXR150
CB125T
GP125 (2-stroke)
FXR150
FXR150
XL125

Damiens photos from round 8, Sunday 12-6-11 at Mt Welly http://www.flickr.com/photos/dty1/sets/72157626941175616/

[wobbly]

Re the Rotax big ends - the rods and bearings are reliable to 13000 all day for 1500KM as long as you realize one small issue.
For some very wierd reason Rotax do not match any of the parts in batches to get the clearances correct.
Every other manufacturer of racing engines measure the pin,rod bore, and needles, marking them and assembling a "kit" to get around 1 micron per pin mm dia total clearance.
ie with a 22mm pin you want around 22 microns clearance.
I used to buy 10 bearings at a time, and measure EVERY roller with a 4 figure digital mike - matching them in sets to with 1/2 micron.
Then measure the pin and bore and matching those with the rollers to get the correct clearance.
The rollers could be up to 2.5 microns different in diameter, thus the big one takes all the load and skids,shitting the cage instantly.
Needle diameter matching is the key to long life of the cranks - along with using the flat section cage shape.
RS250 cranks regularily do 2000Km with no issues as Honda match everything ,and dont trust anyone to rebuild them properly, so no parts are available ex factory for this reason.

[F5 Dave]

. . .
The short strokers would be reliable to over 15000rpm as long as the rod is physically well designed using the good cage design. . . .
My only point is that to be bucket legal these must be non competition parts. Sometimes you get lucky & there are road bikes that have good design cages in the sizes you want. Suzuki bearings don't seem to be that flash, at least on their older models. the MB bearing has been upgraded several times & is actually the same part as used on CR80s. However I am no expert on available sizes out there for common bikes.

But secrets aside - what we really want the beans spilt on is : What vegetable oil do you smear on pipes to make them make a nice clear skin? I've tried Soy & a cheap table oil, bit they all burn off the header.

[wobbly]

Mild steel pipes will always rust and or go black,the only way to help keep them looking OK is to use Castrol R.
You have to rub it on with a rag every time the bike is run, and eventually it will burn in like a wok surface preventing rust, but you cant stop the header going black.

All the common big end sizes are available in the newer flat cage design, as this type is used in all current road and race engines.
And who is going to say to you that your engine is illegal coz its got a modern cage design.

And re the step in a Honda exhaust duct.
When using a T port or a properly designed tripple port exhaust, the area just outside the port is way too big during the blowdown phase,and alot of velocity is lost.
I have found that a good rule of thumb is to gradually reduce the duct exit at the flange, to around 75% of the total chordal area.
This will often equal the area of just the main port in a tripple setup.
If you make the duct exit the width of the header, and then reduce the height, forming an oval to give the correct area, a heap of power is created, in part due to the much better flow from the outer parts of the port width of a T or the
aux ports in a tripple..
Steps work OK, but a CNC formed oval to round transition in the flange works best.
Note well, this technique DOES NOT work in a single Ex port engine, no matter how big it is.

[F5 Dave]

Thanks that is all very interesting.

Castrol R, bean oil. Not sure where the hell I'd get some of that this side of 1970:scratch:

Re the 256 cages I'd heard of a chap boring the cranks & using Aprilia rods as were 2mm bigger. Perhaps the real improvement was the bearings were better made. Which is queer as Aprillia have a big tie up with Rotax & I'd always thought they had made their 2 stroke engines.

The duct info is very interesting & is making my head swim a bit.

[F5 Dave]

So after a brief foray to pick up my newly chromed pipe (don't panic its for my dirtbike where ease of cleaning is a serious prerequisite) I've been thinking.

So you are saying looking at the old RS ex port that this design is pretty big at the outlet. I always thought it looked huge, sadly I (15 years ago) welded a copycat flange onto the outside of an engine & with 2 sub ports added sort of extended it out to meet an RS125 pipe. The flange looks way too big for a 100.


Anyways so you are saying that the RS would have been better with a smaller pipe flange and a transition from the oval shape at the cylinder to a round at the flange of a smaller diameter. Of course this is hard to cast as the taper is the wrong way unless it was investment cast. So fitting a nozzle to adapt this to a smaller flange header is the way to go. Honda Band-aided this with the step.

Have I got this right? Makes sense.

This nozzle must get fairly hot not being a part of the barrel.

[jasonu]

Thanks that is all very interesting.

Castrol R, bean oil. Not sure where the hell I'd get some of that this side of 1970:scratch:

Re the 256 cages I'd heard of a chap boring the cranks & using Aprilia rods as were 2mm bigger. Perhaps the real improvement was the bearings were better made. Which is queer as Aprillia have a big tie up with Rotax & I'd always thought they had made their 2 stroke engines.

The duct info is very interesting & is making my head swim a bit.

Blenzoil is a brand of castor oil comes in a yellow bottle. I used to put it my Maico 490. Smelt grrrrrrreat!!!

[wobbly]

The only connection between Rotax and Aprilia was that the race team used the 250 V twin cases from Rotax at the beginning of their attack on that class.
Very quickly they made their own cylinders, and later their own cases as well.
Then they got sick of the crap gearboxes and did their own, as the original design by Bombardier was for a 125, and this got used even on the 250cc single, with predictable results there as well.
The early Rotax had 20mm pins that were too small, and the later design had 22mm - when Hondas bulletproof cranks were 24 and 25mm.
So yes the uprated design you mentioned probably had some actual QC done on the parts, unlike the Rotax shit - they should have been shot very early on and prevented millions of dollars and grief being spent on broken engines for no good reason.

The nozzle is part of the Exhaust duct, you can weld the duct or counterbore it and press in a sleeve to be ground out to the right shape.
Honda use a cast oval to round transition male spigot flange in the A kit 125 engines, as well as some years of the 250 V twin design.
And yes the RS125 header size is way big for a 100 - but having the correct size oval shape in the duct would reduce its volume and increase velocity and power a heap.
The design I have just done for the RGV100 has an oval duct nozzle the area of a 31mm circle,that transitions out to a 36 diameter round header bore in the flange.
This matches an Ex port area capable of achieving an easy mid 30Hp number.

[Henk]

Castrol R, bean oil. Not sure where the hell I'd get some of that this side of 1970:scratch:


Supercheap. The one in Westate has the stuff on the shelf.

[RMS eng]

Thanks that is all very interesting.

Castrol R, bean oil. Not sure where the hell I'd get some of that this side of 1970:scratch:

Re the 256 cages I'd heard of a chap boring the cranks & using Aprilia rods as were 2mm bigger. Perhaps the real improvement was the bearings were better made. Which is queer as Aprillia have a big tie up with Rotax & I'd always thought they had made their 2 stroke engines.

The duct info is very interesting & is making my head swim a bit.

Dave i sell it $24.00 for 1L,or just go to super cheap.i use it in all my 125 MX bikes.

[F5 Dave]

The only connection between Rotax and Aprilia was that the race team used the 250 V twin cases from Rotax at the beginning of their attack on that class.
Very quickly they made their own cylinders, and later their own cases as well.
Then they got sick of the crap gearboxes and did their own, as the original design by Bombardier was for a 125, and this got used even on the 250cc single, with predictable results there as well.
The early Rotax had 20mm pins that were too small, and the later design had 22mm - when Hondas bulletproof cranks were 24 and 25mm.
So yes the uprated design you mentioned probably had some actual QC done on the parts, unlike the Rotax shit - they should have been shot very early on and prevented millions of dollars and grief being spent on broken engines for no good reason.

The nozzle is part of the Exhaust duct, you can weld the duct or counterbore it and press in a sleeve to be ground out to the right shape.
Honda use a cast oval to round transition male spigot flange in the A kit 125 engines, as well as some years of the 250 V twin design.
And yes the RS125 header size is way big for a 100 - but having the correct size oval shape in the duct would reduce its volume and increase velocity and power a heap.
The design I have just done for the RGV100 has an oval duct nozzle the area of a 31mm circle,that transitions out to a 36 diameter round header bore in the flange.
This matches an Ex port area capable of achieving an easy mid 30Hp number.

OK I'll have to make something similar if I keep with this barrel, -its a bit of an abortion until I get enough time to do another, but I can't seem to find that time with other commitments & projects. Thanks for the background, makes good reading.

Rotax's attitude seems to parallel Konigs if Hannah is to be believed.

[husaberg]

And re the step in a Honda exhaust duct.
When using a T port or a properly designed tripple port exhaust, the area just outside the port is way too big during the blowdown phase,and alot of velocity is lost.
I have found that a good rule of thumb is to gradually reduce the duct exit at the flange, to around 75% of the total chordal area.
This will often equal the area of just the main port in a tripple setup.
If you make the duct exit the width of the header, and then reduce the height, forming an oval to give the correct area, a heap of power is created, in part due to the much better flow from the outer parts of the port width of a T or the
aux ports in a tripple..
Steps work OK, but a CNC formed oval to round transition in the flange works best.
Note well, this technique DOES NOT work in a single Ex port engine, no matter how big it is.



Ok think I got that but what is the step in the pipe at the singer/baffle cone for? why does it cost hp to remove it .The restricting convex?

Ps isn't A747 castor based
Castrol r is available at any cmrr meeting for free if you don.t mind second hand find someone with a manx or G50 or 7r

[husaberg]

The only connection between Rotax and Aprilia was that the race team used the 250 V twin cases from Rotax at the beginning of their attack on that class.


They started with the tandam twin rotax didn't they?
Then I thought the v twin was mostly there work that how i recall it but it wouldn't be the first time i was wrong either.
I've got the step by step story of the engine devlopment somewhere buried if anyone is interested. its a bout 10 pages long in one of the gp autocorse books from when max first took the crown.

[husaberg]

My only point is that to be bucket legal these must be non competition parts. h

I thought parts were ok just weren't allowed to use gearbox or competion based engines.
I would have thought a big end bearing was ok?:innocent:

[husaberg]

I thought parts were ok just weren't allowed to use gearbox or competion based engines.
I would have thought a big end bearing was ok?:innocent:

busy night want a beer? :yes:
thought you would never ask.

[wobbly]

Removing the step from a Honda means you remove the oval nozzle restriction before the header, that increases duct velocity.
Bigger is certainly not better.
As an example when I did testing for the new Luyten 125 cylinders, I counterbored the duct and made inserts to change the oval size.
It started with 41 by 37, I dropped it to 41 by 35 then 41 by 32.The change was worth around 2Hp everywhere, but especially in overev.
Then I added a hand ground 41 by 32 oval, to 41 round, transition in the spigot - and picked up another 1.5 Hp, putting that cylinder over 50 RWHP for the first time.

The Rotax Tandem twin was the first 250 class engine, but it was way too long to get good chassis geometry, they then did the V twin for Aprilia, carrying on making the tandem for karting.

A747 is a synthetic hybrid with caster added, it doesnt work on pipes ( just as well at the price).Probably still the best 2T oil you can use.

[husaberg]

Removing the step from a Honda means you remove the oval nozzle restriction before the header, that increases duct velocity.
Bigger is certainly not better.
As an example when I did testing for the new Luyten 125 cylinders, I counterbored the duct and made inserts to change the oval size.
It started with 41 by 37, I dropped it to 41 by 35 then 41 by 32.The change was worth around 2Hp everywhere, but especially in overev.
Then I added a hand ground 41 by 32 oval, to 41 round, transition in the spigot - and picked up another 1.5 Hp, putting that cylinder over 50 RWHP for the first time.

The Rotax Tandem twin was the first 250 class engine, but it was way too long to get good chassis geometry, they then did the V twin for Aprilia, carrying on making the tandem for karting.

A747 is a synthetic hybrid with caster added, it doesnt work on pipes ( just as well at the price).Probably still the best 2T oil you can use.

I'll repost the pic the bit I am asking about is on the baffle cone /stinger

interestingly I was reading about some chronic shortage of beanstock causing problems with the supply of castor based oil somewhere the other day Drought or flooding or disease or something the other day.

I wounder if a747 goes off I still have about 3.5 litres I am to scared to use It would be 10 years old.
ps you never gave me a hint about the the incident with the euro gp jockey and the asian misgender idenification mix up was it L Cap

[husaberg]

Sometimes you get lucky & there are road bikes that have good design cages in the sizes you want. Suzuki bearings don't seem to be that flash, at least on their older models. the MB bearing has been upgraded several times & is actually the same part as used on CR80s. However I am no expert on available sizes out there for common bikes.
r.

re big ends tkrj list all the sizes for handy cross referncing there a link on here somewhere http://www.tkrj.co.jp/product/m-be-bearing.html
also useful for rings pistons etc cross referencing not sure about the quality but a useful resouce.
Wiesco is also another useful resource for bearing sizes. Gudgeon pins crankpin sizes etc.
Also there was a post a couple of weeks ago regarding flash conrods euro based that have a useful reference for big ends and mains http://www.samarin.net/?productos
As a side note the sites for the honda rs125 offer replacement big ends now not factory but top spec.http://www.sp125racing.com/PerformanceEnginePartsRS125%202011.htm

[wobbly]

Another good source for big ends is Thompson - I use these in KT100 crank rebuilds as the needles are already graded.
The rear cone nozzle in the old Honda manual is well out of date.
A later version was developed by Helmut Fath and was first used on Fast Freddys 250 where one stinger was 150 long the other was 450 long.
This better design has a short 10mm "nozzle" of the correct size to create the pressure restriction, then a short taper, up to a stinger tube approx 2mm bigger in diameter.
The bigger stinger and the reverse taper basically remove this resonant tube from the equation, and the stinger length becomes irrelevant.
Under normal conditions the wave action bouncing up and down the stinger ,off the open end to atmosphere, creates varying bad effects on the reverse cone waves.
The pic shows a section of one for F3 - 400.
Rear cone welds onto LH side, stinger pushes into RH side and welded as well.
Another side effect is that there is no welding ( dags) to affect the flow where the rear cone is attached to the tube.

Dont know about Loris and his anal action, but I was with Benson and the team at Cowes one year having diner on the corner, where Max had a new "girlfriend" that night.The next night the same "person" was on his lap,as a man.
Tell his new wife that one, and see if the bulge in the back of his pants is stronger than the one in front.

[husaberg]

[QUOTE=wobbly;

Dont know about Loris and his anal action, but I was with Benson and the team at Cowes one year having diner on the corner, where Max had a new "girlfriend" that night.The next night the same "person" was on his lap,as a man.
Tell his new wife that one, and see if the bulge in the back of his pants is stronger than the one in front.[/QUOTE]

I hadn't herd about that incident but not that surprisede I hear max was rather "eklecdic"or divese in his interests

But the one I was thinking of was a genuine case of gender confusion where the whole crew knew it was a lady boy and the euro star only cottoned on when attempting to seal the deal .He was not so happy about not being let on about the joke

[F5 Dave]

I thought parts were ok just weren't allowed to use gearbox or competion based engines.
I would have thought a big end bearing was ok?:innocent:
Perhaps refresh yourself with the rules on MNZ site. Parts are parts. If they come from competition engines then they aren't legal. Exception for pistons, ign, carb pipe.
So if one found a source of bearings that weren't specifically for a comp engine then that should be ok.

[husaberg]

Perhaps refresh yourself with the rules on MNZ site. Parts are parts. If they come from competition engines then they aren't legal. Exception for pistons, ign, carb pipe.
So if one found a source of bearings that weren't specifically for a comp engine then that should be ok.

maybe the for competition engines in you quote should be from if we are using your interpration of the rules.


Perhaps refresh yourself with the rules on MNZ site. Parts are parts. If they come from competition engines then they aren't legal. Exception for pistons, ign, carb pipe.
So if one found a source of bearings that weren't specifically from a comp engine then that should be ok.

I could be accused of playing the devils advocate here but......
Here is the rules
24-2-4 Engines must be derived from non-competition motorcycles. Motocross, Road Racing,
Enduro and Go Kart motors and transmission parts are not permitted. There shall be no
restriction on the make, type or design of carburettor, ignition, exhaust, piston, cam, valve
springs or cooling system except for class eligibility. All engines must be normally
aspirated except F4 4 stroke engines of less than 100cc capacity, which may be turbo or
supercharged.
F4 2 stroke engines over 104cc are restricted to carburation equivalent to a single 24mm
carburettor, F5 4 stroke engines over 53cc are restricted to carburation equivalent to a
single 20mm carburettor.

Please point me to the bit that excludes race design or derived big ends,
Note they are not competion derived engines.they are but a very minor not power producing part of one.
The competition based motors was designed to exlude cr80, Rs125, cr125 motors barrels major parts and the like not to excude bearings.
I believe my interpration is in the spirt of buckets not against it.
Ask a lawyer if this is not a loophole that I can drive a bus though.:girlfight::girlfight:

Note people have used Xr200 heads for years and honda called them an enduro bike but who cares they were the same as a xr125s head other than the decompressor.

If I wanted to say something real contraversial point me to the rule that excludes nitros oxide bearing in mind it's not a fuel it is an oxidiser:innocent:
Whoops forget I said that!
Dave sound real grouchy already:not: maybe he should have a look at the smiley on the origional post to!!!!!

[speedpro]

Here is the rules
24-2-4 Engines must be derived from non-competition motorcycles.

Motocross, Road Racing, Enduro and Go Kart motors and transmission [B]parts are not permitted.

Please point me to the bit that excludes race design or derived big ends

This part of the rule clearly states that "parts" from "Motocross, Road Racing, Enduro and Go Kart motors" are not permitted.

If you don't think a bearing can affect how much power an engine can make I can supply you with some lovely bearings for your engine.

Something you MUST do on performance engines is upgrade the bearings. It may be with bearings which have a different clearance or maybe the cages are made with a different material, or design.

[husaberg]

This part of the rule clearly states that "parts" from "Motocross, Road Racing, Enduro and Go Kart motors" are not permitted.

If you don't think a bearing can affect how much power an engine can make I can supply you with some lovely bearings for your engine.

Something you MUST do on performance engines is upgrade the bearings. It may be with bearings which have a different clearance or maybe the cages are made with a different material, or design.

Read it again Mike.
But first slowly take a deep breath and open your mind.
The rule does not say motor parts as you quoted it says it exclude competion based motors and then says transmission parts to exclude close ratio gearboxs do you have a big end in your transmission? or is it a stick of some sort?
I think wobbly said Max did ?

With your interpration if I use a gearbox shim from a cr80 in my Mb5 based transmission I'am cheating please.......:violin:
I have yet to see anyone gain a procecution with a unwriten law it has to be written to be a law or rule.
Although the treaty of Waitangi might be different there appears to be many unwritten bits left still to claim on.:lol:

Clearly ignorance is a defence,
For anyone except the IRD who's to argue I not ignorant.
Inocent until proven guilty I say, trail by jury to, You are not a sheriff Mike we don't lynch people these days. Even in the South Island.

Ps I can't ever remember seeing a part number written on my big end bearings........... its on the packet though I think I threw that away bugger....:killingme

for the record where's your big end bearing from Speedpro?
yes I have seen your avatar.
I to do know a little about bearing thats why mine are not standard. Neither are my clutch plates don't think they are transmision either or have part numbers on them must check the packet.bugger must have thrown that out too......:shifty:
I don't feel the slightest pang of guilt either:dodge:

[gav]

Always sad to see people thinking they can interpret the rules differently to try and gain an advantage. Then when its pointed out to them, they start mentioning the "spirit of buckets" etc etc.

[jasonu]

Always sad to see people thinking they can interpret the rules differently to try and gain an advantage. Then when its pointed out to them, they start mentioning the "spirit of buckets" etc etc.

Well said that man

[husaberg]

Always sad to see people thinking they can interpret the rules differently to try and gain an advantage. Then when its pointed out to them, they start mentioning the "spirit of buckets" etc etc.

Look at the rules again its motors and transmission parts
Not motor and transmission parts
The devil is in the detail.
Expliotation of rules is part of life.I don't think I cheat happy to show you my bearing if they upset you. I did not write the rules but I am allowed to interperate them.
Maybe you should seek clarification regarding the rule from the MNZ if you want.
If they delete the s it changes the rule a lot.

For the record mine is std h100 but i do have some beatiful silver plated nos cr125m big ends that would fit with a mm of either side'
Athough there is bound to be some cheating alegations when the supercharged deisel pig twin project is finished no doubt if it makes 40hp there will be calls for it to l be banned too.

[wobbly]

I think if you read the rule as it was written, but just separate the two main points, you have a perfectly valid interpretation that allows individual components,but NOT Engines ( a whole entity ) or Transmissions Parts ( a main component) from the competition bikes etc

like this

"Motocross, Road Racing, Enduro and Go Kart motors.......... and transmission parts are not permitted".

If you work this backwards for one type mentioned ,you can say.
"Transmission Parts from a Go Kart are not allowed"

and then you can say.
" Go Kart Motors" are not allowed.

Nowhere is there a statement included in the wording, that points to" Individual Parts from a Go Kart engine" are not allowed.

This is NOT a Loophole its a Black Hole thats so bloody obvious I dont understand why there could be any other legal interpretation.
Sorry guys, using a KT100 piston is just as legal as a KT100 rod/bearing/washers, but using a KT100 Engine is out.

This is a little like the F3 rules - where you can build an engine that contains ALL the parts from a GP roadracer,except for the cases that must be road bike based.

[speedpro]

My rod and little end and big end bearings came out of a catalogue which Pete Sales has. None of the parts in my engines are illegal. For the record I am using a Yamaha KT100 kart piston which is fine as pistons are open.

You are right in one thing, the rule is a little ambiguous. It could be taken to read "engines" and "transmission parts". The intent was for it to read "engine and transmission" parts. ie - any parts within the engine or transmission. Every racer to date has interpreted the rule this way.

The other way to read it is that the rule refers to multiple types when referring to the engines and therefore the rule should refer to transmissions?

There is actually no need to specify that your big end bearing is from a competition engine. More than likely there is a legal model whose bearings have been superseded to the one you state you are using. TS100s are like that, the only bearing you can get now is also specified for RMs and is silverplated.

[gav]

Except Pistons are mentioned There shall be no
restriction on the make, type or design of carburettor, ignition, exhaust, piston,
Look, I agree, the way the rules are written does lead them too open for interpretation. :(

[husaberg]

This is NOT a Loophole its a Black Hole thats so bloody obvious I dont understand why there could be any other legal interpretation.
Sorry guys, using a KT100 piston is just as legal as a KT100 rod/bearing/washers, but using a KT100 Engine is out.



Thanks for the support wobby but are you wanting to be lynched as well
There seems to be a posse forming outside my house already and all my white sheets are missing.

[Buckets4Me]

Look at the rules again its motors and transmission parts
Not motor and transmission parts
The devil is in the detail..

so you mean to tell me I can't use an rs125 motor but I can use the parts within the motor

and i can use an rs gearbox but not the parts within ?


and I thought our moded 24mm carbs where iffy
Talk about pushing the rules

[speedpro]

The other thing is that standard Honda MB/H100 cranks are good for 14,000rpm all day for around 6 years of regular bucket racing at Ohakea, Manfeild, and Taupo. There is absolutely no need to use anything except genuine Honda MB/H100 crank parts. The ONLY reason I don't is because Wobbly made me, he's very convincing.

[husaberg]

My rod and little end and big end bearings came out of a catalogue which Pete Sales has.

Is your rod and bearing designed for a competion engine?

I'd hate for anyone to make hypocritical statements Mike
I believe dave came up with the for competition engine bit on your own accord:ar15:


Quote Originally Posted by F5 Dave View Post
Perhaps refresh yourself with the rules on MNZ site. Parts are parts. If they come from competition engines then they aren't legal. Exception for pistons, ign, carb pipe.
So if one found a source of bearings that weren't specifically for a comp engine then that should be ok.

Does that mean dave is saying your cheating to

[Buckets4Me]

Is your rod and bearing designed for a competion engine?

bucket racing is not competion





ITS WAR

[husaberg]

and i can use an rs gearbox but not the parts within ?




no the gearbox contain competion tranmission parts these are clearly defined as not legal

[TZ350]

Maybe you should seek clarification regarding the rule from the MNZ if you want.

Getting clarification on a rule is harder than you think.

Over the last few months I have written three times to MNZ regarding clarification of the 24mm carb rule without any outcome, or even an acknowledgement, and yes I did phone the office to check they had receved them.

At the last Mt Welly meeting JC talked with the Road Race Commisioner about clarification of the carb rule so lets hope something comes of that.

[husaberg]

Getting clarification on a rule is harder than you think, I wrote three times to MNZ regarding clarification of the 24mm carb rule, and even had JC chase it for me but no reply yet.

Sorry for hijacking your thread TZ
But I love a good crap fight hows the engine work going have you considered a mvx250 carb 24mm flat slide I think 3 for $80
Also with you carbs I seem to remember something with disk valve engines needing different emulsion tubes in bells book like a 4 stroke just an idea but I don't think they are replaceable on Keihins are they.

[speedpro]

I don't cheat. There is no satisfaction building a great engine with cheater parts. I haven't "interpreted" the rules to fit a part.
"Technically" if you were to fit a washer from a CR gearbox it would be cheating. Some CR80 gearboxes do fit evidently and have slightly different ratios. Some minor parts could overcome a deficiency allowing an advantage. The rules are written, and generally interpreted, to more or less balance things out.

[husaberg]

I don't cheat. There is no satisfaction building a great engine with cheater parts. I haven't "interpreted" the rules to fit a part.
"Technically" if you were to fit a washer from a CR gearbox it would be cheating. Some CR80 gearboxes do fit evidently and have slightly different ratios. Some minor parts could overcome a deficiency allowing an advantage. The rules are written, and generally interpreted, to more or less balance things out.

Answer the question Mike is you rod and big end crankpin etc designed for a competition motor if they are
Dave says you are cheating not me .
I think you are using the rules as they are written to say you don't interpret the rules is weird did you build your engine without looking at the rule book your game if you did how did you know the engine size then?

[husaberg]

Always sad to see people thinking they can interpret the rules differently to try and gain an advantage. Then when its pointed out to them, they start mentioning the "spirit of buckets" etc etc.

Its always sad to see hipocrocy you are not calling speedpro a cheat are you so whats the diference .

[husaberg]

My rod and little end and big end bearings came out of a catalogue which Pete Sales has. None of the parts in my engines are illegal. For the record I am using a Yamaha KT100 kart piston which is fine as pistons are open.

I hope you are not using Kt100 Gudgeon pins and circlips or shit not kt100 rings too,
because guess what they are not mentioned as free in the rules it says pistons are free no mention of rings pins circlips being open .
So guess what by your own and daves and Gavs and Jasons interpretations You are not with in the rules:killingme
I find it obserd to be called a cheat when I have a std big end it's sad really.Stirrer yes that fair i love doing that.

[bucketracer]

I find it obserd to be called a cheat when I have a std big end it's sad really.Stirrer yes that fair i love doing that.

If you want to bait people, maybe you could start your own thread, and not hijack this one. The Team ESE thread is about show and tell and sharing what your doing, and open to all in the hope they will contributed in a positive way.

[Buckets4Me]

no the gearbox contain competion tranmission parts these are clearly defined as not legal
ye but I dont want to use the parts I want the compleat thing. :killingme
there for legal as are the parts inside the engine (but not the compleat engine)


or so say you


enough of the baiting now lets get back to work


now I have started you a thead. Can we keap the silly talk there please

http://www.kiwibiker.co.nz/forums/showthread.php/139101-Rules-for-husaberg

[wobbly]

Quote "so you mean to tell me I can't use an rs125 motor but I can use the parts within the motor
and i can use an rs gearbox but not the parts within ?"

NO dead right and dead wrong, in parts - read what I said about the KT100. You can use KT100 parts as much as you want, just not a KT100 motor.
So yes, you could use a RS125 crank, and rod etc, but NOT the whole motor, the rule states "Roadrace MOTORS" are not allowed - but NOT that the CRANK from a roadrace motor is illegal.

Same as I said about using a KT100 gearbox ( if it had one ) That would be illegal.
As a competition gearbox part,of any sort, is not allowed.So ANY RS125 gearbox part is illegal.

I dont give a fuck about being "lynched", all im doing is reading the rules as they are written, and having been thru many court cases over rule interpretation in karting, where the outcome could mean the driver gets a shot at F1 or not ( or so the fathers cheque book thinks) this argument is very amature.

Put simply again, an RS125 "MOTOR" is illegal, and ANY RS125 "TRANSMISSION PARTS " are illegal.
Thus the obvious logic is that using individual MOTOR parts from an RS125 are perfectly OK, but using a 2nd gear from a RS125 in say a MB100 if it fitted ,is out.

[husaberg]

If you want to bait people, maybe you could start your own thread, and not hijack this one. The Team ESE thread is about show and tell and sharing what your doing, and open to all in the hope they will contributed in a positive way.

Look my last reply to tz please .

Sorry for hijacking your thread TZ
But I love a good crap fight hows the engine work going have you considered a mvx250 carb 24mm flat slide I think 3 for $80
Also with you carbs I seem to remember something with disk valve engines needing different emulsion tubes in bells book like a 4 stroke just an idea but I don't think they are replaceable on Keihins are they.


Getting clarification on a rule is harder than you think.

Over the last few months I have written three times to MNZ regarding clarification of the 24mm carb rule without any outcome, or even an acknowledgement, and yes I did phone the office to check they had receved them.

At the last Mt Welly meeting JC talked with the Road Race Commisioner about clarification of the carb rule so lets hope something comes of that.

Debate arround the rules is contributing to the tread in a positive way.Debate is healthy.
I agree personal attacks are not.
Do i agree this has gone to far yes of couse it has.
But please read wobblys reply he's smarter than us both put together, and he's actually took the time to read what I posted rather than jumping to conclusions.
Yes I did respond when I was attacked in tandem by dave and Mike but simply because you can not have your cake and eat it to with regards to the rules.
The rules are the rules and I believeI was offering the interpation which is the obvious interperation if you read it properly.
I hate hipocracy displayed by dave and to a greater extent speedpro.This started because I was pointing out souces for better big ends and how to reference them.
Please read the origional post that started the scrap slowly with a open mind .

[Kickaha]

I dont give a fuck about being "lynched", all im doing is reading the rules as they are written, and having been thru many court cases over rule interpretation in karting, where the outcome could mean the driver gets a shot at F1 or not ( or so the fathers cheque book thinks) this argument is very amature.
Couldn't count the number of times I saw protests at Kart racing because someones father was packing a snot about something, some quite prominent Karting families normally involved

I gave up sprint racing for that reason

There used to be a rule in the Kart book that went something along the lines of
"if the rule book doesn't say you can do it then you can't"

[wobbly]

The whole reason I have entered this forum of late, and told you guys shit that you would never even have dreamed of, unless Jennifer Aniston was in on it as well, is that I am happy to pass on good knowledge.
Because no one else would appreciate it.

Real two stoke knowledge and experience is thin on the ground, as most people are still reading Bell and Cameron from 30 years ago as though that shit was the real deal.
What Thiel achieved at Aprilia, and Bartol at KTM is where the current realty lies, along with the huge advancements of late in engine simulation, that sprung out of the work at Queens in Ireland - but is now a quantum leap ahead of that simplistic bullshit code, in producing believable results.
The reality is, that making over 50 Hp from a 125 is easy, just as making 30 Hp from a 100 is easy, in fact the 100 is way easyer.
The fact that no one has done a proper job of a 100 yet, simply means I havnt helped enough of you do the right things.
Mike,TZ and NoMates are 1/2 way there,but there are another 100 secrets hiding in the ladies toilet.
My fault, sorry.
But if we are going to get hung up on bloody big end bearings as an issue, then im very inclined to say fuck off, its not worth the effort, when the rules are crystal clear - all because of an "s" after the word motor.

[husaberg]

The whole reason I have entered this forum of late, and told you guys shit that you would never even have dreamed of, unless Jennifer Aniston was in on it as well, is that I am happy to pass on good knowledge.
Because no one else would appreciate it.

Real two stoke knowledge and experience is thin on the ground, as most people are still reading Bell and Cameron from 30 years ago as though that shit was the real deal.
What Thiel achieved at Aprilia, and Bartol at KTM is where the current realty lies, along with the huge advancements of late in engine simulation, that sprung out of the work at Queens in Ireland - but is now a quantum leap ahead of that simplistic bullshit code, in producing believable results.
The reality is, that making over 50 Hp from a 125 is easy, just as making 30 Hp from a 100 is easy, in fact the 100 is way easyer.
The fact that no one has done a proper job of a 100 yet, simply means I havnt helped enough of you do the right things.
Mike,TZ and NoMates are 1/2 way there,but there are another 100 secrets hiding in the ladies toilet.
My fault, sorry.
But if we are going to get hung up on bloody big end bearings as an issue, then im very inclined to say fuck off, its not worth the effort, when the rules are crystal clear - all because of an "s" after the word motor.

Agreed from me Wayne.
So if I post a rubbing of my cylinder and some pics as well as the basic spec can you show me where I am at Wobbly.
Mine as you have alluded to is all based on bell and Robinson cause thats all i had to go on.

[gav]

But if we are going to get hung up on bloody big end bearings as an issue, then im very inclined to say fuck off, its not worth the effort, when the rules are crystal clear - all because of an "s" after the word motor.

I wonder if that extra S was intended or was a typo?
After all why ban competition transmission parts but allow competition engine parts?
Wonder if there is anyway of getting clarification on that?

[bucketracer]

Getting clarification on a rule is harder than you think.


I wonder if that extra S was intended or was a typo? Wonder if there is anyway of getting clarification on that?

TeeZee hasn't found it easy, if anyone has some pull with MNZ maybe they could get them to look into it.

[kel]

But if we are going to get hung up on bloody big end bearings as an issue, then im very inclined to say fuck off, its not worth the effort,

No you don’t. You keep writing we keep listening (and learning). There’s a ground swell in 2 stroke interest and the bikes that will roll out over the next 6 to 12 months will change the game, and they'll be built within the rules!

[wobbly]

If you want an analysis of an engine spec, send me ALL the info in a PM.
I do this work full time to pay the mortgage, so its gonna cost you, same as everyone else.

I think what we have here is a long standing "assumption" ( an error waiting to be revealed) that competition "parts" are illegal, when in fact the way the rules are written now,this would NOT stand up in court.
If you guys want to stick to what is also assumed was the intent, the "s" must be removed,NOW.

But my position would be that as we are "racing" and the most highly stressed parts in a "racing" engine are the piston and big end bearing, then in the interest of reliability ( and thus cost ) the late model reliable engine parts should be used.
A "racing" based close ratio gearbox is not needed for cost or reliability, so keep that as is - illegal.
But - before the decision is made what to do, alot of thought should be put into the ramifications of allowing competition engine "parts", and what effect this would have on the 4T guys.
If we allow the use of a modified RS125 cylinder, then we must allow the use of a full noise racing Moriwaki head or what ever for a 4T - BUT, the engine must be based on a road bike.
I think this would still keep an equal relativity between the two engines, but is maybe a real can of worms.
Hmmm.

[TZ350]

The whole reason I have entered this forum of late, and told you guys shit, is that I am happy to pass on good knowledge.
Because no one else would appreciate it.

I for one, very much appreciate it.

[ac3_snow]

I for one, very much appreciate it.

Ditto, should also say thanks to you TZ, and all the contributors, this thread provided me with all the motivation and wisdom to build my new bike. Saved me from getting an FXR!!

[speedpro]

Saved me from getting an FXR!!

If it saved even one rider from the dark side then it's all been worth it

[kel]

If it saved even one rider from the dark side then it's all been worth it

יְהִי אוֹר and the light was good.
And of course darkness is the privation of light (thanks Honda).

[TZ350]

There are some realy great action pic's of the last Mt Wellington meet on Damiens site http://www.flickr.com/photos/dty1/sets/72157626941175616/?page=12

[TZ350]

More of Damiens great shots.

Amoungst the pictures are a bunch of FXR150's a very fast CB125T(150cc) and some strokers.

[F5 Dave]

Crumbs, I go away from the PC & this all blows up.

Husaberg I didn't 'attack' you at all, I just suggested you read the rules, so many seem to just go on heresay.

Now at this point I will have to admit that every time I've looked at those rules I've never read them that way. Now I have to agree that the 's' does seem to be an anomaly. Else why would the rules mention exclusions for pistons carbs etc?

Should someone put that through to MNZ for an amendment? or as Wobbly says, you could use an RS barrel in an extreme case.

Anyway I agree lets keep clear of squabbling, I don't come here for that.

[Kickaha]

I don't come here for that.

You come for the porn and beer?

[RMS eng]

Crumbs, I go away from the PC & this all blows up.

Husaberg I didn't 'attack' you at all, I just suggested you read the rules, so many seem to just go on heresay.

Now at this point I will have to admit that every time I've looked at those rules I've never read them that way. Now I have to agree that the 's' does seem to be an anomaly. Else why would the rules mention exclusions for pistons carbs etc?

Should someone put that through to MNZ for an amendment? or as Wobbly says, you could use an RS barrel in an extreme case.

Anyway I agree lets keep clear of squabbling, I don't come here for that.

How do you guys come up with using a RS125 cylinder,rules say non competition motors and parts not permitted,unless you can prove they are the same part as used in road or trail bike,or have the same part number eg RM80 and DS80 use the same rod kit,rules look good and clear to me.

[gav]

Because some read it as referring to a complete motor and transmission parts, and somehow this doesnt mean motor parts.

[Kickaha]

rules say non competition motors and parts not permitted

No they say Motors and transmission parts, not motor and transmission parts, a small but subtle difference

[F5 Dave]

Sadly Chris he's right. Not the intention the rule for sure.

[Kickaha]

Not the intention the rule for sure.

No I doubt it was and certainly not how its been interpreted for a few decades

Funny the difference one letter can make, although I'll be using the "old" interpretation for anything I build

[RMS eng]

Sadly Chris he's right. Not the intention the rule for sure.

no still looks clear to me,first bit said,motors must be derived from non-competition motorcycles ect,and a motor is a complete engine.

[gav]

no still looks clear to me,first bit sad,motors must be derived from non-competition motorcycles ect,and a motor is a complete engine.
But what about using motor PARTS, hence not a complete engine?
eg start with MB100, add RS125 cylinder ....

[jasonu]

But what about using motor PARTS, hence not a complete engine?
eg start with MB100, add RS125 cylinder ....

That argument is pedantic at best. We (Bucket Racers) all know the rules and just because some clever cloggs has noticed a loop hole that might suit his build, the intention is well known and accepted.

[bucketracer]

That argument is pedantic at best. We (Bucket Racers) all know the rules and just because some clever cloggs has noticed a loop hole that might suit his build, the intention is well known and accepted.

Well said Jason totally agree ........

I think the smarty who started arguing the toss has moved to here, where nothing has to work and creative talk can make all things possible.

http://www.kiwibiker.co.nz/forums/showthread.php/139101-Rules-for-husaberg

Probably a great place for everyone who loves to argue, to take the rest of the clever legal eagle ideas to too.
(http://www.kiwibiker.co.nz/forums/showthread.php/139101-Rules-for-husaberg)

[kel]

Found sometime to work on the KE this weekend. Ive decided the arguement for correct blowdown cant be ignored so have reset the transfer back to 128 deg and widened them out as much as possible . While I was in there I decided to match the piston skirt transfer cut outs to the inlet (rotary valve), thankfully TZ saved me just in time as the piston wouldnt have sealed the exhaust port at TDC. (cheers mate owe you a beer for that one). Managed to mount the KX stator as well. A couple more weekends like this one and I might even get it finished by the end of the year.

Now back to the FXR, time to get those new cams in :banana:

[Yow Ling]

Some old coot from Rangiora dropped of this old trail bike engine, its some kind of Kawasaiki looks a bip like the GP125style of things, any good for a bucket?

[jasonu]

any good for a bucket?

No mate total shit. Give you $20 bucks for it (and on sell the cylinder to Kel for $50)

[bucketracer]

GP125style of things, any good for a bucket?

Send it up to Auckland, we will figure out something to do with it.

[kel]

any good for a bucket?
As I said a ground swell of 2 stroke interest, and, a return to Kawasaki dominance. Have a feeling this one will come together quicker than mine.

[gav]

Some old coot from Rangiora dropped of this old trail bike engine, its some kind of Kawasaiki looks a bip like the GP125style of things, any good for a bucket?
Didn't know Kickaha had one of those in his garage?

[Gigglebutton]

Some old coot from Rangiora dropped of this old trail bike engine, its some kind of Kawasaiki looks a bip like the GP125style of things, any good for a bucket?

Thanks Warwick & Mike for your help. This will be Frankenstein's Kwaka. Built from the remains of bikes i have dug up and been given. A perversion in the eyes of the bucket gods, but hopefully with Wobly's help i can achieve the 40hp he has spoken of. If its as good as Robs bikes I'll be happy, If it,s better than his, I'll start cloning it. Fuck yeah, a two stroke zombie army :devil2:

[gav]

Ohhhh 40hp now ??? :killingme

[Gigglebutton]

Ohhhh 40hp now ??? :killingme

Oops That should be 30hp.

[bucketracer]

Its fallen to me again to put the links list together for page 290, I have posted snippets of the interesting tec posts, you have to click on them to read the post.


If you look at the delivery ratio of a race engine, then calculate how much actual mixture is transmitted thru the transfers into the cylinder - compare that to the swept vol of the transfers, you realize that in most engines, what is sitting in the ducts is more than the vol going to the cylinder.,,,,,,,,,,,

Handy references …………….


Chambers sent me this link for those that might want to find a suitable rod, and I think they will even make you one to order.
http://www.samarin.net/?productos


re big ends tkrj list all the sizes for handy cross referencing there a link on here somewhere http://www.tkrj.co.jp/product/m-be-bearing.html
also useful for rings pistons etc cross referencing not sure about the quality but a useful resource.
Wiesco is also another useful resource for bearing sizes. Gudgeon pins crankpin sizes etc.
Also there was a post a couple of weeks ago regarding flash conrods euro based that have a useful reference for big ends and mains http://www.samarin.net/?productos
As a side note the sites for the honda rs125 offer replacement big ends now not factory but top spec.http://www.sp125racing.com/PerformanceEnginePartsRS125%202011.htm


Another good source for big ends is Thompson - I use these in KT100 crank rebuilds as the needles are already graded.

Wobbly talks about how to achieve crank reliability, the posts are worth a read.


……… For some very wierd reason Rotax do not match any of the parts in batches to get the clearances correct………..


Most of the issues with the old cranks will be the cage construction of the big end bearing. The "new" design has a flat outer shape, with no indented rib to support the rollers………


All the common big end sizes are available in the newer flat cage design, as this type is used in all current road and race engines.

Posts also explain a little about Exhaust port duct design ………….. click the links to read it all.


as above found this on Honda rs125


And re the step in a Honda exhaust duct.
When using a T port or a properly designed tripple port exhaust, the area just outside the port is way too big during the blowdown phase,and alot of velocity is lost.
I have found that a good rule of thumb is to gradually reduce the duct exit at the flange, to around 75% of the total chordal area.


The nozzle is part of the Exhaust duct, you can weld the duct or counterbore it and press in a sleeve to be ground out to the right shape.


Removing the step from a Honda means you remove the oval nozzle restriction before the header, that increases duct velocity. Bigger is certainly not better……..

Electric power Jets


The modern take on powerjets is to turn them off after peak power to extend the rev range. This assumes that you are happy for your engine to rev that much further past peak power………..


With all the talk about wanting to utilize only a couple of gear changes per lap, I would have thought that the solenoid powerjet was a gift from heaven.
A late model well tuned RS125 will rev to around 12400 if the PJ is disabled, turn the PJ function back on and it will go to 13800+………..


Oh yea , ordered a piston the other day from Strike in perth, I ordered a 50.6mm so will end up at 101.75cc, oversizes are tiny so you only need to hone to the next size. About NZ$100 for a piston.

Devcon and JB weld…….


Depending on the setup you can use Devcon to glue inlets on. My RG50 had a (piston port) spigot shape into a round loose bore glued & it never failed after many many years …………


Mild steel pipes will always rust and or go black,the only way to help keep them looking OK is to use Castrol R. You have to rub it on with a rag every time the bike is run, and eventually it will burn in like a wok surface preventing rust, but you cant stop the header going black.

Wobbly talks about replacing the function of a stinger with a nozzle, it’s an informative read.


The rear cone nozzle in the old Honda manual is well out of date.
A later version was developed by Helmut Fath and was first used on Fast Freddys 250 where one stinger was 150 long the other was 450 long.

[husaberg]

Some old coot from Rangiora dropped of this old trail bike engine, its some kind of Kawasaiki looks a bip like the GP125style of things, any good for a bucket?

is it 6 speed?
I remember there was a road race bike back in the late 70/s or early 80/s made from one of these for a top racer before he made it big from chchJacks motor cycles with Jungle mcgreggor for a young Brent Jones who did internationals later on in asia anyway it had a genuine RG500 road race top end grafted on he did real well on it.
but I supose there was only MT125s and TA125s and modified chook chashers in the 125 class then.The bike was as described but was in fact assembled at Jacks Motorcycles for Brent Jones he was unbeatable on it for the couple of years that he raced it78-80 ish Interesting I have never seen one in the flesh if it is 6 speed and i think they are 50mm ish stroke unlike the 90/100 it would have an advantage over a gp100/125 they are 5 i think.Pete Sales had a rg400 barrel on trademe.

Also if anyones interested i have a parts manual for the h100 don't know where to host it as a pdf though

reputably

[TZ350]

.

Is Speedpro cheating? as it turns out, its........

Not to hard at all to make a legal GP100 using a KT100 piston.

And expect its much the same deal for an MB100

Checked into this idea of using a KT100 piston and 0.75mm offset pin to make a 100cc screamer.

The GP125 has a 19mm big end pin and the KT100 has a 14mm piston pin.

Now I need a bigend pin that can be ground off set by 0.75mm and a 22mm pin would do for that.

By searching the on line catalogues I have found that the later model GP125 X4 popular in the Philippines has a 22 B/E-14 L/E rod, 241223

In fact there are all manner of road bike rods with these dimensions.

TKRJ GP125 X4 Rod Kit http://www.tkrj.co.jp/goods/m-BS0275A--36A10.php

This TKR site is a good resource for searching out piston/rod/bigend brg dimensions. So basically anyone could make a legal 100cc engine using a KT100 piston.

The Suzuki GP125X4 bikes are popular for sprint racing in the Philippines

[husaberg]

[QUOTE=TZ350;1130091377].

Now I need a bigend pin that can be ground off set by 0.75mm and a 22mm pin would do for that.



Akunar here http://www.akunar.com/STROKER_CRANKSHAFTS.htm list ready made strokers pins for all sorts of bikes the offset is off couse dictated by the position of the crankpin in the crankshaft the stroke lengths options are within reason limitless

[speedpro]

That rod is 100mm centre-centre, mines 105mm. Wobbly said to get a longer rod. It took a bit of searching. You need the 22mm BE pin so you can slip the rod and bearing over the offset.

[ac3_snow]

Akunar here http://www.akunar.com/STROKER_CRANKSHAFTS.htm

I was warned off their conrods, I think another buckateer used an FXR one from them with not so good results.
p.s. link is broken, one too many 'http://'s

So is the offset pin purely to reduce the stroke? I'm assuming this is because you cannot get a shorter conrod with the right dimensions?

[speedpro]

[QUOTE]


Akunar here http://www.akunar.com/STROKER_CRANKSHAFTS.htm (http://http://www.akunar.com/STROKER_CRANKSHAFTS.htm) list ready made strokers pins for all sorts of bikes the offset is off couse dictated by the position of the crankpin in the crankshaft the stroke lengths options are within reason limitless

There's been some discussion about those pins. Evidently the split big end bearing cages don't hack it. I think it was tried in a really big FXR.

[husaberg]

[QUOTE=husaberg;1130091419]

There's been some discussion about those pins. Evidently the split big end bearing cages don't hack it. I think it was tried in a really big FXR.

can't vouch if there any good but I guess the dynamics with a smoothfiring 2 stroke vs a Intermittingly firing four stroke might not rule them out completly yet anyway.
I personally would steer clear of any rod not oem factory or euro usa anyway to much at stake with the rod.

Of course the other way without resorting to off set pins is the top hat bush method where a offset hole is bored into crankwheel and then a bush is inerted allowing the std cranpin to be used.of course it has to be secured well and super acurate.

fixed the link to

for the record i have never really thought personally speedpro was cheating end of the matter me and mike have already settled this I think

I guess you have you considered the changes the piston and all the rest of the changes could make to your port timmings?

[ac3_snow]

So is the offset pin purely to reduce the stroke? I'm assuming this is because you cannot get a shorter conrod with the right dimensions?

Ohk now that I actually think about it, the conrod length does nothing to determine stroke length, the diamter of the crank and location of the crank pin determines how big a cricle the bottom of the conrod spins. So the offset crank pin gives you bigend which spins a 'smaller circle', and therefore less stroke.
Please continue to ignore my foolish questions:facepalm:

[TZ350]

Thanks to Wobbly for some pointers, the Ignitec and RC servo idea now functions.

241226

Wob gave me some ideas on how to try setting the Ignetec software switch up.

241227

Then I wired a light in, easier to see whats going on that way, and tested it.

Now this is what I want the IgniTec and RC servo to do at 6,000 rpm http://www.youtube.com/watch?v=FeB9O6rtLXQ actually I dont want it to flap, just open at 6,000rpm

Testing the Ignitech switch with a light http://www.youtube.com/watch?v=4RSHXNYt6Oc

A bit dark, so you will just have to take my word for it. Here is the Ignitech switching the V Tec RC Servo http://www.youtube.com/watch?v=ar8YST2TYjQ

Everything is functioning as it should, next step is to give it a bit of dyno time and see what we have after a few adjustments.

[kel]

That rod is 100mm centre-centre, mines 105mm. Wobbly said to get a longer rod. It took a bit of searching. You need the 22mm BE pin so you can slip the rod and bearing over the offset.

105mm rod with 22mm BE? Thats easy same as installed in my KE. There were two different lengths for different years (100 and 105mm) but if its hush hush then mums the word.

[F5 Dave]

.

Is Speedpro cheating? as it turns out, its........

Not to hard at all to make a legal GP100 using a KT100 piston.

And expect its much the same deal for an MB100

Checked into this idea of using a KT100 piston and 0.75mm offset pin to make a 100cc screamer.

The GP125 has a 19mm big end pin and the KT100 has a 14mm piston pin.

Now I need a bigend pin that can be ground off set by 0.75mm and a 22mm pin would do for that.

By searching the on line catalogues I have found that the later model GP125 X4 popular in the Philippines has a 22 B/E-14 L/E rod, 241223

In fact there are all manner of road bike rods with these dimensions.

TKRJ GP125 X4 Rod Kit http://www.tkrj.co.jp/goods/m-BS0275A--36A10.php

This TKR site is a good resource for searching out piston/rod/bigend brg dimensions. So basically anyone could make a legal 100cc engine using a KT100 piston.

The Suzuki GP125X4 bikes are popular for sprint racing in the Philippines


Hey TZ that's a pretty wiked tank mural on the last GP there:lol:. Tyres don't fill me with much confidence either. How that's straight line stuff.

As far as Speedpro cheating -I have to say I never inferred that, I've pretty much known how he has built his engine for quite some time, as he does mine & there isn't anything queer in it I am aware of, just some carefully considered engineering.

[Kickaha]

Of course the other way without resorting to off set pins is the top hat bush method where a offset hole is bored into crankwheel and then a bush is inerted allowing the std cranpin to be used.of course it has to be secured well and super acurate.


MY stroker crank in the GN was done that way when the capacity limit changed to 140cc, meant I could still use stock crankpins and bearings

[F5 Dave]

But sometimes there isn't the meat to support a bigger hole.

[husaberg]

But sometimes there isn't the meat to support a bigger hole.

I think i'll leave that reply :lol: open Dave

[TZ350]

241278

Tried the V Tec, works and cleaned up the carburation.

241277

Blue line inlet soft closes 98 ATDC Red line 88

It beats me how closing later picks up some midrange and loses overrev.

[Moooools]

Didn't you just half your power range by using the V-Tec?

[bucketracer]

Didn't you just half your power range by using the V-Tec?

Yep looks bad ...........

[TZ350]

Didn't you just half your power range by using the V-Tec?

241287

Green line is the original setup without the V Tec with the inlet soft closing at 88 Atdc

Red line is the manualy opened V Tec with the inlet soft closing at 88 Atdc

Blue line is auto closing V Tec with the inlet soft closing at 98 Atdc

Certainly lost some power range, but I think it could be caused by the different inlet closing points.

241286

[wobbly]

Lack of meat around the hole is almost as bad as the queer shit possibly going on in Mikes MB100.

In most race applications I have found that 88* is the best compromise.
But that over 90*the troublesome carburation effects overcome any power advantages that you would expect.
As I said in another post - rotary valve tuning is as much about timing ( usefull STA ) as it is about ameliorating the issues with tract resonance affecting the A/F ratio actually seen in the case, and thus the combustion process.
Your intake is relatively long now - thus the resonance effects are seen earlyer, and stronger.

[TZ350]

We ran Chambers Team ESE bike up on the dyno tonight with a conventional OKO 24mm carb with the power jet tube removed and got 25 rwhp.

[TZ350]

In most race applications I have found that 88* is the best compromise..........Your intake is relatively long now - thus the resonance effects are seen earlyer, and stronger.

Looks like I will have to change my inlet timing back to 88.

[kel]

We ran Chambers Team ESE bike up on the dyno tonight with a conventional OKO 24mm carb with the power jet removed and got 25 rwhp.

:confused: havent seen that one before. If Im guessing right then thats bad news for a lot us.

[kel]

How about a variable exhaust header. This one allows 25mm adjustment

241299
241300

Google translate says "a new control to include inflammation of RTD and the like" Thanks Google.

[koba]

We ran another GP125 Team ESE bike up on the dyno tonight with a conventional OKO 24mm carb with the power jet removed and got 25 rwhp.


:confused: havent seen that one before. If Im guessing right then thats bad news for a lot us.

Once you guys bulk up that hole a bit THAT would be a good engine to have, It looks more practically useful to me.

EDIT: Scales can be deceiving BUT I still like the look of that.

[bucketracer]

How about a variable exhaust header. This one allows 25mm adjustment

241299
241300

Google translate says "a new control to include inflammation of RTD and the like" Thanks Google.

That's very interesting, TeeZee has experimented with different mid sections but concluded that for it to be really useful the header would need to be adjusted too.

He has some ideas about a slippery pipe but not one with a moving cone but an elongated butterfly arrangement that starts in the belly section and tapers into the rear cone. When it swings across it effectively reduces the tuned length by shortening the mid section and also changes the angle of the convergent cone from mild to wild.

With a header that varies in length too this could be the go for a broad spread and wild top ............

[bucketracer]

I've seen pics and heard rumor of this bike :drool:


It is something Chambers built up, he wanted to show TeeZee that you don't need a fancy carb to make good hp.

[F5 Dave]

Queer shit in Mikes MB engine? Its that lanky b'stard that is on the outside I'd be more worried about:lol:

That's a pretty cool slippery pipe gadget. Wonder how strong the servo has to be to pull the pipe esp as the header needs to be sealed so some friction is inevitable. Perhaps it doesn't kick in till 4th gear as trying to keep up in lower gears would surely be hard. I wonder how quickly it would respond during gear changes? I mean you can imagine peak revs then bam you change gear, revs drop & try to pull out of it with a short pipe.

[TZ350]

Once you guys bulk up that hole a bit THAT would be a good engine to have.

241323

Chambers has sorted it ................ I expect with a little more fiddling he will get all of the over rev back too. (24mm OKO carb)

[TZ350]

Slippery Pipe

241324

The Blue Line is my current engine. the other lines are tests done with 20-40-60mm expansion pieces in the mid section.

All the extra length did was flatten the top and did not give any extra power range at the bottom which is what I was looking for.

So from this experiment I am unconvinced that a slippery pipe would do much.

[F5 Dave]

Sorry? so you've lost 5hp by adding 20mm? with no other changes? I'd question the pipe's integrity?



What did Chambers do to lose the dip? Ignition adv? Looks very nice.

[Buckets4Me]

Sorry? so you've lost 5hp by adding 20mm? with no other changes? I'd question the pipe's integrity?

I would guess that the 3 lower graphes where done some time ago .In the build up to the engine he has now




What did Chambers do to lose the dip? Ignition adv? Looks very nice.

again would guess that the ignitech had something to do with it
got that one wrong
It was a new pipe

[husaberg]

How about a variable exhaust header. This one allows 25mm adjustment

241299
241300

Google translate says "a new control to include inflammation of RTD and the like" Thanks Google.

Cagiva ran a system in the "lil Jon" days which extended the header pipe with a hydraulic actuation at huge pressure (1500psi) the pump allowed the header pipe to lengthen along the lines of 20mm extra or minus length .I guess they shorten the header length in operation.If I can be bothered I have pics somewhere.
Of course the Honda water injection based system was much simpler.
Interestingly after intensive and exhaustive "getit" searches I have established that neither of these two sucessfull Gp teams (Iebeit one more so than the other) used Speedpros "special" Rod:hug:

[bucketracer]

I would guess that the 3 lower graphes where done some time ago .In the build up to the engine he has now

Even just looking at the 20 and 60 lines there is not much difference between them at the lower end, maybe 200rpm.

[koba]

241323

Chambers has sorted it ................ I expect with a little more fiddling he will get all of the over rev back too. (24mm OKO carb)

That's quite scary as I think it is a very close approximation of where my bike is at, lower in the rev range of course.

Hell, a picture being worth about a grand in word money I shall illustrate:241330

[jasonu]

241323

Chambers has sorted it ................ I expect with a little more fiddling he will get all of the over rev back too. (24mm OKO carb)

I think that is the best looking readout I have seen from you guys.
Now, how will it perform on the track?????

[TZ350]

Now, how will it perform on the track?????

Whats your guess ..............

[TZ350]

NedKelly at the last Taupo TRRS

241341

And Neds new project...........

241340

Team ESE are going to try their hand at 100cc water cooled.

241342

[goose8]

Is it a rg100 ?


NedKelly at the last Taupo TRRS

241341

And Neds new project...........

241340

Team ESE are going to try their hand at 100cc water cooled.

241342

[jasonu]

NedKelly at the last Taupo TRRS

241341

And Neds new project...........

241340

Team ESE are going to try their hand at 100cc water cooled.

241342

Time will tell. I will be interested in throttle response and driveability reports. If the graph is anything to go on then I think it should run pretty dam good. The graph looks like a mix of my when run with an RS pipe and then run with my TZ pipe, the mix I hope to develop into my bike.

Neds bike looks to be in the same state as mine. Is that the chassis someone in Aussie was selling a while ago???

[wobbly]

You guys will of course be putting the sprocket centerline in the right place to get some anti squat, and keeping the front of that engine up high so the angle wont be too steep with a dead straight rubber manifold holding the powerjet carb.
If the static angle is too acute, the fuel in the bowl can uncover the powerjet entry port - it goes lean and goes bang - been there done that.

[TZ350]

Is that the chassis someone in Aussie was selling a while ago???

Errrrr no ....... :confused: ........ but we do know whos got it.

[TZ350]

Is it a rg100 ?

RG150 with a RGV250 barrel sleeved back to 50mm for a 100cc water cooled.

[jasonu]

RG150 with a RGV250 barrel sleeved back to 50mm for a 100cc water cooled.

We looked at that route a few years ago and abandoned it as the KE125/RG400 was easier for us as that build suited our resources at the time.

[TZ350]

Both are hard to do using the GP cases hence the RG150 bottom end ( a RG125 would be better). We were going to go the RG400 way and got a bunch of barrels and heads but gave up on it when YowLing sent us a RG150 engine.

We now have some RG400 heads and barrels to sell or trade if anyone want's to try their hand with one.

[jasonu]

Both are hard to do using the GP cases hence the RG150 bottom end ( a RG125 would be better). We were going to go the RG400 way and got a bunch of barrels and heads but gave up on it when YowLing sent us a RG150 engine.

We now have some RG400 heads and barrels to sell or trade if anyone want's to try their hand with one.

How much pissing about to fit the RGV250 cyl to the RG bottom end?

[TZ350]

How much pissing about to fit the RGV250 cyl to the RG bottom end?

Bolts straight on, rods the problem but YowLing has sussed that.

[jasonu]

Bolts straight on, rods the problem but YowLing has sussed that.

easy pezy lemon squeezy.

[F5 Dave]

You guys will of course be putting the sprocket centerline in the right place to get some anti squat, and keeping the front of that engine up high so the angle wont be too steep with a dead straight rubber manifold holding the powerjet carb.
If the static angle is too acute, the fuel in the bowl can uncover the powerjet entry port - it goes lean and goes bang - been there done that.
Yeah I assumed that they just had the engine sitting there on that pile of firewood a few inches too low.
Ahh - the old fit the carb manifold to the engine sitting on the bench trick! Yes played that game & lost, but just with an engine that emptied the floatbowl of the small carb enough to make it splutter first corner after the straight when the main is sucking (overly short Mikuni button jet) in the air. Fortunately didn't lock up & a curved inlet was hastily added.

[TZ350]

Ok I have shortened the inlet tract by 70mm. Well that's if the theory that reversion happens at any significant change in area is correct. Then reversion should happen now at the V Tec's throttle plate insted of the carb's bellmouth which makes that part of the inlets tuned length about the 135mm Wobbly suggests, and thats significantly shorter than the inlet tract was.

To do this I am revisiting the plenum idea, with an arrangement YowLing suggested to me that allows any fuel/oil that drops out to still be inducted into the motor.

And this also gives me a chance to try the electric power jet carb. Should be finished and ready to run up next week. Hopefully this works as the carb is now tucked in, and well out of the way.

[TZ350]

To increase low end power Wobbly has pointed me towards the Honda ATAC system, he tells me that they had some success with the idea on the BSL500. He sent me this picture and some pointers on where to put it on the header.

241414

"As close to the flange as you can, and get the throttle plate as close to the header as you can to reduce the ill effects when its closed at hi rpm......... Wob"

So I am going to try one on the GP

Other Bits and Bobs about the ATAC system that I scraped from the net........

ATAC System: The Honda Automatic Torque Amplification Chamber system works by effectively increasing or decreasing the volume of the exhaust system with a small butterfly valve located just before the exhaust connection.

A few pictures here:- http://www.scooterhelp.com/moto.barrels/honda.cr250.84_85.overview.html

A bit of YouTube of a guy working on his ATAC http://www.youtube.com/watch?v=tY7D0jLcfws

Atac and vtac differ very little. Vtac is a resonator chamber like kips, with only one inlet/outlet where atac is a bypass chamber with a in and out yet it doesn't block the main exhaust flow even when open so it very much acts like a resonator.

241367 241376



241373

All of these designs stretch the vacuum, phase, and pressure waves that bounce back to the cylinder effectively making the pipe act like it has a longer tuned length when the resonator is open and making the pipe act like it has a shorter tuned length when the resonator is closed.

241375241374

[gav]

Ok I have shortened the inlet tract by 70mm. Well that's if the theory that reversion happens at any significant change in area is correct. Then reversion should happen now at the V Tec's throttle plate insted of the carb's bellmouth which makes that part of the inlets tuned length about the 135mm Wobbly suggests, and thats significantly shorter than the inlet tract was.

To do this I am revisiting the plenum idea, with an arrangement YowLing suggested to me that allows any fuel/oil that drops out to still be inducted into the motor.

And this also gives me a chance to try the electric power jet carb. Should be finished and ready to run up next week. Hopefully this works as the carb is now tucked in, and well out of the way.


Is that a bit of radiator hose you are using? Is it fuel resistant? Maybe try some silicone hoses?

[Henk]

Is that a bit of radiator hose you are using? Is it fuel resistant? Maybe try some silicone hoses?

Been using radiator hose as an inlet manifold for about four months now, no problems so far.

[bucketracer]

There might be some problem with a longish hose collapsing under vacuum when the throttle is closed unless you have a spring inside it like some radiator pipes on the suction side of a radiator have.

[F5 Dave]

. . . .
All of these designs stretch the vacuum, phase, and pressure waves that bounce back to the cylinder effectively making the pipe act like it has a longer tuned length when the resonator is open and making the pipe act like it has a shorter tuned length when the resonator is closed.

241375241374
I'm a bit dubious about the "making the pipe act like it has a longer tuned length" part of the claims made of these systems. & also of the Powervalve cover aftermarket people who market larger covers (for KIPS chambers etc). I've always assumed that the chamber introduces a volume that disrupts the returning wave when it is out of phase with the required engine timing, ie the ports are open longer at low rpm so the pipe waves are disruptively returning at the wrong time.

It just smacks of an easy to make aftermarket part that the punter can bolt on without stripping the engine down. But if bigger were better, then why didn't the manufacturer make them bigger? Or did they design this & forget to test it year after year? Hmm, didn't think so.

But adding one on from scratch? might be worth a try.

[wobbly]

In the testing I have done, the volume of the resonator chamber isnt critical, once you have reached a certain size.The best place to start is equal to the cylinder displacement, and this will "work" every time.
Fitted to a world champ ski engine, these chambers, operated by a flat, throttle slide plate,added over 30% more power at 1/2 peak rpm.
They seem to work very similar to a PV, in that the pipe effects are dramatically reduced in the area where the wave action is way out of phase with the port.
This is seen in the sim, and on the dyno, in that you can change the pipe dramatically, and it has little effect when the PV is down, or the chamber is open.

[F5 Dave]

Thank you. That is rather heartening to read.

Crumbs, 30% that's heaps. Obviously that engine loved it. I'm assuming a jetski engine is high RPM most of the time & has very strong wave action pipe.

[wobbly]

From memory the actual number was near 38%.
But ski engines are limited to only around 8000 rpm due to the pump cavitating, so the chambers added all that extra grunt at 4000, and I think the valve closed at 6200.
The pipes arent that clever in that usually the diameter is limited by the amount of room available.

[F5 Dave]

Heck it was hard enough to get my 496's pipes to give reasonable clearance & fit the bike even with a self restrained dia. Can't imagine a modern TZ750 if such a thing existed being given free rein for pipe design. Actually did that 1100 triple Steve had on his site get past photoshop? That would be silly pipes.

[richban]

silly pipes.

How about these silly pipes. V8 anyone. Wasn't this what you wanted to put in your van Dave.

[bucketracer]

That reminds me of a story Dad tells of Bob Haldane and Bill Buckleys TZ750 based V8 speedway car. The night he went down to watch it at Western Springs it broke three rods during the course of the evening , the rods wrapped up around the bigend pins and the engine kept going. Three broken rods didn't slow it down much apparently.

It was made from four RD350 cases with the gearbox's cut off, the cases were held in a V formation by big end plates and the four engines drove a common center shaft. The four engines were topped with TZ750 cylinders heads and carbs. The motor may still be hanging around Haldanes some place.

[Buckets4Me]

That reminds me of a story Dad tells of Bob Haldane and Bill Buckleys TZ750 based V8 speedway car. The night he went down to watch it at Western Springs it broke three rods during the course of the evening , the rods wrapped up around the bigend pins and the engine kept going. Three broken rods didn't slow it down much apparently.

I remember that night (I think )
was nearly hit buy a tyre comeing over the wire fence :facepalm:
and my ears hurt so bad (dam loud back in those days)
and the poor side car guys (still scares me today watching side cars going around on dirt with niothing but a concreat wall to stop them after they crash,fall off or just stuff up)

[wobbly]

Bill & Bobs V8 had a combination of cylinder sizes to get under the cc limit, was a hell of a thing to see and hear.
It ended up with 8 pumper carbs of a jetski to simplify the tuning.
The 1100 tripple is in my CAD machine 1/2 finished,and I have one prototype cylinder on my bench.
The crank is being built, and I cant go any further till I get that.
The biggest issue was getting all new parts made, as the pipe issue dictated the basic dimensions of the engine, as a short stroke was needed to enable it to rev, thus shortening the pipe length.
But, short strokes limit the available angle/area and thus the power achievable, but its no good having a heap of power if you cant fit the pipes in - even into a ZX10 chassis.
One wanker seriously suggested I turn the cylinders around, and lengthen the swingarm.
I asked what sort of handling would result from adding 400 mm to the wheelbase.
Pic shows cylinder with 54mm Honda Akit piston for size ref.

[F5 Dave]

Yeah that looks like it would fit. Sideways.:shutup:

Would have been a better pic with it in the bore, like a mouse crawling out of a hole.

[wobbly]

It does fit, sideways

[F5 Dave]

thats fkn hilarious!:laugh:

[richban]

Just putting it out there. If you managed to fuse 2 50cc engines together would there be any major benifit over a single hundie? Say in a V config or would parallel be better. Maybe starting with an Apriila RS50 engine or the like. Would more toque be the result rather than HP. Also how come no one puts a 24mm carb on an Aprilia rs125 and races it. Is it not allowed or somthing? Please help O wise 2 stroke men.

I will also dig up a photo of my first bucket soon. I used to ride it to school back in Tauranga The mighty single seat 50e. Also remember Kev almost buying a Zunndapp 50 back in the day. It was very cool. Been watching 50cc GP racing on youtube. Just amazing how fast they went.


http://www.elsberg-tuning.dk/bultaco.html

[richban]

Ok shows what I know.The 50 is a V twin already. Now can you make it a hundred?241514

[Kickaha]

Also how come no one puts a 24mm carb on an Aprilia rs125 and races it. Is it not allowed or somthing? Please help O wise 2 stroke men.

Watercooled stinky 2 strokes are restricted to 100cc

[kel]

Ok shows what I know.The 50 is a V twin already.

Mate have you been sucking on that diesels exhaust pipe? Thats the Aprilia RS250 AKA RGV250.
But yes there are clear advantages in running twins over singles, the problem is finding a suitable platform plus having access to a bank manager willing to finance the build.
Now go and answer my post on aftermarket CDI for the FXR!

[F5 Dave]

yeah read the rules Rich (here we go again. . .)
re the twin;
Trust me I've put a couple of RG50 cases together & considered the union.

Crazyman has a twin GT125 with two watercooled MB50 top ends from the late 80s/early 90s. Was pretty quick too, but fragile & 5 speed box & not a small engine.

[F5 Dave]

Ok shows what I know.The 50 is a V twin already. Now can you make it a hundred?241514
That is using 50 barrels to make a 100, nice looking job from the side. from the top would show if it was done well.

[kel]

That is using 50 barrels to make a 100, nice looking job from the side. from the top would show if it was done well.

:facepalm: Im sure you're just humouring him Dave.

[richban]

Mate have you been sucking on that diesels exhaust pipe? Thats the Aprilia RS250 AKA RGV250.
But yes there are clear advantages in running twins over singles, the problem is finding a suitable platform plus having access to a bank manager willing to finance the build.
Now go and answer my post on aftermarket CDI for the FXR!


Hang on and check the scale. and also this link. http://otosport.addfinal.com/2011/04/aprilia-rs50-gp-replica-with-2-stroke-single-cylinder/

Umm well. igntech is the only way to go and only after you have spent hours on the dyno with you knock ear phones. Ask Pumba if he still has the one I sold him. I will get another one day.

[richban]

Watercooled stinky 2 strokes are restricted to 100cc

Ture ture. What about sleeving it down then? Then can you ride one?

[F5 Dave]

wtf? What is that picture doing there? Didn't realise you'd got that from a proper site.

The RS50 has always used the AM5 or AM6 engine which is a moto minarelli engine used by several euro manufacturers as well as Yam in the last TZR50 like Carls (earlier one like Andrews was their own). But why is there a pic of a twin? They go to great length to say its a single & have a pic of a twin & say GP inspired, but there is a kickstart 250 engine, clearly an RGV250 in RS makeup. (I was dreaming believing it was two 50 barrels, clearly 125 barrels with PVs etc. Power of suggestion & all that).

[wobbly]

The only way you would see any advantage running a twin is if you have the knowledge and wherewithall to build it properly.
This would mean running it to around 20,000 rpm to achieve a higher bmep than the single.
And as we already see in the 100 class, those engines dont rev as hard as the 125 GP single motors, when to see the advantage of a 50mm stroke the 100cc should be going to at least 14000 all day. - so basically, forget it.
A twin wont make as much "torque" but will make alot more "power" if done right.

[ac3_snow]

These crankshaft Balancing Posts started 17th June on Page 70.

(3) What the "Balance Factor" really is.


Spent monday afternoon with the good guys at ESE helping me balance the crank. In the short time I had it running, anything not done up tight on loctite'd on was rattling loose.

Turns out the 'balance factor' was only 29% and with an ideal range of 50-65% it took a fair bit of strategically placed drilling to get the counterbalance weight about right for a 55% balance factor.

Also have used some JB weld to put the reed block back in place with some good terrain gouged into the cylinder and block for it to hang on to.
Still put a couple of screws through into the cylinder just to be sure - cheers gigglebutton.

So with a reed block which should last more than a days running and a hopefully less violent crank will be good to see how it goes.

241574241573

[F5 Dave]

Reedblock looks nice & flat. Those transfer dividers could do with some sharpening though, not sure you could shave with them just yet.

That a TS engine yeah? The sure shake when they are asked to do more than the 6000 max chasing sheep they were designed for. Or maybe AX, think they were 1/2 reed too.

[wobbly]

Sharpen the transfer septums and I will personally bend you over and do horrid things with your arse.
Sharp leading edges are used on supersonic aircraft, when your transfer flow goes supersonic then so will the bike.
Look at the fastest two stroke in the worlds septum, does that look sharp???

[F5 Dave]

I was taking the piss:innocent:


I will admit those are even more square than I would have thought though.


[edit]
Hmm, I've noticed the back of the boostport duct in that pic. It's given me an idea about an engine & how shrouded it may be. Thanks.

[koba]

Sharpen the transfer septums and I will personally bend you over and do horrid things with your arse.
Sharp leading edges are used on supersonic aircraft, when your transfer flow goes supersonic then so will the bike.
Look at the fastest two stroke in the worlds septum, does that look sharp???


I was taking the piss:innocent:


I will admit those are even more square than I would have thought though.


[edit]
Hmm, I've noticed the back of the boostport duct in that pic. It's given me an idea about an engine & how shrouded it may be. Thanks.

I noted that H100 has a much sharper septum than the MB.

How sharp is YOUR septum!
Too sharp and you might get a sore arse!

[bucketracer]

It took a fair bit of strategically placed drilling to get the counterbalance weight about right for a 55% balance factor.
241574241573

Keep posting as your build progresses, great to watch someones work as they go about making a traditional Bucket.

[Bert]

Spent monday afternoon with the good guys at ESE helping me balance the crank. .....

Also have used some JB weld to put the reed block back in place with some good terrain gouged into the cylinder and block for it to hang on to.
Still put a couple of screws through into the cylinder just to be sure - cheers gigglebutton.

So with a reed block which should last more than a days running and a hopefully less violent crank will be good to see how it goes.

241574241573

Nice Work Snow; I like what yo have done with the reed block and intake (and looking back the changes you have made to the casings to improve flow & volume).Make sure you really loctite the f##k out of those screws (holding the reed & now the block) they always come loose on those motors.

If your reed block still loosens; try drilling & pressing little (2-3mm) solid dowlls into the casing and matched to the reed block (building up a "locking foundation") and use 24 hour (high temp) araldite to glue the whole lot solid. it will never come off again.

I'm sure Speedpro will also mention that; one large solid reed (carbon/glass what ever) will work better, the standard suzuki reeds are proned to tear (and flutter above 5k) and make their way into cranks and bores (generally making a mess of all your good work)...

interesting :yes:

[TZ350]

Some MOTA 2-Stroke software on Trademe for a $1 reserve ................... http://www.trademe.co.nz/Browse/Listing.aspx?id=387576544

241810

You can learn quite a bit about 2-Stroke tuning by messing around with this engine development software from MOTA.

[wobbly]

Cutting a 1/2 moon in the piston skirt and creating that duct/slot in the spigot was worth something like 3 Hp in the old tandem twin Rotax.
The factory copied the idea off the 82Hp engine we sent to them from ZipKart, where I worked when Hines won the Superkart title.
They didnt believe we had that much power, but our Hennan Froude eddy current dyno was dead accurate, and their dyno said 85,thanks to the new JL pipes we developed and months of late nights wearing out pistons.
In that engine the entry to the boost port was badly shrouded and cutting away the spigot worked wonders.

[F5 Dave]

yeah my case reed engine is like that (shrouded) but I'd had my eye on other things so it woke me up to that issue. Cheers.

[bucketracer]

Those transfer dividers could do with some sharpening though, not sure you could shave with them just yet.


I was taking the piss :innocent: ....


Sharpen the transfer septums and I will personally bend you over and do horrid things with your arse.

I had a dig around in the shed to check, and found the transfer dividers on a TF/TS are sharp standard.

[Yow Ling]

The planets came into alignment with my engine this week, things started moving.
My piston arrived from Strike in Perth, its a KT100J 50.220 that leaves me heaps of oversizes before I hit the limit at 51.25mm. Also in the mail were an Ignitech ignition and V Force 3 reeds from Wobbly in Tauranga.

Now that I finally had a piston I was able to bore the cylinder, the instructions say to allow 0.08mm, talk about pressure, I thought I would take a few light cuts untill I figured out if my toolsetting was on the money. Seemed to go OK. Piston 50.22mm bore 50.25 leaves me 0.05 left to hone.

Had to go round to diesel pigs to borrow a MB100 small end bearing so I could have a trial fit. Looks pretty good, piston has 8mm interference with the head, ha squish is just for sissys.

Earlier in the week I did a bit on the engine mounts, still have a few mm to go here and there but heading in the right direction.

Heres a few pics of the progress

[Yow Ling]

Couple of engine mount pics

[F5 Dave]

WTF?! what is with that piston? Is that what a J piston looks like? It's um, unusual to say the least. lot of mixture stored under that crown. Am I missing something? Doesn't look anything like an S piston.

[Yow Ling]

WTF?! what is with that piston? Is that what a J piston looks like? It's um, unusual to say the least. lot of mixture stored under that crown. Am I missing something? Doesn't look anything like an S piston.

The big difference is the J piston is legal in this engine a S isnt

[wobbly]

I have looked into the "overangled" issue that creates a problem when using the electronic powerjet carbs.
Its worth plenty of horsepower to keep the intake dead straight, and I am building a KTM250 for a open class kart at present.
I have bored the 38 to 40.5 and mounted it on a straight rubber manifold.
This sits the carb too steep, in that the siphon hole for the powerjet circuit in the side of the bowl is only just "underwater" when sitting static.
Get some serious G forces working and this will be sucking air.
It looks easy enough to Araldite a small external tube running forward to the front of the bowl that has plenty of fuel height above it at all times.
Or maybe drill a hole thru at an angle forwards, and press a small brass tube into this to collect fuel from the front side of the bowl.
I will pic this when I have done it.

[speedpro]

I was looking at this exact thing today with the 36mm Keihin

[richban]

I thought I would post these here just coz the people that visit this thread are mostly old school, bucket racers.

The first Bucket. It also had a full faring that never really got mounted. Not sure what happened to it. And also the 50 I used to ride to school. Check the pipe on it. I am quite sure it never did anything but make a big noise. Did anyone ever race down in Tauranga? Good old Bay Park. We used to lift the bikes over the fence and rip around for ages.

242119242118

[marsheng]

Am I now taking to the Dark side ???

Ok As with 4 strokes, you scale up the details from small engines to larger ones and there is some cutting back on cam timing and compression ratios as you get bigger.

On 2 strokes, will the ports basically follow the same scaling but maybe not quite as radical due to the max RPM is being lowered.

Assuming that we are working with track bikes, are the angles of the ports into the combustion chamber for A B and C ports (or Main Aux and boost port depending on your naming) roughly the same, the height from the top of the cylinder being the main variable to change. (Ie Timing)

Can I take it that the lower part of the transfer ports all come in at the same angle as the piston crown, either flat or 8-12 degrees and the tops of the ports are angled at 12 for A 25 for B and 55 for C as a rough start.

My assumption is that a 50 mm bore and a 75 will scavenge the same. Possibly a 50 bore and x 50 stroke may scavenge differently to a 50 x 75.

Cheers Wallace

[wobbly]

Plenty of unfounded assumptions in there mate.
Big 4 strokes can use more radical cams as the cubes overcomes the lumpyness.
Scaling ports in a 2T is a complete waste of time, the STA numbers are different for every bore/stroke ratio, rpm and swept volume.
In general you want to keep as close to square as you can, as this maximizes the angle area available, and maximizes the safe rpm for the swept volume.
ie a 74 bore on a 58 stroke for 250cc will never make as much power as a 68 square 250 as the angle area of the ports is reduced way more than the short strokes ability to rev ( piston weight notwithstanding) and make power.
The roof angles for A,B,C were reversed years ago from your convention ie 25,8 ,55 , and the floor angles depend upon the inner turn radius size.
Scavenging patterns will be similar for similar bore/stroke ratios ie a 50 square, will be similar to a 75 square, IF the STA numbers are equalized for the max rpm achievable.
ie reving a 50 stroke 100 to only 12500 is nothing like reving a 125 Gp engine to 14500.
Bottom line is that to maximize power, the transfers will need to occupy ALL of the wall area not taken by the Exhaust, and once this is achieved then blowdown STA will ultimately set the power achievable.

[ac3_snow]

The big difference is the J piston is legal in this engine a S isnt

Care to elaborate re J and S pistons? How did you get on with the power valves and the sleeve, I assume you would have had to move the valves to meet the 'new' cylinder (sleeve) wall?


WTF?! what is with that piston? Is that what a J piston looks like? It's um, unusual to say the least. lot of mixture stored under that crown. Am I missing something? Doesn't look anything like an S piston.

Are you just referring to the amount of space between the piston crown and ring?

[Yow Ling]

Care to elaborate re J and S pistons? How did you get on with the power valves and the sleeve, I assume you would have had to move the valves to meet the 'new' cylinder (sleeve) wall?


KT100J pistons are for a junior class, they are 50 to 51mm bore, KT100S are around 52-53mm which would exceed the 104cc limit for my engines stroke

The PV question, to be honest I dont really know, I have read the gap to the piston face isnt critical, time will tell

[marsheng]

[/QUOTE]Scavenging patterns will be similar for similar bore/stroke ratios ie a 50 square, will be similar to a 75 square, IF the STA numbers are equalized for the max rpm achievable.
[/QUOTE]

Thanks for the info. My Bore and stroke is 67 and 70. It was originally an off road bike motor. My measurements are Exhaust 88, Boost 124, and Aux & Main 122 from TDC. The ports narrow quite a bit entering the cylinder. so I will try and enlarge them.

AG Bells book says that for 8500 RPM the transfer ports should be open for approx 126 deg. At 124 from TDC only gives a duration of 112 degs. Is this worth raising for a track bike ?

For the exhaust - he recommends 186 - I have 184 so that seems ok.

It is a Maico reed valve motor.

[marsheng]

floor angles depend upon the inner turn radius siz
I thought the floor angles were there to keep a stream of fuel/air over the piston to keep it cool.

Cheers

[kel]

AG Bells book says that for 8500 RPM the transfer ports should be open for approx 126 deg. At 124 from TDC only gives a duration of 112 degs. Is this worth raising for a track bike ?
For the exhaust - he recommends 186 - I have 184 so that seems ok.
It is a Maico reed valve motor.

Careful as you go. Read as much as you can, dont just go on Bells work from the 80's as its well outdated (yet still relevant in some respects). Try Blairs book for good design over view (theres a link in this thread somewhere, will find and send to you), Jennings for time area analysis, port map analyser software, etc, etc. Its very easy to start cutting the ports only to find out it wasnt the best move. 2 strokes are quarrelsome beasts, not an easy mistress like a four stroke.

[wobbly]

Its impossible to make a statement with any meaning such as " for 8500 rpm the transfers should be open" - as I said, the angle area varies hugely between a short stroke Vs a long stroke, so any calculation must involve all of the elements of the design to achieve any accuracy at all.
There are several programs available now that can point you in the right direction, reading 30 year old books is OK for background info only.

The port floor geometry is super critical for any high performance application.
Fuel/air in the duct is forced to follow the outer wall ,no matter what,but the short turn radius and the floor exit angle combine to keep the flow column "coherent".
When the inner shape is not matched correctly the flow detaches very early, creating huge amounts of turbulence,this ruins the scavenging streams directional control,and as an aside it then also looses contact with the piston face.
Keeping the piston cooler is just a by product of the fact that the transfer streams are kept attached to the inner wall - when they dont everything turns to shit.

Re the PV clearance - I dont know who told you that it isnt critical but thats bullshit.The PV face should be as close as you can get it without snagging the bulging ring face.
Much more than around 0.5mm and you start to loose effectiveness with too much blowby.
This is the whole reason that curved and multi blades were developed, to keep the PV edge as close as possible to the piston during its whole stroke length.
In the RGV you have to modify the valves a heap to get them to work at all.

Edit - please dont take any of my remarks about 2T technology as personal attacks on anyone's knowledge on the subject.
Its just that reading Bell, or Cameron and even much of Blairs early stuff is like swatting up a Tube Radio Repair Manual, and then trying to design a Mosfet power amp.
Even the basic CAD type programs that use STA as a basis for getting the ports in the right place for the rpm,power needed and swept vol are hugely better than the old references.

[TZ350]

Even the basic CAD type programs that use STA as a basis for getting the ports in the right place for the rpm,power needed and swept vol are hugely better than the old references.

A handy (and cheep $16 USD) Porting Calculator from:- http://www.porting-programs.com/ it is based on Blairs and Jennings work. Use the Blair data for STA and blowdown required for a selected power output.

Kel gave me this link to a very interesting book. www.prme.nl/download/engine-1.pdf (http://www.prme.nl/download/engine-1.pdf)

The decade pages from p80 have link collections, links to Jenning and Bells books can be found there somewhere.

[ac3_snow]

The port floor geometry is super critical for any high performance application.
Fuel/air in the duct is forced to follow the outer wall ,no matter what,but the short turn radius and the floor exit angle combine to keep the flow column "coherent".
When the inner shape is not matched correctly the flow detaches very early, creating huge amounts of turbulence,this ruins the scavenging streams directional control,and as an aside it then also looses contact with the piston face.
Keeping the piston cooler is just a by product of the fact that the transfer streams are kept attached to the inner wall - when they dont everything turns to shit.


Cheers for the explanation re. the reasons for port angles etc Wobbly. Very helpful.

[Bert]

rather off topic, but enjoy:
http://rmdmotors.com/kenny-roberts-collection/

If only lotto would roll out the right numbers :crybaby:

[cotswold]

rather off topic, but enjoy:
http://rmdmotors.com/kenny-roberts-collection/

If only lotto would roll out the right numbers :crybaby:

I checked out the price on this little beauty
http://rmdmotors.com/1980-gp-bike-kreidler-van-veen/

1,350,000.00 JPY = 20,218.57 NZD

Bit much to bucket ?

[F5 Dave]

ahh the tyre's flat, knock em down a bit.

Even Husaberg would have trouble justifying that as bucket legal. But yeah hella cool bit of classic kit. Tyres are a bit frightening.

[husaberg]

.

Even Husaberg would have trouble justifying that as bucket legal. But yeah hella cool bit of classic kit. Tyres are a bit frightening.

I thought we had kissed and made up :chase:

[TZ350]

Trying to make sense of my last few dyno sessions.

242655

Blue line, the cylinder with side exhaust ports might be 30hp but its not a very appealing curve compaired to the conventional Suzuki GP125 cylinder.

242654

Running the Vtec improved the carburation and curve but the extra inlet length of the Vtec seems to have knocked back the over rev.

242657 242658

In back to back tests the soft close rotary valve seems to give a little more power and improved the over rev, we noticed this with our other engines too.


242656 242659

Both are Vtec soft close. Red line is the 24-28 sticking out the side carb arrangement, Blue line is the 24-38 tucked out of the way arrangement.

In trying to get the carb tucked in, it has realy upset the curve. There was also another problem, where as I could open the 24-28 up fully at nearly any rpm the 24-38 would stall unless the rpm was 9k or more and I had to be carfull with the throttle to get a good run.

The 24-38 arrangement has more over rev but dropped power every where else. This must be due to the different inlet arrangements. So I figure if I can loose power then by some carefull work I can recover it and may be use the inlet system to fill in the 6-7k rpm area too.

The straight inlet seems best but with the Keihin carb its quite long and the inlet tuned length is to long and the carb sticks out to far. I think the next move is to try a straight inlet with a much shorter Kart pumper carb.

If it wasn't for the 24mm rule, I would actually try something suggested to me by Sonic_V, two carbs with different inlet lengths.

[richban]

Very cool. The last graph 28hp looked really good. Great spread of power really across that range. Looks quite rideable. You would no when to change gear with that big drop anyway. Are there any down draft carb options you could try. Might give more carb position options.

[wobbly]

I think that you are beating a dead horse a bit trying to get a big positive result from intake tuning.
The short pumper carb being able to be run "updraft" was one reason I suggested it.
The rotary valve setup needs the flow to enter the case, moving upward over the crank - not downdraft.
As the wave action in the Exhaust is WAY more powerful, then the result from a PV or a ATAC setup will get much more dramatic results, relatively easy to implement as well..

[F5 Dave]

Its funny I was just thinking the other night about this thread. For the how many pages & pages the main point that has had little discussion is pipes.

[kel]

For the how many pages & pages the main point that has had little discussion is pipes.

:confused: inlet or exhaust?

[F5 Dave]

crack:blink:

[TZ350]

For the how many pages & pages the main point that has had little discussion is pipes.

My interest at the moment is elsewhere

242796

But if you can get Chambers to talk he could tell you about what he is up to.

242786

I see he has lowered the bike to its max and made a mockup of the planned pipe.

242785

And checking for clerance on the front tire.

[F5 Dave]

<!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:PunctuationKerning/> <w:ValidateAgainstSchemas/> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> <w:DontGrowAutofit/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--><!--[if gte mso 9]><xml> <w:LatentStyles DefLockedState="false" LatentStyleCount="156"> </w:LatentStyles> </xml><![endif]--><!--[if gte mso 10]> <style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} </style> <![endif]--> Hmm, yeah he may need to run a heavier spring.:blink: Not sure that gasket pipe technology has been explored before so I salute you, although I can confirm that my bent wire donuts on No.8 didn’t hold further promise so were dropped early in development, but useful for learning how to snake past linkages on bigger bikes.

Yeah that pipe is pretty awkwardly positioned, but most MX bikes are worse. Best to strop the front down & assume there will be additional bending in the frame & forks, although in the RS’s case that will be sod all. On a suzi GP125 as she came its probably a good ½” or more.:shutup:

[wobbly]

If you wana talk pipes, take a gander here.
Prototype set for my 100Hp+ F3 - 400 RZ in Aprilia 250.
Though personally I like the radial Brembos with adapters better.

Having sharp corners, even up at the center section kills power big time - better to have 3 small cuts than one sharp one.

[jasonu]

If you wana talk pipes, take a gander here.
Prototype set for my 100Hp+ F3 - 400 RZ in Aprilia 250.
Though personally I like the radial Brembos with adapters better.

Having sharp corners, even up at the center section kills power big time - better to have 3 small cuts than one sharp one.

Nice looking workmanship

[F5 Dave]

Should be -its in his buss name. Looks good. Presumably large looking stingers are venturied at interface. Pretty serious ign flywheel balancing going on there. But is that a 13mm nylock I see. Oh the shame!

[speedpro]

Not too bad. Funny you should mention "having sharp corners" and then not smooth out the joins between sections. NoMates could've helped there, for a fee.

[wobbly]

Been there tested that on Ti pipes, if you have ever tried to hammer Ti or Stainless you will know its all but impossible.
As long as the angle changes are small like the sections in the pipes shown, with fusion only welds,then hammering the joins makes no difference to power.
Nigel is anal about the hammering and does a real good job just to be better at it than me,but as the testing showed its not needed with quality fusion welds,it makes my customer pipes just a bit more affordable.
If I hammered every weld of a single pipe, it would take 3 days instead of 2.
But even he wanted to have sex with the first set I made for the RS500.
The venturi is 27mm the stinger ID is 28.6

[F5 Dave]

my 496 runs 28.6 (actually might have gone down a size for availability, can't remember) still looks thinner, but that's pictures for you.

[Gigglebutton]

If you wana talk pipes, take a gander here.
Prototype set for my 100Hp+ F3 - 400 RZ in Aprilia 250.
Though personally I like the radial Brembos with adapters better.

Having sharp corners, even up at the center section kills power big time - better to have 3 small cuts than one sharp one.

"Pipe Porn" very nice. :not: Are they stainless?

[wobbly]

Yep, 304 Stainless, a real bitch to roll and work with, but easy to weld.
I hate doing them in SS, and now get Tyga to do the production pipes off my patterns, as 90% of the work is in getting the shape and cuts correct.
Another small point about weld hammering is that if its done "too well" then you get the same issue as found with blown pipes.
The angle changes become smeared and you loose power.
Especially at the interface of the header end, and the rear cone to the mid, these have to be a "sharp" angle change, different issue to a too sharp angle cut, that isnt a change in pipe section.

[diesel pig]

Another small point about weld hammering is that if its done "too well" then you get the same issue as found with blown pipes.
The angle changes become smeared and you loose power.
Especially at the interface of the header end, and the rear cone to the mid, these have to be a "sharp" angle change, different issue to a too sharp angle cut, that isnt a change in pipe section.

Interesting, This probably accounts for the works pipe I Have see on the interweird with blown headers and the rest welded.:sherlock:

[TZ350]

On page 200 there is a simpler 23 rwhp setup using a RG250 chamber modified to RM125 specs. And on this page, the basic details for 27rwhp from a 1978 Suzuki GP125 Engine and RS125 Expansion Chamber.

Trademe http://www.trademe.co.nz/motors/motorbikes/parts-for-sale/complete-engines/auction-391580898.htm

242939

Good hp can easily be pulled from one of these. A bit of work and someone could have a fast ride for the next BOB.

[F5 Dave]

So are you making it down to chch Rob? Very much enjoying the idea if I can make it. Maybe I can race a bike that has more than a 50's worth, Diesel's 100 got me addicted to some power despite being pretty no faster than an FXR, still got me up to 4th in a sprint race.

[TZ350]

So are you making it down to chch Rob? Very much enjoying the idea if I can make it. Maybe I can race a bike that has more than a 50's worth, Diesel's 100 got me addicted to some power despite being pretty no faster than an FXR, still got me up to 4th in a sprint race.

Its a thought but by the time I got there and back I would have to justify the 3,000k on road costs of the company van and two weeks away from work, three if I did Greymouth too, its a long chance but I will talk with the powers that be at work.

[wobbly]

Here is the bowl of the Solenoid PJ carb, with brass tube added to keep the PJ siphon point underwater at the front.

[F5 Dave]

Hopefully the same can be said for the main. Had that issue before after a long straight & a corner. Some of it was size of filling delivery tube (internal), but it sucked air never the less. Made band-aid straw extender on one carb.

[ac3_snow]

I am running a 24mm mikuni round slide carb on my TF125, is some one able to give me a ball park figure for which lean/pilot jet I could start with? I think I have a 40 in there now, need to spend more time on it try a few things but am I close?

160 main seems not too bad for now.

[F5 Dave]

Yes you are in the ballpark. If you give me a full run down of all mods I will predict your jetting to within allowable Mikuni jet sizes (or specify a 2mm drill bit).


Many will miss the subtle sarcasm; read Jetting over internet on heavily modded bikes won't achieve any results worth salt. For pilots just try a different one each session & you will know what it suits pretty soon. The wrong pilot means its horrible off closed throttle so you will be reminded most every slow corner.

[ac3_snow]

lol cheers dave, was expecting an answer along those lines. That is a good help to see what I'm looking for tho in terms of good/bad get size.

[ac3_snow]

So have been fairly busy the last week. As you know I had my engine apart to re glue the reed valve and try and prevent the crank from shaking everything to bits. Also enlisted a little help for some weight savings.

So crank balance worked well! still vibrates a little, but I feel that it is vibrating at mid-low revs and is running pretty darn smooth at higher revs, will confirm this in more time.
243161
Reed valve is now holding much better, did a more permanent job with JB weld and a couple of screws to hold it in place. (didn't want to tack weld it in place as there is a rubber? type surface which the reed seals against and didn't want to damage this)
243160
Found some slight damage to the bottom of the barrel which may have been cause for a air leak, fill it up and file it down.
243162
I had also epoxy'd the cases to fill in the space taken up by the old reed valve. Was a little bit suspect of the pratleys epoxy so decided to re-do this to make it more permanet. Turns out it was stuck fairly good, with my precise modifications to help it stick, it shouldn't be coming out in a hurry.
243164
Got it running again and had the opportunity to get it on a dyno! So spin it up and before I get a chance to even look at much, bam stops quick smart. uh-oh
Strip it down to find a bearing which wasn't cooperating. Had trouble with this particular bearing on sunday trying to put the cases together, so I guess I still didn't have it quite right. Think there was some side load on the bearing due to my cock up during assembly. So off to the bearing shop, no sweat new bearing. Ready to put it back, damaged bearing took the oil seal with it, back to the bearing shop. So buy the time I get all this done and back together got one quick chance for another spin on the dyno, bloody great machines sure beat pushing it around all the time. Runs much better, still rich on a 180 jet so drop to a 160. Didn't have a chance to get a power run but at least it's running (near enough) right now!

So list of things to do is:
Still need to sort out the idle/pilot jet.
I don't know that the timings right, but I wouldn't know much difference really so will see how I go for now.
Try and borrow/make a leak down tester to check everything is sealing up properly.

243166
And there is also a pic of my nice new subframe. Aluminum, weighs 800 grams! weigh, weigh better than the original steel item which was 3.8kgs, just don't know how it will go in a crash test...:shutup:
Now if I can do something about the 4.5kg gas tank and get my new pipe on there I might be down to around 85kgs.

Sorry I know it's not as exciting as those damm sexy pipes wobbly posted up

[wobbly]

Just a small point re main bearings.
You should have the crank floating - ie spin the crank in a lathe with the rod taped down and polish the main journals so that the bearing inner race just slides on by hand.
Some engines have one end locked in place by the drive gear, but then I just float the other side.
In fully floating cranks shoot for a min of 0.2mm and a max of 0.3mm side clearance by shimming behind the bearings,or machining the step on the journal back ( or deepen the case pocket.
And always use C3 or C4 fit bearings,fiber high speed cages are best ( expensive) followed by plastic, I would never use a steel cage in a race engine.
You would be amazed how free a floated crank spins.

[F5 Dave]

I've used steel when immersed in Gearbox oil, but resin for crankcase oiled bearings. Always assumed that with that much oil they would be ok & so far. . . Must admit I've never polished them down like that, just given a tap to centralise. Perhaps I should look at that.


Snow, erm what is that chassis?

[SS90]

I've used steel when immersed in Gearbox oil, but resin for .......

But then again, you have Never worked in the industry....

Any reason for this mind numbing advise?

[marsheng]

In early stages of this thread, the Jaycar programmable ignition was experimented with - Did anything good come out of that ?

[Buddha#81]

But then again, you have Never worked in the industry....

Any reason for this mind numbing advise?

Why do you have to "work" in the industry. I know heaps about stuff that I dont work on? Maybe explain what ya getting at instead of being the usual cock?

[jasonu]

But then again, you have Never worked in the industry....

Any reason for this mind numbing advise?

Yeah Dave jeez you're dumb...

[Buckets4Me]

In early stages of this thread, the Jaycar programmable ignition was experimented with - Did anything good come out of that ?


Yes it was found that $( dont know how much) on a nice new shiny bit of bling worked way better :facepalm:
and cost less and was faster to set up etc etc etc plus it did more thingys

Edit: At the time E.S.E where playing with the Jaycar ignition aftermarket ones where $1200+ and to much.
Now you can buy one from Wobbly for less than half that. So makes sense to do a few hourd overtime and buy one.
Plus you can get them to do other tings as well. like turning on and off water injection or teh vtec idear or a powervalve in the exaust.

so dont waste your time and go ask Wobbly how much and what they can do for you.

[Yow Ling]

http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=121709&d=1236457147

[bucketracer]

I've used steel when immersed in Gearbox oil, but resin for crankcase oiled bearings.

Hi ac3_snow, TeeZee does the same as F5 Dave ...........


GP Crank Assembly

243245

Phenolic caged main bearings, Koyo 6205 and 6304 FG C4 max rpm in oil 15-17,000.

The brgs have been fitted so the open side of the cages face the oil feed holes. The phenolic cages are more reliable than the usual riveted cages which can fly apart under the inertial load of quick crank acceleration, like blipping the throttle.


TeeZee's post gives part numbers for the GP's Phenolic caged main brgs, TF/TS ones are possibly the same.

Koyo uses the suffix FG for Phenolic caged and C4 is the clearance, C1 small ... C4 large.

[gav]

http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=121709&d=1236457147

roflmao :yes:

[wobbly]

One thing some have overlooked here, is that plenty of us know fuck all about stuff we do work on in our chosen industry as well.
But back to more useful time wasting.
C4 isnt just the end float - its the total radial clearance.
Usually its designed in for where the bearing is pressed onto a shaft ( expanding the inner race) and pressed into a housing ( crushing the outer race).
In our application it also gives the case the ability to move around due to heat expansion and not take up all the end float.
Floating at least one inner race allows the crank to self center and reduces rolling friction heaps, doing both with a set amount of total end movement is even better.

[Buddha#81]

One thing some have overlooked here, is that plenty of us know fuck all about stuff we do work on in our chosen industry as well.
But back to more useful time wasting.
C4 isnt just the end float - its the total radial clearance.
Usually its designed in for where the bearing is pressed onto a shaft ( expanding the inner race) and pressed into a housing ( crushing the outer race).
In our application it also gives the case the ability to move around due to heat expansion and not take up all the end float.
Floating at least one inner race allows the crank to self center and reduces rolling friction heaps, doing both with a set amount of total end movement is even better.

See that there is some usefull info......means fook all to me, but at least its constructive.

[F5 Dave]

But then again, you have Never worked in the industry....

Any reason for this mind numbing advise?
How do you know I've never worked in the industry? I could easily have spent a year as a grease monkey changing tyres & wheel bearings on flogged out dirtbikes, or reassembling exploded GN250 motors. But I had better things to do. Like spend my working day thinking about tuning 2 stroke engines. & the evenings with the dremel. Don't have much time for that these days.

I didn't offer my comments as 'advice', I was stating that that was my practice & had worked ok for me, at least in terms of reliability. If Wobbly had come back & said for instance 'Steel cages create more drag than resin no matter what they were run in' then I would listened because I respect his advice.

But I doubt that is the case as the rest of the gearbox runs steel cages immersed in oil. The difference of course is the speed of the shafts & I have no quantifiable way of measuring that this side of consecutive dyno runs with a lot of work in between.
Either way I have gleaned a lot more or challenged my own understanding since Wobbly has been contributing to this thread.

SS if I have numbed your mind then I'm sorry, clearly your clear thinking incites have been lost on me, someone who shamefully has never worked in the industry.:violin: Must be because I'm stupid.

[marsheng]

I now have sets of FXR 150 cam sprocket verniers adjusters for sale. I do an exchange with your sprockets as they need to be drilled and slotted for the verniers.

Each tooth on the sprocket is 10.6 degrees. The verniers split the 10.6 degrees into 10 equal measurements. The disks labelled 0-5, 0 being 0 degrees and 5 being 5.3 degrees. To get from 5.3 to 10.6, you advance the sprocket 1 tooth and put the verniers in back to front.

The verniers can be changed without removing the sprocket from the camshaft. Very easy.

The exchange set is $85

243268

[F5 Dave]

No disprespect, but keep your Feeelthy 4 stroke parts out of this fine 2 stroke thread into some other Diesel thread.

We don't need no Steekin camshafts.

[timg]

I now have sets of FXR 150 cam sprocket verniers adjusters for sale. I do an exchange with your sprockets as they need to be drilled and slotted for the verniers.

Each tooth on the sprocket is 10.6 degrees. The verniers split the 10.6 degrees into 10 equal measurements. The disks labelled 0-5, 0 being 0 degrees and 5 being 5.3 degrees. To get from 5.3 to 10.6, you advance the sprocket 1 tooth and put the verniers in back to front.

The verniers can be changed without removing the sprocket from the camshaft. Very easy.

The exchange set is $85

243268 Hope you've still got the rest of my set :yes: We must get around to finishing the job one day....

[koba]

One thing some have overlooked here, is that plenty of us know fuck all about stuff we do work on in our chosen industry as well.
But back to more useful time wasting.
C4 isnt just the end float - its the total radial clearance.
Usually its designed in for where the bearing is pressed onto a shaft ( expanding the inner race) and pressed into a housing ( crushing the outer race).
In our application it also gives the case the ability to move around due to heat expansion and not take up all the end float.
Floating at least one inner race allows the crank to self center and reduces rolling friction heaps, doing both with a set amount of total end movement is even better.

My old RG 150 engine had one journal that was a very loose fit, I was never sure if it was a design aspect or simply due to wear. I still don't know but what I have learnt is that I probably shouldn't have used bearing retainer on it...

[husaberg]

Now if I can do something about the 4.5kg gas tank and get my new pipe on there I might be down to around 85kgs.

Are you planning to gut the tank?
An easy couple of KGs in there.
I used gut the tanks and use the std oil tank as a fuel cell good for 10 minutes at least.
I just rammed a lawn mower accessory fuel tap in it. It also helps to keep the slosh factor down when running a light fuel load.
Be aware though I no longer work in the industry.
So my suggestions may not be SS90 approved.
Then again John Britten was a property developer. He came up with a lot of his innovations like the cats cradle method for the carbon fibre and using plywood sheets as per the blueprints for the crankcase patterns because he had less preconceived ideas of how it should be done than some who work in the industry
RIP John.
Hard to believe it will be 16 years this September.

[TZ350]

STA or Specific Time Area, (Port Time Area) is at the heart of 2-Stroke port timing design.

For what its worth and as I understand it. How to determine the STA numbers you have.

Mean open Port Area is the effective port aperture seen when the piston is positioned half way in terms of crank angle between the port starting to open and fully open.

For an Exhaust port that starts to open at 80 deg ATDC and is fully open at 180 deg ATDC. Then the mean port area will be the area of the port uncovered by the piston with the crank angle set half way between 80 and 180 ie, at 130 deg ATDC.

The rough rule of thumb is that this exposes about 70% of the port window, rod length and the bore/stroke ratio influence the actual amount.

The units for STA numbers are Time Area per Unit Displacement or “sec-cm2/cm3”

Derived by dividing the Mean-Port-Area in “cm2” by the cylinder volume in “cm3” and then multiplying it all by the time in seconds “sec” that the port is open (time of total duration).

The number of revolutions in one second = RPM/60

The total number of degrees the crank has turned in one second = (RPM/60)*360 or RPM*6

Finding the Time in seconds of the Total Port Duration. = Total Port Duration / (RPM*6)

Your STA = (Mean Port Area / Cylinder Volume) * Time of Total Port Duration

After measuring Yamaha’s TR3 GP racer and as many other good racing engines as he could using only graph paper, compass and a ruler. And doing the “(Mean Port Area / Cylinder Volume) * Time of Total Port Duration” math, Jennings came up with these numbers and called them Port-Time-Area.

Exhaust 0.00014 to 0.00015 sec-cm2/cm3
Transfer 0.00008 to 0.00010 sec-cm2/cm3
Piston Port Inlet 0.00014 to 0.00016 sec-cm2/cm3
Rotary Valve Inlet 0.00018 to 0.00019 sec-cm2/cm3

In his ground breaking reveal all book that showed the budding tuner how to modify their own cylinders to get GP like porting.

243287

Jennings didn’t give a number for Blow Down. And for that reason, I think the importance of the “Blow-Down-Time-Area” and its affect on power output was largely over looked by the old style home tuners.

Bells book with its useful list of port timings for various engine capacities and RPM was also a blessing and a curse as it also didn’t emphasis the importance of blow down. It was great to see what the ballpark timings were, but too many tuners just used the numbers blindly.

With the result cylinders were packed up with spacer plates to get the transfer timing numbers right and the inlet and
exhaust was then ported to match their own set of essential numbers found in Bells book without much regard for blow down area.

Whether you used Jennings Port-Time-Areas or Bells numbers for the inlet, transfer and exhaust the end result was that the essential Blow Down Time Area was often overlooked and a lot of the old engines were less successful than they could have been.

243284 Port timing by itself does not mean much, its the STA numbers that are important.

243285 243286 Early Honda RS125

Low and wide for the transfers is the trick to getting good Blow-Down STA numbers.

Gordon Blair after studying many 2-stroke engines and their behaviour developed a number of formulae that covered the various ports. The beauty of these formulas is that they allowed the designer to start from a target RPM and BMEP or Power-Output and use a computer to crunch the numbers.

Blair called the results of a port time area calculated by his formula based on a specific rpm and target power output, a STA or Specific Time Area for that design criteria.

Blairs STA numbers for a GP racer turning 11,500rpm and producing 26.5kW at 11 Bar

Exhaust 0.000162 sec-cm2/cm3
Blowdown 0.00113 sec-cm2/cm3
Transfer 0.0086 to 0.0185 sec-cm2/cm3
Piston Port Inlet 0.0162 sec-cm2/cm3

Blairs calculated STA results and Jennings Port-Time-Areas are both physically measured in the same way. = (Mean Port Area / Cylinder Volume) * Time of Total Port Duration. The difference is that Jennings very cleverly figured out what the Factory was up to and Blair developed a method of predicting what is required.


Even the basic CAD type programs that use STA as a basis for getting the ports in the right place for the rpm,power needed and swept vol are hugely better than the old references.

A handy (and cheep $16 USD) Porting Calculator from:- http://www.porting-programs.com/ it is based on Blairs and Jennings work. Use the Blair data for STA and blowdown required for a selected power output.

Kel gave me this link to Blairs very interesting book. www.prme.nl/download/engine-1.pdf (http://www.prme.nl/download/engine-1.pdf)

The decade pages from p80 have link collections, links to Jenning and Bells books can be found there somewhere.

[ac3_snow]

Cheers for the advice re bearings, I will get to that some as soon as I have the spare $ and time to pull it down again. I was only aware of the c3/c4 clearance when I brought that last bearing and asked specifically for c3, I have no idea what the others may be, I simply took in the old ones from the original TF and asked for new versions.

Dave: its a 1991 CBR250RR (MC22), is fairly wide, will let you know how it handles after next weekend.

The standard roundslide mikuni carbs have three small holes in the bottom of the inlet trumpet. one is blocked by a brass ball, the middle one lets air through into the main jet(?) and the third one is a little smaller, should this third one be blocked? I suspect it somehow helps with the pilot jet operation but mine appears to be blocked. Below is a pic not of my carb but just to show what I'm talking about.
http://images.trademe.co.nz/photoserver/tq/59/177521359.jpg

[husaberg]

Kel gave me this link to Blairs very interesting book.

www.prme.nl/download/engine-1.pdf (http://www.suzuki-rg500.com/water.htm)

What about Fleck , Hiroshi Naito (1971) and Robinson in regards to STA

http://www.suzuki-rg500.com/water.htm

WATER INJECTION
By Randy Norian
SAE paper 931506, expanding the torque curve of a Two Stroke Motorcycle race engine by exhaust water injection", by Robert Fleck at QUB. In this paper, they built a simple system to inject water into the headpipe of a 125cc test motor and recorded power gains of up to 24% in the lower midrange. I decided to copy their setup and was able to reproduce their results on the dyno. After that, I decided to built a usable system that would function smoothly on my streetlracebike.
But first, some numbers.
Fleck recorded pipe temps at several points along the exhaust pipe. In the diffuser, without water injection, he recorded gas temps rising from 425 deg Cat 9000rpm, to 510 deg Cat 10800 rpm.
With the water injection active, the same sensor recorded temps of 150 degrees Cat 9K RPM, rising to 420 deg Cat 10800 rpm.
Lets go back to the equation for tuned length.
If we consider a stock RG500, this distance is about 84cm, (33 inches) and Eo is 188 degrees. Using Vs of 1700 fps, this formula predicts a peak power RPM of 9684 RPM. This is a pretty good estimate, as my bike peaked at 9500 rpm in stock form.
Now we consider Vs with water injection active, let’s say we have a mean 200 degreee C drop in gas temps. If we use Vs of 1700 fps with no water, this figures to a new Vs of about 1430 fps with water. Plug that into the equation for tuned length, and our same exhaust pipe is now tuned for a peak of 8150RPM. So we have been able to shift our peak power down almost 1500 rpm, by injecting water. Obviously, this will reduce the peak rpms of our motor, so the trick here is to turn off the water at some point and let the engine rev out normally on top.
If we were able to cool the pipes all the way down to room temperature, the stock Gamma would have a peaking RPM of just 6270 RPM. Clearly, pipe temperature has a huge role in determining the rev range of a pipe/port combination.
Controlling pipe temperature is an effective way to alter the tune of a 2 stroke

I note Aprilia used use carbon sleeves to raise the temp of the pipe for top end

[kel]

STA or Specific Time Area, (Port Time Area) is at the heart of 2-Stroke port timing design..

Nicely done TZ :niceone:

[kel]

What about Fleck and Robinson
Controlling pipe temperature is an effective way to alter the tune of a 2 stroke
The Robinson book was a waste of money, I still have it and still looks like new. Bells book fell apart years ago from over use!
The pipe temp cant be changed quick enough with water injection, I posted the Honda article a couple of months back, basically they stated the gains to be had could be easily realised in other areas so the water injection was dropped.

[husaberg]

The Robinson book was a waste of money, I still have it and still looks like new. Bells book fell apart years ago from over use!
The pipe temp cant be changed quick enough with water injection, I posted the Honda article a couple of months back, basically they stated the gains to be had could be easily realised in other areas so the water injection was dropped.

Did you follow the link?

Honda didn't really follow through in my opinion.
The cooling medium need not have to be water.

Remember rotary valves were at least 50 years old when Walter Kaaden reinvented the idea.
I did try to read the article but it wouldn't pop up .

Had the same trouble with the bell book to.
But the Robinson book does cover STA and if you read between the lines it does share quite a bit.
it even had a program for calculating STA.shame its in BBC.

[gav]

I now have sets of FXR 150 cam sprocket verniers adjusters for sale. I do an exchange with your sprockets as they need to be drilled and slotted for the verniers.

Each tooth on the sprocket is 10.6 degrees. The verniers split the 10.6 degrees into 10 equal measurements. The disks labelled 0-5, 0 being 0 degrees and 5 being 5.3 degrees. To get from 5.3 to 10.6, you advance the sprocket 1 tooth and put the verniers in back to front.

The verniers can be changed without removing the sprocket from the camshaft. Very easy.

The exchange set is $85

243268

How about I just drop my bike off, you fit and dial in my cams or whatever it is you do? :innocent: .


And yeah Ive worked in the industry (errr ... what industry we talking about again?) and I know fuck all ... :shutup:

[husaberg]

And yeah Ive worked in the industry (errr ... what industry we talking about again?) and I know fuck all ... :shutup:

My best guess is our English correspondent is referring to the “industry” previously based at Manchester ST:no:
But I could be wrong.
I thought at first he was refering to the adult film "industry" so I fessed up as well.
I did lurk there more than work there though.

[wobbly]

I was in the pit at Philip Island when Doohan tested the NSR with the water solenoids on the headers.
He did 3 laps, immediately full noise as he always did.
Came in and said it was a piece of shit till 1/2 way down the straight, but had heaps of power off the bottom and lost around 1000 rpm on top.
They plugged in the laptops, and I assume wound back the squirt volume.
Another 3 laps, and he said it now came on song much earlyer, but had lost most of the bottom end, and was still 800 rpm down on top speed..
More festering on the laptop, back out again.
This time no useable gain in bottom end,slow to come on the pipe, and still no overev power.
Mick just said - "maaaete,turn the fuckin things off and give it a go."
Went out and put it on pole,easily.
Talking to Burgess in the Cowes pub that night he said it seemed that to get enough water into the pipe to do some good for the bottom end, it took too long for the temp to rise back to "normal" again, so they had ripped the whole thing off, and binned the idea.
Adjusting the PV curve gave better, repeatable results.