ESE's works engine tuner

[speedpro]

While we are at it (bit of a sidetrack interlude) at it there was this piece of rolling history in somewhat of a sad state of repair but would still be pretty competitive today in 50 class & is current NZ 50cc record land speed holder (complete with bucket of parts, oh hilarious)

I've spent quite a bit of time chasing that #67 round various bucket tracks on my AC50. Me and Pete had many a good race, then same again when we both got F4s.

[diesel pig]

While we are at it (bit of a sidetrack interlude) at it there was this piece of rolling history in somewhat of a sad state of repair but would still be pretty competitive today in 50 class & is current NZ 50cc record land speed holder (complete with bucket of parts, oh hilarious)

So what exactly is this 80.21mph record holding machine?

[speedpro]

It started life as a Suzuki GT50 then Pete Sales bought it.

[SS90]

Hey Teezee,

While the subject of Expansion chambers can drive many people batty, I recall that you based your design on an Old 1970's RM125 design from Gordon Jennings..... And you used a header from (I think) a RG250?

Do you by chance have either a detailed series of pictures, or perhaps a diagram of your design that you can post?

[fi5hy]

Devcon .

If any one needs some I sell the Devcon titanium filler for $20 + gst

[F5 Dave]

Yeah GT50 water cooled with washing machine parts if I remember correctly. Just before he sold it it got some further work & got faster again then the next Pete bought it & we had some good races, then Regan bought it & he pedaled it ok too. . . . But there it has stayed along with the RD50 Pete built later for Tim & several other iconic bikes like Ziffle's Pepsi TF & Wheels hub centre front end Kawi & the GT125 with 2 MB50 top ends watercooled.

[TZ350]

Thomas recommends these books on Two Stroke Tuning.
(Some of these are PDF's that can be down loaded, read them then get yourself a copy of the book)

Graham Bell
http://www.kreidler.nl/artikelen/per...raham-bell.pdf

Gordon Jennings
http://www.vintagesleds.com/library/...20Handbook.pdf

http://toostroke.blogspot.com/2007/1...-handbook.html

Engine Formulas
http://members.bellatlantic.net/~vze...es/engine1.htm

Reading Plugs.
http://www.dragstuff.com/techarticle...ark-plugs.html

Rate of fuel burn and how it affects power output
http://www.factorypro.com/tech_tunin..._vs_power.html

Hey Teezee,

While the subject of Expansion chambers can drive many people batty, I recall that you based your design on an Old 1970's RM125 design from Gordon Jennings..... And you used a header from (I think) a RG250?

Do you by chance have either a detailed series of pictures, or perhaps a diagram of your design that you can post?

Thomas used the MOTA computer program to model and develop the Suzuki GP125

Using MOTA he settled on port timings of:-

Ex opens 86 ATDC, Trans opens 115 ATDC and inlet opens 145 BTDC / closes 55 ATDC for short tracks.

Ex opens 83 or 81 ATDC, Trans open 114 ATDC and inlet opens 145 BTDC / closes 85 ATDC for long tracks.

This was achieved by turning 1.75 and 1.5mm from the top of the barrels and lifting them up with spacers. The 1.75 long track barrel also had its port raised and widened to 70% of the bore.

Later when we were able to measure a RM125 we found Thomases work was very similar and was close to Bells specs for a RM125. We say we use Bells specs as an easy way to describe our port and pipe work..

For the RM125 pipe specs we used, see Fig 4.7 PDF Page 76, or Page 82 in the book..........

PDF of Graham Bell's Book. http://www.kreidler.nl/artikelen/per...raham-bell.pdf

RM125B General Hot-Up PDF Page 186-188, or Page 193-195 in the book..........

RM125C General Hot-Up PDF Page 200-202, or Page 208-210 in the book..........

RM125C Dyno test results PDF Page 171-172, or Page 178-179 in the book..........

PDF of Graham Bell's Book. http://www.kreidler.nl/artikelen/per...raham-bell.pdf

First pic is of the RG250 pipe, second pic is the cut-out front section we found we could use as it was very close to the RM specs.

Third pic is the RG/RM spec pipe, fourth pic shows where we cut the flange end off and turned it down in the lathe to fit the GP cylinder. Cutting it here made it easy to re-align the pipe to fit onto the GP.

Last pics are a comparison between the original RG pipe and the RM spec one. Thomas made the RM spec one in the original heavy gauge metal to better withstand the argy bargy of Bucket racing at Mt Wellington.

.

[koba]

Last pics are a comparison between the original RG pipe and the RM spec one. Thomas made the RM spec one in the original heavy gauge metal to better withstand the argy bargy of Bucket racing at Mt Wellington.

Hmm, not strictly on-topic but I notice the leathers in the background.
If those are the ones you were wearing at taupo I did notice you on the track.
I was on a 150 and noted your bike in my brain as VERY rapid in a straight line.
I think in staight line grunt it was probably in the top 3, the fastest didn't last long either.
This is all totally subjective and not really relevant but don't think all your efforts so far aren't working because it was punting along ok

I can't remember if this was early (cooler motor) or not but It probably was either very early or very late in the races or warmup laps.

[TZ350]

Thanks Koba for noticing one of us, the bike and rider you saw was "Chambers" another rider in the ESE team with a bike built to the same specs.

.

[SS90]

Thomas used the MOTA computer program to model and develop the Suzuki GP125

Using MOTA he settled on port timings of:-

Ex opens 86 ATDC, Trans opens 115 ATDC and inlet opens 145 BTDC / closes 55 ATDC for short tracks.

Ex opens 83 or 81 ATDC, Trans open 114 ATDC and inlet opens 145 BTDC / closes 85 ATDC for long tracks.

This was achieved by turning 1.75 and 1.5mm from the top of the barrels and lifting them up with spacers. The 1.75 long track barrel also had its port raised and widened to 70% of the bore.

Later when we were able to measure a RM125 we found Thomases work was very similar and was close to Bells specs for a RM125. We say we use Bells specs as an easy way to describe our port and pipe work..

For the RM125 pipe specs we used, see Fig 4.7 PDF Page 76, or Page 82 in the book..........

PDF of Graham Bell's Book. http://www.kreidler.nl/artikelen/per...raham-bell.pdf

RM125B General Hot-Up PDF Page 186-188, or Page 193-195 in the book..........

RM125C General Hot-Up PDF Page 200-202, or Page 208-210 in the book..........

RM125C Dyno test results PDF Page 171-172, or Page 178-179 in the book..........

PDF of Graham Bell's Book. http://www.kreidler.nl/artikelen/per...raham-bell.pdf

First pic is of the RG250 pipe, second pic is the cut-out front section we found we could use as it was very close to the RM specs.

Third pic is the RG/RM spec pipe, fourth pic shows where we cut the flange end off and turned it down in the lathe to fit the GP cylinder. Cutting it here made it easy to re-align the pipe to fit onto the GP.

Last pics are a comparison between the original RG pipe and the RM spec one. Thomas made the RM spec one in the original heavy gauge metal to better withstand the argy bargy of Bucket racing at Mt Wellington.

.

Cool pipe!,

In all honesty, while it is quite dated in the design, it's not too bad... bit of "old, and "new" (of course it's hard to tell exactly from here, but comparing it to the RG pipe is a good reference!)

Just as a matter of curiousity..... if you get the opportunity (wife having a Tupperware evening and you banished to the shed, or something like that), could you measure the "tuned length".... Although it's fair to assume you have already done that though....

I would use the specs from the A G Bell book to get the length, but obviously you have made a few changes to that design!

I have been playing with a theoretical pipe design for your engine at work today, and would just like to compare it to what you have... I think it would be very interesting!

[TZ350]

I would use the specs from the A G Bell book to get the length, but obviously you have made a few changes to that design!

I have been playing with a theoretical pipe design for your engine at work today, and would just like to compare it to what you have... I think it would be very interesting!

Allthough Thomas used the RG front pipe, to get a good shape in the header section we followed the specs from Bells book carefully and all length measurements start from the piston and diameters are internal diameters. It should be close to Bells specs for a RM, close as we can get anyway.

.

[SHELRACING]

Hey TZ, just wondering. As you know I am experimenting. Chambers aside how much influence does the Tailpipe (muffler) have. Do different tailpipes affect the end results, in what way ?

[Buckets4Me]

Hey TZ, just wondering. As you know I am experimenting. Chambers aside how much influence does the Tailpipe (muffler) have. Do different tailpipes affect the end results, in what way ?

The last section of the expansion chamber, called the 'stinger', is in reality a bleed
pipe. Its function is to restrict gas flow out of the exhaust and create back pressure by
slowly bleeding off exhaust gas. This serves to assist the positive pulse wave in pushing
any spilled fuel/air charge back into the motor.


the stinger dimensions which I have found to be most
successful. You may find that a minor reduction in pipe diameter will raise the power
output, but do be careful. A stinger pipe smaller in diameter or longer than specified
could easily result in engine overheating and seizure. Therefore, I would suggest you
make only small changes and then thoroughly test the pipe before going any smaller.
Engine overheating, in its early stages, is indicated by the presence of oil burnt dark
brown under the piston crown. On the next stage the burnt oil turns black, until finally
'death ash' appears. After this, the piston can be holed at any time.

thank you Graham Bell

[Skunk]

Hey TZ, just wondering. As you know I am experimenting. Chambers aside how much influence does the Tailpipe (muffler) have. Do different tailpipes affect the end results, in what way ?

I do the stinger to the calculated dimensions and add the muffler on to the end of the stinger using an ID somewhat larger than the OD of the stinger.

[TZ350]

Now we realy truly know! The last word on ceramic coatings for the combustion chamber.

Abstract from:- http://www.sae.org/technical/papers/941911

The combustion chamber surface was coated with a 0.5-mm thickness of ceramic. Test results indicate that the thin ceramic-coated combustion chamber improves the part load to medium load operation considerably.

The performance of a conventional, carbureted, two-stroke spark-ignition (SI) engine can be improved by providing moderate thermal insulation in the combustion chamber. This will help to improve the vaporization characteristics in particular at part load and medium loads.

But it affects the performance at higher speeds and at higher loads to the extent of knock and loss of brake power by about 18%.

So now we know for sure, ceramic coating does not work for high performance 2-stroke race engines running on petrol.

.