ESE's works engine tuner

[gav]

These are the specs of Avalons Team ESE's BOB Suzuki GP125 20 rwhp engine:

Skim the barrel 1.5mm and “o” ring it, no head gasket, thin alloy spacer plate under the barrel and Suzuki RG250 pipe modified to RM125 specs, KX80 ignition. Raise the exhaust to open 83 deg ATDC, and widen to 70% of the bore, cut 30 deg from the closing point of the rotary disk, so inlet opens 145 BTDC and closes 85 ATDC. Champher the inlet side of the crank at 45 deg to aid inlet flow. Set the mj about 102.5 105 107.5 and ignition timing, 26-28 BTDC using a dyno. A link to Bells book and the RM pipe specs can be found on page 100 of this thread.

Cheep easy effective mods that most anybody can do and get 20 rwhp.
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And what carb would you suggest using?

[TZ350]

Funny that, can't recall the bike ever being in front of the CBR150?

Were you riding or lap scoring? I have only heard reports about the race from the pit crew myself, a super light/fast rider is certainly the biger part of it, for certain sure it couldn't/wouldn't have happened if I was riding.

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[TZ350]

And what carb would you suggest using?

38mm Keihin Flatslide like in Pic-01 and Pic-02

The 24mm Keihin diffuser carb in Pic-03 may be the way of the future, we will know more after Taupo.

The above specs of Avalons engine are all the mods done to a std GP125 to get 20 rwhp, she was running the std GP125 carb.

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[gav]

Were you riding or lap scoring? I have only heard reports about the race from the pit crew myself, a super light/fast rider is certainly the biger part of it, for certain sure it couldn't/wouldn't have happened if I was riding.

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I was riding, when ever the CBR150 lapped me Avalon wasn't far behind, but the gap was getting slowly bigger. Shame she had problems, she was flying for sure!

[TZ350]

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On a good day, I am a bit of a mid-fielder myself, and have seen some great racing action from there that I am sure you don't get to see from the side lines.

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[TZ350]

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Well I had another fairly depressing day at the dyno.

Dave I know your pain, Picture 01 and 02 are of my new piston. I was running the new engine set-up on the dyno trying different pipes. I just couldn’t tune it for any more power and when I pulled the barrel of I found these seizure marks.

Could it be that the 1.0 thou clearance measured at the bottom of the skirt was to tight.

Or were they the result of over advancing the ignition or too much retard, we moved the ignition both ways to find the limits.

Or the couple of times we forgot to turn the cooling fans on before doing a run and I saw 200 degc on the barrel and 160 on the head.

Or may be the diffuser carb leans out too much at the top end, although I think it goes rich but without an EGA who knows?

During one series of runs there was brown soot blowing out the exhaust. I have seen that before on some road cars under heavy acceleration, so what is that brown stuff? it's not rust!

Or a cold seizure, where the engine is run under load before its properly warmed up and the piston expands faster than the barrel.

And then there is the exhaust gas temperatures, I have measured every thing from 250 to 600 at different parts of the pipe.

I have no idea when it happened only that it lost power at some stage while I was swapping pipes and fiddling with the tuning and couldn’t get all the power back.

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[F5 Dave]

one thou clearance on an air cooled barrel?!?? I run 2 thou on aircooled & I wouldn't run 1 thou on anything, even my 50.

[TZ350]

I had been reading up on piston clearances and how Yamaha selected their clearance according to the power output of the engine and that they ran air cooled tighter than water cooled because the air cooled cylinders expanded more than water cooled ones so the air cooled piston needed less initial clearance.

I filed the high spots off, I guess my piston has more than a thou clerance now. any way its all back together with a new copy of a Darcy pipe from post 1507 page 101 and it runs ok, reputedly 170 rwhp on a RG500, hopefull get back to Johns dyno again tommorow, 24+ rwhp at 10500 would be Ok.

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[speedpro]

i assembled the last motor with .0015" clearance, more or less. I did spend a whole day creeping round the kart track running it in. Seems good as gold now and has only wear marks and no scuffs when pulled down. I agree with Dave, .001" is a bit tight. I know what I'm doing Friday night . . . . .

[bucketracer]

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I know what I'm doing Friday night . . . .

.

"Friday Night Drags"............don't tell me, your going to get all dressed up again..............like you and Dad did last week......

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[Buckets4Me]

Funny that, can't recall the bike ever being in front of the CBR150?
Oh, and that CBR150 won a 150 Streetstock race too! And a standard FXR ran inside the top 10 of the 150SS too.

I think the secret is having super fast lightweight riders.

all the E.S.E bikes have run in the top 10 of the ss150's at taupo
so thats no surprise about the fxr (even an rg50 can do it)
and I dont think any of them had super light riders 80+ kg (sorry dad)
apart from maby mine with Keith on it

[sonic_v]

CO meter is a handy tool for this type of work. The cheap type as sold by motor factors is not up to the job though. You require one that uses the ndir (non-dispersive infrared) method.

[sonic_v]

I had been reading up on piston clearances and how Yamaha selected their clearance according to the power output of the engine and that they ran air cooled tighter than water cooled because the air cooled cylinders expanded more than water cooled ones so the air cooled piston needed less initial clearance.

I filed the high spots off, I guess my piston has more than a thou clerance now. any way its all back together with a new copy of a Darcy pipe from post 1507 page 101 and it runs ok, reputedly 170 rwhp on a RG500, hopefull get back to Johns dyno again tommorow, 24+ rwhp at 10500 would be Ok.

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The peak power shown at the dyno curves link from above show a peak power of 128 bhp or is this not the Darcy pipe?

http://homepage.mac.com/rg500delta/d...cy%20test1.jpg

[ajturbo]

These are the specs of Avalons Team ESE's BOB Suzuki GP125 20 rwhp engine:

Skim the barrel 1.5mm and “o” ring it, no head gasket, thin alloy spacer plate under the barrel and Suzuki RG250 pipe modified to RM125 specs, KX80 ignition. Raise the exhaust to open 83 deg ATDC, and widen to 70% of the bore, cut 30 deg from the closing point of the rotary disk, so inlet opens 145 BTDC and closes 85 ATDC. Champher the inlet side of the crank at 45 deg to aid inlet flow. Set the mj about 102.5 105 107.5 and ignition timing, 26-28 BTDC using a dyno. A link to Bells book and the RM pipe specs can be found on page 100 of this thread.

Cheep easy effective mods that most anybody can do and get 20 rwhp.
.

this wouldn't help me would it
.. as i have a spare GT125 twin engine... .....

would anyone notice if i put both in a frame???

[ajturbo]

a serious question here...

the positioning of the front brake caliper...

on my GT it is on the left fork, BEHIND the fork

i have just seen a photo of one with it on the RIGHT, therefore in FRONT of the fork

question::::

which is better????