ESE's works engine tuner

**Gigglebutton** · 7th April 2011, 13:53

I have opposite problem on my RG50. I have got the motor apart and found the transfers are 1.1mm to low. Doh!! So instead of 116* i have 121*. Hopefully fixing these will make my battle with the FXR's easier

**wobbly** · 7th April 2011, 19:28

Be careful when lifting the transfers you dont restrict the blowdown STA

**Gigglebutton** · 7th April 2011, 20:55

Originally Posted by wobbly

Be careful when lifting the transfers you dont restrict the blowdown STA

Thanks. I'll get TZ to have a look at them before i cut into them

**TZ350** · 9th April 2011, 10:55

Fitted the original 27hp cylinder to the engine with the wide clearance crank and richened it up every where.

I wanted to test the wide clearance crank against a setup that I had real confidence in the results from previous tests.
Warmed it up properly and then it nipped on the first pull............

I will pull it down Monday night to see what the damage is.

**RMS eng** · 10th April 2011, 08:54

Originally Posted by Gigglebutton

I have opposite problem on my RG50. I have got the motor apart and found the transfers are 1.1mm to low. Doh!! So instead of 116* i have 121*. Hopefully fixing these will make my battle with the FXR's easier

this is what i had on my RG50 which is a good start. port timing,trans 132-134* Ex 196-198* inlet 155* 24-26mm carb,STD pipe with new rear cone and RM80-85 ignition,this made a nice smooth 11 hp,good set up for a kart track,but would be 2-3 hp down for a big track.12 years ago this motor in a RG50 with STD forks and running crap 90 yoko tyres did 31.5 s at MT wellington.

**Gigglebutton** · 10th April 2011, 20:03

Originally Posted by RMS eng

this is what i had on my RG50 which is a good start. port timing,trans 132-134* Ex 196-198* inlet 155* 24-26mm carb,STD pipe with new rear cone and RM80-85 ignition,this made a nice smooth 11 hp,good set up for a kart track,but would be 2-3 hp down for a big track.12 years ago this motor in a RG50 with STD forks and running crap 90 yoko tyres did 31.5 s at MT wellington.

Cheers.. I have spent 3 nights this week and part of Saturday & Sunday , thinking over what to do & working on it. It seems the more i read , talk to people and work on it , the more complex things become. So many theories!!!! So many variables.!!!!!! It's driving me f#*%ing mad.

50cc's of pure agony and joy. Hopefully it all pays off.

**bucketracer** · 12th April 2011, 21:29

Originally Posted by TZ350

Fitted the original 27hp cylinder to the engine with the wide clearance crank and richened it up every where. Warmed it up properly and then it nipped on the first pull............

I saw TeeZee hard at work tonight linishing the high spots of his piston. At least this time he didn't have to take 0.004" of to get the piston to fit. When I asked him about it, he said, I guess 0.002" clearance was not enough and it should have been 0.003" like Wiseco said.

It looks like the bike will be back together and ready for another run in a night or two.

**TZ350** · 13th April 2011, 17:44

Ok............... it did not nip up this time.

I think 0.002"clearance is not the problem, the problem possibly was/is that KX125 pistons for water cooled motors dont have enough "cam""on them as this piston siezed either side of the gudgen boss, not for/aft on the skirt. So I camed it up with a good linishing around the sides, and left the 0.002" piston/bore clearance the same.

Click image for larger version.

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Blue line is the original 27hp motor with the stock 1mm clearance around the crank, the Red line is the same motor with 2mm clearance and the extra 50cc crankcase volume.

It looks like 3.5k rpm usefull power spread and I think it could be better yet with a bit of fiddling with the jets and ignition.

Now that I have something running again, we can also look at Devconning the transfers in the 30hp cly to see what happens.

**gatch** · 13th April 2011, 18:33

Originally Posted by TZ350

It looks like 3.5k rpm usefull power spread and I think it could be better yet with a bit of fiddling with the jets and ignition.

Now that I have something running again, we can also look at Devconning the transfers in the 30hp cly to see what happens.

That's a wicked flat torque curve. Awesome.

**kel** · 13th April 2011, 20:26

Originally Posted by TZ350

It looks like 3.5k rpm usefull power spread and I think it could be better yet with a bit of fiddling with the jets and ignition.

Firstly thats a seriously fat curve, and anything but peaky.
If memory serves me right this is the cylinder with 200deg exhaust duration and 225deg inlet yet it produces such a fat curve? The cylinder although seemingly wild by todays timings has obviously matched the time areas in all respects yet still runs Bells 1980's suggested durations.
What am I burbling about? Simple, for the torque curve and power output of a thirty + year old air cooled 125 to be that fat then its been engineered to near perfection through utilisation of the teachings of all the readily available texts even though they dont always agree with the modern standards (2mm crank gap and fancy ignition curve aside)

I suggest this motor should be preserved for its engineering prowess and not be let loose on the track, especially not with a certain 125 racer on board!

**RMS eng** · 13th April 2011, 21:20

Originally Posted by kel

Firstly thats a seriously fat curve, and anything but peaky.
If memory serves me right this is the cylinder with 200deg exhaust duration and 225deg inlet yet it produces such a fat curve? The cylinder although seemingly wild by todays timings has obviously matched the time areas in all respects yet still runs Bells 1980's suggested durations.
What am I burbling about? Simple, for the torque curve and power output of a thirty + year old air cooled 125 to be that fat then its been engineered to near perfection through utilisation of the teachings of all the readily available texts even though they dont always agree with the modern standards (2mm crank gap and fancy ignition curve aside)

I suggest this motor should be preserved for its engineering prowess and not be let loose on the track, especially not with a certain 125 racer on board!

give me a break Kelly,this thing needs to go to the track to see what it can do and if it will last a days racing.dyno sheet looks sweet,should be good for sub 29 at MT welly.mark beat that 125 rider two races ago on his 16HP TS100 and has done a 29.9 lap on that bike.so if ESE put this 27HP motor in a good frame it should be a rocket?

**bucketracer** · 13th April 2011, 21:37

Originally Posted by RMS eng

mark beat that 125 rider two races ago on his 16HP TS100

Didn't beat her a second time though ........... and sadly paid the price later for over riding trying to keep up, crashing and breaking his collar bone.

**Henk** · 13th April 2011, 21:56

Originally Posted by RMS eng

if ESE put this 27HP motor in a good frame it should be a rocket?

And for Mt Welly I suspect that is the key.

**kel** · 13th April 2011, 22:01

Originally Posted by RMS eng

give me a break Kelly,

Nope wont have it.
Read through this enormous thread, ESE havent just opened up a modern two stroke and tried to copy it. They have probably read, absorbed and implemented more info than the rest of the 2 stroke bucket racing fraternity put together, and guess what their learnings and results arent locked away they're dispalyed here for everyone to share. Well done guys!

**RMS eng** · 13th April 2011, 22:16

Originally Posted by bucketracer

Didn't beat her a second time though ........... and sadly paid the price later for over riding trying to keep up, crashing and breaking his collar bone.

that would be right and what you get for starting mid pack on the grid,Derbi 80s are still the best two strokes at the track at this time.