Topic: JE 836 12.5:1 pistons

[joe p]

Just wondering if anyone has used these pistons with mild port work and say around 370 lift cam. What kind of HP would you expect?  I'm just looking around at different combinations. I have not built one of these motors in 15 years and I swear there are more parts for them now.

[Tintop]

12.5:1 pistons would require high octane fuel, probably 105 to 110.  Doubtful that pump gas would cut it.

[Sam Green Racing]

I wouldn't say there are more parts available now but there is a greater choice.
Like Brian said, the right fuel will play a big part with compression that high.
Another thing to look at/think about when looking for HP figures, most people don't stop at pistons, porting and a cam.
It seems pointless doing those three mods without carbs, ignition and exhaust.

Sam.

[Doctor_D]

+1 for Sam and Tintop, but strictly speaking - add 5% to the output of a similar 10.25:1 836 for a ballpark number.

[joe p]

I'm sorry I should have been clearer . This is a wheelie bar hand clutch drag bike only.  I have header, all dyna ignition, Mikuni carb . 

[jweeks]

Low 11's at around 108 depending on tune, porting, traction, altitude, and overall weight.

[joe p]

Thanks for the information. That would be plenty of motor for me, for what I'm trying to do.