Opinions on engine piston compression.

[jasonp]

I have a JE 10.5:1 85mm piston that I installed in my bike. After getting the deck clearance to about .055" or so I ended up with around 11:3.1. You can run even less deck about .035" to .040" and come up with even more compression and also it will fight off detonation as the closer the deck is it creates more turbulance inside the combustion chamber and will run cooler and help the charge air fuel mix and burn better.
I guess my question is how do you guy's with the 12:1's actually keep the heat down. Seriously! I was riding around yesterday with the temps pretty high around 90 degrees and had the jetting a hair on the rich side and the oil cooler was super hot to the touch, like you couldn't even touch it and I had to pull timing out of the engine to help prevent detonation. Damn air cooled engine.
I'm really glad right now that I didn't go any higher compression piston. I would hate to have to run racing gas for 6.00 dollars a gallon.

 

[dave76]

Whats the cc of the Warrior head. 35 or 38????

 

[jasonp]

Dave mine was 35cc's from what I remember. I cc'd it after it came back from duncan racing so they may have taken a little off but I don't know..

 

[dswwarrior350]

My 12:1 does run significantly hotter than with the wiseco i had. I dont run an oil cooler and with race gas i never had a problem with it getting too hot. I always just keep it in the wind as much as possible. It also helps to not let it idle very long... I never really had a problem with it. In fact ive got away with 93 octane and some maxima booster before.

 

[yakuza]

Race gas will keep it cooler, but you already knew that. If you don't want to spend the big bucks on full race fuel, try mixing 50/50 with 93 or 94 and the rest 104. Not sure how much benefit you'd get from the mixed race/premium but it's got to be better than just pump gas. Hell I can get 100 octane straight out of the pump at the local gas station. Cheaper than 104 but better than the 93.

 

[dave76]

I've been mixing 50/50 with Sunoco purple 110 for the 446 and I've been using the NGK D9EA for summer riding.

 

[yakuza]

How's the 110 workin for you? It's leaded so I've been hesitant to use it. As I understand it there's a posibiblity of the lead additives gunking up your motor. Did it all look good when you tore it apart?