[chucklz76]

I am needing to bore my cylinder probally .040 and as i was looking at pistons
Stock is 8.5:1 and i seen a 9.5:1 and a 10.5:1.
has anyone ever had any problems going 9.5:1? i hear that 10.5:1 is very hard on the engine and i would like the extra HP!! but i want it to be a rider and not a work-on every weekend thing,i wouldnt mind a bi-yearly rebuild.

thanks
scott

2004 Honda Foreman 450ES

 

[69quadracer]

Welcome to the forums! you can run a 10/5-1 and be way good will not be any harder on the motor than the 8-1 you are running now, the one behind the handle bars is whats hard on the motors, i run a 14-1 in my TRX450ER never have any problems but i do have to rum 110 oct fuel when you get above 13-5-1 you have to run highet oct fuel, do the 10/5-1 and a little cam and you will be happy.

 

[TRX2fiveO]

Agree. ^^^ the con of a high comp piston is that you will never go back to stock...well maybe thats not a con after all.. lol

 

[chucklz76]

Does more compression require jetting of the carb

 

[ivan-ator]

i have a 86 foutrax 250 and i am using 91 oct fuel is that ok for stock??
thank to all

 

[Helmut]

i have a 86 foutrax 250 and i am using 91 oct fuel is that ok for stock??
thank to all

Yes, that's fine.

 

[ivan-ator]

ok cool thank you