changeing plug with higer octane

[culookn]

i have an 04 450r and im getting the 13:1 je piston, getting some 110 octane fuel and hopefully it should run awesome after that. will i have to change out myspark plug to a hotter /colder plug?

[2muchquad]

you dont want to change your spark plug temp range unless instructed to do so by your engine builder.just run the required fuel for your high comp piston and you should be fine.

[boystoys]

i was thinking about doing the same for this summer... well my 400 internals are all stock... i was going to try Cam2 i think its 102 oct...
then next winter maybe do a rebuild to a 415 high comp, stage 2 cam, gt thunder CDI...


would 102oct gas do anything good and bad for a stock engine with a filter and pipe? would it be worth it...
I figure race gas is only like a dollar more per gallon and if it offer any gains at all ill spend the extra 5 bucks to fill my can.....

:-)

[2muchquad]

it will not be of any benefit unless you require high octane due to a high compression piston.i have seen TOO many people waste money on race gas with a stock or nearly stock motor.my yzf 426 mx bike calls for 91 octane and it has 12.5 to 1 stock piston.it runs fine on pump.:)

[400exrider707]

Originally posted by boystoys
i was thinking about doing the same for this summer... well my 400 internals are all stock... i was going to try Cam2 i think its 102 oct...
then next winter maybe do a rebuild to a 415 high comp, stage 2 cam, gt thunder CDI...


would 102oct gas do anything good and bad for a stock engine with a filter and pipe? would it be worth it...
I figure race gas is only like a dollar more per gallon and if it offer any gains at all ill spend the extra 5 bucks to fill my can.....

:-)

Exactly what 2muchquad said. It would be a waste of money and if anything will only make your quad harder to start, as if 400exs need to be started any harder (especially when its cold out). the higher the octane the higher the temp needs to be to combust therefore making it harder to ignite the gas. Save your money man. I ran my stock EX on nothing but 87 and it ran fine. Also stay away from octane boosters, I've heard nothing but troubles with that stuff!

[85atc350x]

You'll have to take it for a run and check the color of the stock plug. If you're running 13:1 comp and 110 octane fuel you might have to go with a colder plug.

[wilkin250r]

Two points I'll make.

First, higher compression means higher cylinder pressures and higher cylinder tempuratures. You may need a colder plug.

Second, race gas CAN be a benifit in a stock engine, under certain conditions. I don't know about the 450R, but I know many offroad engines have rather advanced ignition timing (perhaps to meet emmisions requirements). Advanced ignition can rob your power, expecially in the upper RPMs, and race gas will cure that. I've HEARD of people gaining an extra 1000 peak RPMs by running race gas, due to the effective timing change it gives you. But that's a highly specialized scenario. For most people up against a rev limit caused by the CDI, race gas will not have any benifit.