[bear2007]

am wanting to install some hi comp pistons on my 07 warrior. current mods arecIII, vance & hines pro pipes, k & n filters. want to know if i will have any problems after i install the pistons due to the 10.2:1 rated comp. i have tried 87 oct. fuel but runs better with 93 oct. i have raced a 1200cc sportster with the screaming eagle package and had to ease off the throttle in between gears so he could keep up but was disappointed once i reached 4th gear. i did pull away but not like the 1st 3 gears.....

 

[Bladerunr]

They run gooood on 93 octain. Go for it!





Pings like a banshee on Left Coast 91

 

[Churchkey]

" want to know if i will have any problems after i install the pistons due to the 10.2:1 rated comp."


Yes you will. Your face will hurt due to the permanent grin. Don't go into a girly-boy bar.

 

[independent_lemming]

am wanting to install some hi comp pistons on my 07 warrior. current mods arecIII, vance & hines pro pipes, k & n filters. want to know if i will have any problems after i install the pistons due to the 10.2:1 rated comp. i have tried 87 oct. fuel but runs better with 93 oct. i have raced a 1200cc sportster with the screaming eagle package and had to ease off the throttle in between gears so he could keep up but was disappointed once i reached 4th gear. i did pull away but not like the 1st 3 gears.....

Ran the 10.5:1's with cam and regularly speed shifted without easing off (thats with a chain drive) and no issues.

 

[YFM700R]

HC pistons were the first thing i wanted to do, but now have had the heads ported and am installing the cam. will be fun to find out numbers when i am done!


the pistons are a must in my eyes.

 

[ratphlem]

I have OE 10.5:1's and normally still run 87 octane. If it's not pinging, you should run the lowest octane you can get away with...

 

[cruisemissile]

I have 10.5:1 pistons in mine and only run 93 oct. No pings. You will need a new map with your new compression.


You'll notice the pulling difference as soon as you romp on it for the first time.

 

[bear2007]

thanks for all of your replies. next question is: what is the best place to get them from? the cheapest i have seen the kit is around $305.00

 

[SuicideD_45]

thanks for all of your replies. next question is: what is the best place to get them from? the cheapest i have seen the kit is around $305.00

Hey Bear, www.Yamahasportsplaza.com has them for $281 US.

There was
a set of Speedstar valve springs on Ebay yesterday for $200...not sure
if they are there still though.