What Piston?

[jtsurfer]

I have a 03 KFX that is piped,jetted,stage 1 hotcams,and a high rev cdi. just wondering what would be the best wiseco piston to put in for abit more power but still keeping it reliable? the 12.2:1 or the 13.5:1 and what gasket the stock one or the DRZ one? Thanks for any info

[DVX440]

You can run 13.5:1 (high compression) and get alot of bottom-end power, but you have to run race gas. If you use the DRZ gasket then that ups the compression by 1 point, so that would put you at 14.5:1, which would snap the stock crank.
To be reliable, I would use the 12.2:1 and the DRZ gasket, and then run like 100-105 octane gas.

[jtsurfer]

Hey DVX440,thanks for the info. How are you guys getting your octane so high? The fuel here is 94 octane. Do you add some kind of additive to your fuel?

[charly-d]

you can use VP racing fuel like C12 or you can also put some additive in your gas and find the best mix and always keep it
I own a KFX with a 440 and 13.5:1 compression and my bike is running very well.
P.S. if you have a 13.5:1 compression piston be sure you crank is in good shape because I just snapp mine and this is not very funny !!!lol
have fun

[jtsurfer]

Hey Charly-d, Thanks for the info. You guys have any good ATV websites in Quebec? I live on Vancouver Island BC. We have www.quadconnection.com on the Island

[charly-d]

if you want you can visite www.shiftnrace.com this is a very good forum for atv

[osmond.mark]

Just to correct you, not trying to be a jerk but if you have a 13.5:1 piston then your not really getting the 13.5 unless you have the drz base gasket. With that gasket you will have 13.5:1. Just clearing that up.

[jtsurfer]

So if you put in the 12.2:1 with the stock base gasket you would only have stock compression roughly?

[osmond.mark]

Yes your correct. In order to get the axual 12.2:1 you need the drz base gasket.

[jtsurfer]

So if i put the 13.5:1 piston in and use the stock gasket i would have 12.5:1 compression? Just abit more than using the 12.2:1 with the DRZ gasket. In your opinion which would be better. Thanks

[osmond.mark]

Yes I belive thats correct. It may not be exactly 12.5:1 but its somewhere close. I thikn the drz gasket adds 0.9 so it would be 12.6:1 I guess without the gasket.

It all depends. With the 13.5:1 and drz gasket youll be needing race fuel. Without im not sure. Havent heard of many people doing it that way. If it was me I would go with the drz gasket and if you want to run race fuel for the better bottom then get the 13.5 if not get the 12.5. Thats just my opinion.