wiseco piston- 13.5:1 on pump gas?

4 replies to this topic
  • bluebreadtruck

Posted January 10, 2009 - 07:15 PM


i have every bolton and need more power. short of swapping a 450, i was thinking some hotcams and a wiseco highcomp 13.5:1 setup....piston and cams made a HUGE difference on my old raptor and hopefully will on this bike also.

my only question; can i run on 91 or (93?) pump gas and n0t get the detonation?

i heard a while ago that anything over 11;1 is a nono on a 4-stroke? anyone try this?

  • brad the best

Posted January 10, 2009 - 08:57 PM


i know all the new 600 cc crotch rocket's are 13:1 and they run pump gas , there also efi and have a different ingnition curve ,adv etc .

but 13:1 on pump gas is totally do able , but with the ignition timing of the wr i can not say .

i would say super premium would do just fine on that bike , if you want buy a octane booster . there like 10$ for a couple bottles , they treat a fair amount of gas when its for a dirt bike .

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  • Birdy426

Posted January 11, 2009 - 04:34 AM


I have a big bore 13.5:1 on my bike. I normally run 91 octane pump gas without issue, and have even run 89 octane when that's all that was available. Every once in a while, I will get a tank-full of shit-gas and the bike will ping. Adding a bit of octane booster or cutting the bad gas with race as clears it right up.

  • bluebreadtruck

Posted January 11, 2009 - 07:31 PM


that helps alot guys, ok, I think im gonna go for it. I had a 400ex that had ping issues with a high compression piston and dident want to deal with that again.....

  • knuckleduster271

Posted January 11, 2009 - 07:56 PM


My wr has that piston. I always run pump gas in with no problems what so ever


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