8 replies to this topic
  • whitetrashracing

Posted August 03, 2004 - 03:33 PM


i recently did an overhaul on 98 400 put in wiseco 13.5:1high comp piston bike seemed to be runng awesome with no pinging on 92 oct pump gas went o oregon dunes and the dealership knuckle buster told me i had to use 110 oct bike was running perfect without it i called techs at wiseco and they say that the recommended fuel is 110 im confused if i get no pinging with 92 do i really need to go to 110 and after about a gallon of gas was ran thru the bike the plug looked like it was hot and i lost commpression ssome compression there but not alot poss exhuast valve stuck? and can i run 100:1 2smoker gas for a few mins with high comp piston

  • DoctorRzed

Posted August 03, 2004 - 03:51 PM


Why wouldyou wantto run 100:1 2smoker gas? :thumbsup:

  • whitetrashracing

Posted August 03, 2004 - 04:00 PM


lost compression has some but not alot i think one of the exhaust valves is stuck open wanted to know if 100:1 would be ok to use to clean out exhaust with high comp piston or am i gonna blow it sky high

  • thumperslider54

Posted August 03, 2004 - 04:29 PM


I put A high comp piston in my xr200 A couple of years ago and ignored wiseco's advice and ran amoco premium and melted the top of my piston.Higher comp creates more heat which causes detonation.High octane leaded fuel burns slower with more reaction when it does burn.no detonation.trust wiseco they know. :thumbsup:

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  • yz426onNOS

Posted August 03, 2004 - 07:21 PM


You had better listen to them. Also did you measure the ring clearances, piston, and cylinder wall? Wiesco has problems with there pistons not being perfect (from what I am told). I have the 13.5.1 and I have a rattle/tapping noise in the cylinder. Either my wrist pin or piston. That’s with about 20 gal. of gas on the new motor. You will be stunned at the throttle response and performance of the bike on race gas. My bike did not like VP, but it love Klotz! The only time I would use anything but race gas is if I was stuck in the middle of no were and thats all I had.

  • whitetrashracing

Posted August 03, 2004 - 08:22 PM


thank everyone for responses!!! the bike was running absolutely perfect inthe dunes i ran 10 gals. of pump gas with no apparent problems i ran it for about 2 hrs in the woods on the same gas and still no apprent problems. the only reason i tried race gas was the dealer in coos bay told me i had better run race gas or i would blow it up so i did and it still seemed to run the same no knocks no pings on either gas . i did all the checks on the piston before i put it in ring gap the whole bit everything is in specs. doesnt blow any smoke. what i dont understand is why all of a sudden it lost compression it has some but not alot there is no hole in the piston u can look down the spark plug hole and see that. looking at similiar probs. that are posted i think it is stuck valves on the exhaust side. now can i run 100.1 2smoke gas through it to clear out some carbon? coupla post recomended that, but with high comp piston will it damage anything?i know i can do it with factory pistonbut not sure about high comp

  • Jeffro426

Posted August 03, 2004 - 08:28 PM


I ran a 13.5:1 in my 426 and it had a steady diet of 91 octane the whole time and i never had a problem with it. if it doesnt ping, or run like crap, there really no reason for hte race gas...i tried a few types in mine with no real difference in performance.

  • whitetrashracing

Posted August 03, 2004 - 08:34 PM


thank you i ran up in the trails here and actually broke the bike in on 92 oct pump gas and didnt here any thing odd in fact it was running freakin awesome and wasnt overheating

  • yz426onNOS

Posted August 03, 2004 - 08:47 PM


Yes you can run 2-smoke gas. Sure it wont hurt anything. You can also use vegetable oil as motor oil. :thumbsup: It's your bike do what you want. All it's going to do is foul your plug's and prob. gum everything up.

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