Keyser Soze Posted April 25, 2009 Report Posted April 25, 2009 I just started using some 28MM flatside mikunis. Jetting was pretty lean so I went from 320 to 370. Today it ran awesome..like it should but the headpipes were really super hot.The silencers burned little holes in my plastic. My CRJ temp gauge never went past 185..which is pretty good for tight, muddy trails. After about 10-15 minutes of running hard it starts to cut out under hard throttle. Seems to run fine mid range and sputter on the bottom and top.....I let it cool off for about 15 minutes and it was back to running hard again. My compression is at 135 with +4 timing, today i ran 89 octane. I typically run 93.....could that be a problem? Anyone ever heard of such? Quote
FireHead Posted April 25, 2009 Report Posted April 25, 2009 I just started using some 28MM flatside mikunis. Jetting was pretty lean so I went from 320 to 370. Today it ran awesome..like it should but the headpipes were really super hot.The silencers burned little holes in my plastic. My CRJ temp gauge never went past 185..which is pretty good for tight, muddy trails. After about 10-15 minutes of running hard it starts to cut out under hard throttle. Seems to run fine mid range and sputter on the bottom and top.....I let it cool off for about 15 minutes and it was back to running hard again. My compression is at 135 with +4 timing, today i ran 89 octane. I typically run 93.....could that be a problem? Anyone ever heard of such? My guess would be that you have an air leak that is causing your EGT's to go really high........ ........a bad load of fuel could also be a possibility. Quote
dragbanshee Posted April 25, 2009 Report Posted April 25, 2009 What did you do, stael that 89 oct from your lawnmower? lol Quote
banman350 Posted April 25, 2009 Report Posted April 25, 2009 with +4 you shouldnt run 89 thats probly why it was cuttin out, whats your mix ratio Quote
Keyser Soze Posted April 25, 2009 Author Report Posted April 25, 2009 40:1 Yea for whatever reason the gas station was out of premium. Really wanted to ride today so what can you do. I checked for obvious air leaks but sometimes those boots can have splits you can hardly see. Didnt have any starting fluid on me or anything. I'm hoping it was the 89 octane but I dont see why it would run hard for the first 15 minutes or so. Quote
Keyser Soze Posted April 25, 2009 Author Report Posted April 25, 2009 educate me about heat cycling Quote
jbooker82 Posted April 25, 2009 Report Posted April 25, 2009 Make sure you dont have an air leak. I would say your rich on the top end if it runs hard for the first 15 minutes. The engine starts heating the air up that is being pulled in through the engine. Hot air is less dense to it needs less fuel. I would start backing down one jet size at a time. Until you find one that pulls hard when warm at wide opean throttle. Pipes are supose to be hot. josh Quote
sheefreak Posted April 25, 2009 Report Posted April 25, 2009 I agree on being rich. It explains both why your pipes are so hot and why it runs worse the longer you ride it. If you are too rich and it can't burn all the fuel, he excess may be igniting and burning in the pipe. What do your plugs look like? Quote
Keyser Soze Posted April 25, 2009 Author Report Posted April 25, 2009 Really 370 to right with 28mm flatside mikunis. Pod filters, Trail porting, Boyseen rad valve, +4 timing. DMC 916's Quote
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