motomanandy Posted January 15, 2012 Report Share Posted January 15, 2012 Is anyone else having detonation issues? I bought the bike in summer 315r 2003, i noticed it was detonating so i switched fuel to 97 ron bt ultimate which cured it...until now it came back im thinking i might need to run an octain booster!!?? Quote Link to comment Share on other sites More sharing options...
paul w Posted January 15, 2012 Report Share Posted January 15, 2012 it needs a right good de-coke. barrel off, head off, piston off , rings off, the lot. once done, no detonation. Quote Link to comment Share on other sites More sharing options...
furse Posted January 15, 2012 Report Share Posted January 15, 2012 I would run pro boost as well if you run it on the road. All Monts will pink a bit. Quote Link to comment Share on other sites More sharing options...
motomanandy Posted January 15, 2012 Author Report Share Posted January 15, 2012 it needs a right good de-coke. barrel off, head off, piston off , rings off, the lot. once done, no detonation. I can understand if the piston crown has a build-up of carbon it will lower the compression causing it to pink but why the head and rings out? compression was tested a month ago and was stock! surly its just an octane issue! Quote Link to comment Share on other sites More sharing options...
paul w Posted January 15, 2012 Report Share Posted January 15, 2012 I can understand if the piston crown has a build-up of carbon it will lower the compression causing it to pink but why the head and rings out? compression was tested a month ago and was stock! surly its just an octane issue! if you doing half the job anyway why not do it all? pre-detonation can be caused by several combinations of issues, one being small particals of carbon on the piston igniting the mixture before the spark. When you switched to a higher octane fuel the engine ran cooler, but the carbon still built up, hence the problem has returned. Quote Link to comment Share on other sites More sharing options...
motomanandy Posted January 16, 2012 Author Report Share Posted January 16, 2012 if you doing half the job anyway why not do it all? pre-detonation can be caused by several combinations of issues, one being small particals of carbon on the piston igniting the mixture before the spark. When you switched to a higher octane fuel the engine ran cooler, but the carbon still built up, hence the problem has returned. i usually remove the plug inject some carbon-x leave a few hours move the piston down the cylinder then blow it stright through the exhaust port its worked a treat on my exc! Quote Link to comment Share on other sites More sharing options...
paul w Posted January 16, 2012 Report Share Posted January 16, 2012 well try that then Quote Link to comment Share on other sites More sharing options...
fastducs Posted January 17, 2012 Report Share Posted January 17, 2012 Carbon buildup on the piston and/or on the head will raise compression ratio, not lower it. Plus, carbon has a tendency to glow. Those two factors can be contributing to your detonation problem. But another issue is the temperature, which affects jetting requirements. If you are running with the same jetting you had in the summer, then it might be too lean for cold temperatures. Also, gasoline blends which you buy at the pump are seasonal, i.e. the oil companies blend them differently based on the season. The only way to have consistent fuel is to buy expensive race fuel in canisters. Quote Link to comment Share on other sites More sharing options...
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