stephen1967 Posted December 6, 2009 Report Share Posted December 6, 2009 Hi my bike makes a knocking sound when it is under strain,ie going up steep hills.I think the piston needs replacing. How much should I reasonably expect to pay for a new piston and a rebore,parts and labour included.Thank you Quote Link to comment Share on other sites More sharing options...
tilertrialler Posted December 6, 2009 Report Share Posted December 6, 2009 is it definitely piston knock, it may be pinking if you are not running on the super leaded petrol, mine knocks on standard unleaded. Quote Link to comment Share on other sites More sharing options...
matt_urban Posted December 6, 2009 Report Share Posted December 6, 2009 piston and rings are about 185 pound and i dont think you can get a re bore only a chromium (sp?) replate so try super and make sure you have the right mix 70;1 or 60;1 to little oil will make it knock . super burns cleaner and faster so you can run a bit more oil Quote Link to comment Share on other sites More sharing options...
lee harris Posted December 6, 2009 Report Share Posted December 6, 2009 piston and rings are about 185 pound and i dont think you can get a re bore only a chromium (sp?) replate so try super and make sure you have the right mix 70;1 or 60;1 to little oil will make it knock . super burns cleaner and faster so you can run a bit more oil running more oil lowers the octane. i would use optimax and 70 to 1 Quote Link to comment Share on other sites More sharing options...
nzralphy Posted December 6, 2009 Report Share Posted December 6, 2009 Most Rev3's do it. It is pinking. Remove the head and polish the top of the piston and the cylinder head (get some Autosol polish). Use the best petrol you can find. Use fresh petrol. Raise the needle a notch helps some bikes (but also makes other '4-stroke'... run rich). Check the air mixture screw is correctly adjusted. Then when this is done..... just put up with it cos i never fully got rid of it on mine. Ralph Quote Link to comment Share on other sites More sharing options...
samo Posted December 7, 2009 Report Share Posted December 7, 2009 Mine has the same problem and I solved it by raising the fuel level and optimizing the air screw. I tryed raising the needle but the mixture was too rich. Your bike just need richer mixture. Now you have too much air and too little petrol.. Quote Link to comment Share on other sites More sharing options...
graeme17 Posted December 7, 2009 Report Share Posted December 7, 2009 Mine has the same problem and I solved it by raising the fuel level and optimizing the air screw. I tryed raising the needle but the mixture was too rich.Your bike just need richer mixture. Now you have too much air and too little petrol.. I almost agree, I have the same bike and suffered the problem as described on the original post. I tried all the things described above and although it did make a difference, it didn't sort the underlying problem. The problem turned out to be a partial blockage of the pilot jet which required the jet to be removed and the foreign material pushed out with a pin. I had previously blown through all the jets with the airline and all seemed well but just goes to show its worth inspecting closely. After the blockage was removed the bike ran better than it had for years!!! Quote Link to comment Share on other sites More sharing options...
samo Posted December 8, 2009 Report Share Posted December 8, 2009 Most Rev3's do it. It is pinking. Remove the head and polish the top of the piston and the cylinder head (get some Autosol polish). Use the best petrol you can find. Use fresh petrol. Raise the needle a notch helps some bikes (but also makes other '4-stroke'... run rich). Check the air mixture screw is correctly adjusted.Then when this is done..... just put up with it cos i never fully got rid of it on mine. Ralph Ralph, if you clean piston and head is it enough take of just head? Not whole cylinder? Quote Link to comment Share on other sites More sharing options...
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