Scadigan Posted May 19, 2010 Share Posted May 19, 2010 i just bought a yoshi rs2 slipon exhaust and a twin air filter for my 2006 crf450r and i was expecting some jetting info to come with the pipe but nothing so now i have really no idea what size of jets im going to need do i need a bigger main jet and pilot jet? i live in pahrump and only ride at dumont/desert not many places with higher altitudes the stock main jet size is a 165 and the pilot jet is a 42 so any ideas? thanks.. Quote Link to comment Share on other sites More sharing options...
sandawg Posted May 19, 2010 Share Posted May 19, 2010 i just bought a yoshi rs2 slipon exhaust and a twin air filter for my 2006 crf450r and i was expecting some jetting info to come with the pipe but nothing so now i have really no idea what size of jets im going to need do i need a bigger main jet and pilot jet? i live in pahrump and only ride at dumont/desert not many places with higher altitudes the stock main jet size is a 165 and the pilot jet is a 42 so any ideas? thanks.. Call the manufacturer! they should know abnd tell you. Usuallly you go bigger when you breath better! Quote Link to comment Share on other sites More sharing options...
mineurbiz Posted May 19, 2010 Share Posted May 19, 2010 Pat is right, call Yoshi, they will tell you the jets needed and keep it a tiny bit rich. Quote Link to comment Share on other sites More sharing options...
seadoojumper Posted December 7, 2010 Share Posted December 7, 2010 Yosh will not give jetting specs any more. (neither will FMF, Pro Circuit or any other exhaust manufacturer. it's a liability thing.) It is trial and error. I would start 2 sizes up on the main and idle jet and go from there. Run the bike for about ten minutes with a fresh plug and check the spark plug after that. if it's bright white keep going up. if it's dark black go down. you want the plug to be a nice toast brown when it's all good. P.S. some bikes are very particular about jetting. things like temperature and humidity will change the jetting. so what works at home in june may not work at Dumont in Novemnber. Quote Link to comment Share on other sites More sharing options...
TheAlaskan Posted December 7, 2010 Share Posted December 7, 2010 And remember, if it starts acting up after you re jet it remember where in the throttle it was Acting up. Good rule of thumb; no throttle to 1/4 throttle= pilot, 1/4 to 3/4= needle, and 3/4 to full throttle= main jet. Its all trial.and error, just keep.playing with it and you'll get it. Quote Link to comment Share on other sites More sharing options...
EY3BA11 Posted December 7, 2010 Share Posted December 7, 2010 i would go up one on the main.. and depending wether or not it pops on decel 1 up on the pilot as well.. Quote Link to comment Share on other sites More sharing options...
dunefreak Posted December 8, 2010 Share Posted December 8, 2010 I hope he figured it out. He's had seven months to mess with it since he started this thread. Quote Link to comment Share on other sites More sharing options...
SandBurro Posted December 8, 2010 Share Posted December 8, 2010 Yosh will not give jetting specs any more. (neither will FMF, Pro Circuit or any other exhaust manufacturer. it's a liability thing.) It is trial and error. I would start 2 sizes up on the main and idle jet and go from there. Run the bike for about ten minutes with a fresh plug and check the spark plug after that. if it's bright white keep going up. if it's dark black go down. you want the plug to be a nice toast brown when it's all good. P.S. some bikes are very particular about jetting. things like temperature and humidity will change the jetting. so what works at home in june may not work at Dumont in Novemnber. Depending on what type of Jet's you decide to use, I would call the jet manufacturer and ask them what your set up is and go from there. Be carefull and dont go by the number sizes as some manufactures sizes indicate the orifice of the jet and others indicate their jet size by the fuel flow that flows through the jet. Last time i installed a jet set on my 350 now bored to 459, i received my jet spec's from HMF's forum. They had no issue giving me jet numbers. Quote Link to comment Share on other sites More sharing options...
TheAlaskan Posted December 8, 2010 Share Posted December 8, 2010 I hope he figured it out. He's had seven months to mess with it since he started this thread. LOL didn't even pay attention when someone resurrected this. Quote Link to comment Share on other sites More sharing options...
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