Just bought a clean '87 Honda TRX250R, bone stock except for K&N filter and no air box lid. I bought a FMF SST pipe and FMF power core II silencer for it. Does anyone have an idea to what is the correct slow and main jet to install?.....and what really works? FMF website says, 58=slow jet, 158 or 160=main jet. I have been told they bump it up on the rich side for liability reasons. Any suggestions would be greatly appreciated. Thanks!

 

Mine was about 155 when I had that same set up.

 

I agree with dragracer,155-158 main, 55 or 58 pilot.You can rarely get perfect jetting specs when your asking anyone in the country for advise.However this is a good baseline to start with.Elevation,temperature and humidity are all factors that effect the performance of your quad with any one carb tuning.