HEY I HAVE A 2000 TRAIL BOOS AND I AM PUTTING A STAGE ONE KIT ON IT .THE KIT INCLUDES A NEW JET .AND I WAS WONDERING DO YOU HAVE TO TUNE IT UP OR SET THE AIR TO FUEL RATIO .I WAS JUST WONDERING IF I NEED TO DO ANYTHING IF I PUT A NEW JET ON ..THANKS FOR ANY REPLIES :MIKE

 

I am not an expert in jetting but I have dabbled a little so I will give you my understanding of it.
When rejetting there are 3 areas to be considered WOT (wide-open throttle) MRT (mid range throttle) and LRT (low range throttle). The jet in your kit is the main jet and it only comes into play in the top 1/3 of your throttle range.
Starting with the LRT, run the engine until it is at normal operating temperature. Adjust the pilot jet on the carb so that the engine starts easily without having to jab at the throttle to get it going. Next install a clean or new spark plug and run the quad at near full throttle up a relatively steep hill, stop, remove the plug and check the colour. It should be a rusty brown colour. Black is too rich and white or grey is too lean. (Never run it for any length of time when it's too lean, serious engine damage will occur). If the plug is black install a smaller main jet (one size at a time and repeat the testing process). Now do the test at 1/2 throttle and check the plug again. This also should be a rusty brown colour. To change the air/fuel ratio at mid throttle remove the slide and needle in the carb and raise the needle to richen the mixture, lower the needle to lean it out. There is no definite lines between LRT, MRT and WOT as there is overlap between them. In other words adjusting the pilot jet (LRT)can effect the MRT and the same applies to the main jet effecting the MRT etc.
This whole process is trial and error and it takes time to do it right.
Altitude will effect rejetting so try to do the testing at the altitude you intend to ride. If you ride at different altitudes set the jetting for the lowest altitude.
That’s a lot of words, I hope it makes sense

 

see my friend had a trail boss too and when we put a new jet in his we just swiched them and that was that ..his bike seemed to run fine ..and i was wondering if it was ok to do it that way or do i have to do anything else..thanks:mike

 

The instructions Rick sends with the RCR stage 1 kit tell you to turn the screw out 1/4 to 1/2 turn. If you havent turned it enough, it will backfire when you let off from a WOT run.

 

thanks for the replies