Ok, me and my friend got it started. 1st, the motor idles nice and smooth, but when i hit the throttle after ideal the motor bogs, then the rpms shoot up, also, when riding the quad, and keeping it at a steady rpm, like 5,000rpm in 3ed gear, the motor backfired alot. Maybee my Jetting is too lean? Im going to get a 200, a 210, and 220. But what is the off-idle bog??

 

try messing with your air/fuel screw, and also your pilot jet...

 

I show a stock main jet to be a 210, and I run a 270 with the FMF Pipe. It sounds lean to me on the top end.

 

This is LT250Rfatty im at my friends house.

Yea, ill look into it. My Manual says a 200 is the stock jet, and FMF reccomends using a 210. But i will see. Now, my Piolit is a 45, do you think its to lean which is causing the off-idle bog? The 45 Piolit is what FMF also reccomends. Ill get a 210, 220, and 230 and see how it runs. Any idea's on the Piolit size? 45 was also FMF's reccomended size.

 

your backfireing is your main, unless you at very high alt your main is tooo lean i am at 1000 i beleve and i am running a 280with various mods including a bore on my carb completed by me and my dremel. when your backfiring you are starving your engine of fuel!
is better too start out rich on your main and be bogging out at high rpm adn lean it out from there than to be too lean to start out and the real question is why are you having to rejett, was there problems before your not stating???

 

I have an 87 and went with FMF recommendations at first when I put on the Fatty Gold Series and silencer. I went with a 210 main and 45 pilot. It had a low end bog so I went to a 37.5 or 37 in for the pilot. I also run with the K&N air filter with the prefilter and the airbox lid off. It rips now.

I have checked the plug at all rpm's and it is perfect. Looks like a nicely toasted marsh mellow. lol

I raced a modded raptor and modded vforce 2 Saturdays ago and had no problem running with them on a 400 foot strip. I actually took the raptor several times. It depended on the start.