Went riding this weekend, only put on about 100 miles because the machine was running crappy! I could only give about 3/4 throttle before it would break up real bad. It was fine at first, but when we got to about the 20 mile mark it would start to spit, sputter and stumble on wide open throttle. It would be worse under load as if I was going up hill? At about 35 mile mark I put gas in thinking I was running out of gas, and I put in 3 gals. This concerned me since that averaged out to about 10-11 miles per gallan, which is way under the norm. At about 50 mile mark we stopped and were taking a break and I looked and found that my stupid FST intake came partially off the carb (I modified the air box as the instructions say and can still not get it to fit great?). I put it back on thinking it would solve the problem and it did not. Now After we stopped for lunch it seemed to run better until we got a couple of miles down the trail it started up again. It did this for the rest of the trip.
It was off and on rainy and the trails were a little wet. I hit a couple of puddles but did not come up past the axles. The air temperature was about 40 degrees. I checked the plug when I got home and it was a little on the dark side but not fowled out. It never started hard or stalled on me.
Please help as I am stumped. Could I be flooding it on the wide open throttle, or could I have gotten something in the carb when the air intake came off? Any thought s are appreciated.

Thanks for your time in advance.-Seth

 

Sounds to me like you have a partially blocked jet inside the carb. If the intake boot did in fact come off, it is likely that you sucked something inside. I believe on the newer syle carbed bikes, you can loosen the screws on the boots and rotate the carb around in order to drop the bowl. Do this, give a look see inside and see what you find.

Good Luck.

 

Yes that is one of the things I will check and yes the carb can be rotated to drop the fuel bowl. THat is how I changed the jets when I did. Thanks for the reply.

 

Sounds just like what happened to mine. just got it back from the shop. they took apart the carb and found something in it. When it was cold it ran fine but when it warmed up it would suck it into the jet and then it would run just like you described. Now it runs fine just took a hundred dollars to find the problem.