[lt250r]

I have a 1996 formula III 600 triple with 2600 miles on it. It runs but not very good. When you put new plugs in it it runs great a couple minutes and then it starts backfiring and smokes and does not run right. It starts up and idles but when you try to take off it just backfires and doesnt hardly move. I have cleaned the carbs out good and found the third choke was stuck in it. I cleaned it out and put it back together. I took out the rave valves and they had a lot of black oil on them but no buildup. After all that i put new plugs in it and it took right off but then after a couple minutes it did the same thing. Maybe the choke is still stuck. Any ideas??? Please help. Thanks.

 

[Snowsk5054]

I dont have much experience in this area, but my dirtbike did that when I left the choke on and started it. It backfired alot then just died. I called my mechanic and he said that my spark plug is shot or I have gas in the crankcase. What happens is the crank gets going and it then ignites the gas which creates a backfire. I dont know if this is true, but I did drain my crankcase and add new oil to it and put in a new plug. It didnt backfire once since.

Enough with the story, drain your crankcase, fill it with new oil, get new plugs, and check your choke, Just in case.

I dont know if this helps, but good luck to you, and dont take my word on it.