I have a 98 400 Scrambler that just died on me. It has a pipe, clutch kit, and .20 over. I wanted to try a bigger carb so I put a 38mm flatslide on it and modified the air box. It seemed to be running great for about 30 min and it died and will not start. I have fire to the plug and the gas line flows fine. I even put the old 34mm back on it and still no luck. The reeds look okay also. Any Ideas?
Would low compression cause this?
Is having a bigger carb going to be a problem?

Thanks

 

Well the 38 has a reputation of having a very lean midrange.You will most likely have to do a compression test,under 100psi and it will not start.Was this 38 on another 400 ? Oh, welcome to the forums.

 

Yep, I bet you where running too lean and cooked the piston. Was the ceramic on the spark plug white? When setting up the new carb its always best to go very rich with it and work your way down, doing plug checks often.

 

It was new in the box. Main jet is 230, needle on 3rd clip.

 

Sounds like it's Wiseco time.

 

Sounds like u fried it.......

 

Well Boys, after deeper research and a compression check, I have a 10 inch crack in the crank case just below the head bolts. So I quess a rebuild is soon to follow.