I just installed my 39 PWK and got the jetting set. I went out for a ride and we covered about 20 miles and everthing was good. Going down a dirt road to another trail, we were running wide open for about half a mile and it started to bog slighty like I was runnuing out gas and then it just shut down like you shut the key off. I coasted in and let it cool a little bit and pulled the plug. It was still a nice medium brown. I also checked the spark and it looked good also. I also put a new plug in it while I had it out. After it cooled I tried to start it and no go. I'm going to get a compression gauge and see what I have for sure but you couldn't keep the hole covered whith your finger when I turned the engine over. Any other suggetions on things to check.

 

Are you sure you have spark?

 

Sure did, nice and strong to. Can you and what happens if you break a reed pettle? The reason I ask is that I remeber it doesn't seam to suck air as strong when you crank it with the air box off. Before you could here it suck over the starter when you would crank it without the airbox on and now its not as noticeable. Hopefully I can get to it after work tomorrow, do a compression check and pull the reed cage and check it out.