I'm totally stumped on tryin to jet my 350x right. I've tried a 138, 145, and a 152 main and a 40 and a 42 pilot jet......still the same freakin problem. When I rev it up from idle to 3/4 throttle it wants to bog and backfire really bad. Could my timing be way way off or is it still the jetting?????? I'm just **** out of ideas so any help would be awesome. Thanks a lot. Later.

 

I would check your "fire timing"
check you valve adjustment
then check you mechanical timing

Check it all twice.......then rotate the engine 360 deg, and check it again!!!!!
One mistake I made on my first one was I didnt make 100% sure the timing was correct....I ended up timing everything on the "F" by mistake........onece I found that.........never again; I tripple check if I have even the slightest doubt it is off...one tooth makes a big difference.

 

I think that my timing was off a tad because I took the took the cam back out and put it in time again and it doesn't backfire while I try to rev it up. Now it wants to pop when i let off the gas after its been revved hard. Does this sound rich or lean to you? Thx. Later.

 

Classic symptom of lean idle circuit. Check for leaks in the intake, and exhaust system. If they look good, go richer on the mixture screw, and if thats not enough...youll need a bigger pilot jet.