PlanetMinis Forums banner
1 - 5 of 5 Posts

·
Registered
Joined
·
4,659 Posts
Discussion Starter · #1 ·
I know there are many many threads about this, but, they don't help me. So the build is: TB 88 kit with race head and race cam. Using 0.38mm head gasket. Using original ShengWey 20mm carb. and the TB dual stage air filter without the red prefilter. ProCircuit T4 exhaust with the spark arrestor removed. Jetting is 95 main, stock pilot, needle in 4th position from top or 2nd position from bottom. Air screw 1/4 turn richer than factory setting. Running on 93 octane gas at 300 ft above sea level. Runs fast as hell but backfires like crazy upon decel. When I pulled the plug, it was white as paper. So white it scared me that I was running my new high dollar motor that lean. So I'm using the biggest main in the jet kit, how do I make it richer? Or, if you know, how do I make it run at the correct mixture?
 

·
Registered
Joined
·
213 Posts
^^^ Also I had a leak between the head and the cylinder. I used a lot of High Temp silicone gasket stuff to fix it. It was sucking in air and making my plug white. I only noticed that because it started leaking oil eventually. I'd thought I'd share that as the symptom you describe are very much like what I had.
 

·
Registered
Joined
·
4,659 Posts
Discussion Starter · #5 ·
I checked the exhaust gasket. It was damaged a bit (don't know how) so I replaced it. It didn't show signs of leaking but it was run for such a short time it might not have had time to leave any evidence. I will check for intake and head gasket leaks just to be safe but I don't think I'll find any. I also took the advice dirtbkr188 sent me. He said that my main problem was in the pilot jet. A quick remedy is to run the air screw pretty far in (appx. 1/2 turn out), and put the needle and main jet back to stock. I did adjust the air screw and it made a world of difference. Better starts, smoother idle, light tan color on the plug (still a tad lean I think). I did notice a slight blubber as it revved out, I'm assuming this is because I still have the 95 main instead of the stock 89 Tim suggested. I might pick up the TB pilot jet kit but I'll decide after I try a couple more things with my current parts selection. Thanks a lot for contributing.
 
1 - 5 of 5 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top