after I take off it will go away and run great. cold starts its fine, imediate hot starts, fine. let it sit 5-10 minutes and it pops thru the carb. S&S super B. It will stop after a 1/4 mile and idle perfect. What is wrong?
2007-02-22 01:12:04 · 4 answers · asked by Mark W 2 in Cars & Transportation ➔ Motorcycles
The only thing that causes "backfire", for those unfamiliar with the term. Backfire refers to "combustion" moving in the "wrong direction". Backfire, or popping thru the carb, comes from fuel/air ratio being "too lean". The Super B carb is a great carb but suffers from fuel evaporation from the bowl after the engine is shut down. When you shut down your Shovel the heat transfers from the heads to the carb via the intake manifold. This heat transfer creates a loss of liquid fuel and until the carb cools from running and receiving new fuel it runs in a slight vapor lock condition. The best cure I have found is to make a spacer out of phenolic plastic, the canvas based is the best, and install this between the intake and the carb. This will insulate the carb and your popping will magically go away. Match your ports, use about a 1/2" of material, a little more thickness will straighten out the fuel/air mix as it enters the engine, better low end torque. I even use a phenolic spacer on my EVO's as well as my Pan and Shovel. You will like the results. Ride Safe
2007-02-22 02:48:30 · answer #1 · answered by scooterdude1340 3 · 3⤊ 0⤋
Could be part blocked first-jet in carb. Try blowing thru jet.
2007-02-22 01:16:57 · answer #2 · answered by DAVE 6 · 0⤊ 0⤋
sounds like the carbs are over loaden or the points are needing replaced,,could also be a air leak round the manifold
2007-02-22 04:50:47 · answer #3 · answered by rusted 2 · 0⤊ 0⤋
pull carb out and check the jets
2007-02-22 01:19:11 · answer #4 · answered by l8model35 2 · 0⤊ 0⤋