April 23, 201214 yr Hi guys My beta 4T, when ride at medium speed and I shut off gas i can hear some "bangs" through the exhaust.. Is it that normal? or should I tune up the carb in some way? Thanks mates.
April 24, 201214 yr Run the engine and spray some starter fluid around the carb. Wiggle the carb and see if the idle changes -- to find the air leak.
April 24, 201214 yr "Bang"? Like a loud popcorn popping sound? Perhaps several in a row? If so, this is a common sound when shutting down the throttle on the Evo 4t, especially when going down an incline. My only sugenstion is to ensure your jetting is set correct. I had to adjust my pilot and main jet as the bike was too lean and the popcorn sound diminished a fair amount. The air boots on the carb are "hard fitting" and the front boot can shimmy back causing an air leak. So, double check that fitting and don't over-tighten the boot clamp as it will cut through the boot in a short time if too tight.
April 24, 201214 yr Needle in 4th or 5th groove and fuel mixture screw 3-4 turns out may help and check for air leaks in intake system.
April 26, 201214 yr Author Thanks guys! it was an air leak between the carb manifold and the carb union hose, the hose clamps were too loose and the carb was a little backwards. I pushed the carb in place, tighten the clamps a bit and... problem solved! Edited April 26, 201214 yr by trialholic
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