Backfire should be normal
 

Most buggys have a one a piston engine via a 150 to 250 and if you have your foot in it and let off the gas quickly it has or is still receiving fuel intake to that point and excess gas has to be expelled so it will bang pop or boom!!!If you fill it is excessive let the brains here know to help you. mancoman

I run on the lean side and always have popping and flames trailing my tailpipes- I agree -perfectly normal for a gutted or performance/low restriction muffler.

Not sure about this none of mine backfire unless I have an exhaust leak, that is 150's, 250's, 400 2 strokes, and 500's

The richer you run a carb the cooler the spark plug,head,piston,exhaust pipe,ect...thus the lack of heat from these items to ignite the vaporized fuel after throttle release remaining in the exhaust system. Running a hotter plug (as I do in most my engines) contributes to this also- there is a fine balance when it comes to jetting,air/fuel mixture screw,spark plug combination and the wanted throttle response for tuning- My Harley is a prime example of this and the lean burning condition I prefer to have the best throttle response. All of my tail pipes run tan/gray due to this tuning method. This habit came from my racing days-
****You have to be careful when doing this to avoid a burnt piston though.****

This is off a 2001 Ken Bar Streaker 2 seat buggy that had a paper covered with a foam filter exhaust.It was powered by a Tecumseh 10 hp with a fuel pump and was very fast on the road as it was rated high performance.It was built for speed and was not an off road buggy and the foam filter was to be dipped in engine oil and excess to be gently squeezed off.This engine would backfire at times like a car or truck like a shotgun and it was 100% all stock with no mods period. mancoman

Mine was the top picture oval 3 stage exhaust including the paper- foam and cover with wing nut.The engine was the HM100 and it backfired when downgrading by letting off the gas and slowing as that was the reason to lube the foam filter cover.How a man could have all these buggys and never have backfires:dunno:? mancoman