This is about my sled but could be buggy related. Last year I blew up my sled engine, so I rebuilt it. I did a complete overhaul on the engine chaincase and suspenssion. Everything was new, bearings, seals, gaskets, fuel lines, oil lines and filters, plugs. Everything!!
It has had a bog issue at around 6500 rpm from the start since it was rebuilt. I cleaned the carbs 4 times all together, I cleaned the clutches, I changed the clutches, I changed the clip setting on the jet needle, I checked the timing, I tried eveything and nothing worked. After exhausting all of my options and after being extremly frustrated, I was sitting having a rum, that seems to fix everything, and thought, the only thing that I didn't do was change the plugs. But why should I they are brand new. I changed them any way. Guess what? It purrs like a kitten now. Must have been a dud from the factory