01' 426 backfire issue

my neighbors 426 has been sitting for about a year and i decided to take it off his hands. when i run the bike it backfires excessively and runs extremely hot. ive checked the valves, they are ok, changed the oil, cleaned the carburetor and jets, adjusted the idle screw, put new fuel in, checked the coolant and air filter. the one thing i havnt done is adjusted the pilot screw. i dont know the factory number of turns so i havnt touched it. could that resolve my problem and is there anything else i should look for?

I think my pilot screw was turned 1 3/8 out from the factory. But the weather changes daily and so does my fuel screw setting. Turn the fuel screw until the response feels crisp and make sure you don't have any exhaust leaks. A properly tuned YZF will still have a minimal amount of popping and backfiring, so don't go crazy trying to fix all the popping.

I had a 2000 426-raise the needle one clip- I will still backfire but not as much. Usually on heavy deceleration,plus it scares the crap out of some people in a race and they even move over.

have you checked the hot start? When I crank the bike using the hot start button it will backfire excessively until I push it back in. It might need adjusting or be stuck or something....just a thought maybe it will help

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