1996 440 backfires under certain conditions
I have a pair of Arctic Cat 440s (ditch pickles, as someone recently pointed out to me) one '96 and one '97. I just got them last year from a relative, and they needed quite a bit of cleaning up to get them running after they sat (with gas - yikes) for 3 years. I completely disassembled the carbs and gave them a thorough cleaning, new gas lines, filters, plugs, etc etc. They both run great now with the following exception:
When warm, with back pressure (medium-hard deceleration, braking, etc) the '96 will cut to a very low idle and sometimes backfire. When I say "cut" I mean that it's very immediate - almost seems like the kill switch was hit, but it doesn't quite stall, just drops to a lower idle than normal (600rpm?) and backfires. This only happens when it's several miles warm. Slight pressure on the throttle while slowing or braking will prevent this, or recover from it if it starts happening. It's performing fine otherwise - plenty of pep.
This was happening last year too. Tanks and bowls were drained last summer, and they started easily this season with new gas and plugs. The Mikuni web site or carb manual didn't help with this particular problem, but it's a little bit of an oddball as far as I can tell. Any help would be appreciated.