87 Aspencade 1200 backfires between shifts and backfires deceleration and acceleration. Have had carbs cleaned and replacement kits installed. new spark plugs. synchronization of carbs also. Checked compression and timing. New fuel filters and checked fuel pump.

I suspect the carburetor needs tuned to correct the air-fuel mixture in the mid-range.It's possible that the carb
was not thoroughly cleaned and/or the fuel system upstream of the carb was not cleaned and has re-contaminated
the clean carb.

This sounds like a fuel flow problem. I suggest removing and rebuilding and cleaning the entire system, meaning Carbs, filters and strainers in the tank. Old fuel turns to gel, and floats absorb fuel, sometimes, so inspedt everything. When finished set carbs with carb sticks, both at idle and at 2000 RPM, using hand throttle.

The most common reason for backfiring is lack of back pressure from changing the exhaust. To compensate for the flat spot you get you put in a jet kit. This leaves the possibility of more unburned gas getting into the exhaust. Honda uses Kei Hin carbs with a fuel shut off diaphragm to help limit this condition (backfiring) by turning off the fuel to the carbs during deceleration. Even stock exhaust can pop or backfire. Typically it is caused by air getting into the exhaust either past the copper o-ring gaskets in the head or leaking muffler connections from the head pipes to the mufflers. Try replacing all the exhaust gaskets and you should minimize this condition.

A lot of backfiring on deceleration is related to reused or leaking exhaust gaskets in the head . The gaskets are leaking air into the exhaust. If you are experiencing carbon on the intake side , I would recommend replacing the intake o-rings and gaskets, spark plugs, and spark plug caps. These can all be related to backfiring through the carburetors.

Your idle mixture is too lean. You can adjust this by locating the mixture screw on the carb(carbs) and turning it counter-clockwise an 1/8th turn at a time. This will not affect running above 1/4 throttle, but will richen your idle circuit and the lean popping on deceleration. If you have misses above 1/4 throttle when accelerating, tou likely have trash in your jets and the carb will need to be removed and thoroughly cleaned.




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EASY!!!! sit at your kitchet table with some towels laid out. BUY a REBUILD KIT. Have fun : ) Easy

1. Check timing belts and ignition timing.
2. Service carburetors

You have a bent shift fork. The repair is major surgery by the dealer. Sorry for the bad news.

Sounds like you've got a carb with a clogged jet. My guess is that the surging was a moment where the carb was actually operating well enough for the bike to run properly on that cylinder. Could also be a spark problem but you should be able to determine if this is the case rather quickly. I'd probably go ahead and replace the plugs if you haven't already...that could help...but my guess is still going to be carbs.