anybody run into this

[slobell62]

Ever since I cleaned and reinstalled the carbs on my /2 I have problems that were not there before. 1) the idle speed will run steady for awhile and then drop down to an rpm so low you think its about to stall but it dose not and then recovers to normal speed. Then repeat the cycle. 2) When I shut down normally I close the fuel valve and run the fuel down some. Now when I close the fuel valve the engine immediately speeds up. Quite a bit actually .200 rpm maybe. I checked the seal between the carb and engine by spraying some starting ether around the seal and the engine did not speed up at all. I used a little rtv sealant on the gasket when reinstalling them so I really do not think there is a leak.Both these problems are likely related but what is going on? Any ideas out there ?

[Daves79x]

I assume you completely disassembled the carbs to clean? If so, then you must start from scratch to tune them. Set the idle screws so both JUST start to lift the slides. Then set the mixture screws (actually air screws) to the base recommendation. This is usually 2 to 2 1/2 turns out from seated. This is sometimes a problem because the threads are gummed up, not allowing full seating of the screws. This gives you a false setting. Make sure the screws are seating the whole way. Then run the bike on one cylinder at a time, slowly turning the air screws out until the bike stutters then in until it stutters. Your setting should be halfway in between, at the highest idle, then maybe an 1/8-1/4 turn in (richer).

Then sync your idle screws and your off-idle throttle cable sync. This is most easily done with Empi gauges. Unless you have a good, experienced ear to set these with.

All this assumes you got all the circuitry clean.

Dave

[Andrew]

Hi , if when you switch the fuel off whilst running and it starts to speed up it sounds like one of the may be not sealing correctly allowing too much fuel into the float chamber , so when the fuel is switched off the level of fuel goes down to a correct level . hope this helps . Andrew

[slobell62]

I followed the adjustment procedure as laid out in the Bing manufactures book and as Ausherman recommended as best I could.They are almost the same as you described Dave.I will try again. The "hunting rpm" must be something in the idle circuit .I think I cleaned them out pretty well.I feel like even if i didn't get the idle screw adjustment spot on I got it pretty close and that my slightly bad adjustment would not be enough to be the cause of this problem.
Maybe Andrew is on to something.Too high a level in the float bowl might cause one cylinder to flood slightly at idle and slow down and then speed up when it came down to the right level.But if the float was not closing off the fuel wouldn't it overflow the bowl eventually at shut down if the fuel was left on? Have to test that out. Anyway, thanks for helping guys.