Bing leak gone!

Restoration forum Bmwbike.com
Post Reply
Pierre Michaud

Bing leak gone!

Post by Pierre Michaud »

I decided to check out my assumptions vis a vis the float level and added one brass nut (M3 by 3,15 mm thick) together with the 1,55 mm washer supplied with lever top. The leak stopped but ended up starving the engine on the left side due to low petrol level. So I decided to remove the lever tops, clean them really good, action the shut off valve up and down thinking perhaps the new lever tops needed to be "broken in". I sprayed some WD 40 on the unit as I was actioning the lever. I then put the lever top back on the carb and opened the pet cock. To my amazement no leak even after leaving the petcock on for 30 minutes. I then shook the bike left and right front and back and again no leak. The idle air screw is still bone dry. So I guess what was happening is that the shut off needles were binding somewhat and are now working properly. Having remedied this situation I then proceeded to balance the carbs. The operation went well but now I am faced with another problem. When the engine was stopped (had reached it's normal operating temperature) and restarted, the RPM started normal at idle but then started to speed without warning to the point I had to turn it off as there was nothing I could do to slow it down fast enough. I started it a second time and it started racing again. Does this sound like a centrifugal advance sticking or is it carb related? The idle on both cylinders is perfect when they run separately from each other....It's when I have them firing together that they pick up rpm. I have the proper slack in the bowden cables.
Allan Atherton

Re: Idle (was Bing leak gone!)

Post by Allan Atherton »

It sounds like you need to back the idle adjustment screws out until each cylinder barely idles by itself. Then when they fire together, the idle speed will be proper.
Post Reply