Hi,

I have looked through the forum for an answer, but cant seem to find it. After running the bike for a while the engine idles very fast. I have no control over it. There is no choke on this bike, is this the problem.....?

Thank you.

Hi Glen..Not fitting a choke slide assembly won't matter in itself. However, you have to blank off the hole in the top of the carb where the choke cable adjustment screw fits..air will be drawn in here weakening the mixture and speeding up the tickover.
Also check for air leaks at the carb flange and that your head gasket is good.(I would recommend a solid copper one torqued down to 28-30 ft. lbs.)
Check also that when hot the slide is returning to the 'fully down' position, that you have clearance at the exhaust valve tappet when hot and that the exhaust valve lifter has sufficient clearance under the tappet head. The last two items would probably cause a lack of compression as well if not set correctly, if you are not experiencing this leave them till last!....Ian

email (option): ian@wright52.plus.com

Ian,

Thanks for the quick reply. The hole at the top of the carb was blocked. Currently have the carb apart. I am restoring the bike and firstly want to get it running correctly. I am replacing the slide / choke assembly but not sure which slide is correct also have a 170 jet is this correct...?

The carb is a 276DR/1AT is this correct for a 44/45 m20

Glen

Hi Glen..Slide should be a 6/4 (no.4 cutaway).They are marked on the top face by the needle clip. A 170 main jet is correct for an M20....Ian

email (option): ian@wright52.plus.com

Ian,

The slide is a 6/3 would this be a problem. I have just found a blocked passage in the jet block which is part of the piolt air adjustment. would this be the cause of the high idling problem.....?