Have fitted new points condenser and spark plug. Bike won't tickover, the air screw and throttle slide screw have no effect. The pilot jet is a 40 and main jet 123 as checked by Bultaco uk. I have had the float level and needle up and down no difference - bing carb. It starts first or second kick but just won't tickover yet you can keep it at a near acceptable tickover a speed on the throttle cable. It revs slowly. I took the silencer off (original big black thing) and was going to see dremel it and repack it but it blows through fairly easily and I just can't see it being that that is causing the issue. Any ideas? Where is the advance retard on these? I bought the manual but it makes a new 'cut n paste' Haynes one look impressive..Thanks P.S. we had it going in the field and it went quite well though, just seems low speed. The slide is well worn but it doesn't rattle.

hi,reading you have worked on the ignition it seems to me that the timing is incorrect possibly to retarded,check it out hopefully this will sort out your problem.

Taking one step at a time if you can make it tickover ok with the throttle then the issue is simply the screw is not adjusting the slide up enough to mimic the tickover?

The first thing I would do is replace the worn slide.

http://www.trialscentral.com/forums/topic/61138-stumped-by-my-sherpa/page-3

Yes I agree with but you can't and shouldn't have a cable hanging to get a tickover. I noted the cutaway is a zero and I am not sure what should be fitted to a Sherpa? It was a second hand carb and the guy fitted need some jets making me think it came from a pursang?

The Bing carb that was mounted to my Sherpa T 350 has a cutaway of about 5 mm.

never heard of a slide with zero cutaway. Is it fitted the right way around?

Zero is the number stamped on it. Think it's a bing thing but yes cutaway looks about 5mm.