ok thanks for that i had a bit of luck today i went to my mates bike shop and the mechanic said to me that he had an old crm carb somewhere i went back this afternoon and hey presto he found it its got PE31C on it same as mine so im going to do a swap and see if that works and if it does he wants £25 for it.Im off a few days next week so will look at it then,going to leave it alone till then as im getting the ache with it and that leads to me loosing my temper and getting my big hammer out.Cheers for all the help guys

P.S could the reed valves cause a problem with tickover issues im having

Possibly if they are not sealing. New Boyesen Reeds are an inexpensive investment.