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[Hugh]

Realise this is an Enfield forum but given we all are interested in classic bikes and I have an excellent Bullet as well I wonder if I could ask for advice on a 1970 A65L BSA pre OiF lightning problem? The bike starts really well and when warm ticks over fine except that it speeds up and slows down at what seems like pretty regular intervals on that tick over. There is no choke on the bike as just reimported from States where the West coast climate (bliss!) probably doesn't need it. The bike appears to be in good mechancial order from my observations so far so am wondering where to start and what to tick of inturn on a check list until I resolve it. Its been rebored so is running in. Naturally I am concerned if drive it if I coulod do any damage. Any help appreciated and regards to all, Hugh

[Noel (ogri)]

My suggestion is to check your float height

[Paulk]

Hugh, You could do worse than read http://www.hitchcocksmotorcycles.com/mo ... in-engines - don't worry about monoblock/concentric, in tuning respects they behave the same - pay attention to the pilot jets and throttle stop stuff. If you don't have the chokes installed blank off the holes where the cables would have gone. After that get a strobe on the ignition to check the timing and the advance/retard. After that it could be worn slides, worn body, air leak manifold side. If you do a plug chop after running at 50-60 mph and the colour looks ok you are more than likely not doing any harm since your issues are at tickover.
Better still find someone with experience with setting up twin carbs and bribe them with drink.

[Alan R]

Hi matey-------That rise and fall of the idling speed is known as "Hunting"...usually associated with a vac.leak on inlet manifold (Probably from the re-build etc ??)-Is there a vac. balance pipe between the two carbs. and between them and the cyl. head ??-....Try spraying WD40 over the outside and listen for a change in idling speed.. But here's a couple of "quickie" checks to try first}------a)Remove air filters, check that both slides lift and lower together (using the two kitchen matchsticks technique ).... b)Try rattling the slides with your finger one at a time..Are they sloppy ??...Now start engine and let it warm up...Repeat b) again--if there is any change in idling the slides will need renewing...

[Hugh]

Just to say thanks to all for the comments. Hugh