I rebuilt my B40 last year but didn't do much to the engine which I believe had been rebuilt in the recent past.
I haven't put many miles on it but decided to change the oil, check valve clearances ( which were way out - too tight!) and points gap.
The points gap was about 20 thou and there was no way I could close them by sliding the fixed point so I slightly enlarged the slot on the distributor body and that gave me enough adjustment. However, with the gap set to 15thou the performance dropped off greatly.
So, probably too retarded. I then noticed one of the balance weight was loose in the bottom of the distributor.
Questions:
1. How do I strip the distributor? I cannot find where the clamp screw is to remove it from the bike.
2. Can I leave the body in situ and just remove the base plate?
3. What is the best way to time the engine. I am hoping I can repair the advance mechanism but if not - any advice appreciated!
Had another look at it today - think I've sorted it.
Took out the distributor and removed the cam and springs. One of the weights was not attached to the cam plate - I bet it had been like that for some time when it was last dismantled. Nothing broken so everything replaced, points gap set, replaced and retimed as best I could with a rod down the plug hole to indicate 1/16 inch btdc. Different bike now, lots of power compared to before.
2 things to say:
Points gap is a ball ache with the distributor on the bike - still difficult to maintain the gap when doing it on the bench so a bit of trial and error to get it right.
Tappets- another pain in the proverbial. Found it easier to remove tank and drop carburettor a little to gain access. Even then difficult to hold the little square adjuster and do up locknut. Also had to bend severely 2 feeler gauges for access.