Hi, just to continue the saga of my b40 engine running problem, I thought there may be a problem with the electronic ignition on my B40, the engine seemed to be running very lean/ hot and backfiring through the exhaust and sometimes even 8 stroking, anyway I've borrowed a electrix electronic ignition from a mate installed and fitted as per instructions, the bike again ticked over but would not rev and ran very hot, I advanced the ignition as far as the slots on the stator would allow and the bike now runs a lot better but still not right ( I maybe need to pull and refit the rota so as I can advance the ignition a bit more) anyway when I've checked the spark plug it's very wet with un-burnt fuel, anyone had a similar issue or ideas to fix it.
Have you checked the carburettor properly and cleaned all the fine drillings within the body? Have you got the recommended jets fitted and the correct ( or approx. correct) adjustment - start with 1 1/4 turn out with the mixture screw?
If so, I would be tempted to refit the standard points and condenser back. Start with a known simple system. Timing only needs to be approx. for these low stressed engines to run. I would take out the plug and adjust the timing so the points are opening perhaps 3/16 inch before TDC and try and start the bike. It should run at these settings and if so make any fine tuning adjustments from there.
Then report back.
Check assembly of the carb.
The original monoblocs, which take a thick O ring do not have a fibre washer between float seat and carb body. If one is fitted the fuel level is too high and can cause flooding.
The "new" monblocs, which take a thin O ring like the concentric, have a fibre washer between float seat and carb body. The body has a recess machined to seat the fibre washer, see photos of the "new" monobloc. Leave it out and fue level is too low.