starting a bsa b31

[caravan]

Hi
   Iwonder if anyone out there can give some advice on starting my bsa b31.
    The problem is when i take it out for a spin and stop it , it will not start when it,s hot .
   Starts first time when it,s cold.
  MY BIKE IS A BSA B31 350CC 1946.
            Cheers
             Tony

[BSAPhill]

Sounds like it maybe your carb, chck all the usual, Float height and the like, check the slide for wear and if the jets are correct.  Maybe insulate (heat wise) the carb from the head by use of a plastic spacer.

Check the timing if this don't work have the Mag checked over.

Or all of the above...

It will be something basic, Fuel evaperation is my fave, so once you have her just past TDC and the timing retarded, give the carb a good tickle and then go for it...

[TBS]

Sounds like a mag problem to me, so check your spark at the plug when the engine is hot and difficult to start.
 
Hugh

www.thebikeshed.net

[VintageBike]

Definitely sounds like the mag to me too.  Just had my Goldie mag serviced, and now starts well hot and cold.

Nigel.

[Bob McGrath]

Standard answer for your problem is a dying magneto, especially a failing condenser within the magneto.
You can fuffle about all you like and kid yourself a new sparkplug, fiddling with the carb, blah, blah is making things better but it is merely putting off the evil day you have a complete magneto failure.
Just get your magneto overhauled (not fiddled with) and you'll have good ignition for the next 50 years.
Cheers, Bob