B31 ignition problem & gearbox question

[Bambridge]

I have just finished (or rather I thought I had) completely rebuilding a 1956 B31.  I was pleasantly surprised (amazed) when it started virtually the first kick.  It spits back (flames) through the carb fairly regularly but runs basically well and starts very easily.  However when I advance the ignition it instantly dies like the spark has gone.  It starts too easily to believe that it is over advancing and I can only think that something is happening in the mag (which has been professionally rebuilt).  I hope someone can help please?

My second problem is that the kickstart pawl jams (not unusual I know) but I would rather not have to take the whole gearbox out to replace it so can I take the side of the gearbox off complete with the kickstarter in situ?

Thanks in anticipation.  Dermot

[idie]

It sounds as if it is timed to far in advance . Yes you take off the outer cover to access the kickstart quadrant and gear. It is usually the first tooth on the quadrant that wears. If replacing any parts on kickstart make sure that they match. You can get parts with pointed teeth or flat topped teeth if mixed they tend to lock up.

[morven21]

D'accord. Had same thing with mine, wayback, too advanced. Reset ignition back a bit. Just trial an error, really. You'll know if on right track when keeps running on "max advance", an engine slowsan plods on retard.

[Bambridge]

Thanks to both of you - I will re-time the spark later.  I did not think that it was the timing advanced because it does not kick back as previous bikes have done if so far advanced.  Just goes to show you learn something new every day.  I let you know how I get on.

[Pete C]

while you are retiming the ignition you might want to double check the valve timing. Flames  through the carb suggests the inlet valve may not be closed fully when it sparks 

[idie]

Very easy to get the timing marks one tooth out. Did it myself last year on my B33.

[Bambridge]

Thank you all for your advice.  The valve timing was spot on but the timing was out as was the points gap.  The engine now runs sweetly and today the gearbox comes apart to replace the kickstart quadrant - that's an expensive part isn't it?  Cheers Dermot