C10 Staring problem when warm.

[Rick Rybicki]

Hi, 1946 C10. Runs well. Usually starts well. But when it's warm.......you can kick hell out of it and it wont start. Leave it for an hour or so and it starts, sometimes with difficulty??? Leave it overnight and it starts with 1 - 3 kicks.
Do I prime the carb?    Yes.
Have I cleaned and gapped the plug? Yes.
Does the plug spark outside the cylinder when tested? Yes.
Do I have a heat resistant gasket between carb and cylinder? Yes.
When running, does it run smoothly? Yes.

The problem seems to happen mainly on very warm days. Any helpful suggestions please. And no, I don't want to carry a bucket of cold water around with me! Although, this morning, after my visit to the Doc's I would have happily drowned the damn thing. Went with a van to collect it a few hours later and after quite a bit of effort it started. Rode it home, stopped it, wouldn't re start!!!!!!!

[idie]

It sounds as if the coil is breaking down when hot or the condenser is failing to earth. It could also be something as simple as the spark plug. All easy to change.

[Rick Rybicki]

Hi Idie, thanks for that. Yes, I'll check the earths but just for a thought.....Coil,......the plug was sparking outside the cylinder when the engine, and therefore coil, were hot. Bike was running perfectly well before I stopped it. And as above for condenser.......I'll start with a new plug and work from there, although I've had two different (old) plugs in there and they've both had good sparks outside the pot and it did start with one of them in after sitting a couple of hours.
As a p.s. I've just tried to start it after about 3 hours standing.....and not a pop.
Cheers, Rick

[Blackthou]

Understand your frustraion and all the good points you put forwards.

How about doing a compression check? I knew once of a similar scenario that turned out to be an exhaust valve seat.

[chaz]

does it run ok when colder days? maybe fuel is evaporating in the carb. is the tufnol plate thick enough?

[idie]

When you check for a spark outside of the cylinder there is no compression so no load on the coil. When sparking in a combustion chamber the coil has to work hard for the spark to develop. If the coil is breaking down the spark will be weak and basically the compression is stopping it from forming.

[Greenfield]

It sounds like classic symptoms of fuel evaporation either in the carb or fuel line. I don't know your starting procedure, but if you flood the carb both hot and cold you will find out if its fuel or electrical. I suspect there's a simple solution to this rather than dismantling the entire engine!

[TTJOHN]

You mention everything, bar he obvious, to me anyway, have you checked the points gap? That sometimes can give this sort of trouble but as someone has already said the next thing would be condenser.

TTJ

[Rick Rybicki]

Thanks Guys for your suggestions. I'm going to start working through them today. Starting with the easiest and least expensive. Plug, condenser, extra heat resistant gasket on carb. Just about to call Draganfly!
To answer some points raised, I'm not equipped for a compression test unless someone has a Heath Robinson solution.
The bike generally starts fine but when warm can be unpredictable. This time it's become damn near impossible!
When its running, it runs smoothly. No misfiring, no popping back on the overrun and doesn't kick back when starting it.
When I had the head off a few months ago, the bore, piston and rings were good, and there was no evidence of bad valve seats.
I'll be happy to hear any further thoughts and I'll report back on results. Cheers, Rick.

PS. TTJohn, Thanks, that will be on the list when new condenser, coil, carb heat gasket arrive.

[Rick Rybicki]

Right Guys, new ignition components and carb insulator ordered. This may sound like a daft question......but I'm asking it anyway. I've ordered a new ignition coil. As you will know, it hangs from the left side of the fuel tank. A new shiny coil on an unrestored 70+ year old bike will stand out like the legendary bits on a bulldog. Question, is it OK to paint a shiny new coil? I'm pretty sure it is but just checking. Cheers, Rick.

[idie]

Yes it is just a case. The coil part is inside.

[Rick Rybicki]

Cheers, Thought so. R.

[Rick Rybicki]

Hi Guys, well I said I would report back. I know it's been some time but believe it or not, I've had issues to deal with that are more important that the bike!
Fitted new points, coil, condenser, plug and a extra heat resistant gasket on inlet. Sorted. Starting easily from cold and at a range of temperatures. Running like a "Ten Bob Watch".
Thanks for the advice. Rick.

[Blackthou]

Well done. Must be very satisfying for you.