BSA C15 Non Starter!!!!! HELP NEEDED!!

[Paulo]

Hi

3 weeks ago i installed an electronic ingnition unit on my C15. The timing was spot on and it didnt give me any problems. The other week a friend of mine (who rides a jap bike) had a go on the c15 and came off it!! It hit the ground hard.

The bike ran for about 15 miles after that but it konked out when i was on the way back from work. I now cannot start the bike. I have tested for a spark, but when i place the plug on the crank case and kick it over, there is no spark between the plug electrodes!! However, if i move the plug away from the engine (not touching it) I get a spark from the plug to the engine. Is this normal?? Is this causing it not to start or should i be looking elsewhere.   

thanks

Paulo

[L.A.B.]

Have you tried a different spark plug?

[Paulo]

L.a.b

yeah, i have tried 2 plugs and i get the same thing.

thanks


Paulo

[twolitre]

However, if i move the plug away from the engine (not touching it) I get a spark from the plug to the engine. Is this normal??

To get a spark from the plug body to the engine is not possible with a sound plug unless the points gap is closed up (except with phenomenal voltage and then it would have to jump the points gap also). You MUST have faulty plugs with either cracked insulator porcelain or some deposit on the porcelain insulator allowing the electricity to track down the outside from the cap to the main body. Check that the insulator porcelain inside the plug end around the centre electrode is not cracked.

[Rex]

Sounds like the plug is fouled and shorting. I agree with the other posters, try a known-working plug..

[Paulo]

Hi all.
thanks for the replies!


I put a new plug in. As i held the plug cap ready to check the spark i switched the ignition on with the key. This gave me a shock!

I put the new plug against the engine with both electrodes touching the engine, kicked it over and i did get sparks in the plug gap (all be it weak..) I then replaced the plug and cap and kicked the engine over, it fired about 4 times then died again. And now nothing. The new plug is known the work, but this again was sparking to the engine when a few cm's away!

I am going to replace the ignition plug lead tomorrow and see if that does anything. The horn and lights are working fine and the ignition is electronic so i cant understand why the spark is weak and intermittant...

[Paulo]

Got a new plug, a new 5k resistor cap. Have fitted them and still get a weak and intermittant spark so the Engine wont start!

Could it be an earthing issue? All the connections seem fine. I am pulling my hair out now..


thanks

Paul

[wernstriumph]

Maybe when your friend dropped the bike, something bent and is now pinching a wire causing an intermittant short. Possibly even a dented coil or a faulty kill switch.

[twolitre]

I put the new plug against the engine with both electrodes touching the engine, kicked it over and i did get sparks in the plug gap (all be it weak..)

What do you mean by "both electrodes touching the engine"? Neither of the electrodes should touch the engine! The normal thing is to lay the plug BODY (the bit you turn with the plug spanner) on the engine, making sure the terminal and plug lead connector are clear of the engine. Then observe the spark (or lack) as you crank the engine.

Twice in my life I have been faced and stranded with roadside failure of electronic ignition. Consequently my bikes have straight-forward contact breaker, condenser and coil ignition which is simple to check out at the roadside with just a bit of scrap wire. Having said that I have never had to. Maybe with fancy engine management systems there is a good case for electronic systems, but on older basic engines?

Oh, and they both always start first kick, though they are both over 50 years old.

[huron]

Hello non starter,
At any rate there is voltage on your wire when you turn the ignition key on.You said you felt something.You are trying to kick start a BSA with no E-starter.Right.You didnt say who made your electronic ignition.Maybe it has a timer in it that shuts off the thing after awhile?Did you try a direct wire around all from Battery to ignition ?Is your Battery OK?
Will it start if you push it?
huron

[Paulo]

Thanks to all posters.

Hi got a new plug cap, checked my wiring, mended loose connection and found an OLD Champion Plug that i hadnt tried. Hey presto, It started.
I got a decent idle but at medium revs, there was popping and back firing in the silencer!!

The timing shouldnt have moved since the installation of the electronic ignition! I can only put it down to the spill my mate had. Its a Pazon System so it has the capacity to advance or retard on the ignition plate. I'm sure i the timing is set at 7mm BTDC. Is it wise to adjust the timing by advancing or retarding the ignition plate or is it best to re-check the timing again?

cheers

Paulo