My NC29 was doing something very strange

If the bike is left for 30 - 60 mins after riding it wont start, it turns over fine, bump it and it goes fine. Leave all day or over night and its fine.

Replaced the starter motor - no change.
Cleaned and rebuilt carbs - no change.
Cleaned and tested start/stop kill switch - had two at the time - no change.
Cleaned connector on Computer - no change.
Cleaned connectors on starter solenoid - no change.
New batt and regulator - no change.
Started bike from alternative batt - car - no change.
Checked fuel flow - fuel always in carb - petrol cap open to stop air lock.
New fuel filter - no change.
Checked pick up coil - within tolerance.
New plugs and leads last year.
Checked side stand and clutch switch - both fine

At this point was getting a bit miffed, and was thinking valves duff or rings gone.

As I cant fix that heavy kind of thing I decided to start with the electrical stuff and connect my DVM to the Pick Up Coil and leave it in the boot of the bike. Connected up all the time as I rode around.

Guess what - after trying for nearly 7 hours for the thing to NOT START. The coil finally went open circuit. After 10 mins it went back to its correct reading and the bike started again.

I think it was latent heat from the engine seeping through the case, ride around and it was fine as the left hand casing is exposed to the air flow. Stop and the engine continues to heat up and as the heat dissipates thru the engine case the coil picks up this heat and goes open circuit. When the engine is cool its starts again.

Replaced and PROBLEM SOLVED!

Well done tracking the problem down. I'd have given up by step two! Lol

Excellent work, sorry I couldnt give praise earlier been working.. Its give me the idea to check my coil.

good one

Durka Durka wrote:Excellent work, sorry I couldnt give praise earlier been working.. Its give me the idea to check my coil.

good one

Cheers for that.

I think I got lucky trying the pick up coil first.

I tried that first as it was easy to get to, I didn't have to remove the tank whilst I connected it up just held it up with a large handle screwdriver.

I was on the verge of buying a new CDI - but as I could repeat the fault over and over again I kept thinking it was a heat related problem.

As a result of rebuilding the carbs the bike now starts better, idles better and runs better. On my first test run the pick up from low revs was superb, before it felt bogged down and sluggish till the power came in.