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Doug E.
Doug E., Kawasaki Master Technician
Category: Motorcycle
Satisfied Customers: 2886
Experience:  Professional motorcycle mechanic since 1978. Vintage motorcycle restorer.
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Hi, i left my Triumph Bonneville 03 - 790cc Speedmaster running

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Hi, i left my Triumph Bonneville 03 - 790cc Speedmaster running on tick over and unfortunatley forgot about it so it ran for about an hour in hot weather, on my return it had stoppped and i cannot get it to restart, it has plenty of fuel. Any suggestions? Many thanks, Eddie
Hi Eddie,

You will need to check for spark to see if one of the engine electrical components overheated and you will need to check the compression to see if one of the valves stuck. If I had to guess I would say a valve is hanging open.

Let me know what you find.

Customer: replied 8 years ago.

Hi Doug, no spark i'm afraid, have checked all the fuses, they are OK, checked the HT leads they are OK, HT coils are OK (checked with multi meter). I'm a bit stuck now.

PS compression OK.

Well it's very good news that the compression is ok. The stator windings or triggering coil probably fused itself together from the heat. You might even smell burned wiring in the oil. (You should change oil by the way as it was so hot.)

I'm going to opt out and see if one of the guys who works on new Triumphs can get you the test specs for your bike. I only work on vintage models but wanted to get you pointed in the right direction. Good luck.

Customer: replied 8 years ago.
Thanks Doug, cheers. Eddie.
Hi Eddie,

I was out of town this weekend and was surprised to see nobody answered your question being I had already narrowed it down. As soon as I get to my other computer with a high speed connection I will download a manual and find the test specifications for you.

I think the coating melted off of the stator windings so you will need a multimeter to run a few ohm tests. I'll get back to you later today.

Customer: replied 8 years ago.

Thanks Doug, i have run a meter test on HT leads, they are OK, i have tested the ignition coils they are OK.

It might be the pick up coil unfotunatley Triumph do not release any resistance details, as there was no resistance i'm guessing it might be that, what do you think.


I tried to get a visual of the coil which is situated behind the alternator cover, but could undo the bolts OK but could'nt pull the cover off and was reluctant to use brute force, so i might end up having to take it to a garage anyway.


If i could have your thoughts about resitance on the pick up coil and any ideas on how to get the alternator cover off i would be gratefull.


Also am i on the right lines in tracking through the ignition system? as if its not the pick up coil it must be the Ignition control unit?

Many thanks. Eddie.


These are general numbers for pick-up coils on other brands.

Meter set to Rx100
400-490 ohms

When the motor is spinning over there should be a .5 volt AC pulse from the coil.

Those might not be the exact numbers for yours, but you are right in that you should get some reading from it.

Customer: replied 8 years ago.

Thanks Doug looks like its the pick up coil then as there is no resistance (pulse) so it look like an open circuit. Because i can't get the alternator cover off i'm stuck as it might be the air gap has closed but my best guess is that because it ran hot for so long its been damaged, is that a fair assessment?

At least if i have to take it to the garage i have done some of the diagnostics which should save some time, any other thoughts?


If it has no ohm or pulse readings then it is toast for sure. There may also be damage to other wiring but if you can't get the cover off, it's hard to say.

I don't have the manual so I don't know if there is a trick to pulling that cover or not. As soon as I can get a manual downloaded I'll check into that.

Doug E. and 2 other Motorcycle Specialists are ready to help you
Customer: replied 8 years ago.

Thanks Doug i am going to accept your answer so don't worry about the manual now, my gut feeling is the cover has welded itself a bit so i'm not going to touch it and leave it to my local garage to sort.

Might be an expensive lesson for me doing other jobs and forgetting about the bike but hey ho s**t happens, thanks for your help, Eddie.

It could be much worse. The rod could have fused to the crank and junked the motor. Let me know what they find out.

Customer: replied 8 years ago.
Will do, cheers XXXXX XXXXX Eddie.
The manual says that cover pulls right off, LOL. It's worthless for testing the ignition system so there must be a secret manual or maybe they pass that information down from generation to generation. Sorry I can't be of more help.


Customer: replied 8 years ago.
Hi Doug ,just to sign this off, it was the pick up coil and no other damage, bikes back now and running fine, expensive lesson but thats life, thanks for your help, regards. eddie.
Great to hear you are up and running. Happy roads to you!


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