Stopped dead - no spark UPDATE

On a 650F1 out of at least 9 years storagefor nearly six months now. Died approx 3/4 mile push from home the other night.

Until now most of what I have done has been directed by searches on this forum, in order of relevance (I think):

NEW:
Plugs, caps, leads, coils, points, condensers.
Jets, needles etc (carb rebuild) , stock airbox,
throttle cable,
clutch cable.
ALSO:
Multiple cleanings of the carbs, balanced carbs,
timing adjusted, coil mod.

The last things done before the unscheduled halt in services was a new clutch cable, airbox and balanced carbs. I assume these aren't related.

Post edited by: mark.wilde, at: 2007/02/15 05:18

OK, checks last night, after battery charged.

Weak spark when engine first turns then nothing.

Battery 12.2 volts, Coil 11.1 volts.

The right hand point showed some mysterious earth which vanished just as mysteriously.

Please help because given all the stuff I've replaced I can't see whats wrong.

Boy... You sound frustrated! When the bike died, did it still have power? To troubleshoot this problem, we have to figure out WHY the bike died. It could have run out of gas. It could have run out of spark. You then measured power at the battery and coils. Was this running or just with the key switched on? You mentioned that the bike has "weak spark when engine first turns then nothing". Does this mean that you have spark initially then the bike continues to turn and you have no spark?

From the various comments, I would guess an electrical problem but go back to where the bike died while being operated. You started the bike. Did you first charge the battery? Then you went for a ride... how far did you ride before it died?

Bike had power, was running best it has in the time I've had it.

It just jerked once and stopped. Not like running out of gas.

It wasn't running when I measured the power.

Spark is exactly that - crap spark then nada however much cranking.

It certainly seems electrical to me - there are no nasty noises coming from down below.

Battery was charged before I investigated power at battery and coils. The right hand point gave a circuit to earth when open but after WD40 to all connections between point and coil it vanished (search me - I have no idea where it was grounding OR why it stopped!). Points and coils were all before christmas. To be honest I was thinking that I had sorted out all the old long term storage gremlins and could just enjoy it for a bit.

I had ridden about 15 miles of a 16 mile journey when it gave up, and it was running as well as ever - there are definitely some minor issues causing hesitations at top of the rev range but that wasfor another day. I find that as long as it's running it's a damn site easier to work out why it's not running properly if you get my drift.

Bike has not started since but there is compression at the kickstart.

Coils measure 4.7 and 5.2 ohms, working fine since just before christmas.

Does that answer everything? (Or even make sense)

Thanks for any help at all - it's hard to think where to carry on from here.

Don't ask me how but I posted this reply and it ended up in a thread I've never even read. Now I'm frustrated - or is that confused?

First off, one coil exceeds the factory specs for resistance, while the other is real close, so I suggest replacing them.
Factory spec is 3.2-4.8 ohms.

Second, you have a problem with the points, the WD40 just temporarily fixed the problem, probably by providing an insulating layer.

Third, if you don't have a manual you really need to get one.

Your problem does sound like it's electrical in nature, so check all connections including grounds.

Coils - I will recheck because they are 3 weeks old and solved a previous problem and were working ok for that time.

The points grounding are truly wierd because I chased it all the way to the coil and then it vanished. Step by step, here's how it goes:

1st the points gave a circuit to ground when open, so disconnect the coils and the circuit is open when the points are open.

2nd check condenser - no circuit to ground, good.

3rd check wiring where it attaches to the points - circuit to ground.

4th up the wire to where it connects to the coil - circuit to ground.

5th disconnect coil, no ground to wire from points, coil grounds. Recheck and it doesn't.

6th reconnect all in reverse order cleaning contacts with WD on the way. No grounds at any point.

My digital multimeter has a very useful setting where it beeps if testing resistance whenever there is a circuit so this test was straightfoward if confusing.

That point also did something similar when I replaced it but bike ran then.

When you check one circuit, you must isolate it from the other circuit. When you check ohm readings on one set of points, it matters what the other set of points is doing. To isolate them, put a piece of paper in the other set of points so they won't affect the readings.

What happens is the current backtracks through the coil to the junction where the coils connect together, then goes through the opposite points to ground.

Post edited by: loudhvx, at: 2007/02/15 17:38

That explanation was much more informative so I would also guess it is electrical. I don't deal with points very much. Since you just replaced them, as well as the coils, my first instinct would be a bad condensor. I think that after you replace the points/condensors a few times, it would have been more cost effective to install an electronic ignition. Check with www.z1enterprises.com for a price on a Dyna S and get rid of those points! They ship overseas and have pretty good prices on their stuff. The owner is also a Brit although he is getting as stout as any American! hehe Tell him I sent you. Also, look at the Coil Repowering article on our web site.

Last, given you rode 15 miles or so, you may have a charging problem. It isn't easy to determine just checking battery voltages. An easy and informative test of the regulator/rectifier is to recharge the battery and start the bike. Once running, put a multimeter on the battery in VDC scale and at idle you should see about 12.5 VDC. Rev the engine to 4K rpm and note the voltage. If it goes DOWN, you are likely not getting a good supply of AC from the stator OR you have a wiring issue; normally a loose ground. If the power goes up to about 14 VDC, then it is likely there is no problem with the charging system and if it goes above 14 VDC, then suspect a bad regulator/rectifier.

Firstly to steell - I hope you don't think I was dismissing your advice out of hand, it's just the coils are new and if they had failed I would have expected

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WHAT THE HELL HAPPENED THERE?

Anyway the internet just ate a post essentially saying THANK YOU to all for taking the time to try to help - I am currently sitting on this problem for a couple of days.

Post edited by: mark.wilde, at: 2007/01/07 08:29

This is lame, I know, but is it possible the kill switch is shorting out?

More lame stuff -- possible wiring short "somewhere" before battery voltage reaches the dual connector feeding the coils. Could test with temporary wire from battery positive terminal connected to both coil input wires (direct wire by-pass from battery positive to coil input wires).

Finally got an afternoon out to look this thing over again. Put the battery on charge and checked over the basics - connections etc. Rechecked ohms on the coils - they are in (just) so I did measure wrong.
Daylight and space are sometimes the best tools you can get.
After this fiddling - and that really was all it was - I tried to crank it over. You could feel it wanting to but the battery was really dull. So cup of tea, cigarette, slice of chocolate cake. Then back to it, I decided to let the charger go a little longer so I polished and waxed the tank. It started. I always say dirty bikes sulk.