craigacc Posted January 4, 2020 Report Share Posted January 4, 2020 Hi all,I have a 1975 M66 Ural which is nearing the end of a restoration. The ignition switch gets very hot on the 'points' which join together when the key is pushed in. I've an inline fuse by the battery on the positive lead. Low amperage fuses blow immediately you push the inition key in, the ignition switch gets got at the 'points' when using a higher amperage fuseOtherwise the lights etc all work OK, though not tested the spark at the plugs yet (was all OK when the bike was stripped)I know the generator is suspect, but disconnecting it does not stop the ignition switch getting hotIt has a brand new regulator/rectifier fittedOther aspects of the wiring have all been refurbished and proper modern connectors fitted. The ignition switch is original, but cleaned up and wiring connections refreshed. So current is 'leaking' into a short circuit somewhere. Any ideas? Many thanks. Craig. Quote Link to comment Share on other sites More sharing options...
Vance Blosser Posted January 4, 2020 Report Share Posted January 4, 2020 I'd start with the coil, as they can short internally. Then the lights one by one. Something is drawing too much current. Did you disconnect the regulator? Quote Link to comment Share on other sites More sharing options...
RussN Posted January 4, 2020 Report Share Posted January 4, 2020 Assuming you have several fuses, you can remove them one at a time to isolate circuits, and see which one eliminates the hot ignition switch issue.Then trouble-shoot that circuit for shorts.Measuring current through each fuse is most useful. Vance's suggestion about the coil is good. Do that first.Happy New Year!RN Quote Link to comment Share on other sites More sharing options...
craigacc Posted January 5, 2020 Author Report Share Posted January 5, 2020 Thanks for the replies - very much appreciated. Yes, the culprit is the feed from the switch to the points and coil. Will investigate further. Curious as it was all working OK when stripped down, Cheers, Craig. Quote Link to comment Share on other sites More sharing options...
racepres Posted January 5, 2020 Report Share Posted January 5, 2020 For troubleshooting...ensure that the points are open...or even disconnected...The coil and associated circuitry will indeed get quite Hot with closed points... this is in fact normal...especially if points are endergized and closed for some time...to the point it is not uncommon to "blow" a Coil, by leaving it energized... this is Normal!!!Isolate this component if trouble is suspected elsewhere... even a piece of plastic between the points contacts... Quote Link to comment Share on other sites More sharing options...
craigacc Posted January 6, 2020 Author Report Share Posted January 6, 2020 I tracked the problem down. The ignition switch 'points' heats up when the actual ignition points are closed. So there's a strong power drain through the coil and into the points. When the ignition points are open, the rest of the wiring and lights etc are all fine. Does this suggest a faulty coil? Or is this normal as suggested above - I get where the author of the last reply is coming from (thanks for your input BTW) But to add further info, I added a fuse straight after the battery positive. It blows fuses less than 25amps. The contact in the ignition switch don't just get warm, they get extremely hot very fast and would be a fire risk if left for any period of time. I appreciate that current will run straight through the coil to ground via the ignition points when they are shut, this is normal. But on other points based ignition systems, it's the coil that warms up if it's left not running in this state for any length of time, not the entire ignition circuit. Suggests to me that the coil is breaking down inside? Any further thoughts? Craig. Quote Link to comment Share on other sites More sharing options...
Vance Blosser Posted January 6, 2020 Report Share Posted January 6, 2020 Is it a 6 volt system? If so that means the amperage is doubled to do the same job. And points in cars have been known to burn if the ignition was left on with the points closed. But a new coil might not be a bad idea. Quote Link to comment Share on other sites More sharing options...
racepres Posted January 6, 2020 Report Share Posted January 6, 2020 Again.... The coil and associated circuitry will indeed get quite Hot with closed points... this is in fact normal...especially if points are energized and closed for some time...to the point it is not uncommon to "blow" a Coil, by leaving it energized... this is Normal!!! Vance; I have Never encountered a Shorted Coillots and lots Burned open however... ie, when the coil quits heating up when constantly energized...it has probably Burned OpenA simple Ohms test of the primary windings [out of circuit] should show roughly 5 Ohms... more up to 6 or 7 is probably OK... Less ie 4 and down is Bad...and points will be burned...Next thing is usually...it will start and idle... but not pick up RPMs.... = bad Condenser!!!! And burned points again! Quote Link to comment Share on other sites More sharing options...
Vance Blosser Posted January 7, 2020 Report Share Posted January 7, 2020 On my 94 Ural I had a coil that shorted partway through the coil when it got hot. The resistance would go down and the spark would get weak. That's the only one I have personally seen however. Things can fail in strange ways! Quote Link to comment Share on other sites More sharing options...
dowey Posted January 7, 2020 Report Share Posted January 7, 2020 there are wee black boxes out there that send micro voltages to the points ..i put one on the Dnepr an didn't look at the points after :) Quote Link to comment Share on other sites More sharing options...
racepres Posted January 7, 2020 Report Share Posted January 7, 2020 On my 94 Ural I had a coil that shorted partway through the coil when it got hot. The resistance would go down and the spark would get weak. That's the only one I have personally seen however. Things can fail in strange ways! Interesting... Only some of the windings shorted... I have heard of coils failing only when hot... may be exactly what was experienced...there are wee black boxes out there that send micro voltages to the points ..i put one on the Dnepr an didn't look at the points after :)Electronic points... generally a hall effect pick-up... work just fine... long as the mechanical advance mechanism [mixing bowl of doom] stays viable... Quote Link to comment Share on other sites More sharing options...
Northernduck Posted January 9, 2020 Report Share Posted January 9, 2020 A short to ground can also be through a bad condenser, but in this case opening the points removes the problem so it seems everything points to the coil. ND. Quote Link to comment Share on other sites More sharing options...
luca.stere Posted January 11, 2020 Report Share Posted January 11, 2020 he ignition switch 'points' heats up when the actual ignition points are closed. I suspect you have an electronic ignition coil type. Electronic ignition coils draws too much current if conected with points. Quote Link to comment Share on other sites More sharing options...
racepres Posted January 12, 2020 Report Share Posted January 12, 2020 craigacc; idea!!! put a old fashioned fuse in the line. about 5or 10 ampif this blows... we gots problems... if not....well, back to brainstorming!!! Quote Link to comment Share on other sites More sharing options...
craigacc Posted January 26, 2020 Author Report Share Posted January 26, 2020 Problem resolved. A new ignition switch sorted it out. It must have been shorting somewhere, though I couldn't spot the problem with the old switch. the contact in the new switch doesn't even get warm when the ignition points are closed and the bike runs fine. Now onto a charging issue. On this though, the generator is farped I think. Tried repolarising it, but it's dead - no 'flashing' sparks when doing the repolarisation and the charge warning light stays brightly on. Time for a new one. It is 45 years old and nothing lasts forever. Thanks for all the feedback on the question I asked. Quote Link to comment Share on other sites More sharing options...
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