Electricals kaput..!!

[z1100r]

You probably wont remember, but I bought the G80s below off a mate early last year. Well, I used it most of the summer/Autumn just fine but towards the end it started to refuse to start when hot. Starts first kick when cold, but even slightly warm it wont start. Something is wrong with the magneto I think.

Next thing, on my last trip home in the dark, the lights went out. I was pulled by the police, but luckily my lights started working again and they let me on my way...they soon konked out again though. When tested the dynamo produced next to nothing. The regulator is a right battered looking thing but seems to work OK.

Does it seem likely that the Magneto would suffer when warm..??
Where can I get my seperate mag and dynamo rebuilt...??

Both are the 1952 originals, as is the voltage reg. I dont want to swap to 12v and I dont want any electronic stuff. I would like to keep it all original if posible.

[Rob Harknett]

Have you checked the dynamo, quiet often it only needs a good clean, perhaps new brushes, to kick it back into life again. Also clean earth contacts on frame and headlamp at least. This sort of thing often needs doing even after a long winter lay up.

[dave16mct]

Also please turn that front wheel the right way round. Very dangerous the way it is! The torque stay should be in tension. Dave.

[Les Howard]

Hi Z. There is a possibility that the capacitor( Condensor) is failing when the mag heats up and if so then the armature requires a rewind where a new capacitor is also installed. However, it could be other things that are causing the problem when warm, so before you send your mag off, take the time and trouble to test for a spark with the the mag warm. I would take a new plug along with me, and when you experience the next failure to start, simply remove the plug cap and swap it onto the new plug. Depress the valve lifter so you can get a good fast swing and monitor the spark. With your helmet off, you should be able to hear a decent crack and a fatish blue spark. If it does not spark or sparks with a feeble white spark then it could be the mag has a problem. Otherwise if the spark looks good but the bike won't start, it could be you have too rich a mixture or your teqnique is wrong (try starting with a closed throttle?) Anyway here is a link:
http://www.davelindsley.co.uk/
As Rob says the dynamo's problem might be easily cured and if your OK with the spanners a dynamo can be rebuilt quite easily including buying a new armature to fit. Unlike the mag there are lots of connections on the lighting side and regulator so you have to painstakingly check all these too. When you say the dynamo is producing next to nothing, did you simply short the A to the F terminal at the dynamo end and then measure with a running engine? This should maximise the dynamos output and irradicate the regulator as being at fault..

[z1100r]

The mag does seem to spark OK when warm...I have tested that. Its a bit weird. Its not a technique or mixture issue, and thinking about it, its very similar to a problem I've had previously which turned out to be a crack in a piston. Hmm...
I just spoke to the previous owner and he said he has had warm starting issues for years and years. Funnily enough he says it all started in 1976 when he took the piss out of all the boiling up Escorts/Marinas/Cortinas trying to get up Horseshoe Pass. He rode up and down it all day long, but it became hard to start after that if it was hot.

I'll get the dynamo to bits and have a look. Brushes look new and there is no loose wires or anything simple.
As I say all was fine with both of them all summer then almost in the same week they both stared mis-behaving.

Thanks for suggestions..geat stuff.

oh yeah...front wheel was put right the first week i had it. Someone else on here gave me a bollocking for that. Edited by - z1100r on 17 Jan 2012 1:06:25 PMEdited by - z1100r on 17 Jan 2012 1:07:25 PM

[zwarts]

It is unlikely to be a magneto/heat problem as they don't get all that warm when mounted in front of the cylinder. To eliminate the mag you need to remove it and get it tested by someone who knows what they are doing. Sparking with the plug out of the engine is no real check . The voltage required to produce a spark in such low pressure conditions is very much lower than that required when the plug is in the engine. Hence the need for a more thorough test.
Bob.

[bigwol]

Sounds like it might have been cooked going up and down horseshoe pass ........
Is the compression ok when warm?

[z1100r]

I think its just a knee jerk reaction from me. Along the lines of 'these two items are old and electrical, It must be them, I might aswell get them both rebuilt'. I know I'll have to eventually.

It could be just a tired engine, it's got nowhere near the same objection to movement on the kickstart as my 54 500 Bullet. Its done 42,000 genuine miles and the main engine has never been touched. Rings must be shagged I guess and probably the barrel and piston. It was owned by an 18 year old exhuberant kid for alot of that mileage.

I got rid of the stupidly restrictive Armours exhaust 3 or 4 weeks before it started playing up. That brougt back the performance in a huge way and consequently I was thrashing it a bit for a few weeks enjoying that.
I could of opened up old wounds - barrel and piston wise - or slashed in some new ones I guess.

Think I'll strip it over the next couple of months and do some restoring/rebuilding.

My original plan was to "ride it as it is until the inevitable problems start cropping up and then restore it". Its just happened sooner than I wanted it to.

[rex.webb]

DO NOT FORGET !!
TO CHANGE that FRONT WHEEL ROUND !
PLEASE AS SAID EARLIER .
RIDE with CARE and LIVE LONG to ENJOY your BIKES ans Scooters .
Insured with Peter James.

[bigwol]

He already has Rex, is just an old photo.