Coil short

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Hey guys I'm a little confused about what happened to my coil a few days ago. The right side exhaust in my bike since I got it running has had some backfire, nothing serious, or nothing too worrisome, until a few days ago. I was just pulling into second leaving my house When I heard an extremely loud pop. It was backfire on my right side. It seems, after some investigation that my coil shorted out, and when I try to accelerate it starts to short out. I switched out my coil, and its back to normal. I'm worried something is off in my timing which caused the backfire & and short. And I'm worried it will happen again due to a possibly timing problem. Ps. mine is an 80 I don't run points.

Any advice would be awesome, possibly on some replacement parts, or someway to fix this. Thanks! :thumbsup:
 
Jtporter9

Popping and the occasional bang on a well-set-up engine indicates a lean mixture. But let's not jump the gun - ;et's make sure you have set things up right before diagnosing.

You'll see this repeated many times, but the mantra you will repeat, too, is 1. cam chain adjustment, 2. valve clearance adjustment, 3, timing, 4 carburettors - in that order.

If (or when) you have done 1, 2, and 3 and the popping persists, you will have narrowed it down to carbs or an electrical fault. Start by pulling the plugs and inspecting. Recognise the signs for burning lean or rich - then read the carb guide and modify as necessary. If, after all that, popping is still there, get out the multimeter, and test the HT leads (just get new cables, cheap enough) and plug caps. Then test the grounds - dirt, corrosion, failed connectors, all kinds of things go on..

Step-by-step, be patient, enjoy - and there is help.

Welcome to the forum

ANLAF
 
Sweet thanks a ton. I know how to adjust/check carbs, plugs, coil, and all that, but I didn't know to check the cam chain, and valve clearance, and I don't know how to check the timing. But I'll start from there and keep adjust until she runs good, thanks for the input!
 
Low voltage can play havoc with the TCI. I might suggest you check your charging system out put and battery condition.
Leo
 
I have previously checked my rotor, and it is still good, my regulator is regulating my power just fine, and my battery is brand new. It would make sense that it would be the charging system as well. But it makes a lot of sense to me that my vavlue adjustment might off especially after watching the video on valve adjustment in the tech section. becuase I have always had one side run lean and the other rich, I think this is playing a big impact in that, because I have messed with the carbs plenty, and it hasn't changed so that they are about the same. Ill do both, thanks. But as far as the rest of my charging system what else would be good to check, and how would I do it? (im sure I can find how in the tech section.) like maybe the stator? what else would I check? thanks.
 
All you need to check is the battery voltage at idle, 12-13 volts, at around 2000 rpms, about 14.1 to 14.5, and it should not go higher as you rev it higher, go to 5000 or so rpms to check.
If it only reaches around 13.5 or so then you need to read the charging system troubleshooting guide. You can find it in the XS650 TECH.
Leo
 
also ANLAF I found the tech guides to do the cam chain adjustment, and the valve adjustment, so im good on that but how do I do the timing??? and references to videos??
 
Jtporter
If you are happy cam chain is to spec, valves are to spec, then:
1. remove circular Yamaha inspection cover to the rotor.
2. remove spark plugs
3. 17 mm socket on rotor centre nut - turn rotor anti-clockwise until timing mark lines up with the mark at the letter 'T''. Your pistons should be at TDC (top dead centre) and you can look in the plug holes to see them Careful not to let anything down into the cylinders.
4. From here, if you are on points you will need to follow the manual, or one of the guys will take you through. If you are on electonic ignition, such as Pamco or Boyer, that's really simple. Type in XS650 in Youtube and see what comes up - hundreds of videos.

ANLAF
 
If you have the TCI ignition the timing is fixed and triggered by a magnet in the charging rotor. Basicly all you can do is verify the ignition timing with a timing light which should be right on the factory spec unless the rotor has been removed, the key left out and the rotor moved on the crankshaft. There have been a few mentions of the magnet in the rotor becoming weak which can cause some interesting spark problems but it can be easily, form what I have read, remedied with an additional magnet affixed to the rotor. The info on that is available in the forum I am just to lazy to go searching for it right now. Now there was a mod, by XSJohn I believe, that would allow some adjustment of the timing of the TCI ignition but you would have to do some research on it, it's here somewhere and like I said I am to lazy to go searching for it right now.
 
A "mod by XSJohn...that would allow some adjustment..."?! Right, TCI timing is preset at the factory, but whenever a stator is swapped out or the TCI pickup is replaced, timing has to be set, and guess what? There's a procedure in the FACTORY MANUAL for it. John's only "mod" was to retard ignition timing a touch and use fasteners with conventional drive heads instead of the fasteners with breakaway heads in the factory setup. In case anybody hasn't gotten the message yet, free downloads of the late factory manual are available for those who are not too lazy to use it at www.biker.net , thanks to the generosity of Jean Akers.

One more thing. Charging system trouble is not the only reason for weak voltage to the ignition. Use the damn multitester and find out what's actually getting to the coils and igniter box and compare that to battery voltage. If you find a big difference, get to work and start cleaning connectors and switches.

BTW, timing error, etc. won't cause ignition coils to go bad. Like anything else on an old motorcycle, they're affected by age and vibration, and if somebody had installed a Chinese unit a lot of the damage was already done at the factory.
 
A "mod by XSJohn...that would allow some adjustment..."?! Right, TCI timing is preset at the factory, but whenever a stator is swapped out or the TCI pickup is replaced, timing has to be set, and guess what? There's a procedure in the FACTORY MANUAL for it. John's only "mod" was to retard ignition timing a touch and use fasteners with conventional drive heads instead of the fasteners with breakaway heads in the factory setup. In case anybody hasn't gotten the message yet, free downloads of the late factory manual are available for those who are not too lazy to use it at www.biker.net , thanks to the generosity of Jean Akers.

One more thing. Charging system trouble is not the only reason for weak voltage to the ignition. Use the damn multitester and find out what's actually getting to the coils and igniter box and compare that to battery voltage. If you find a big difference, get to work and start cleaning connectors and switches.

BTW, timing error, etc. won't cause ignition coils to go bad. Like anything else on an old motorcycle, they're affected by age and vibration, and if somebody had installed a Chinese unit a lot of the damage was already done at the factory.

grizld1, That was exactly what i was referring to. I just never did anything with it myself so I was trying to get the OP to do the searching for it first. I was trying to prevent any confusion for the OP when he tried to adjust the timing on his '80 with a TCI ignition.

Thanks for the clarification and additional areas of interest. And as always a manual is a must have.
 
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