ITS IT THE COIL?
 

Hi Team

After a stirlingeffort of 4000miles most of it 2 up to the Sahara and back the XT600 3aj is being a little neglected and now refuses to start poor thing.

I think its the coil as the spark is weak and I have changed the HT cable to check its not thta new plugs etc.

Am I right and if so where can I get a cheap new one the local Yamaha store want £44

Cheers BD

Coils hardly die, just measure the resistance and you know more. 3AJ has CDI ignition which sooner or later will be braindead.

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Fred, XTZ660, Holland.

The CDI box itself may be fine. You also need to check the resistance of the ignition pickup as descrided in the manual.

Did it work when you stopped using it?

If it did, I would think it unlikely that it is the CDI or coil.

Have you tried just draining the carb and getting some fresh petrol into it?

Muro

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RIGHT battery is on charge and I have drained and refuled the tank, So tonight we will know wether it starts. What are the symptoms of a knackered CDI UNIT? If its is the CDI are the after market parts at £75 better than the orginals.

I have a very weak spark at the moment and 10ohms resiotance across both sets of widings in the coil.

BD

Hi

You should also check the resistance of the coil that provides power to the CDI, can't remember what they call it.

From memory ther is this coil that provides the power to drive the electronics in the cdi unit, a second coil that provides a signal when the engine is at top dead centre and a third that provides a signal shortly after that, which is used to determine engine speed, and hence required ignition advance, by looking at the time betwen these 2 signals.

I had a problem with this "power" winding which resulted in needing to fit a new spark plug each and every time I wanted to start the engine ! Ran fine but wouldn't restart.
Finally descoverted pattern windings "power" winding a few ohms lower (no more than 10%) that figure stated in Clymer manual, changed the windings and has been fine since, over 20 000 miles.

Also, don't forget to drain the float bowl, often it is enough to do this, the petrol seems to go off in the carb worse than it does in the tank.

Another favorite for starting problems is the carb to head inlet stubs leaking, the rubber comes unstuck fron the aluminium part of the stub.

Good luck

Mark

Its alive.

It was a combination of a badly charged battery (the optimate I have had for years has fianlly snuffed it) and old petrol. I checked the windings and they both gave the same resitance so I reassembled drained the tank and the carbs and reprimed. Hit the starter after charging the battery and she sang.

Thanks for the help all of you , off to plug around the salibury plain now and get back in shape.

BD