bad coil blowing fuses

[Guest]

I kept blowing a fuse and traced it back to the coil so I am wondering, can you fry a coil by holding down the start button way to long? I am hoping that, that is what happened so that if I replace it, the new one doesn't go bad, encase something else might have caused it. any thoughts?

[pdqford]

I kept blowing a fuse and traced it back to the coil so I am wondering, can you fry a coil by holding down the start button way to long?

I wouldn't think so as the coil should be turning on and off while you are cranking it. But now if you have a points ignition and you should happen to leave the ignition key on when the points are in the closed position....

[Steve]

But now if you have a points ignition and you should happen to leave the ignition key on when the points are in the closed position....

True, but if you do have points ignition, you stand a chance that it's only one coil.

With the electronic ignition of later bikes, current flows through BOTH coils until the sensors at the end of the crank 'see' the magnet come by to trigger an interruption.

.

[tkent02]

Holding the start button is no worse on the coil than having the ignition switched on by itself, like when the bike is running...

[eil]

Holding the start button down for too long is bad for the starter, however. (And battery, to a degree.)

[posplayr]

I kept blowing a fuse and traced it back to the coil so I am wondering, can you fry a coil by holding down the start button way to long? I am hoping that, that is what happened so that if I replace it, the new one doesn't go bad, encase something else might have caused it. any thoughts?

If you are blowing a fuse with a coil, then there must be a short in the coil primary.

can you measure 3-4 ohms? it should pull something like 3-4 amps and that is it which should not blow a 10 amp fuse.

Apparently when one coil is charging the other is off as total ignition current is about the same.

And leaving the key on without running is something the points or a DynaS does not like. All the coil current goes through one set of points/transistor.

[slayer61]

can you measure 3-4 ohms? it should pull something like 3-4 amps and that is it which should not blow a 10 amp fuse.

That's right! I=E/R

In other words Current is equal to voltage divided by resistance.

In order to blow a 10 amp fuse with a 12 volt power supply your resistance had to be in the neighborhood of 1.2 ohms.

[Redman]

I kept blowing a fuse and traced it back to the coil so I am wondering, can you fry a coil by holding down the start button way to long?.....

No.
When holding the starter button, the coils are not experiencing much of anything different from all the other time the engine is running, well, other than slower engine rpm.

.

[akaerik21]

But now if you have a points ignition and you should happen to leave the ignition key on when the points are in the closed position....

I am going to have to think that this was the problem sense only one coil is causing the fuse to blow. Thanks for the help. I had no idea that leaving the ignition on a bike like this could cause problems. My last bike was an 03 Intruder 800 and it was pretty much a start and go bike, that I never had to fuss with. So this is old GS550 is a whole new world to me.

[tkent02]

True with any car or other vehicle old enough to have points type ignitions. Leaving the key on when the engine was not running was a no-no, but usually it would damage the points, not blow a fuse... Sometimes the points would actually weld themselves together.