fj600 charging system help

So I have this 1990 FJ600, bought it a while back non running. It's running now but the charging system doesn't seem to be putting out anything. Voltmeter at the battery shows a drop when running, 12.3 volts instead of 13-14 volts like it should be. I checked the leads coming from the alternator and the resistance seems fine, .5 ohms. Took off the connector at the regulator and the wires are fried. Any idea what would cause this? Is there a way of checking the current coming out of the alternator at this connector? I see there are a bunch of replacements available for this on Ebay, made in China for other models.

 

Corrosion increases resistance. Increased resistance increases temperature at the connectors. Increased temperatures lead to melting.
Replace the spade terminals and see if she chooches.

 

Yes , probably right. I'll replace the connector and I ordered a new regulator, they're pretty cheap. It was hard finding a parts diagram that showed this regulator. The older models had the larger one with the fins on it. There was no 1990 FJ600 in the US market.

 

One other question, on my bike the alternator is at the end of the crank behind the left side engine cover. So what's behind the engine? I thought that was the alternator, but the manual doesn't say anything about the unit tucked between the starter and engine. were earlier models different? This is a pic of an '84 fj600 engine.

 

Are you sure that your bike is a FJ600? Or are you mistaken?
All FJ/XJ's, have the alternator behind the cylinders. The pick up coils are on the end of the left side crankshaft. The only XJ with the alternator on the end of the crankshaft is the XJ1100 and that is on the right hand side anyway.
Have you got anymore pictures of your bike and what is the engine number?
Could it be a FZR600? The alternator is on the left hand end of the crankshaft.

 

fzr600 alt on crank

 

The FJ600 and XJ600 of that year use the same engine.


The aforementioned 1990 FZR600


Note that the OP has a round tube frame. The FZR does not.
We need more pics of the bike, and preferably the VIN from both the frame and the engine.
I can't see how an FZR engine would transplant into an FJ frame, but it sure does sound like that might be what happened.


Unless, you're mistaking the ignition rotor and pickups for an alternator.

 

Yamaha changed the position of the alternator in about 1984/5 on the fj and xj 600. that's the same motor as mine, "in my avatar"
the chamber behind the cylinder block and above the final drive is now an empty chamber.
also the unfinned regulator is same as xj600
I did a full restoration thread on this bike ,but photobucket wiped all the photos, don't know if theres a way of restoring them ,here
bensalf's 4 year café racer build
stu

 

Thanks for the info. Yes it's an fj600, seems strange that they would move the alternator behind the engine to make it narrower then later on move it back. Never took that finned cover off so didn't know there was nothing in there! Manufacture date of this bike is 12/89. I think I have every other issue with the bike fixed , the only part I couldn't get was the airbox connector boots, obsolete. But the old ones are ok for now.

 

http://www.electrosport.com/media/pdf/fault-finding-diagram.pdf