Computer Dead?

Big problems.

I was comming home last night and all the warning lights came on and stayed on. I have been having little weird things happening lately with the electrical system so i didnt think much of it. Well the bike wouldnt start this mornin so i charged the battery up and got her running. All the lights are still on and now i don't even have power to the headlight. i took the atari apart and everything looed ok. the headlight bulb looked ok. Bike runs great, starts right up.

Is the computer dead?would that be what is causing the headlight problem?

 

The computer does not have anything to do with starting, so it won't be a factor there.

It does verify that the headlight is drawing current, and it does that by running the headlight current through a resistor in the computer. If the connections related to this, or the resistor itself, are bad, then the headlight wouldn't come on.

However, the fact that you had to charge your battery, makes me think you have an alternator problem. The headlight relay activates based on charging current from the alternator. If your alternator (brushes, etc) is bad, that would explain at least some of what you're seeing.

 

Thanks SQL, i'll look into it.

 

ok i opened it up and first thing i saw one one of these contacts was shorter than the other. should that be like that?

Sorry but i'm tottaly new at alternators. I'm not familiar with what everything is, hell i couldnt even open it up any further cause i dont know how to stop it from spinning safely.

 

Re: Computer Dead? Alternator problems ?

are those the alternator brushes?

 

Yes. They should be no shorter than 10mm. New ones are 17mm.

 

If you look carefully at the rotor you will notice that the outer contact is considerably longer than the inner one. The outer brush will wear faster.

 

the shorter one is 18mm and the other one is 21mm. I cant find anything about alternator brushes in my Manual. Weird. I figured i should just replace them anyway, Len has a set on the way. Having done buissiness with Len before i should see them under my pillow when i wake up in the morning.

Thanks Guys! Without you guys and Len i would be screwd!

 

no luck. Got the new brushes in and still nothing. No headlight, all the warning lights. Not charging the battery.

Any ideas on what to check next?

 

Just a thought, have you checked your fuses/fuse box?

 

Remove your seat and check the connector that comes up from the alternator and see if its melted or has a bad connector. I have two bikes with that connector bypassed due to bad connections. Let us know.

MN

 

Other things to check -

Unplug both alternator plugs.

Check for low Ohms resistance between the Br/G wires of the alternator, and also low resistance between each of the white wires of the alternator and each of the other two white wires. The resistance between any two white wires should be about the same.

If these check out, and the connectors themselves are OK, then the likely problem is your rectifier/regulator module. If you can borrow one from another bike to try, it would be handy, although Haynes does have a test procedure for it. Thaeir test procedure, though, is relatively complicated and requires two multimeters.

 

I had very close to if not the same problem and it was what MN-Maxims
explained. I would check into that. I know for a fact that if that connection is bad it will not take a charge and your headlight will not work.

 

You guys freggin rock!

THe harnes with the three white wires had meleted inside between the two parallel wires. i would have never seen it if i didnt take it apart to test it.

SHES ALIVE!!

P.S. Chacal is still the land speed record holder for geting those brushes deliverd. Thanks Len!

 

That and the failing fuse box were standard on all Yamahas in the 70s and 80s. If you ever run into someone having electrical problems on an older Yamaha you can suggest those two things and 9 times out of 10 you'll look like a genius.