Vintage and Classic Hondas

New (to me) bike

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boostaholic

New (to me) bike

Hello everyone,

So I just picked up a 80' cb750k, not running, for 200 bucks. The owner had it for 15 years, hasn't touched it in 5 years. He originally put it away because it wouldn't run, and in his diagnosis, he believed it to be no spark. He pulled the side cover off the pulser generator, for some reason, thinking it would be the issue. So, upon initial inspection I know the carbs need to be cleaned. The throttle is a little sticky, not a problem. The bike only has 10000 miles on it, to me, I think any issue would be with parts like the wires and/or coils. Pulling the wires off the coils, it appears there is a lot of corrosion on the points, and the plug caps fell off the wires.

So, a few questions. Can I test the coils? before I buy new ones i'd like to know they are actually bad. Check the resistance on them or something? Next, where can I buy good wires for it as well as the coils if need be?

-G
-

TOOLS1

Re: New (to me) bike

Administrator

The DOHC bikes (which a 1980 model should be) are known for crappy electrics. However they do not have points.

You can download the factory service manual from the manuals thread at the top of the home page here, for free. It has very detailed instructions on how to test the coils and other electrical components. There is also a good write up in the repair tips and tricks section on cleaning and rebuilding the CV carbs.
TOOLS

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1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
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shinyribs

Re: New (to me) bike

Administrator

I like my buddy Tools, but I'm not so sure that DOHC's have crappy electrics.

Yes, they have a charging systems that uses brushes, unlike the zero-wear-item SOHC bikes, that will destroy a charging rotor of you let the brushes wear down and allow the springs to gouge the copper rings. Otherwise, they are set up like pretty much every other Honda, regarding electrics.

As far as no spark, definitely hit up the FSM. It could be something as simple as the air gap at the pulse generators. BTW, they rarely ever fail. They aren't actually electronic, rather just magnetic switches. Easily tested with just a screwdriver.

Truck

Re: New (to me) bike

I don't know about "crappy" but I do know the weak point on the DOHC is the electronics. However if you get everything sorted it should be trouble free for awhile.

It's only illegal if you get caught.

If at first you don't succeed, use more lighter fluid

95% of Harley Davidsons ever made are still on the road... The other 5% made it home.

New Baltimore, Va '82 CB900c, 1980 CB985F/K 'Mutt"

motogrady

Re: New (to me) bike

Administrator

With my bike, it was bad connections In a few molex connectors.
The bike can make all the juice it should, but if it can't get to the battery.........