Just bought a 1980 cb 650 cant get it running..

[akasoldats]

I guess I should start off with an intro. My names Steve, I live in the western LA area. I've ridden bikes before and tinkered on them with friends but haven't ever owned one up until now.

The other day I picked up a 1980 CB 650 Custom that had been dropped. It has a little damage here and there and isn't currently running. I figured I was up for a little project so why not buy it? When I got it, it had a dead battery, broken ignition and a broken bracket for the headlight.

So I bought a battery, checked the fluids, and then tried to crank it over. Since the ignition is broken I temporarily made a jumper for the two pins that turn the bike on.

Now on to the issue... When I hit the start button the engine cranks real slow until the battery seemingly doesn't have enough power to turn it anymore. I threw a voltmeter on the battery and it stays around 11-12 volts depending on how long I try to crank it. I also pulled the cover of what I think is the crank case and manually turned the engine over. It doesn't feel seized so my question is what should I check next?

Again I'm new to the bike scene but I've worked on cars and atv's before so yeah. Any guidance would be greatly appreciated. I don't really know what to check next.

 

[VonYinzer]

Charge the battery. Should be near 13v when fully charged. Are you sure that there's no internal engine damage?

 

[akasoldats]

The battery is brand spankin new. But I'll throw it on the charger. I can't be certain the internals are in great shape without ripping into it but it seems to crank smoothly if I manually turn it over. :-\

 

[AlphaDogChoppers]

Use an external battery such as from a car, with jumper cables to be sure you are providing enough power. (With the car NOT running.)

After fully charging the battery, take it to an auto parts store and have it load tested.

 

[akasoldats]

I"ll see if I can find someone that will let me try and jump it tomorrow. I read somewhere (cant remember where now) that the headlight is a ground on the 650's. Could that somehow give me a lover voltage at the starter since one of the brackets is snapped off?

 

[AlphaDogChoppers]

There should be a ground directly to the engine. Corrosion at that connection is a common cause of slow cranking.

Your headlight is not involved in the engine ground. Make sure your engine ground is clean. Use some sandpaper, then apply dielectric grease to inhibit future corrosion.

 

[nicknonsense]

I'm no expert at all bit I have the same bike and I got it running with a regular charged battery attached directly to the engine and frame as s ground after cleaning the carbs. I don't know if this helps but I hope you get that engine running again!

 

[akasoldats]

So I traced the main ground back to the frame and removed it. Sanded it a bit, even though it looked fine to me and put everything back together. And to my surprise it turned over and started in less than 10 revolutions. Then promptly died since I havent put any gas in it... Regardless thanks everyone for the help. Now on to the oil change, and cosmetic issues.