Topic: 81 cb650 custom starter need advice

[alfredreed]

New battery, good solenoid, good ground, continuity in starter cable. But all i get is a solenoid click when i use the starter button, and when I short it across the solenoid posts all I get is a spark.

Mine is the type that sits behind the cylinder above the alternator and comes out by  removing two bolts. It is a straightforward armature, brushes, commutator, with a spline that meshes with the flywheel -- no clutch.

So I took it off the bike and used jumpers on terminal and case, and it spins fine. I thought maybe the cable connection just needed tightening, but when I reinstalled it there was no difference.

Before I take it apart to rebuild it, do you think it might just need brushes and a cleaned commutator so it spins with greater torque than without any load? That's my guess other than something gone bad -- it ran fine up to when i shut it off to store it for winter. I expected it to fire right up as it has only been sitting for the winter.

Would appreciate any insight before I take it apart -- I am a little pressed for time to work on it. Thanks

[scottly]

So I took it off the bike and used jumpers on terminal and case, and it spins fine.

Did you use the bike battery for this test, or a different battery?

[alfredreed]

I used a separate charged bike battery for the spin test off the bike. It spins OK but not when installed in the bike

[CBGhia]

Can you try using that other battery on the bike? 
When was the last time you turned the engine over?  Does it turn by hand?

[alfredreed]

The battery in the bike is brand new and charged, better than the extra one. It's not a battery issue here, it's the starter spins off the bike but only sparks when installed. I think the problem is internal so I will just have to take it apart and check the brushes when I get the time.

[CBGhia]

But the engine turns over easily?  It's not locked up is it?

[alfredreed]

I can't turn the engine over because of the starter problem. I don't know of any other way to turn it over. It ran fine when I parked it for the winter in the garage. 

I thought of taking it out of the garage and trying to run start it but with the cold-natured  starting problem these things have I could be running all day. Plus I'm not sure I could get it back into the garage again.

[CBGhia]

make sure it's in neutral and pull the rotor cover (clutch/shifter side) and put a wrench on that to turn the engine over.  Pull the spark plugs first to release compression.  Then see how it goes.   You may want to drop just a put of oil in the spark plug holes. 
It should turn easy.  If it doesn't, then you may have rings rusted to the walls. 
Drop a little Marvel Mystery oil down each spark plug hole and let it sit overnight and try again.

[TwoTired]

Got a center stand?
Use it, and select top gear.  Can you make the motor turn from the rear wheel?  If not, take out the spark plugs and try again.
You could also roll it around the garage while in top gear and the plugs out.
That would tell you if the engine siezed.  (probably not).

Got a DMM?  Monitor the battery voltage while you bridge the big terminals on the solenoid.  If it is drawing current, the voltage will drop.  If the starter is shorted armature to field (bad bearings) the voltage will drop a whole bunch.  However, a bad battery will also drop lots of voltage with normal starter loads.
It IS possible that a new battery can be defective.

If the voltage doesn't drop at all with starter connected, then the brushes or wire connections are open.

Cheers,

[alfredreed]

Thanks, lots of good suggestions since I last posted. I will have a little free time tomorrow morning and will put them to use and get back to post the results.

I will be surprised if the engine is seized because I added a good amount of Sea Foam to the tank and ran it well before storing it, so the cylinders shouldn't be suffering from raw gas rust, but.......

[DaveBarbier]

I agree with CBGhia that it could be a red flag that you're using one battery to test off the bike and a different battery to test on the bike. I know you say it's not the battery, but it's super easy to hold the starter in your hand while touching to the battery that's in the bike. Just to be COMPLETELY sure

Also, if you're rotating the engine with the starter in it, make sure you rotate the proper way (same direction as the wheels turn). The 650 starter doesn't spin free hand so it will bind if you rotate the motor the opposite way. Or just remove the starter and spin either direction.


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