Is it the starter motor?

[neat street]

Hi all, just round to trying to start the 500 and it kicks over OK, but when trying to use the button, it clicks and sometimes turns very slowly for very short time. I think the starter motor may be U/S but anyone got other ideas or how to test please?
I am using a car battery at the moment fully charged with the earth going straight to the frame (cleaned part) and the other to the terminal. Thank you in advance

[TrickyMicky]

Try putting the earth to the gearchange shaft, no paint or grime to impede the current.

[McCabe-Thiele (Ted)]

On my Superdream I stripped and cleaned the starter motor, very satisfying job.
I fitted some new brushes that came with a bunch of spares, new long bolts were available.
I suspect the 500 starter is a similar design.
A recent post by a 400 owner here  with a quite similar issue.

[Otis]

If there is another bike nearby that you know of perhaps a good idea to swap over the motors as a very easy thing to do,

[Coppertop1234]

Mine was the issue on the 400 even though it started first click.
You would not believe the difference in the speed of turn over when I put a replacement in

You may be able to clean carbon out and sort it or new brushes if an option


I was fortunate enough to have a spare available

[Oddjob]

I’ve seen one, and one only where the bronze bush in one of the end caps went oval, it would spin sometimes but not every time. However it took so much power to get it to spin that the battery was dead within seconds and the motor was starting to smoke.

I’ve got a few spare starter motors if you end up needing one but they are heavy as you know so postage would be high I reckon.

I’ve also started to mod the cable entry into the starter body, I’ll bet yours is like them all, braided cable showing bent at 90 degrees? I cut the cable off, solder on a stainless steel nut and bolt and replaced the black cable with some nice red cable. If it’s carrying high power it should be red imo, I even made a new battery to solenoid  cable in red. Just looks better and less chance of confusing it with the neg cable.

[neat street]

Thank you all for your helpful tips..
Tricky Micky, the earth is on a nice clean section with no loss of current, so thank you, but this is not the issue here.
Ted, Thank you for the suggestion, could be an option, I supose that will be the next step, strip and check :-)
Otis, only have a CB750F1 which without checking, I think is different to the 500??
Coppertop, as this was a full rebuild, It wont start that easy I`m afraid as I cant get it to run and do the fine tunning... Lucky you had a spare :-)
Oddjob, Thanks for the suggestions, I guess the next thing is to take off and check. Maybe check the comutator for carbon build up and see if I can get some carbon brushes?? Good idea on the red cables.. maybe something worth thinking about later if I can get this one working :-)

[Oddjob]

Just an idea but the starter earths through its 2 mounting bolts, the oring around the part in the engine isolates that part as it’s essentially rubber. If you’ve painted the crankcase maybe the earthing point is compromised by paint. Not sure if the metal spindle in the motor would make an earth, possibly.

I’ll post some pics of the starter motor modifications if you’re interested.

[neat street]

Thank you oddjob, yes plese post the pics of the upgrade :-) no paint done around the area, but thanks for the thought.

[neat street]

Well, after getting the starter out, have found that the bearing has gone oval and allowed the armature to rub on the stator.... I have checked for coninuity from the comutator and the main shaft and also the the laminations and I have continuity, so from here I would say its toast :-( found a couple of second hand ones on ebay, next stop order one.
Thank you all again for your input :-)

[Oddjob]

Not anywhere near as bad as the one I had but bad enough I suppose. How much are the starters on eBay inc p&p btw. Not sure how many starters I have but you’re welcome to one if it helps. Just cover postage. I was going to mod them all and sell them but that looks a little optimistic at the moment with my health.

[neat street]

Thank you for the offer, but ordered one this morning asking for 48.99 plus 6.95 post or best offer, paid £44.95 all in.
How is your health now? hope your much better and still improving?

[Oddjob]

Getting better. It’s kinda subjective though, as soon as I tell the doctors that they start to test for something else. I’m kinda tired of being prodded and poked.