Starter Turns Slowly

[Arclight88]

The starter turns very slowly at first then speeds up, almost as is the starter motor itself is cold but gets warmer with spinning.

Motorcycle will start, but not until the starting revs are 'faster'.

Brand new, appropriately charged battery was installed 11/26/11. Ground strap from Batt to engine block removed, connections wire brushed, and reconnected. Batt has full charge (13.6v no load/12.1v with test lamp circuit). Still the starter turns slowly. I suspect the starter relay, circuit wiring, or the starter brushes.

Any thoughts would be appreiciated.

 

[drewpy]

the starter relay may or may not create a resistance but its quite rare and if it works, it will work well.
I suspect brushes myself, but you may just get away with cleaning the commutator, the copper fingers the brushes rest on.

could be just that the bike hasn't been used for a while and is a bit clogged with a higher internal friction due to standing?

 

[Arclight88]

the starter relay may or may not create a resistance but its quite rare and if it works, it will work well.
I suspect brushes myself, but you may just get away with cleaning the commutator, the copper fingers the brushes rest on.

could be just that the bike hasn't been used for a while and is a bit clogged with a higher internal friction due to standing?

Thank you, Drewpy. That it is a good thought on the relay. I have seen them fail, but I have not experienced them merely degrading over time.

So I think I will commence with maintaining the starter.

I think your idea about the bike not having been used for a while has great merit. I worked for some time in the aircraft maintenance anaysis section of a busy maintenance depot. The planes that required the most care were the ones with the least operational hours. Do not let machines built to operate sit idle - it's hard on them!

 

[63-Coupe]

Try jumping directly from the battery to the starter side of the relay. If there is no difference then you have definitely eliminated the relay as a problem.

I know you have cleaned the ground strap between the block and battery but it could also be a poor ground to the starter body itself. Over the years I have learned the hard way to meticulously eliminate any grounding issue first on any automotive electrical problem.

 

[Arclight88]

Try jumping directly from the battery to the starter side of the relay. If there is no difference then you have definitely eliminated the relay as a problem.

I know you have cleaned the ground strap between the block and battery but it could also be a poor ground to the starter body itself. Over the years I have learned the hard way to meticulously eliminate any grounding issue first on any automotive electrical problem.

Sounds good, I will try that and post results before I get into the starter.

 

[Arclight88]

Sounds good, I will try that and post results before I get into the starter.

So I tried the test of connecting the Batt to the starter relay hot post. This was accomplished by, firstly, removing all connections to the Batt, then grounding the Batt to the engine block with a jumper cable, then a like connection to the starter relay hot post. The result was that the starter still turned slowly.

Which leads me to believe that the starter brushes, or the commutator, needs to be serviced.

 

[63-Coupe]

I agree that more and more it is looking like the starter itself but that is assuming that you have a good ground between the block and the starter. So far you have eliminated the starter relay, the starter button, and the ground to the block, however before you take it apart give it on more quick and easy check to ensure that the ground betwwen the starter and the block is good. Just because you have a good ground to the block do not assume that means you have a good ground to the starter.

Earlier this year I bought a running parts bike with a supposedly bad starter. It would only just make a clicking noise when you hit the button. I wasn't concerned because that was not a part I was after. When I did mess around with it however it turned out that the bolts holding the starter in were not quite tight enough so it did not have a good ground. Gave the bolts a little more torque to snug them up and the starter has been working perfectly ever since.

I also ran into a similar problem with an F-150 that I had where the bell housing had some surface rust and the face of the starter motor was not getting a good connection. I had that mother out of the truck 3 times before I concluded that there was nothing wrong with the starter. A quick wire brushing of the bell housing and that starter was still working perfectly when I sold the truck 8 years later.

Good luck and let us know how you make out.

 

[Arclight88]

I agree that more and more it is looking like the starter itself but that is assuming that you have a good ground between the block and the starter. So far you have eliminated the starter relay, the starter button, and the ground to the block, however before you take it apart give it on more quick and easy check to ensure that the ground betwwen the starter and the block is good. Just because you have a good ground to the block do not assume that means you have a good ground to the starter.

Earlier this year I bought a running parts bike with a supposedly bad starter. It would only just make a clicking noise when you hit the button. I wasn't concerned because that was not a part I was after. When I did mess around with it however it turned out that the bolts holding the starter in were not quite tight enough so it did not have a good ground. Gave the bolts a little more torque to snug them up and the starter has been working perfectly ever since.

I also ran into a similar problem with an F-150 that I had where the bell housing had some surface rust and the face of the starter motor was not getting a good connection. I had that mother out of the truck 3 times before I concluded that there was nothing wrong with the starter. A quick wire brushing of the bell housing and that starter was still working perfectly when I sold the truck 8 years later.

Good luck and let us know how you make out.

Thanks, 63-Coupe.

That is logical, and I can try that too before I actually get into the starter.

My Haynes Manual does not appear to list the torque spec for the starter motor, but it does list a range of 5.7 to 7.2 ft/lbs for 6mm bolts. I am tempted to use these values on the starter mount screws...unless you have an alternate suggestion.

 

[63-Coupe]

Try grounding the motor with a jumper wire first. If that does it then tightening the bolts may resolve it like on mine. If that doesn't work you have now pretty much eliminated the circuit to the starter and the ground as being the culprits so you are probably finished with the quick and easy stuff and are into the starter itself. I have never done one myself but from what I have seen it should not be too difficult a job.

I did not use a torque wrench on it. All I remember was that when I put a socket on the two bolts both were snug but not tight. I did not really lean into them, they are only 6 mm after all, I just tightened them up a bit, less than 1/4 turn, and the starter worked fine after that.