Starter turns engine very slowly when hot.

[William_86]

this problem seems to have lots of causes...

for me it can be..

weak battery, charging system (!), weak starter, a burned wire...

i tested by bike with the battery of my firends 93 750cc nighthawk and didn't got to start.. tested his bike with my batery and worked perfect... but after buying the batery charger and charged 100% started fine when cold but seems like my alternator isn't working 100% and it wont start if hot

[dank]

Hi,
Yes, it can caused by many different things. In my case, after doing all the preliminary wiring, connector, contacts checking, battery load test, including installing a brand new gel battery on it, I rebuilt the starter with the kit I got from eBay ($28.), and finally got to do it last week.

It now spins the engine so fast I find it hard to believe. It works great both hot and cold, no difference in performance, that I can tell. I only noticed a slight scratch in both the armature and the stator, as if some piece of metal had been going around, but I don't think that was the problem. More likely the armature contac bars needed cleaning, and it needed new brushes. I cleaned the contact bars with a good pencil eraser.

Thanks to everyone in this forum that gave me advice on the subject. It's not a job for the faint of heart, but if you're good with your hands, you can do it.

I also have a good tip on how to remove that little bearing against the armature contacts. I went to an starter shop and asked them for help because I didn't have the special puller needed to remove it. He said: "yeah, it's called prybars". He proceeded to put the armature in a vice, horizontally, so that the bearing was just at the end of the jaws. He then used two 24" prybars, and, using the vice jaws as the fulcrum point, put either tip of the sharp edge of the prybars on the edge at the rear of the bearing, pushed on the bars ever so lightly, and it came out like butter!!! He offered to install the new bearing in, which took 2 seconds, and didn't even charge me for anything!!

Cheers!