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Starter only works when cold

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VikingRider

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The starter on my 95 Fatboy only cranks when the engine is cold. When I turn it off after the engine is warm (oil temp 150 degrees plus) the bike won't start. All I hear is a click from the relay. When the bike has cooled down, the starter works fine again.

I replaced the starter relay, but the problem still remains.

I've ordered a solenoid-mounted push-button starter, will this do the trick?
 
That will do the trick but the problem could be either in the solenoid contacts , the brushes in the starter or a bad connection on the battery. Could even be the contacts in the key switch too. Worth exploring in any event.
 
My guess is that it is going to come down to being the armature in the starter,if they have been overheated in the past it is not uncommon for the winding to be damaged and the shellac burnt off and will only create a full curcuit with the brushes when cold.It will only do this for a bit till it gives up completely.
 
Could be a bad cell in the battery or bad connection(s), way to tell is too do the "poor mans" load test, look at how much the headlight dims when starting the bike cold and when the bike is hot...with more engine compression, the starter stall speed and current draw is at it's worst. If headlight nearly goes out, you definitely have a low voltage problem...and is best to tackle the easy stuff by scrape'ing all heavy primary wiring: plus, minus and starter at both ends, have the battery load tested. When starting the starter can draw 150-200 Amps especially when hot. As Steve says, the last thing to change out is the starter (the most costly and time consuming item to troubleshoot).
 
Thanks all -

Turns out the bolts connecting the starter to the primary had loosened. When I wiggled the starter, it worked again. So I tightened the bolts - with LockTite this time - and that fixed it! Don't know why it worked when hot, but all's well now.
 
Things expand when hot so it probably had an electrical path to ground to complete the circuit when it was hot.
 
VikingRider said:
Thanks all -

Turns out the bolts connecting the starter to the primary had loosened. When I wiggled the starter, it worked again. So I tightened the bolts - with LockTite this time - and that fixed it! Don't know why it worked when hot, but all's well now.
Click to expand...

Your original post in this thread said it only worked when cold????
 
VikingRider said:
Yes - typo. It worked when cold, not when hot. Don't know why, but after I tightened the bolts it works fine either way.
Click to expand...

Does actually make sense. When cold, the metal bolts had contracted enough to reestablish a ground (your negative cable is attached to one of those starter mounting bolts). Once the bike heated up and everything expanded, the loose bolt and the difference in thermal expansion compromised that ground - click, click, click!!

I would bet that the majority of starting problems or just electrical problems in general are associated with the battery connections and related grounds. Taking the cables off periodically for a good steel brushing and resecuring is pretty good advice. Then do the same to the other end of the cables and the miscellaneous grounds around the bike.

TQ
 
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