hot starting problems

[Guest]

My bike (in sig) starts fine when cold, but when it has been run for a while the starter has a hard time turning the engine over, wont flip over enough to start.
After the rebuild now that it is getiing broken in and compression is coming up this has started to get worse.
I have checked the charging system, new battery just topped up with fluid (distilled water).
I am looking at the cables to the solenoid and to the starter and the ground wire to the engine, and they seem kinda small, would upgrading to larger wire help? Or maybe my starter is starting to die
Ideas?

[hampshirehog]

75% of the time the problems you describe are caused by worn starter motor brushes and / or a dirty armature. Brush minimum length is about 1cm I think but your manual will tell you for sure.

Make sure you check your earths first though.

[gearhead13]

I have never taken one of these starters apart.
Do these starters have roller bearings or plain bearings?

[hampshirehog]

You don't have to worry about the bearings - you'll see where the brushes fit in when you've removed it from the bike. It's a real easy job and I think you can pull your starter without having to remove the carbs.

[Texas Don]

No bearings to pull. Your starter has bushings. Pull the starter and disassemble it. It is really pretty intuitive. Replace the brushes and reinstall the starter. It's about a 1 hour job from start to finish if you've never done it before. Don't forget to mark the starter end caps so that you can install them back in the same relative position.

[DanTheMan]

75% of the time the problems you describe are caused by worn starter motor brushes and / or a dirty armature. Brush minimum length is about 1cm I think but your manual will tell you for sure.

Make sure you check your earths first though.

The other 25% of the time (or more) it's because your carb float valves are leaking by when it's hot and your cylinders are full of gasoline causing a hydrolock situation that the starter can't turn against. Eventually it'll cause starter failure, thereby escalating the problem. A leaky petcock assists in the problem.

[1_v8_merc]

Here's some pics from my starter, that was worn down.


----This is where the starter is located, I had to raise the carbs up to get to the starter motor.





This is one end of the starter motor casing that surrounds the actual motor.
You can see how those 2 contact pieces are worn down, and aren't working correctly anymore.





You can clearly see how worn the contact surface is, just sprayed it with contact cleaner and took a knife in between each metal Rectangle to get rid of the crud in there! That way the 2 contact pieces above are able to get to it.
(sorry don't know all the technical terms!)






I dunno, this is just a gear that goes into the motor-side.

[49er]

Could be a leaking petcock, but you might be running too tight ring gaps.

What ring clearances did you set, during the engine rebuild?

When the engine is cold, you would have enough clearance to prevent ring binding. As the engine reached running temperatures, the ring ends could be touching. If this occurs, you would normally hear odd noises from the internals, at idle.

[landshark]

What about Valve clearance?

[DanTheMan]

What about Valve clearance?

If the valve clearances are too tight, cold starting would also be a problem.

[chuck hahn]

The things in the cover are called brushes and the motor part is called the armerature. I would take the whole thing to an old school starter repair shop and see if they could replace the brushes..no harm no foul for a quick trip just to see.

[chuck hahn]

which bike..you got 3 listed........

[gearhead13]

This started when I went to check compression for the first time after some head work I had done, 1,3 and 4 were at 150-165 psi and #2 was at 140psi. I put the plugs back in and it wouldnt turn enough to start. Last I checked the charging system was working fine. But I went down after she cooled down a bit and checked battery voltage and it didnt go higher than 12.4 v. Stator tests out fine so I suspect its the RR.
So, part of my problem seems to be the charging system, although it has struggled to turn over when hot for quite some time. So, I think I will take the starter apart to have a boo, although this engine only has ~40k km on it or so. The ring gaps were right on the money when I put this together, so I think I am ok there.
This is my only bike and the only transportation I have when the wife has the truck.

[old_chopper]

If your ring gap was tight enough to touch and bind I'd expect the engine to try to seize breaking the ring, piston, both, more... That is usually a catastrophic failure.
Change the brushes and clean the entire starter really good. Cable size from the factory was good enough but the cables may have corrosion inside the insulation. (maybe)

[chef1366]

Try Stockers.com and buy a rebuild kit for the starter.
If your compression is so high that a stock starter will not turn over the engine I'd worry about pump gas.