Starter motor failure under load

[sax_000]

Has anyone had a genuine starter motor failure?  I don't mean the "hot, no start" problem (i've had that in the past), I guess you'd call this a "stone cold, no start" problem.  I havn't ridden the bike for a month or so, so I charged the battery for 24 hours.
I hit the start button and just got a 'click' and a 'whirrrr'.  The battery (SSB RTZ14s) is 7 years  (!!) old so I figured that was the problem so I bought a new battery (same model), charged it for 12 hours, whacked it in, hit the button........  and exactly the same result ('click, whirrrrr').
Thinking that there might be a problem with the new battery, I got the emergency battery cables from the car and connected them directly to the power input post on the starter motor and a frame bolt (earth) and then to the car battery (only about 4 months old and working fine). The engine turned over but really slow, like 1 rev every 2 seconds.
So the problem has to be the starter motor, right? I should mention at this point that the bike is a '12 SE with the revised 9 spline starter system and Stoltec fat power cables.
I pulled the starter motor out and connected it to the car battery and it spun-up fine (well, as far as I know, I've havn't tried this with a "good" motor).  I figured it might just need cleaning-out (bike is 11 years old with about 50,000kms).
I dismantled it and it was much cleaner inside than I expected but I gave everything a good clean with isopropyl alcohol and had a good squizz at everything.  The brushes were good (new-12mm, mine - 11.6mm) and the brush copper cables looked good. I ran a full continuity check (thanks Pommy guy on Youtube for a full tutorial) and everything seemed fine.  I bent the earthing tangs on the brush plate VERY slightly down to ensure a good earth contact on reassembly.
Put it back together, spun it up on the car battery (did it spin a bit faster than before? Not sure). Put it back in the bike, connected the starter directly to the car battery again, but still the same result - very slow crank about 1 rev every second (so slightly faster than before).
Figured this had to be a "load" problem so I removed the spark plugs (isn't it a fun time removing all the bodywork, tank and airfilter box to get to the plugs?), connected the starter directly to the car battery and it turned over reasonably fast (maybe just fast enough to start the engine). Put one spark plug back in, tried again and much slower. two plugs in and really slow.

So I figure the starter motor is kaput.  Has anyone had a similar problem?

A new starter motor from Triumph is about AU$1300!!!  I can get a starter motor from Rick's Motorsport (not OEM) for about AU$500 delivered.

Anyone got any other ideas?  I'm all ears.

Seeya

Saxo

[Freddy]

Replace the starter relay.  It sounds like the contacts are burnt, which they were on my son's Tiger when we opened it up.

[sax_000]

To quote Dr Frankenstein - "IT LIVES!!!

I reassembled all the bits I took off (in particular, the starter motor and battery) and pulled out the solenoid from where it hides under a frame rail. I disconnected the cable from it and gave it a good squirt of Inox and then shorted the two terminals with a 19mm spanner.  The engine immediately turned over at good speed.  I turned the key on and hit the start button.  On the first push nothing happened, not a squeak, so I hit it again and the engine spun properly. I put the fuel tank back on along with all the various hoses and couplings, hit the start button and away it went!  Success!!!

I'm not exactly sure what fixed it, it may have just wanted some TLC.

Seeya

Saxo

[Freddy]

Nah, it wants a new starter relay/solenoid.