Need Bosch starter advice

[driggs]

Bike is an '88 RT with around 105K on the clock, new to me last summer. The starter was a little lazy from the beginning, and testing the battery revealed it had a dead cell so I replaced it. But even with the brand new battery, the starter still wouldn't spin the motor all that vigorously so I planned on replacing the starter. I should mention that the starter relay seems to work fine and all of the electrical connections appear to be clean and corrosion free. I pulled the starter relay, cleaned the contacts and greased the connections with dielectric grease. Everything was pretty clean before I touched it.

I pulled the Bosch starter this afternoon and disassembled it. There was dried grease and carbon dust on the gears and armature, but after cleaning it up and inspecting, I found that it didn't look too bad. The bushings look good, the brushes are still serviceable and the surface where the brushes ride on the armature is within spec and was clean. Testing with an ohmmeter shows no failures or shorts in the windings.

So now I'm not sure what to do. I planned on a new Enduralast starter, but now I'm not all that convinced that it will solve my problem. I could reassemble and see how it spins after the cleanup, but I find it a little hard to believe that some carbon dust and a little grimyness choked the starter so much that it slowed it way down like that.

Anyone offer advice or experiences? Thanks!

[SteveD]

reassemble and see how it spins after the cleanup

You might get lucky and save some money for petrol..

[chasbmw]

I would replace the bushes anyway, wear here is the main reason forbosch starters slowing down.

[Ken in Oklahoma]

. . . Testing with an ohmmeter shows no failures or shorts in the windings. . .

A few thought come to mind, condition of cables, condition of connections, and validity of testing.

I presume you've done a bench test with the starter, that is to connect the bare starter to the battery, and watching that it spins freely. To do that you would use a jump cable to connect the battery negative to the starter body and then jump from the body positive to the post where the solenoid output connects to the starter motor. You'll want to control the starter motor because it should jump.

I also wouldn't trust a multimeter to evaluate high current/high load starter performance. A meter may show good continuity (i.e. low resistance) but the starter demands amps where the meter demands milliamps or microamps.

I'm presuming you've already "scrubbed" the high current connections. Another area of concern would be hidden damage within the battery cables. Sometimes corrosion will work itself under the cable jacket and you have a bad cable to terminal connection and don't know it. With everything buttoned up ready to go, I would place a jump cable parallel to the negative battery cable to ensure a good current path. It would be harder to jump around, but I would also suspect the positive battery cable, devising a way to jump around it once you've exhausted other avenues.

I presume during all your testing that you've never heard the sound of the starter solenoid clicking/chattering. When you hear that it's a dead giveaway that there is insufficient voltage under load to the starter. The voltage could be low due to a battery that can't deliver the current, the cables, or connections that aren't passing the current.



Ken

[dougie]

+1 what Ken said about battery cables.
I replaced mine by making new ones with #4 welding cable.
That and a new battery was all it needed.

[Roy Gavin]

EME sells the Valeo knock off for around $120-, and upgraded battery cables for around $20-.

So you can change the relay as well and it will still cost less than a third of the fancy alternative - I did over 3 years/110,000 km back and everything is still working the way it did when it was fitted, and that was perfectly.

[driggs]

EME sells the Valeo knock off for around $120-, and upgraded battery cables for around $20-.

So you can change the relay as well and it will still cost less than a third of the fancy alternative - I did over 3 years/110,000 km back and everything is still working the way it did when it was fitted, and that was perfectly.

This was the route I was going to go, but I was really expecting to see the lazy starter to be in worse shape than it was.

I think I'll do it anyway, new starter, cables and relay, then I'll be set for the next 105K!

[Garnet]

EME sells the Valeo knock off for around $120-, and upgraded battery cables for around $20-.

So you can change the relay as well and it will still cost less than a third of the fancy alternative - I did over 3 years/110,000 km back and everything is still working the way it did when it was fitted, and that was perfectly.

I had one of those in the /5 I just sold. It seemed to work better, or at least was quieter than the genuine Valeo that I have in my conversion.

[dougie]

Another starter option -
http://www.motoelekt.com/starter.htm