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View Full Version : starter rolling slow....R75/5


James.A
03-25-2008, 09:55 AM
Here's the deal, 2 R75/5's. Both 1973's. Odyssey batteries in both. Both over 80,000 miles.

1 of them, (white) which I acquired in 2000, started right up after 30 seconds of cranking last week, having been in hibernation over the winter.

The other, which I acquired in 1989, has always been been reluctant to start in cooler temps. When I installed the odyssey 2 years ago it helped with the slow starter problem, but this year, the starter performance has degraded to more typical difficulty. The battery shows good surface charge(12.6v) and stands up well to a load test. Still the starter rolls slow and makes the ratcheting solenoid sound usually associated with a weak battery. At this point I swapped out the starter with a spare that I saved from a 1974 R90/6 parts bike that came my way several years ago. The result was much the same. My next operation involved a bench re-build of the original starter that involved new bushings and brushes, polishing the commutator, a good cleaning and lubricating the drive mechanism. Still the same result when installed. At every step, I pulled the plugs to compare the starter performance with and without motor compression. In each instance, the starter (either of them) would roll the motor faster and with minimal solenoid ratcheting when not fighting compression. For todays effort I connected an automotive battery as a jumper, and then the motor cranked for less than a minute and started right up.

Now I'm quizzing the readers here. I'm not opposed to buying and installing one of those Nippondenso starters that have come available in recent years. What are the chances that 2 Bosch starters of nearly equal age would be similarly rendered lame? Am I missing something? Any ideas? I am less inclined to dismantle the running bike to swap out parts.

felaw
03-25-2008, 10:31 AM
I traced my loss of power in the starter to the cables. You couldn't see the corrosion at the terminals but under the cover the wires were dicey especially at the battery end. Same with the ground from the battery to the transmission. Just for the heck of it I got some cables at Napa about the same length and they're still on after a few years. It's just a thought.

keelerb
03-25-2008, 11:26 AM
Check voltage drop from battery all the way to positive terminal on starter. If it's not insignificant, you can then check various portions of the connections from the two endpoints.

James.A
03-25-2008, 12:09 PM
Check voltage drop from battery all the way to positive terminal on starter. If it's not insignificant, you can then check various portions of the connections from the two endpoints.

Great idea!, I'll give that a try. I replaced the ground cable last sunday with a short cable from Autozone. The original was less than great at the transmission end. Now, several hours after having been jump started out of a long sleep, it will start on it's own but still not rolling over very well.

Braddog
03-25-2008, 12:44 PM
Having had some starter issues on my RS, I think going the electrical route is definitely the way to go. A new battery compensated for my crappy starter for awhile, but eventually, I had to rebuild it. Now it'll start even with a crappy battery.

Just because your battery shows 12.6 at the terminals, doesn't mean that it's providing all the cranking amps that you want it to at the starter. As others have suggested, check your drops along the cables.

Also, don't discount the fact that even your new battery may not be quite up to par. You could always try swapping batteries with your other bike.

I'll wait patiently for this to be solved. Please be sure to share the solution with us, Jim, when you get there.
:lurk

boxermaf
03-25-2008, 09:23 PM
I am not as familiar with /5 electrics, but if this were a mid-80s airhead I would also check the starter relay while checking the wiring. If contacts
are corroded/worn or not making good contact your going to get less juice. Just another item to check !

James.A
03-26-2008, 06:01 PM
....it was the battery,... the very first thing that needs to be put right. Details to follow.