XJ900 Starter Motor - The Benefit of Experience

Over the last week or two it has been getting noticeably harder to start the engine, moreso when having ridden for a bit, turned it off and tried starting again. Press the starter button and it sounded like a very weak battery in operation. But, having been down this path before the first place I looked was IN the starter motor.

Sure enough, once off the bike I opened it up it was like the black hole...literally...dark powdery carbon deposits everywhere and especially on the commutator which was nearly all black anyway covered in this dust. Took out the armature and cleaned it up and made the commutator shiny again. But, the commutator has a distinct groove in it so I guess it must be coming to the end of its useful life; 25 years ain't all that bad. Anyway, and hour of my time after work one evening had it all going again...it helps if you have a good idea of the first place to look for a problem. Ahhh...experience! All those blind alleys and frustrating searches actually has a plus side eventually.

Popped everything back together again, clean and dry, hooked it up and bingo, a strong start straight away. New brushes on order though as the old ones we getting a little short.

Question: anyone got a good contact for either a new or very good used armature that's not going to cost an arm and a leg, or...a used or reconditioned starter motor for a 1985 XJ900 that if I order through the post I will be guaranteed of getting one that is in good workable condition and that the insides are in much better condition than the commutator on mine (the groove worn by the brushes on the comm are quite distinct).

 

I wonder what THESE guys would charge to rebuild your starter motor..

 

You're NOT limited to a Starter from the 900 Family.

Yamaha used the SAME Starter on a whole bunch of Pushbutton Starter-upper's.

The whole line of Xj-750's have Starters that will fit the 900 Bikes.

 

Hi Wiz...I rang that crowd you put up the link to and they were helpful in saying that they don't usually do starter motors or things that small. Mainly industrial type motors up to around 6000 kilowatts!!! Might be a bit powerful for my starter motor unless I wanted to see pistons and bearings flying in all directions...

They did say that to replace the commutator they would need to rewind the armature in it could cost around $600 - not cheap and I could probably find one at a wrecker for much less. And as Rick said...all XJ's around that period had the same motor.

I guess ebay might be a line of enquiry now.

Cheers.

K.

 

I read the list of companies they deal with & Yamaha was there, hey, ho.
Have you called Ron at Pakenham Wreckers, 5940 2402

 

I believe KZ750 starters are the same as well.

You can pull the center carbon electrode in a carbon-zinc battery (the cheap ones) and shape it to size in a pinch.

 

Well I have a happy postscript to this little story.

After cleaning up the original starter motor the other day it worked really well for a couple of days and then it started getting sluggish again. I guess the commutator is probably getting to the end of its useful life...there's quite a groove on the commutator so with worn brushes I guess the connection and flow of current is getting a little tenuous. Maybe it might be improved for a while with new brushes but one day that commutator is going to give up the ghost. I'll post a pic this weekend if I get a chance.

Anyway,cast around and let my fingers do the walkin' and came across ACE Motorcycle Wreckers in Bell St Heidelberg (for those in Oz and other locals) and they had no less than 4 starter motors from XJ900's...at $150 each.

Went down there this morning and picked one up, bolted it in place and hit the starter. Vrooom...no problems.

I'll keep the old one as a spare or for parts but I think this new/old one I just got might see the life of the bike out. I'm tempted to pull it apart and check the inside but might leave that when I have a few days off from work and can do a big service on the machine with some outstanding jobs...new clutch cable, stainless steel brake lines and a couple of other improvements.

Pics of the armature/commutator on the way for interest soon.

 

Good outcome and thanks for the update! Hard to know if a starter from a wreckers has a similar problem but it sounds like you got away with it!

 

Re: XJ900 Starter Motor - Pics of the Commutator

Ok...as promised, photos of the starter motor commutator. Three photos from varying parts on the commutator. Some areas not worn much but others are worn down and the ratio of brass to mica as you can see is huge. No wonder it was causing problems. And...this is clean. When I took it out the first time it was covered in black carbon dust thereby adding to the problem.

Check the photos and see what YOU think.

 

Where are the pictures, Red?

 

Hmmm...I'm working on it. What did I miss doing?

 

You missed posting the pictures.lol...........

 

Very funny...how do I insert it into a post. I can add it to the gallery easily enough.

 

Ok...I have uploaded 3 photos of the commutator for the starter motor. They are in gallery so please have a look. When I get a few extra moments later I'll insert one into a post.

Anyone who looks, I'd be interested in their opinions.

 

Re: XJ900 Starter Motor

Ok...one photo below of the starter motor commutator. The other 2 are in my gallery...go for a wander and have a look see...

And let me know your opinions if you think it has any serviceable life left in it:



red

 

That would make an excellent small boat anchor, or perhaps a door stop.........!

 

There's a technical term for that commutator, Red:

Done.

 

Re: XJ900 Starter Motor - Pics

Finally managed to insert the photo into the post...! Two more pics in my gallery for interested XJers.

 

That is "Cattle trucked" where I come from!

 

So I guess no-one is surprised I was having trouble with starting the bike! And, imagine that commutator covered in fine black carbon dust from the brushes. It must have been a miracle that it was turning over at all.

Interesting thing though if you have a look at the other 2 pics in my gallery is that the other side of the commutator looks in fairly good condition but the side that's shown above is heavily worn.

Not sure why one part of the surface would wear down more than other parts as I would have thought it gets even use over time when in contact with the brushes. Maybe 20+ years of use tends to cut into a slightly softer part of the metal etc.