Uh-oh, Oil in my starter. What gives?

I got the bike back together today, looking forward to firing it up, but my starter motor had other plans. It cranks (albeit slower than it should), but would not start the bike.

So. I took it off, opened it up, and there's oil everywhere, even at the opposite end from the starter gear. LOTS of oil.

There doesn't appear to be a seal at the bearing end which goes into the motor, and the bearing is fine (not loose), so why am I getting that much oil in there? I know I don't have any restrictions in the crankcase breather. I'm stumped.

What do you think?

 

My starter had the same problem. Couldn't work out what it was either.

I beleive I have fixed the problem but havent had the starter off for a while to see if it has got any more oil in it. Might take it off today and have a look.

Basically I think I solved it with two new O-rings at each end of the starter assembly where the end housings attached. My old ones were very loose and as my engine is very tired I reckon the engine is breathing too much.

My theory is, If the starter is not sealed tight then the engine breathing is slowly allowing crankcase fumes and oil to get into the starter. Also grease the gears in the starter as this has the added effect of helping to seal the shaft.

Hope all this makes sense and helps.

Dont forget to give that starter a GOOD clean and rub the stator and brush connections with some fine sandpaper.

 

Thanks! Good to see I'm not the only one.

You know what? I had that same thought about the engine breathing too much, especially since I'm not running the stock airbox. (I got it this way)

I just got done cleaning it up (and did sand it up pretty good) and got it back together, but it's still performing pretty marginally. I'm afraid I might have to replace it with a reman. (The armature has started to "lobe" on the commutator, which chewed up the brushes pretty good since the last time I had it apart).

I think it might just be past it's prime (wiring, magnetic fields, o-rings, and all).

I'll let you know what comes of it.

 

Eek! Is it possible that the PO lubed it with oil? There is no direct path for oil to get that far into the system that I am aware of. Is oil leaking onto it from above or in front of it? Just some quick thoughts.

 

Check out http://www.oldbikebarn.com/motorcycle_p ... %20Brushes for starter compatibility with other models. They are a standard Mitsubi starter.

I ended up putting a starter form a KZ750 in mine as I found one at the wreckers in excellent condition.

Parts here are a little hard to find for the XJ550's.


Just had to change the end plates and it fitted perfectly.

Cheers
HG

 

Robert, Oil can get in to them via the shaft which is internal to the crankcase. There is no seal inside apart from the sealed bearing in the front shaft. While my bearing is still in good condition replacing it is a bit risky to change as it is pressed in to the flimsy alloy housing. Pressure from the crankcase can force oil through here.

Only small amounts of oil can pass through here but over time it equates to enough to clog up the brushes.

Another problem can be the gears inside the starter. If the engine gets hot the grease can "melt" into an oily substance and there are no seals between that area and the brush end.

Grease choice could be an issue. Maybe a higher temp, less dissolvable grease may be in order.


Cheers
HG

 

Humm... reviewing the manual I see that you are right Goon, I am educated once more. Thanks. I regularly pull my starter, clean and regrease the little bugger with high pressure Moly grease. Haven't experienced oil intrusion (yet, God willing, never). There would have to be quite a bit of case pressure to get the oil into that local when the PCV system is right there with a vacuum applied. Gad, I'd hate to have that going on in my case, what a mess! New rings, bearings, ouch, lotta dough.

 

Well guys, the starter's apart again, and I'm having a guy at work turn the commutator on a lathe to clean it up. The brushes were totally worn to the end of their travel, and the bushing for the drive gear end of the armature is a little sloppy.

Fortunately, a rebuild kit including brushes, brush plate, shaft bushing plate, and o-ring seals is available from cyclewareables.com for $89 (US). If for some reason that doesn't pan out, I found a remanufactured starter for $189 (US).

As for the "oil inside" problem, I think Hired_Goon is right on target. With my crankcase ventilation hose just hanging out the side of the bike (with a chrome filter attached to the end), it doesn't have the same "draw" as it would attached to the stock airbox (my bike has the four pod filters, one on each carb). With the starter o-rings poorly sealed from age, the crankcase vapors are just finding their way in over time.

Hopefully this rebuild will do the trick!

Thanks for your advice, guys.

 

Here's an update. I've been riding for a couple weeks since the starter repair, but I sort of took a shortcut.

The $89 rebuild kit was on backorder for who knows how long, so I let the beautiful weather pressure me into just getting a new brush plate with brushes from the local dealer. That means I didn't get new seals for the starter case. I tried regular o-rings, but they just squeezed out of the grooves.

I'm afraid to open up the starter again because I know there's bound to be oil in there. But I think I'm going to have to open it up again, clean it again, and just apply some sealant to the seals.

By the way, the new brushes made a HUGE difference (even after two days of sitting, I just touch the start button and she comes to life), and the new Progressive Fork Springs and new fluid feel great. I highly recommend them.

Thanks again for your advice, guys.

 

Here is another thought. If the oil continues to intrude in large quantities, you may need to have the housing (reduction gear box or the motor casing, the Haynes shows bushings in each) for the input shaft bushed with a new bushing. How much play does the geared shaft have? Anyone know what the tolerances are supposed to be? The Haynes doesn't specify but I'll bet not more than 0.003 or 0.004 inches. Pity you didn't have your friend look at this when you had the commutator cut. They could have checked it out and installed a new bushing at that time I'll bet. Good luck Maverick.