ST1100 Final Drive Shaft

Working thru the manual, checking everything twice on my 'new' 1991 1100........There is NO mention of lubrication of the universal joint. Is something missing, or is this a maintenance-free component?

Oldbikefixr said:

or is this a maintenance-free component

Click to expand...

Correct - If you are doing a thorough strip down of the bike though, including pulling the swing arm, then lube the splines on the output shaft and the driveshaft splines too.

The u-joint is a sealed unit. No way to lube it.

All moving things generally love lubrication, Remember to lube all the "O"rings and check the rubber bushings in the rear hub for wear.

Thanks, Jonb/Bush...The manual is specific on what assembly needs which oil. I was concerned about the universal joint (haven't removed the swing arm yet so I haven't seen it in person). I lubed the corresponding joint on my GL1000's with chain lube every month...never had a problem with them.

There have been some universal joint failures but it's not a chronic problem (having said that... )

Oldbikefixr said:

There is NO mention of lubrication of the universal joint. Is something missing, or is this a maintenance-free component?

Click to expand...

There is no regular maintenance interval on that prop-shaft, but there some essential check and lubrication points during a re-assembly after having removed the swing-arm...
You'll find plenty of very useful info in the workshop manual. Getting hold of a copy is priceless... ;-)

Bush said:

Correct - If you are doing a thorough strip down of the bike though, including pulling the swing arm, then lube the splines on the output shaft and the driveshaft splines too.

The u-joint is a sealed unit. No way to lube it.

Click to expand...

+1 .

And if you remove the swing arm, you can inspect the u-joint by rotating it in both axis. If it's bad, you will feel roughness. And then you can also clean & re-grease the swing arm bearings, before re-assembly.

Note the driveshaft, joint, and pinion cup splines get 3% moly grease. The trannie output shaft and driveshaft u-joint splines get >40% moly paste.

John
via iPhone 6

Thanks for all the comments. I finished the job this morning, using the manual specified lubes. Like I have mentioned before, the bike has only 17,300 some miles on it. Just bought it after 20 years in the PO's garage....looks nearly new. BUT...as we can all attest (me included), age related problems can kill you, so I am checking what I can before hell goes away and the Fall riding season begins.

The final shaft and drive unit looked unworn and the universal joint has no significant play. ALL the lubes were still doing their job. Fresh looking hypoid poured from the shaft housing, greases were still doing their job. I am used to chiseling out (literally) early 1960's congealed grease, even from low mileage bikes. I'm impressed with the ST's build quality and performance of modern (for 1991) lubricants.

Feeling better about this purchase.

Next weekend....timing belt change.

Some timing belt R&R info here, if you haven't already seen it:
https://www.st-owners.com/forums/showthread.php?147405-Starting-the-Timing-Belt-WP-today!

Good luck. Love hearing about a classic '91 rejoining the active fleet!

John
via iPhone 6

OK....been staring at it and poking it all afternoon. It's apparent this meditation thing isn't going to enlighten me. How does the chrome breather cap come off of the final drive unit? Press fit? Screws off?

Oldbikefixr said:

OK....been staring at it and poking it all afternoon. It's apparent this meditation thing isn't going to enlighten me. How does the chrome breather cap come off of the final drive unit? Press fit? Screws off?

Click to expand...

It doesn't come off. There's a filler cap (don't over torque!), and a drain plug... not chrome.

Oldbikefixr said:

OK....been staring at it and poking it all afternoon. It's apparent this meditation thing isn't going to enlighten me. How does the chrome breather cap come off of the final drive unit? Press fit? Screws off?

Click to expand...

If you're talking about the chrome breather plug on top of the final drive unit, it does come off. Honda might have press fit into place.
[h=1]41306-MB0-010 CAP, BREATHER[/h]
When I got my current bike, instead of the usual chrome plug there, it was missing and PO put a plastic rubber plug on the vent hole
I bought the plug and asked my mech to use a mallet to knock it back into place. The OEM chrome plug has a stem and will slide into the hole tight but strength is needed to push that in

raygks said:

If you're talking about the chrome breather plug on top of the final drive unit, it does come off. Honda might have press fit into place.
41306-MB0-010 CAP, BREATHER

When I got my current bike, instead of the usual chrome plug there, it was missing and PO put a plastic rubber plug on the vent hole
I bought the plug and asked my mech to use a mallet to knock it back into place. The OEM chrome plug has a stem and will slide into the hole tight but strength is needed to push that in

Click to expand...

That's the part. My Honda manual simply says 'clean the breather hole and reinstall'. No mention of a removal method. Looks like the Honda writers were taking lessons from the Haynes manual folks.
I will probably order a replacement (if they are still available). A new part will tell me what I can get away with on the existing part. I DO NOT want to risk damaging the final drive housing.

I wouldn't recommend to remove that cap and clean it, you'll need alot of strength to pull it out & will probably bent/deform/destroy it by doing that(material is probably aluminium) and will lead to a new replacement.
Unless you want to replace it, else I'd suggest to leave it alone & spend on something else worthwhile

The cap comes with a stem in the middle of it & on the top of the stem, right under the chrome cap bottom, you'll see 2 tiny holes for venting the final drive casing.
Part should still be available as some other models are also using it.

Ray

you're in there far enough to expose the damper cam and spring , they should be in a bath of 30cc's of hypoid gear oil ( 1.0oz sae #80)