Article [11] ST1100 - O-rings in the final drive (rear wheel)

[CYYJ]

Interestingly enough, shelf-life of O-rings seems to be less and less of a concern with the materials they are made of now...

Hi Andrew:

I don't disagree with you so far as shelf life of an unused O-ring is concerned. Unless the package is marked with an expiry date (common practice in aviation & foodservice, less common for other applications), an unused O-ring is "good to go" if it passes visual inspection.

Things change once the O-ring enters service. In most applications, the O-ring is used either to prevent fluids from passing a point, or to prevent external matter from entering a point. This is when the stress on the material begins, either from a fluid, from airborne material, or from the atmosphere the O-ring is exposed to.

Michael

 

[Andrew Shadow]

Hi Andrew:

I don't disagree with you so far as shelf life of an unused O-ring is concerned. Unless the package is marked with an expiry date (common practice in aviation & foodservice, less common for other applications), an unused O-ring is "good to go" if it passes visual inspection.

Things change once the O-ring enters service. In most applications, the O-ring is used either to prevent fluids from passing a point, or to prevent external matter from entering a point. This is when the stress on the material begins, either from a fluid, from airborne material, or from the atmosphere the O-ring is exposed to.

Michael

No argument from me. The reason why I also included the below statement in my response;

Shelf-life is not an indicator of how long an O-ring can remain in service of course, ......

 

[dtcoleman]

To reiterate the previous conversations.
Yes. Replace all 3 O-rings.
BTW did the dealer reimburse you for the damaged drive pinion? Since the master mechanic found the problem? Or did i miss that comment in the thread?

 

[John OoSTerhuis]

Hey George. Good to see you poSTing.

Another reason for failure of the o-rings is failure to realign the final drive after it has been removed for any reason. Simple procedure: fully install and tighten the rear axle without the wheel in place before tightening and turning the 4 pumpkin nuts.

I think you meant: tighten the axle WITH the wheel installed, THEN tighten the Final Drive nuts. Link

John

 

[CYYJ]

BTW did the dealer reimburse you for the damaged drive pinion? [see last three paragraph & picture in post #1]

Yes, they were very good about it. They replaced all the components in the final drive assembly (both gears, seals, etc.) at their own expense - it cost them over $1,000 in parts to do this, and this was back around 2003 or 2004).

 

[Cyclehead]

Rob Parker used to provide new o-rings for the cost of postage. Don't believe he's still around. Quick search returns this site as a potential source. ...

Large quantities of o-rings are usually very cheap. It would be a nice thing to get this going again for the forum. Who has the o-ring sizes, and recommended materials?

 

[Taffy]

Hi All.. thanks for this post.

As someone who has not even removed the back wheel yet, but committed to removing the swing arm for inspection and possible repair/replacement this winter, I find this article and others like it so amazingly useful. Thanks very much again and again.

 

[Cyclehead]

Large quantities of o-rings are usually very cheap. It would be a nice thing to get this going again for the forum. Who has the o-ring sizes, and recommended materials?

Answering my own question - I see the o-ring sizes. I have a source for Buna N 70 hardness o-rings. If these specs are appropriate, I may consider ordering a batch of the three o-rings for the rear wheel & final drive, and re-starting Ron's practice of providing o-rings for the cost of postage. Can anyone confirm this is the best material and hardness?

 

[BumbleBerry]

Photo of used O-rings in final drive:

Here are the three o-rings. I don't know when was the last time they were changed. Definitely not for the past 22,000 km I put on the bike and most probably a few thousands km before that.
I changed the tires 18,500 km ago (Jan 2022) and forgot to tell the shop to change these o-rings. So, this time around I bought the parts and made sure to get them replaced. I also asked for the old ones back. As can be seen in the photo, the large diameter o-ring (the thinnest one) was really abused. It is much more obvious once looked at really closely, it is thinner at places and overall feels it may snap. The middle size o-ring is very rigid and has lost its rubbery feel. The smallest o-ring is the one that seems in good condition by itself, but when compared to a new replacement, then the difference can be felt.



Since I put on close to 18500 km on a pair of tires, for me changing these o-rings is definitely a must, and also advised by Honda maintenance manual. The parts in Canada cost me about $24 with taxes. They can be obtained cheaper from US, about $15. I am going to order a few sets now, for the future tire changes.