Swing arm bearing question

[Berto]

On my 2004 ST, I have the swing arm off to inspect and grease bearings. My manuals are a little sketchy on the details. The left side has traditional needles, no problem there.

On the right, that appears to be a sealed bearing behind the grease seal. What's to be done with it lube wise? Book doesn't say. Other sealed bearings I've dealt with you either replace or leave alone.

Advice appreciated. My search for previous threads of this didn't find much.

--Paul

[oldndumb]

As with bearing mfgr instructions, you do not repack/re-service them. They are line replacement items.

However, there are people that insist they can be serviced with a variety of grease injection methods.

The first fault with that method is the assumption that bearings have an infinite life. All bearing mfgrs include the bearing service life in their specifications. Simply replacing the grease without doing a bearing inspection is a poor maintenance practice.

The next fault with trying to repack/re-service a sealed bearing is that all bearings are specified to operate with a specific amount of grease (never as much as you would expect). In most applications, more grease than specified is applied with no resultant problems. That is because the quantity specification is not that significant in normal applications. However it does become significant in a sealed bearing. Injecting too much grease into a sealed bearing will cause that bearing to generate more heat than normal, and possibly cause a seal failure.

The final, and most controversial aspect of repacking/re-servicing sealed bearings is the grease compatibility issue. Inject an incompatible grease and you could end up with the grease solidifying or the lubricating oil could separate from the carrier medium. Determining what type of grease was installed in the bearing by the manufacturer can be very difficult.

Are you certain that the bearing installation you are looking at is indeed a sealed bearing? It is unusual to have a separate grease seal in conjunction with a sealed bearing.

[steve speed]

if i was going to the trouble of pulling out the swing arm i would change the bearings , it just does not make any sense to me to go to all that trouble striping it all down then not renewing a such an important part ,,, but thats just me

[Berto]

Originally Posted by oldndumb

Are you certain that the bearing installation you are looking at is indeed a sealed bearing? It is unusual to have a separate grease seal in conjunction with a sealed bearing.

Sure looks sealed. On the needle side--and this is normal for all the suspension components, dogbone, plates and so forth--that I have seen on all my bikes, there's a removable sleeve. Draw it out with your finger, then all the needles fall out on the bench, even though this time you said you'd catch them.

This bearing seems to have attached races.

--Paul

[Berto]

Originally Posted by steve speed

if i was going to the trouble of pulling out the swing arm i would change the bearings , it just does not make any sense to me to go to all that trouble striping it all down then not renewing a such an important part ,,, but thats just me

I dunno---I hate replacing perfectly good parts whose proabability of failure is fairly low. I don't get why Triumph wants the thing removed at 12K or three years. It's all in pristine shape.

I found swing arm removal fairly easy, once I'd made the tools for the Jeezus nut. I 'spose it's not that much more work to make a drift to drive it out. Need grease seals.

Crap, this the longest motorcycle maintenance project in the history of western civilization.

--Paul

[steve speed]

just drink plenty of beer you will be fine

[pushr0d]

Paul,

IIRC, the maintenance action just calls for inspect and repack. You do indeed have a sealed bearing and an open needle bearing.

I 'inspected' my sealed bearing by rotating it and feeling for rough spots.

Somewhere OnD has a fine post on the whole procedure. However, he did not mention the third seal that is located in the cush drive. It is the same size (45x55x4) as the two in the hub.

At 24K, all three of my seals looked fine, but I replaced them anyway, since I'd already bought new ones.

The other 'gotcha' is to make sure you have the eccentric either set 'high' or 'low' to suit your requirements when you put the chain back on.

[oldndumb]

Bit of confusion here, I believe.

The OP said "Swing Arm Bearing Question". Some responders are describing the wheel bearing installation. If the OP meant the wheel bearing instead of the swing arm bearings, this might help.

http://www.triumphrat.net/maintenanc...earings-2.html

But, I am betting he knows the difference and is speaking of the swing arm bearings.

[oldndumb]

Well, what is the verdict, Berto?

[Berto]

Originally Posted by pushr0d

The other 'gotcha' is to make sure you have the eccentric either set 'high' or 'low' to suit your requirements when you put the chain back on.

Ah, good tip. Thanks.

My first experience with a single side and it all seems rather...odd.

--Paul