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-   -   U-joints; Twin Shock vs Paralever (http://www.advrider.com/forums/showthread.php?t=883172)

Big Bamboo 04-29-2013 07:50 PM

U-joints; Twin Shock vs Paralever
 
I know the twin shock BMWs require a bit of gear oil in the swingarm, but the Paralevers do not. Are their U-joints of a fundamentally different design, such that a Paralever is lubricated for life? Or is the oil there primarily to lubricate the splines where the shaft mates to the rear drive? (done with grease on the Paralever)

bmweuro 04-29-2013 10:31 PM

Quote:

Originally Posted by Big Bamboo (Post 21297116)
I know the twin shock BMWs require a bit of gear oil in the swingarm, but the Paralevers do not. Are their U-joints of a fundamentally different design, such that a Paralever is lubricated for life? Or is the oil there primarily to lubricate the splines where the shaft mates to the rear drive? (done with grease on the Paralever)

The u-joints are the same on pretty much all BMW's produced after 1970, minus the new new bikes. The oil in the early bikes did more for the splined end at the rear drive.

More_Miles 04-30-2013 03:44 AM

Quote:

Originally Posted by bmweuro (Post 21297967)
The u-joints are the same on pretty much all BMW's produced after 1970, minus the new new bikes. The oil in the early bikes did more for the splined end at the rear drive.

While I don't disagree about being mostly for spline lubrication, I think there is more than a little oiling going on at the U-joint on the twin-shock models. I base this solely on the personal and anecdotal observation that I've never removed the rubber boot at the transmission output without having to dump a tablespoon or so of oil out of it. It had to get there somehow, and once there, probably provides some splash lubrication with bumps, jolts, etc. In my opinion, any lubrication in this application, even accidental (at least in a closed system like a twin shock swing arm anyway) is better than none.

The description "lubricated for life" is accurate. Bearings, joints and the like usually die through lack of lubrication. I'm sufficiently old-school to still want grease fittings on U-joints, ball joints, and bearing oilers where appropriate.

ME 109 04-30-2013 04:13 AM

What about the dust seals on uni joints?
They probably prevent any significant amount of oil from getting into the needle rollers.
I cant remember what the oe uni joint looks like, but the Hardy Spicer unit I used as a replacement on my RS had dust seals on it. As far as I can remember, I didn't take them off and that was a long time ago.

SOLO LOBO 04-30-2013 10:53 AM

Here's a shot of the joint on my R80G/S.. the factory one being replaced by an HPMGuy replaceable one...

http://i56.photobucket.com/albums/g1...o/DSC04905.jpg

bmweuro 04-30-2013 01:10 PM

Here is a driveshaft I built for one of my projects. Part /6 and part R1150 showing the u-joints are all the same. With that said the paralever models do not have oil in the housing and the u-joints last just as long as the earlier models.

https://sphotos-b.xx.fbcdn.net/hphot...37189745_n.jpg

ME 109 04-30-2013 02:11 PM

Quote:

Originally Posted by SOLO LOBO (Post 21301404)
Here's a shot of the joint on my R80G/S.. the factory one being replaced by an HPMGuy replaceable one...

http://i56.photobucket.com/albums/g1...o/DSC04905.jpg

Interesting, half circlip and half welded washer.

Stagehand 04-30-2013 02:28 PM

Quote:

Originally Posted by ME 109 (Post 21302855)
Interesting, half circlip and half welded washer.

welded washers hold the circlips in :deal

ME 109 04-30-2013 02:38 PM

Quote:

Originally Posted by Stagehand (Post 21302988)
welded washers hold the circlips in :deal

So what's with the shaft in the pic, only two washers?
Washer and circlip doesn't make much sense to me, either way should be good on its own.

Stagehand 04-30-2013 02:57 PM

Quote:

Originally Posted by ME 109 (Post 21303062)
So what's with the shaft in the pic, only two washers?
Washer and circlip doesn't make much sense to me, either way should be good on its own.


Sorry- to retrofit the circlips onto the shaft, where the cardans were originally staked in, washers need to be welded onto all four apertures. They become the de-facto "hold the circlips in" devices. Without the washers which are not longer washers in this application, but have become forward material to bear against the outer surface of the circlip, you would have to somehow grind a trough out of the yoke material for the circlip to ride in to hold the cardan in.
There probly isnt enough material there to do that job, even if you could grind an interior radius like that, so you weld a washer on top, and the space between becomes the shelf where the circlips ride.

Clear as mud, eh? :lol

ME 109 04-30-2013 03:11 PM

I just used washers, although a belt and suspender approach can't hurt.

http://i277.photobucket.com/albums/k...ikehead087.jpg

Stagehand 04-30-2013 03:24 PM

Well the whole point of circlips is that theyre replaceable ie rebuildable without future grinding and welding

Like putting clips on your suspenders and not sewing your belt to your pants :)

mattcfish 10-07-2014 03:16 PM

Part #?
 
Anybody have a part # for the u joint on a 70 to 80's airhead? Can you get them through Spicer? Not readily available anywhere I've checked. I've got a shaft I need to rehabilitate. I like ME 109's DIY method. Probably quicker to grind off the 2 spot welds than to remove a fiddly circlip. Should last another 100,000 miles anyway.

To answer the question about oil getting to the u-joint. When you go down hill lots of oil gets to the front of the shaft. You'll find this out if you ever get a split in the rubber boot.

ME 109 10-07-2014 04:12 PM

The hardie spicer uni cost me about 175 delivered. Bloody expensive! I got caught out because I didn't ask for a price..........because I didn't recall it being so expensive 15 years ago when I last repaired the driveshaft uni.

There will be other brands for a lot less. Just need to cross reference the size.

I can measure my old uni when I get home, unless someone else knows?

RecycledRS 10-07-2014 09:28 PM

Got a part number? Failing that dimentions would be appreciated.


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