Rear UJ slightly notchy.

[mspenz]

The front UJ is smooth and free in every direction but the rear has a strange feel and only through one direction, holding it with the locating spline on the shaft uppermost (GSA has a locating notch) the up / down movement has slight resistance going each way and then becomes smooth but it definitely wants to locate into the middle.
The side to side is smooth and it feels similar to the front joint, and I can't feel any loose play.

I don't suppose that this is normal but nothing would surprise me any more, or is the UJ on it's way out? If it is failing can I just get a replacement rear knuckle as everything else seems good?


So that's a clutch kit, slave cylinder, g/box input shaft etc, swing arm and paralever bearings...and maybe a UJ

Mike.

 

[Slipperyeel]

Mike, if it's the rear UJ you're worried about, at least that one is relatively easy to replace. But what you describe sounds ok if what you feel is a very gentle/soft 'notch'. Does it flop around ok if you shake it (I mean the rear UJ ). If yes, I'd leave it alone.

Failing that, maybe try to pick up a second hand rear UJ from MW?

 

[mspenz]

Mike, if it's the rear UJ you're worried about, at least that one is relatively easy to replace. But what you describe sounds ok if what you feel is a very gentle/soft 'notch'. Does it flop around ok if you shake it (I mean the rear UJ ). If yes, I'd leave it alone.

Failing that, maybe try to pick up a second hand rear UJ from MW?

Yeah, I'm sure that it's fine but I'll probably source a replacement anyway as I imagine that it might add some unwanted vibration, I have to call M/Works on Monday morning with an expensive shopping list
I'm also going to have to wait 2 weeks to get the gearbox input shaft replaced and this is what greets me in the shed now...a molested GSA

<a href="http://s40.photobucket.com/user/mspenz/media/P1010424_zpsy3ubb0xx.jpg.html" target="_blank"><img src="http://i40.photobucket.com/albums/e249/mspenz/P1010424_zpsy3ubb0xx.jpg" border="0" alt=" photo P1010424_zpsy3ubb0xx.jpg"/></a>

Anyway, it's my UJ and I can shake it as much as I want

Cheers,

Mike.

 

[mspenz]

Mike, if it's the rear UJ you're worried about, at least that one is relatively easy to replace. But what you describe sounds ok if what you feel is a very gentle/soft 'notch'. Does it flop around ok if you shake it (I mean the rear UJ ). If yes, I'd leave it alone.

Failing that, maybe try to pick up a second hand rear UJ from MW?

I'm going to order one of those 'upgrade' paralever bearing kits, how is yours holding up (fnar fnar)?

 

[Schtum]

Just be sure to check the UJ's on a used drive shaft very carefully. I saw one that Motorworks had supplied recently that wasn't much better than the shaft that it was bought to replace. They took it back and supplied one that was ok but it was additional time and work.

 

[mspenz]

Just be sure to check the UJ's on a used drive shaft very carefully. I saw one the Motorworks had supplied recently that wasn't much better than the shaft that it was bought to replace. They took it back and supplied one that was ok but it was additional time and work.

Good info and makes sense, I'll maybe also check with my local precision engineering outfit to see if they can re-furbish the joint

 

[Slipperyeel]

I'm going to order one of those 'upgrade' paralever bearing kits, how is yours holding up (fnar fnar)?

I've just been working on the bike this morning doing the throttle bodies and valves (got some micro vibes from somewhere...I'll be posting on here about it soon if today's fiddling hasn't fixed it!).

I read your post so deliberately checked for play on the rear. Absolutely nothing, not even a smidgeon of play. That's now 9-10k miles in since I fitted them. I attempted to squeeze in some more grease about 3k miles after fitting them, but really not sure how much went in.

So the short answer is, they seem to be working just fine

 

[Mac Henderson]

I imagine that it might add some unwanted vibration,

It certainly will cause unwanted vibration. I've just had the the FD rebuilt due to a leaky pinion seal. During the strip down, I noticed I had a "soft notch" in the rear UJ, nothing serious and, like yours, only in the one plane, but enough to notice. Clearly it wasn't designed to have a notchy UJ so I bit the bullet and had Mikeyboy rebuild the UJ when he did the bearings and seals in the FD.

With the rebuilt UJ, the improvement is immediately noticeable. Before, the footpegs used to start buzzing around 3400 rpm increasing in intensity until they really lit up around 4500rpm and beyond; I always put the vibes down to the Fastway pegs with no rubber inserts, but after todays, 80 mile test ride, I can confirm its not the pegs. Things are a lot smoother across the whole rev range and theres a lot less vibration under hard acceleration and on the the overrun. Sounds like you're already thinking about changing the UJ; I thoroughly recommend you do, particularly as you have the back end in bits anyway.

I also had a knackered paralever bearing, so they got replaced with the Motorwerks upgrade kit. As they've only done around 80 miles, I can't comment on the durability yet, but they are nicely made and finished and were a piece of cake to install.

Good luck with the rebuild.

Mac

 

[Slipperyeel]

Mac. Interesting comments. You've got me thinking about mine now. Especially since I am trying to identify a new 'micro vibration' that's very recently developed. Tho yesterday I did discover one of the crash bars is loose... I'm hoping that proves to be the source.

But when i replaced the paralever bearings last year I thought I could feel a really soft notch in the rear UJ. But it was so soft I wasn't sure if it was me making it up?

If I haven't fixed mine with the crash bar fix then I might have to whip off the FD and take a look. There could be a big rush on for rear UJs before you know it

 

[Packer]

As it's all apart there doesn't seem to be much point in putting a failing UJ back in place, refurbish if possible or replace. A slight notchiness at this stage will only get worse and quite possibly quickly get worse. I wouldn't entertain a used item if new is available or your own one can be properly refurb'd.

 

[mspenz]

It certainly will cause unwanted vibration. I've just had the the FD rebuilt due to a leaky pinion seal. During the strip down, I noticed I had a "soft notch" in the rear UJ, nothing serious and, like yours, only in the one plane, but enough to notice. Clearly it wasn't designed to have a notchy UJ so I bit the bullet and had Mikeyboy rebuild the UJ when he did the bearings and seals in the FD.

With the rebuilt UJ, the improvement is immediately noticeable. Before, the footpegs used to start buzzing around 3400 rpm increasing in intensity until they really lit up around 4500rpm and beyond; I always put the vibes down to the Fastway pegs with no rubber inserts, but after todays, 80 mile test ride, I can confirm its not the pegs. Things are a lot smoother across the whole rev range and theres a lot less vibration under hard acceleration and on the the overrun. Sounds like you're already thinking about changing the UJ; I thoroughly recommend you do, particularly as you have the back end in bits anyway.

I also had a knackered paralever bearing, so they got replaced with the Motorwerks upgrade kit. As they've only done around 80 miles, I can't comment on the durability yet, but they are nicely made and finished and were a piece of cake to install.

Good luck with the rebuild.

Mac

Pretty much what I've been experiencing Mac, same vibrations and at similar rpm but I was blaming it on rear wheel balance so tried experimenting with weights with no success.
My UJ has that 'soft notch' feel you describe and is now with my local precision engineers who are pretty confident that they can sort it if they can source the correct size cross joint, if they can't it's good to know that there are others around who can.

Cheers, Mike.

 

[mspenz]

Mac. Interesting comments. You've got me thinking about mine now. Especially since I am trying to identify a new 'micro vibration' that's very recently developed. Tho yesterday I did discover one of the crash bars is loose... I'm hoping that proves to be the source.

But when i replaced the paralever bearings last year I thought I could feel a really soft notch in the rear UJ. But it was so soft I wasn't sure if it was me making it up?

If I haven't fixed mine with the crash bar fix then I might have to whip off the FD and take a look. There could be a big rush on for rear UJs before you know it

Those UJs (GSA particularly) are like rocking horse shit it seems but you shouldn't have any problems finding someone close to you who can do the business

 

[Slipperyeel]

Hello Mike. I got the bike out for a proper spin. I think I'm in luck for once. After doing the valves and throttle bodies and yes, tightened up the crash bar mounting, it's all smooth again (smooth for a boxer I mean ). But stupidly I did all that at once so I can't be 100% sure what was to blame. My guess is it was the crash bar.

So good news. Only one of us is looking for rocking horse shit

What's your plan? To rebuild the one you have?

 

[Slipperyeel]

ps. My 7yr old has just seen the picture of half your bike. He reckons you could just weld that tandem onto the rear end to fix it.

He might have an idea if you can't get the UJ sorted

 

[mspenz]

Got me thinking as well now, my FD is damp (but not dripping..yet) round the pinion seal and the threads on the drain plug don't feel particularly solid so now might be the time to get everything sorted out.
Didn't Mikeyboy buy over Scriminger, that website is down now so is the best way to contact him through the forum or does he have another site up?

Mike.

 

[mspenz]

ps. My 7yr old has just seen the picture of half your bike. He reckons you could just weld that tandem onto the rear end to fix it.

He might have an idea if you can't get the UJ sorted

I just love how young minds work I'll get the MIG fired up...or maybe I could just graft on the unicycle for the missus

 

[Slipperyeel]

Got me thinking as well now, my FD is damp (but not dripping..yet) round the pinion seal and the threads on the drain plug don't feel particularly solid so now might be the time to get everything sorted out.
Didn't Mikeyboy buy over Scriminger, that website is down now so is the best way to contact him through the forum or does he have another site up?

Mike.

If it is the pinion seal, then yes, Mikeyboy could be your answer. It will need some special tools...

Mikeyboy had a treasure trove of parts down there

 

[mspenz]

Anyone know if Mikeyboy has another contact address, he hasn't been active on the forum for a while so he probably won't pick up a PM?

 

[Mac Henderson]

Anyone know if Mikeyboy has another contact address, he hasn't been active on the forum for a while so he probably won't pick up a PM?

Hi Mike,

When I picked up my FD from Mikeyboy ( 13th June) he said he was off to the Pyrenees for a couple of weeks, so he's been busy riding bikes instead of fixing them. You can mail him at [email protected]

The pinion seal is retained by a castellated collar and as Slipperyeel says, needs a special tool to remove it, but Mikey has the tool and a whole lot more besides. More importantly, he clearly knows what to do! Yes, he did take over Scrimingers book when they shut up shop.

I note you say your FD is only damp; so was mine until I removed the clamp band on the boot, then the oil came pissing out. Mikey found that the spring band on the rear face of the seal had come off and was rotating on the input shaft;obviously with no spring band to force the seal against the shaft, the oil had an easy path. It would be interesting to know if yours is the same; could a failed input seal be caused by the vibration from a failing UJ shaking the spring band off the seal?? Discuss.

Mikey replaced my UJ with a new one for £90 and as previously posted the improvement was immediately noticeable and worth every penny.Keep an eye on here for his next oilhead service day; I did the one in early May and had a great day; good company, good food and a full days worth of service tips from a master

 

[mspenz]

Excellent reply Mac, I'll get on the case and post up how I get on.
One of those service days would certainly be interesting but unfortunately it would be around about a 1400 mile return trip for me !

Cheers.