U-Joint Replacement

Message

ceemes · #1 Unread post by **ceemes** » Sat Jul 25, 2009 4:48 pm

Hi all,

Looks like I am going to have to replace the U-joints on the old Sabre, every time I pull out I hear a god awful CLUNK coming from the shaft drive and it is getting progressively worse.

Has anyone any experience in replacing the U-joints of a shafty and if so, what should I be looking out for? Any and all advice is most welcome from this less then mechanically inclined noob.

#2 Unread post by **Wrider** » Sat Jul 25, 2009 7:44 pm

I couldn't think of any U-Joints on a shafty, so I looked up an 83 Sabre 750 schematic, and I was right. No U-Joints I could find.
http://www.bikebandit.com/houseofmotorc ... 77sch13183
Anyway, where exactly is the clunking coming from? Front of the shaft? Rear? Middle somewhere? I'm thinking you may have some splines and a shaft with clearance in there where there shouldn't be. Shafties aren't that hard to work on, just make sure you grease em up well!

slimcolo · #3 Unread post by **slimcolo** » Sat Jul 25, 2009 10:03 pm

U joint is #1 under "rear fork" in Wriders link. (BB calls it a joint yoke)
I think this may have a better resolution http://www.powersportspro.com/pages/par ... amaha.aspx (and they use the American term swing arm instead of the English term rear fork) You will need to go to site and enter your bike as their default keeps putting URL back to Yamaha when I cut and paste.

Not sure about your bike, but shaft looks a lot like a BMW style shaft. If it is there is no way to change just the U joint as it is swedged onto the shaft (unlike a Gold wing where U joint is splined on both sides) If this is the case the shaft can be reworked (both machining and welding) to accept a u joint from an atv. Eurotech (and some others) http://www.eurotechmotorsports.com/index.cfm in California do this for BMW shafts (the single sided swing arm paralever munches the u joint, and thus needs a new shaft, about every 30-40K) Not sure if they can do a Honda shaft and I can not find the shaft rebuild service on their site. (it was there before they redesigned their site so you might call them)

Also if this is like a BMW (SSPL) the bearings in u joint are sealed and cannot be greased, much like the factory u joints on most newer cars. (the older BMWs ran oil in the swing arm and u joints on them lasted 200K+)

With BMW (prices are from 9 years ago) a new shaft cost $379 (shipping inc. from BMW dealer) and took about four days to ship. To have a shaft reworked only cost $220 + shipping in both directions, but took up to four months turn around time in the Summer. To replace a u joint on a reworked shaft cost about $25 (and they can be greased)

#4 Unread post by **Wrider** » Sun Jul 26, 2009 5:56 am

Looks like Slim is right. I was just looking at the Final Drive.
I'm betting that when you take it apart the U-Joint is splined on there. It's a lot easier for manufacturers to do that. So you'll have to get the U-Joint and part it's attached to in all probability because of the clunking making clearances between the two. Might become a fairly complicated process to be honest with you. At the same time, there's gonna be lots of grease and women love the "been working on my vehicle all day" look!

ceemes · #5 Unread post by **ceemes** » Sun Jul 26, 2009 9:16 am

Wrider wrote: Looks like Slim is right. I was just looking at the Final Drive.
I'm betting that when you take it apart the U-Joint is splined on there. It's a lot easier for manufacturers to do that. So you'll have to get the U-Joint and part it's attached to in all probability because of the clunking making clearances between the two. Might become a fairly complicated process to be honest with you. At the same time, there's gonna be lots of grease and women love the "been working on my vehicle all day" look!

Bugger that, I think I'll get it done properly and let my local grease monkey do the job. She is bloody good.