Rear hub upgrade

nudude53 · Posted: July 2, 2009, 1:15 pm Post subject: Rear hub upgrade

I saw a posting a while back about switching up to a TX750 rear hub to improve the braking. I bought a complete rear wheel assembly from ebay and took some specs from it before I mount it to the bike.
It is noticeably larger both in diameter and width.

XS650 hub:
Diameter--- 9 1/2''
Brake shoe width-- 1 3/16"

TX750 hub:
Diameter--- 11"
Brake shoe width--- 1 9/16"

Unfortunately the pictures don't really show the difference, the TX750 rim is on the right.

650skull · Support Staff Joined: Jul 19, 2007 Posts: 1186

I have seen them laced to a 16in rim, very short spokes. Are you lacing it to your TX650 rim, and is the TX750 rim the same as the 650

nudude53 · Posted: July 2, 2009, 1:52 pm Post subject: Re: Rear hub upgrade

The rim is the same as the '74 up models, shouldered rim.
It will be a bolt-on swap, the TX750 hub is so wide that the right side wheel spacer is not needed. I also thought about lacing it to a 16" rim, it would surely be stout with minimal side flex, but where would I get the spokes?

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

deleted

weekendrider · Posted: July 2, 2009, 6:50 pm Post subject: Re: Rear hub upgrade

nudude53 maybe www.buchananspokes.net/
I've been thinking about a 15" wheel off a Virago so you could fit a fatter tire? With a 18" on the front would the geometry be the same as the 16/19?Talk about a short space.

nudude53 · Posted: July 2, 2009, 7:06 pm Post subject: Re: Rear hub upgrade

5twins:
I'll look it over real well the next time I'm at the shop. I hadn't planned on re-lacing yet, was going to mount it and see how it handled first and maybe re-lace to a brand new rim this winter. I never thought to measure the spokes they appeared to be shorter than the 650 though.

Q: How did the 750 swing arm work out for you?
Q: Is it the same length as the 650 arm on the post '74 models?
Q: Will the post '74 style chain guard fit it?

Looking back I think it is you that I got this idea from by looking at your gallery pictures, thank you for planting the seed and doing the leg work. We'll have to keep pursuing this until we get it right.

nudude53 · Posted: July 2, 2009, 7:20 pm Post subject: Re: Rear hub upgrade

weekendrider:
The only problem that I see with mounting a smaller rim on the back is that the taller tire is a little wider in the sidewall and might rub the swing arm up towards the front where it comes together. But I don't know for sure because I haven't tried it yet. As far as a smaller front rim, you could also make up the difference in the diameter of the tire with a taller size and it shouldn't have any clearance problems with the forks. The handling may be somewhat different, maybe the bobber guys could answer that question better for you. I've seen quite a few bobbers with altered front rim sizes.

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

nudude53 · Posted: July 3, 2009, 8:38 am Post subject: Re: Rear hub upgrade

Thanks 5twins:
That answers alot of my questions.
In doing some more research I discovered that the early 650 and 750 chain guards did not share the same part #'s. So evidently although the mount points are similar the cases are different, not only in appearence but in length also.

There are two different part numbers for the spokes as well.
TX750- 341-25034-00-00
TX650- 256-25034-00-00
The steel and aluminum rims share the same spokes.

I'll take some measurements on the spokes and get back with you ASAP.

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

nudude53 · Posted: July 3, 2009, 9:28 am Post subject: Re: Rear hub upgrade

Ok, but I can't understand why the length would be the same if the hub is larger in diameter. Perhaps you can cross that part # with an aftermarket supplier.

The last time I tried to re-lace a rim by myself I ended up throwing in the towel and taking it to the Yamaha shop, that was over 40 years ago. There's a sport bike shop close to me that will do it for $40, well worth the expense in my opinion.

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

nudude53 · Posted: July 3, 2009, 10:27 am Post subject: Re: Rear hub upgrade

This gets stranger all the time. Just checked the part#'s for the rim.

'74 TX650A rim----94421-18106-00 & 94421-18146-00 (both #'s for a 2.15x18 rim)
'74 TX750A rim----94421-18146-00
'73 TX750 rim---- (same #)

Now, why the different #'s for the 650 in '74?

weekendrider · Posted: July 3, 2009, 10:55 am Post subject: Re: Rear hub upgrade

You are looking at to early a model?

nudude53 · Posted: July 3, 2009, 12:59 pm Post subject: Re: Rear hub upgrade

The TX750 was only built for 2 years, that is the hub/rim that we're referring to. The part # for the rim that is shown on your chart above was the same on the Yamaha website parts list for the '74 TX650A.

Although, I have found mistakes in the online parts lists. For example, on the Dillon Bros. site if you look at the part # for a '75 XSB muffler it gives you one for a carb float.

weekendrider · Posted: July 3, 2009, 6:12 pm Post subject: Re: Rear hub upgrade

My bad. I'll get out of yo bidness now. I thought you were talking about.

nudude53 · Posted: July 3, 2009, 7:16 pm Post subject: Re: Rear hub upgrade

weekendrider:
Don't run off just yet, that last pic looks like the swingarm we're talking about. Wanna sell it?

weekendrider · Posted: July 3, 2009, 9:59 pm Post subject: Re: Rear hub upgrade

nudude53 wrote:

that last pic looks like the swingarm we're talking about.

I'm sure it couldn't be sense I have no ider wat youse wer referring twos.

nudude53 wrote:

wanna sell it

ROFLMAO

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

highspeedhamish · Full Member Joined: Jun 25, 2009 Posts: 62

Looking for a drum brake swinger? When I pull this one off you can have it..

What Happened to 650rider.com?

Yamaha xs650