rear drive problems

[brew]

yesterday i was riding my 79 standard and while i was shifting gears it was clicking into gear and it was noticeably louder than normal, but everything felt fine. i stopped the bike and got on about 2 hrs later and it would not go in gear. it just has a grinding sound, but it seems to be coming from the final drive on the rear wheel hub, like the teeth are not catching all the sudden. of course i am going to pull off the rear wheel and check it out. i was just wondering if anyone had any ideas/advice for me.

[prometheus578]

"Look elsewhere..."

Not going into gear should have nothing to do with the rear wheel.
Clutch, Tranny gears.. possably even middle drive might be suspect.

[Jerry]

This happened to me last year coming home from a trip. Splines on the shaft and the final drive literally wore out. My fault, I had not pulled the drive shaft and lubricated it regularly, and I often pull a small trailer which accelerated the spline wear.

The grease point on the back of the drive shaft is useless; the grease does not get onto the splines. The only way to lubricate these is to pull the final drive / drive shaft and manually grease the splines.

Fix is to replace the drive shaft and rear end. A list member may have a spare, or they go on eBay for around $40.00.

An option is to convert an XS 850 / 750 final drive. These give a lower RPM at cruising speeds due to a drive ration of 2.9:1 instead of the XS's 3.3:1. Price on eBay is about the same as a stock final drive, but you do have to do some work to make the swap.Several threads posted on how to do this is, suggest you start with this one:
http://www.xs11.com/forum/showthread...ht=final+drive

Unfortunatly the photos have been removed, but the text is still there. I have not done this swap - pulling the trailer I am concerned with low-end grunt - but several people have and all have reported good to excellent results. If you need to replace the drive shaft and final due to wear anyway you may want to consider this swap. Note: It does need a good XS 11 drive shaft.

The only difference in the XS or XJ final drives is the color. Most are silver, but the XJ and maybe the Midnight Specials use a black unit...the difference is only paint. Mechanically they are the same and are interchangeable.

[DiverRay]

Brew,
It does sound as if you lost the drive shaft and final drive due to no grease. Here is the number for an ebay auction for a complete swingarm and final drive. Price is good so far! 110226698487 It's off an 80, but will fit your machine.

[Jerry]

A couple photos showing the worn-out splines on the drive shaft:

Worn shaft on right.


Worn shaft on left.


Worn shaft on left. Could not get a good shot of the final drive splines, but all you have to do is look at the drive shaft splines to get some idea of how the FD splines looked.

Moral of this story: Pull and grease the drive shaft and fnal drive splines regularly!

[prometheus578]

Jerry and Ray....

(Awesome pics, Jerry)
Yes, I understand why the spline issue... when I put the bike in gear, makes it sound like my truck with bad U-Joints.
But his bike doesn't go into gear.
Why would this be rear-end related?
With the clutch disengaged, it should go in gear whether the rear end is good, worn or locked up.
Of course, I may be wrong.

Brew needs to write again and tell us what happens when he puts the bike up on the centerstand and tries to spin the rear wheel.

[John]

Maybe he thinks it's not going into gear because the splines are stripped, and he can't tell if the trans is engaged or not.

[DiverRay]

John, That was my thought. As he is in Southern Cal, and I'm loosing my "work place" because of moving, I figured just turn him on to the replacement parts cheap. From what he said, hearing the noise as he was riding, it probably is the driveshaft final drive splines. Most people do NOT realize the grease fitting does no good. On the 750/850 models, the gear oil lubed the splines.

[Jerry]

From Prom:

But his bike doesn't go into gear.

From John:

Maybe he thinks it's not going into gear because the splines are stripped, and he can't tell if the trans is engaged or not.

When my splines went, my first thought was the bike was not going into gear, particularly as I had been having first-gear problems. When I tried all the gears and got the same grinding, it dawned on me that my driveshaft / final drive splines had bit the dust. The final straw happened was when torque was applied to get rolling from a dead stop; I was at the bottom of an off-ramp, waiting for traffic to clear.

Brew's description (1st post in thread) seemed to me like it was the same set of circumstances, particularly the noise description and the fact that he was trying to get started from a dead stop. I will admit I could be wrong - would not be the first time! - so further examination is in order.

Putting the bike on the stand and seeing if the wheel spins is not conclusive; with the bike up the drive shaft is fully extended into the end of the splines in the FD and it can catch just enough to turn the wheel. Trust me on this.

Other failures of the tranny and middle drive generally seem to apply to either a single gear (transmission) or complete lockup (middle drive) but rarely involve all the gears becoming inoperative at once, particularly if the bike was shifting when parked. Again, examination will show, but the situation sounds just like my experience with the worn drive shaft / final drive.

[prometheus578]

"Well, you know how it is, Jerry..."

Unless we're actually there, running the tests and interpretting our results... we're pretty crippled in terms of making motorcycle diagnoses from behind a computer monitor.

[brew]

ok, so i have an update. i took it all apart and found out that the part that broke was the teeth between the drive shaft and the rear hub. i found a local XS mechanic that had the new rear hub for me, $50 which i think is a little high but the teeth were in excellent condition. a few XS'ers are helping me out with the drive shaft. hopefully i will have it back on the road within a week. in the down time, i installed an HID kit. WOW does it light up everything better.

[prometheus578]

"Boo Hoo...."

Looks like the other moderators are ganging up on me.
That's ok... I can take it.

Glad you found the problem, Brew.

[John]

Originally posted by brew
ok, so i have an update. i took it all apart and found out that the part that broke was the teeth between the drive shaft and the rear hub. i found a local XS mechanic that had the new rear hub for me, $50 which i think is a little high but the teeth were in excellent condition. a few XS'ers are helping me out with the drive shaft. hopefully i will have it back on the road within a week. in the down time, i installed an HID kit. WOW does it light up everything better.

You think $50 is too high? Are you high? $50 isn't bad at all. $50 to get your bike back on the road? Try pricing one in a salvage yard. I went to a salvage yard last year to buy up some 750-850 final drives and they wanted $75 apiece, and that was for five of them. No price for for that many of them. How is the drive shaft? I would think the shaft would fail before the drive, as that is the easier piece to replace.

[andreashweiss]

rear drive hub

If anyone else ever needs a rear wheel final drive hub send me an e-mail . $10 in my price for that part plus ship. andreas

[Jerry]

I would think the shaft would fail before the drive, as that is the easier piece to replace.

My experience, FWIW, is that the set (drive shaft and final drive splines) wear as a pair. By the time you get to actual grinding and no movement the FD splines are to far gone to work with a new drive shaft. As long as you have the rear end off to replace the shaft you should replace the FD.

The part on the FD that wears is called a coupling. Parts list does show it as a replaceable item. (2H7-46123-00-00 COUPLING, GEAR) I would be curious as to how big a job it would be to replace it. I have my old FD in the garage, may try this if I feel I need a spare around.