Beginning to hate the rain

[trbig]

Remember when I posted that list of things to do and ended with, "Sure I'll find something else along the way."


I went to check on the final drive tonight. When I tipped it downward, I saw that the oil would come out between that round collar and the bracket the 4 studs go through seen here....





Also, this outside collar would slide up and down easily.. maybe a 1/2"? With all the grease packed into the area where the nut is, I couldn't see, but figured the nut had maybe loosened off. I stuck the drive onto the wheel and stuck a broom handle through the rim and cranked that nut down pretty hard, but only got a few turns. I though that would be too tight, so I went to back it off, and the whole assembly came out of the drive housing. Is this normal?








When I would move that collar back and forth, the bearings were engaging and disengaging the race. You can see how much movement is had here...









Now... the best part for last. Who wants to bet if I'll find some nice metal pieces when I drain the oil out of the final drive?







Now for a question. What determines the gearing for the different final drives? Since the gears I can see in the final drive that these mate with still look good, would it be possible to take this part from an 1100 final drive and stick it in there, or would that essentially make it the same gearing as the 1100 and be a waste of time? I ask because I have a couple of the 1100 F/Ds but MUCH prefer the 750.

Any ideas what exactly happened here? It seems the bearing got pushed down the shaft toward the gear for some reason.. but not sure.


Tod

[Ivan]

What's wrong with that? Pt some JB weld on it and run it.

I haven't been in many Final drives for motorcycles, but have done my fair share of swaps on cars. Usually on those, a different gear ratio in the same housing needed a different thickness for the ring gear. A lower gear with a smaller pinion would need a "thicker" ring gear. Not sure what type, maybe a Ford 9" that had a really radical ratio over the generic 4.10 needed a spacer between the ring and the third member.

So, I suspect the ring gear from the XS11 will be thicker than the ring in the 750, since it is a shorter ratio in the same basic housing. I may be wrong though.

[trbig]

Yeah, I guess I can run one of these 1100 final drives, But I'd hate to make my trip next month on it. I didn't see any 750/850s that they weren't DANG proud of on Ebay.

Tod

[XSokieSPECIAL]

That seal that you say is leaking, the one with the arrow pointing to it, is exactly what I was speaking of last night.

It looks like the crush sleeve between the pinion bearings was damaged in the process when the washer was installed ( crushed too far ). That would cause there to be too much lash between the pinion and ring gears.

That would cause a heel/toe problem with the pinion and result in that sort of damage to the gears.

Yes, it is normal for the pinion gear to come out like that when the F/D is removed from the swing arm. Those studs and the nuts that hold the F/D to the swing arm are what keeps it in there.

At least that's I how I understand it to work after 30 years in the automotive repair biz.

But, I've been wrong before.

I hope I didn't jack mine.

[Ivan]

I wonder if some of those older XJ750 FDs might work. They look about the same but without the fins. Dunno.

[DGXSER]

I think from looking at this that the nut backed off and gave the room for that pinion gear to slop around in there.

That looks like it is the older 78 and before 750 FD, the type I. that type used different size spacers under the washer to set the lash. It is also the type that will let the pinion pull out like that when you remove the four nuts. With this style it is critical, as pointed out in the tech tip, to reset the bearing preload. The shaft drive manual details the procedure for both types.

The type II which started in 79 IIRC has a phillips head screw in a hole that is off center on one of the four side edges between the gear coupling and the edge of the FD. kind of the area you see that small hole in the one Tod has there, but off center. That phillips head is what keeps the pinion in place when you pull the nuts off. The type II also used a crushwasher to set the pinion spacing. That is why with the type II it is not as critical to torque the nut down when you reinstall after replacing the washer. I have so far only retightend the nut to achieve roughly the 3-4 in-lbs of turning torque.

The seapage/leak Tod indicated is caused by the oil seal going bad. Look at the gear coupling and you will see where it steps down in diameter. That smaller cylinder slides through an oil seal that keeps oil from being in the area where Tod's FD is leaking. I originally thought that was the source on the one I was working on, then I noticed all the oil leak I had was inside the gear coupling near the nut.

Honestly this looks to me like one of those chicken or the egg situations. Which happened first, the nut loosening, the pinion getting eaten up, or the U-joint going out. All three could cause the others to occur IMO.

[trbig]

Well.. the nut wasn't loose. It's just extra tight now.. lol.

Yeah, not sure the year, but that was from an earlier XS. When it was put on, it was a quick little blip from an impact.. nothing technical or measured. It held fine for over two years... and only recently got that leak since the u-joint went out.

Now if I can just find another of those type 2s.

Tod

[XSokieSPECIAL]

Honestly this looks to me like one of those chicken or the egg situations. Which happened first, the nut loosening, the pinion getting eaten up, or the U-joint going out. All three could cause the others to occur IMO.

I can see the bad u joint causing the problems with the F/D due to the vibration , but I don't see the gear problem causing a u joint to go out. Those roller bearings in that u joint cap look pretty dry.

The chicken and the egg are the nut and the pinion gear IMO. The loosening, or maladjusted nut, being first. It was the only thing that was fiddled with in the swap.

Unless the F/D was damaged to begin with.

It's ALL Tod's fault!

[DGXSER]

Greg,

In the tech tip, in an addendum, they talk about the need to make sure you reset the pinion preload torque. And to correct my earlier post, Tod's pictures do NOT show the gear coupling removed, the area below the flange that mates with the swing arm is actually a bearing housing that serves as a race for the upper and lower tapered roller bearings, one of which IS shown in Tod's pic. (If I knew how to get a PDF to post I would put up the diagram of the FD from the shaft drive manual. But I have yet to figure out how to get from a PDF to something that will post here.) The torque and or spacers applied with the nut on the end of the pinion shaft sets the preload or spacing of the upper and lower bearings in that housing. On the type I you have to set up the right spacer under that nut to get the preload correct as mentioned before. On the type II they used a crush type spacer between the bearings which does not get loosened due to the previously mentioned phillips screw. The author of the tech tip had a FD get eaten as well from not doing setting the preload IIRC.

So, it could have been the FD pinion getting eaten which would cause vibration that could have loosened the nut, and then took out the U-joint.

Obviously, if the nut went first, it would have allowed the free play for the pinion to move and change its interface with the ring gear casuing the damage and vibration that could have destroyed the U-joint.

If the U-joint went first, it could again have caused vibration in the drive shaft that could have caused either of the prior two cases in the FD.JMO

In the end, Tod stated the nut was not actually loose. I think option three minus the loose nut is now most likely. Just alot of loose screws here.

[trbig]

I'll take the part in with me today to clean them up so I can see better, but it almost seems to me that for some reason, the lower bearing got shoved down towards the gear, creating too much room between the two bearings. UNLESS... the nut did actually back off some and the threads got mucked up enough to where it felt like the nut was bottoming out?

A new F/D is in order no matter what the cause/outcome. Maybe a coincidence... but that u-joint was gone because of no grease. You couldn't rotate it one way by hand... Nothing else caused it to go bad.. it was just time. Pretty sure the u-joint is to blame somehow... but either way, a new F/D is in order.

Tod

[XSokieSPECIAL]

Ha-Ha Agreed DG

[XJOK2PLAY]

On the type I you have to set up the right spacer under that nut to get the preload correct as mentioned before. On the type II they used a crush type spacer between the bearings which does not get loosened due to the previously mentioned phillips screw. The author of the tech tip had a FD get eaten as well from not doing setting the preload IIRC.

My oh my... IMHO... that boy could break a steel ball! LOL

Seriously, though... this is what I was referencing to a while back in one of the FD threads... Cody told me about the 'lockup at speed deal', a while after he had swapped FD's. He also was telling me about how critical the preload is, and the spacer thickness... and he thinks there is a difference between a 750 FD & a 850 FD...

Question, Don... is the type I / type II deal concerning years... or could it be between drives? (750 vs. 850?)

[XSokieSPECIAL]

A new F/D is in order no matter what the cause/outcome. Tod

Sorry Tod, This is all that is on ebay right now.

http://cgi.ebay.com/ebaymotors/ws/eB...=STRK:MEWAX:IT

[bikerphil]

Plenty o' 750 FD's....

http://shop.ebay.com/?_from=R40&_trk...All-Categories

[XSokieSPECIAL]

Here's a good one from Phil's list. Its from a newer 850. From what I've learned here these seem to be the way to go. It's what I put in mine.

http://cgi.ebay.com/ebaymotors/80-81...Q5fAccessories