Final Drive Swap Poll

[crazy steve]

Out of curiosity, have there been 750 FD's on an 1100 that failed under hard riding as described by downshifting and getting a drive out of the corners, or other hard riding?

Actually, there's been two; Greg mentioned that another XS rider had killed one, but that guy is supposedly known for breaking parts. Looking at the poll results and adding the numbers, that's two failures out of 34, or almost 6%...

[TopCatGr58]

It may be just a matter of time and miles? Scott had to put on 40K miles before his failed. Tod/Trbig has a very strong XJ and he does like to ride spiritedly, and both may also have contributed to an early demise of the FD?

Just like the MikesXS Black coils that I had put on mine 4 years ago, and promoted that others do it, they did, but they put on a real years worth of use...10-12Kmiles a year and they were failing/burning out in 1 year. I only put on 2-3K miles a year, so it took mine 4 years before they failed, BUT they did eventually fail!

I think we'll probably see reports of more 750FD failures before it's all done, mostly because folks are probably driving their FD modded machines the same way they drove their OEM FD's, and so under those kinds of continued stresses, it will probably just take time and miles before the parts fail!

I've not done the FD swap, I also like Marty like to ride the twisties, don't need to drive 100 miles just to get into town, etc, and I'm used to riding it in the higher rpms anyways, just my style!

T.C.

[James England]

folks are probably driving their FD modded machines the same way they drove their OEM FD's, T.C.

You may have a point there. I've found that I like the lower RPM's at top speed but have to stop myself getting to those speeds as if I'm still on the OEM FD.

[3Phase]

I think Maximan said in the Mod that he lunched one final drive and had to find the Yamaha Shaft Drive Manual/PDF to find the correct way to set up a final drive so he didn't do it again.

Even though I was trying to make the 750 drive fail on my bike the worst I could get was a sort of rubberband/boing feeling from the drive train as it flexed under load. If you do it just right, riding the crest of the flex is kind of fun when it unwinds, too. So, yes, the 750/850 final drives are tough but when mine started to go bad it went bad pretty quickly; within 4,000 miles from when I first discovered visible metal in the drain oil.

Along the way there was a lot of hard acceleration with lots of fun and high speed at high altitude on mountain roads. Add to that all of the long distance, sustained high-speed highway riding in several deserts and the long trips with camping gear or two-up and the whole bike, not just the running gear, has done a fantastic job and has held up really well!


The biggest problem I can see with the 750 Mod isn't that the 750/850 drives are weaker than the 1100 drive, it's that all of the drives are getting a little old and long in the tooth. Unless you check a drive before using it then it could be difficult to tell if it's in good condition. If you don't know what to look for a supposed low-mileage drive as claimed by a trader or seller could be a drive with 100,000 + claimed mileage and it's about to spew oil and parts.

[CaptonZap]

Even though I was trying to make the 750 drive fail on my bike the worst I could get was a sort of rubberband/boing feeling from the drive train as it flexed under load. If you do it just right, riding the crest of the flex is kind of fun when it unwinds, too. So, yes, the 750/850 final drives are tough but when mine started to go bad it went bad pretty quickly; within 4,000 miles from when I first discovered visible metal in the drain oil.

The biggest problem I can see with the 750 Mod isn't that the 750/850 drives are weaker than the 1100 drive, it's that all of the drives are getting a little old and long in the tooth. Unless you check a drive before using it then it could be difficult to tell if it's in good condition. If you don't know what to look for a supposed low-mileage drive as claimed by a trader or seller could be a drive with 100,000 + claimed mileage and it's about to spew oil and parts.

Howdy Scott,
I was reading some of the past postings a few months ago, and if I remember right, in one of them you stated that when you first got the 750 FD, you took it apart, and it showed signs of being already abused. Am I remembering right?
If so, the fact that you got as much hard use, in it's already somewhat less than new state, another testiment to the dependability of the drive.
And yes, there is more metal surrounding the center tube in an 850 than there is in a 750, but for the mature touring rider, I would think that the 750 would be more than adequate.
Needless to say, I replaced my 750 with an 850, just in case I have a moment of regression.
For those of you who are considering the switch, download the manual from Catatonic Bugs web site, get the dial indicator, make the clamp on arm, and measure the free lash. (take the side plate off, wash the insides out with solvent, and reinstall the plate, it makes it easier to take a reading)
If the wear pattern on the teeth looks good, and the lash is in limits, put the side plate back on, torque to factory specs, fill it with oil, and don't worry, be happy, the factory did a pretty good job.
And your good for another few thou'.
CZ

[3Phase]

How's it going, Cap! Replies in-line!

Howdy Scott,
I was reading some of the past postings a few months ago, and if I remember right, in one of them you stated that when you first got the 750 FD, you took it apart, and it showed signs of being already abused. Am I remembering right?

If so, the fact that you got as much hard use, in it's already somewhat less than new state, another testiment to the dependability of the drive.

The first '750 drive I bought was a Type II. Someone had overtightened the pinion nut when the bike was disassembled and that crushed the crush washer. I checked the gears and bearings and it was totally obvious that the final drive hadn't been ridden like that because the input coupler was so hard to turn that the drive would have eaten the pinion bearings and grenaded in just a couple of miles. The pinion bearings were tight!

I bought another crush washer; set the torque; rode it like I stole it.

And yes, there is more metal surrounding the center tube in an 850 than there is in a 750, but for the mature touring rider, I would think that the 750 would be more than adequate.

Needless to say, I replaced my 750 with an 850, just in case I have a moment of regression.

You got it! Either drive will work with the edge going to the '850 drive. The weak part of the drive is the side cover and carrier bearing. The '750/850 drives have smaller and weaker gear teeth than the '1100 but the thinner side covers and smaller carrier bearings are the problem. The side cover flexes so stuff 'breathes' under hard acceleration and deceleration and wears out the carrier bearing and the gears.

Keep it mellow and you'll be a happy camper for many, many, moons!

For those of you who are considering the switch, download the manual from Catatonic Bugs web site, get the dial indicator, make the clamp on arm, and measure the free lash. (take the side plate off, wash the insides out with solvent, and reinstall the plate, it makes it easier to take a reading)
If the wear pattern on the teeth looks good, and the lash is in limits, put the side plate back on, torque to factory specs, fill it with oil, and don't worry, be happy, the factory did a pretty good job.

And your good for another few thou'.
CZ

Exactly!

Be careful reinstalling the side cover, it's a very tight, precision fit. Do NOT force the parts back together, gently tap them into place with your hand or a rubber/rawhide mallet.

If the cover starts to bind part way down, tap it back off and start over again. If you try to straighten it while it's jammed or just force it past the 'bind' or use the side cover nuts straighten it out and seat the cover and bearing then it'll gall and possibly distort the aluminum. That's not something that you want to do!

[DonLaw]

newbie to driveshafts

alway had dirtbikes and harleys. I have put 2-3k miles on my xs11 since april/may (mostly highway) and get about 30mpg. 60mph is around 3800rpm. what all parts do i need to gear up? anyone have a set up for sale?

[crazy steve]

FD swap

Look here.... http://www.xs11.com/forum/showthread.php?t=11703

[BA80]

If your only getting 30MPG you need to take another look at those carbs or your riding habits.. I get 34 - 38 normally and if I keep the RPMs at or near 4K on the highway ( about 65 or 70 w/the 850 FD) I can get up to 42 -44MPG.

Here's a link to the instructions for the swap. It's on another site but it's easier for me to do it this way. It's here on .com too but I don't remember where or how to get to it.

http://hitechkc.dyndns.org:78/phpbb3....php?f=5&t=108

[Geezer]

I have an 850 final drive I'd take $50 for but it hasn't been modified yet.

Geezer

[Bonz]

DonLaw,

Take Geezer up on that offer!