750 Final Drive swap

[Paul Kelley]

Hi everyone,
I just got done swapping A final drive into my XS11F, and only took me 2hrs. I did notice on the 750FD it didn't have the tapered washer??? on the inside spline where the wheel connects. I tried with no luck to get the one out of the 11FD. So far everything is working great!!!
Have A Great Night Paul

[DGXSER]

Any one have a suggestion for how to hold the FD to pull the bolt wihtout a wheel to mount it to? I'd like to do that work prior to pulling my bike apart. I have a little time to do the prework, but not quite enough time to do the swap. That and I want to paint the drive after I finish filling the lube holes and putting the 1/2" washer in place and get the bolt torqued back down. Rather the painting time not take away from the riding time I have available with alot of travel in the next week or two.

[TopCatGr58]

Hey DG,

I assume you're referring to this photo illustration!?


The outside of the spline coupling on the FD, although machined very smooth, doesn't actually make contact with anything, and so I would think you could get a vicegrip chain strap wrench and grab it around that cylinder, wedge it against the ground or even one of the 4 FD to swingarm bolts to keep it from turning/spinning while you break that large nut loose? If you have some old timing belt or other thin belt rubber material or even leather, you could wrap the cylinder with that to keep the chain from marring the surface, but I don't think it's critical, again that smooth surface isn't rubbing/sliding against anything inside the swingarm housing, so some minor knicks in it should not be of any consequence!
T.C.

[DGXSER]

Thanks TC

A small oil filter wrench held it fine for removing the bolt and got the old OEM washer out. I now have the new 1/2" washer with black RTV back on and the nut is tightened up some. My strap wrench nor my oil filter wrench want to hold it strong enough to apply the 75-105 ft lbs of torque to the nut though. But, I feel good enough about where it is to finsih the painting and such and then be ready for the swap.

Thanks for the tip!!

Now to unhijack the thread....Congrats on oyur swap Paul!! Hope it continues to give you miles of smiles!!

[Paul Kelley]

75 to 100ftlbs torque

Thanks guys,
When I tried to torque the pinoin nut 75#s gave me too much spinning ressistance ie 10 to 15 inch lbs. Maybe I need to change the crush sleeve in the pinion?I rode it this morning and I love the feel and the motor sounds relived also. I felt the FD after the ride (26 miles) and it was a little hot but could still hold my hand on it. No funny noises yet either. Does anyone have an exploded view of A 750FD?
Once again this is A great place for info!!
Paul

[TopCatGr58]

Hey Paul,

I'll try to post it from the Yamaha Site, but if it doesn't work, just go to this link: http://www.yamaha-motor.com/sport/parts/home.aspx

Select to go directly to the parts catalog, then select from the drop down menus, Motorcycle, 1979, XS750D , you can then zoom in to your liking!



T.C.

[DGXSER]

So.. now I need to get an inch pound torque wrench. Had not figured on measuring the preload, just thought if I torqued it between 75 and 105 it would be right.

[Paul Kelley]

preload

Hey DGXSER,
I'm going by the tech info I've read on this site. I'm still trying to find more info all the time. Topcatgr58 found me A great exploded view that helps alot.If you go to the tech site from 06 it gives you torque and preload specs for the 750 and 850.My first tank with 750FD I'm over 38 mpg, YEA!!!!!!
I'm still learning but will tell all I find out.
Having fun Paul

[Pat Kelly]

Bump

Rather than starting another 750FD thread, I thought I would post here (this thread went dormant 7/13/09).

Got a 750 FD off Ebay for $35 shipped. Sorry if I outbid someone here.
I see from above that the copper spacer will work. I'll do the usual pre-prep of the 750FD before installation onto the E.
That will be a project as I have to remove the exhaust and hardbags to remove the rear wheel (PITA). Need to replace the brake pads and the driveshaft boot (have a new one already) so that will be a good time to do that.
Might adjust the valves at that time (means removing the fairing/lowers) as I now have a small assortment of shims, probably none of the right size.

[DGXSER]

Nice buy on the drive. what year did the drive come from? Does it have a phillips screw in the face of the flange where it mounts to the swing arm?

[Pat Kelly]

It was listed as off a 79 Special.
Yes, it has the phillips screw.
To avoid others' problem, I have a spare (the original) back wheel to hold the gears for disassembly. It is currently drained of lube but it does spin freely by hand. I will check contact pattern and backlash before installing (I've set-up many automotive differentials in the past).
My conundrum is, what color to paint it. Silver as original, black like the swingarm/frame, or blue like the body od the bike.

At this time I do not intend to do this mod on my LG. I want that higher gear ratio accelleration.

[DGXSER]

Since it has that phillips screw, it is the type II. This means you should not need to worry about backlash and such. The screw holds all that together so you do not change it. When you pull the nut off and replace the washer with the 1/2" washer, you will want to carefully retorque the nut to just tight enough so you do not create to much friction when turning it, so it is as loose as it is now.

On the type II there is a cruch washer for setting the spacing instead of spacers under the nut. So as long as you do not pull the philips screw, no worries on spacing.

[Pat Kelly]

Thanks for the heads-up. I guess I'll use my beam torque wrench to measure current friction/tension, then tighten pinion nut to match the previous friction/tension.
I already have a bunch of 3/4" copper couplings from our home XSpansion project.
Instead of the O-ring I may use a dab of RTV to hold the spacer in place

[joceiphus]

Good luck Pat.

[DGXSER]

Honestly, I'd say the RTV will do just fine. The drive shaft and the sleeve it rides inside that the coupling pushes against all turn together.

So the only thing putting any pressure on the copper coupling is the push of the spring back at the final drive pushing the drive shaft into the fitting. It pushes the copper coupling against the u joint fitting.