850 MNS Final Drive issue

[CatatonicBug]

I managed to get a good deal on a final drive for an 850 MNS. In comparing the shaft length to the tech tip, I am a bit confused. The 750 FD is said to be 10-13/16", and the 1100 FD is said to be 10-1/8". However, the 850 FD that I got is MUCH shorter, and has one end that looks like the 1100 shaft, and one end that looks like the 750 shaft. The 850 shaft I have is 9-7/16" long.

What does this mean for adding the copper spacer to the 1100 shaft?

[CatatonicBug]

Well, after finding an old thread about XSChop's research on this mod, I think I have answered my own question, but I'm still not 100% sure... It appears that the XS850 has the same yoke as the XS11, but the FD end is the same as the XS750. That tells me that I still need to add the 16mm spacer and 2 o-rings to make up for the added depth that the shaft sits into the FD (as compared to the XS11 FD).

The part I don't understand is why, if the 750 shaft is longer than the 1100 one, is the 850 shaft shorter?? Did it have a shorter wheelbase than the 750 & 1100?

[TomRodgers]

Maybe you need a new tape measure??? LOL

[DenyP]

Well, after finding an old thread about XSChop's research on this mod, I think I have answered my own question, but I'm still not 100% sure... It appears that the XS850 has the same yoke as the XS11, but the FD end is the same as the XS750. That tells me that I still need to add the 16mm spacer and 2 o-rings to make up for the added depth that the shaft sits into the FD (as compared to the XS11 FD).

The part I don't understand is why, if the 750 shaft is longer than the 1100 one, is the 850 shaft shorter?? Did it have a shorter wheelbase than the 750 & 1100?

I'll measure Little Mo and post an answer latter. I can tell you XSCHOP's directions are right on when using an 850 rear end for the mod!

Deny

[John]

The early 750's had a CV type of joint at the engine end of the drive shaft, so the shaft is a different length. The 850 shaft is not the right length either. Use the 1100's shaft and all will be good. I have done 4-5 of these mods, and Chop's instructions are right on.