xs750 final drive

[THE BUTCHER]

Hi Folks,
I remember a while back a disscusion on using an xs750 final drive on an xs1100 to up the gear ratio. I need to know if anyone has tried this, as i have a sidecar outfit with 15" front and rear wheels, and i dont want to run them if it makes my bike real slow. If there is someone on here thats tried a xs750 hub on a 15" wheel and found that the gear ratio ups the top speed, please could you let me know, as i dont want to do the conversion if it makes no differance, and if it does make a differance, by how much?
regards THE BUTCHER.

[TopCatGr58]

Hey Butcher,

Where've you been lately, this is old news!

Check out this tech tip for all the info. Many people have done the conversion and are very happy with it. IT drops the rpms about 400 over every gear. However, these are with either 16 or 17" rims depending on whether they were put on a Special or Standard. So...IF you are using a 15" rim??, then you may not see as much of a drop in rpms?
T.C.

[THE BUTCHER]

Thanks TC, Well if there is anyone thats done it on 15" rims, i would love to know.
Thanks again TC.

[xschop]

15"

would definitely be a benefit to you....and your fuel tank

[THE BUTCHER]

Another question is, will i need the xs750 shaft for the conversion, or is the conversion shown using the xs1100 shaft?

[trbig]

Use your 1100 shaft. I just did this final drive mod on my bike for this Texsessive rally. I am told that I had an older 750 drive... mid 70's possibly... but the shaft was considerably smaller (Skinnier) than the 1100's. I don't have a 15" wheel and I know that's who you're wanting to hear from, but on the way down to Texas, at 75mph, I was running 5k on the rpm's. Afterwards, I was running about 42-4300 rpm. 70 is 3900. I haven't noticed a huge jump in gas mileage, but the motor seems to love it, and it feels right.... you don't try to pull up for another gear when you're already in 5th. I used to be able to slow down to about 25 in 5th and still continue on... now I can't go much less than 35 without downshifting. The one downside I have, is that it is a bit harder on the clutch on starts... especially starting going uphill. It's not really bad, but with the additional weight of the sidecar, it may be?? It isn't too hard to do, and not very expensive of a mod. If you find out that it won't work for you, simply put it back the way it was.

Tod

[fredintoon]

Check the OD

Hi Butcher,
with the added weight and air drag of a chair, if you stay with the stock wheels & axle ratio the rig will go fastest in 4th while 5th will act as an overdrive.
With the lower final drive ratio of the 750 unit and stock wheels you may even have two overdrives. But WTF, that's your decision. Remember that what you gain in top speed you may loose in acceleration besides overstressing the clutch when pulling away from a stop. However, before doing anything drastic, what size tyres are on those 15" rims? Measure the actual outside diameters of the stock rear tyre and of the 15" rear tyre and compare them, rather than just the rim diameters.
Note that (for instance) the 400-18 rear on my XS650 and the optional 500-16 rear have exactly the same OD.
Fred Hill, S'toon.