cutting driveshaft gear splines?

No eBay APP ID and/or Cert ID defined in Kunena configurationHey guys,

So I'm busy fitting a 1100 drivesahft and swingarm to my 750, because its 30mm longer. The front of the 1100 driveshaft bolts right up to the engine side of the 750. However, the rear "splined sleeve coupling" that connects to the final drive is bigger. 40mm OD vs 35mm on the 750.

I'm wondering what's the best way to resolve this?

One idea is to cut the 1100 drive shaft splines down to the 750 size, then continue with the 750 spline sleeve coupling to the final drive as per normal.
Another idea is to cut spline into the outside of the 750 sleeve that mate to the inside of the 1100 sleeve.

Any thoughts?

these pics are similar to what Im referring to



thumbs.ebaystatic.com/images/g/yZoAAOSwaB5Xo5Yp/s-l225.jpg

Would it be easier to use an 1100 rear gear?

TexasKZ wrote: Would it be easier to use an 1100 rear gear?

That is off course another option yes, but that rear final drive is bigger so I'd need a different rear wheel. Most suitable would be the 17" wheel from a 1000 ST. The 750 has an 18" rear wheel.

Then there's the issue of final drive ratios. Looks like 1000/1100 is around 2.29 to 2.45. Haven't quite figured out which is which yet. Need to find the 750 ratio to ensure the ratios stay at least similar.

Will the 750 gear case bolt up to the 1100 swingarm? Will the axle hole in the 750 case allow the axle to line up properly?

If everything else works out, an adaptor coupling would be an interesting solution, but finding a machine shop with that expertise might be a challenge.

TexasKZ wrote: Will the 750 gear case bolt up to the 1100 swingarm? Will the axle hole in the 750 case allow the axle to line up properly?

The 750 bolt pattern is slightly smaller at the swing arm, but can be resolved with some notching of the swingarm flange. This will also centre the axle. But I guess it may offset the wheel itself a bit to the left as the 1000 swing arm seems marginally wider at the rear axle side.

At the same time the swing arm pivot is about 5mm narrower, which will require a spacer to resolve. However I need to keep the driveshaft in the same position as the original.

TexasKZ wrote: If everything else works out, an adaptor coupling would be an interesting solution, but finding a machine shop with that expertise might be a challenge.

True. The places I spoke to said they need to first measure the hardness of the driveshaft to decide if they can cut or mill it.

I'm leaning more and more towards the 1000 st final drive and rear wheel. The wheel is 17x3 vs the 18x2.15 of the 750. So I should be able to run a wider tyre. Might be a stretch for a 3" rim but a 150/70/17 would be a good look for the bike.

Also keen on the 18x2.15 front off a kz1300, but need to first investigate if it will work in my gpz750 turbo front end,

custom beemer bike builders sometimes cut drive shafts and slide a piece of suitable tubing over the outside and weld it back to lengthen them.
i see no reason you couldn't do the same and use the 750 on one end and the 1100 on the other to suit.

that's my .02 fwiw.

leon

I decided to take the path of least resistance. Went with the st1000 rear wheel and hub, and swingarm. It's pretty much going to be plug and play now, aside from the narrower swingarm which I'm still resolving.

Interesting that the 750 has the widest frame pivot section from all the shafties... Will update with pics in my build thread.