[vinnysd]

I just received my 1500 final drive for my 04 VL800 and will be removing the drive shaft this weekend and taking it to the machine shop. I have a diagram from the VR sight drawn by M50DAVE on May 2012. It shows how much to shorten the splines,.098 and how much to machine back off the shoulder .187. My question is, Viper has said the machining of the spines are not needed for the drive conversion as previously thought,so does the shoulder still need to be machined? Also why was it once felt that the splines needed milled and now they don't need it? Thanks for any response Viper or anyone with there thoughts too.

 

[Mickey]

Shaft Work

Hey there,
The VL800 driveshaft needs to be machined exactly as per MoDZuKi's 05/11/12 post to be used with your VL1500 final drive!!!!!
Mike

 

[kcroz]

Look at MoDZuKi’s drawings very carefully, particularly the note:

MAKE SURE WHEN MACHINING THE SHOULDER TO MACHINE THE SHAFT TO THE ROOT OF THE SPLINES SO IT WILL SLIP IN THE U-JOINT AND THE SHOULDER WILL BUTT UP TO THE END OF THE U-JOINT WITHOUT BINDING.

Based on my C-50 shaft, here’s why (at least it’s what I thought)

See how the ruler is level in the trough

As you move the ruler toward the shoulder it begins to rise. This area could bind and not allow the new shoulder to butt against the U-Joint.

Here’s how I had mine machined:

Good luck with your project. You're going to love the transformation!

 

[472viper]

The original modification, done by DJHillis, did not call for shortening the length of the splines. His mods were done to C90 driveshafts and the spline end on those are longer than the spline end on the C50/VL800.

Some of us armchair machinests noticed that the C90 splines were longer than the C50 splines and wondered if protruding deeper into the U-joint would interfere with the action of the U-joint.

I think, after further review, some of us (self included) concluded it really isn't necessary. Some people remove 2mm from the end of the C90 driveshaft splines as an added measure. No one has ever produced concrete evidence that it is necessary.

Hillis probably produced a couple hundred drives and did not shorten the splines.

 

[mpawul]

Clarification: which components needed?

Firstly, thanks to everyone who have taken the time to research and post what evidently is an excellent modification.

Okay, my C90 drive will be delivered in a few days. From everything I have read, I have two options for the drive shaft. Please correct me if I am wrong.

1. Cut and splice the C90 shaft, with special consideration of the 15.750 critical dim., and install the .9880 spacer. This option does not require any machining of the splines and leaves you with the stock C50 shaft.

2. Machine the shoulder and splines of the C50 shaft per David Yates engineering dwg. dated May 2012. This mod does not require the .9880 spacer.

Both mods require a press fit axle bushing to the C90 drive and, unless you grind or otherwise machine the C90 final drive casing, makes it so you cannot install the left side "fake" swing arm.

Besides the above confirmation request, I do have one question. Is the length of the axle bushing .750 and what material is everyone using for this bushing and the spacer?

Thank you.
Mike

 

[472viper]

I think there may be some confusion.

Option 1
Cut and splice a C90 driveshaft in manner to achieve the 15.750 inch is correct.

I believe that .9880 spacer was done to correct a measuring mistake and is not necessary if that 15.750 measurement is achieved.

Option 2
Machine the shoulder back on a C50 driveshaft (yes this will catch some part of the splines in the process). Again, goal is to achieve critical measurement of 15.750.

Don't confuse axle bushings and axle spacers.

A spacer is used to register the proper spacing between wheel hub and drive case. It slides over the axle, Just like the one you remove from the C50 axle. But the C50 spacer is 2mm too long. You can either make a new one out of straight tube (I have always used DOM tube) or shorten a C50 axle spacer.

A bushing is required to reduce the C90 axle hole to accept the smaller C50 axle. Yes it is .75 in length. Looks like any mild steel, I let my machinest decide on type of material to use. I don't like to quote I.D. and O.D. measurements on that bushing, because I have found some tolerance between drive axle holes. Best to let you machinest take some measurements.

Rather than grind material away from that nice drive case, I prefer to grind material away from the back side of the swing arm itself and make it fit.