FJR rear end problem on 1st gen

[dingy]

Another glitch I am having during the bikes total over haul is my FJR rear end won't cooperate.

 

I have a seemingly good condition rear end that came off of a 2004 FJR.

 

On the bench it turns fine, no problems.

 

I mount it on the bike and as the rear axle is torqued down the rear end binds up. It finally becomes almost impossible to turn by hand.

 

I can hear no unusual noises as this is occurring.

 

Prior to torquing axle and with drive shaft in, wheel turns just as it should.

 

I have tried this with a shim in place of the thickness that Skydoc recommends and several thinner thicknesses of shim with exact same results. Also same with no shim in place.

 

I even tried an experiment shown in first two attached pictures where I torqued wheel down without going through the right side of the swing arm. I felt this would eliminate the shim variation from the process. I used a piece of 5/8" threaded rod with a nut on left side of rear end and other nut up against wheel bearing.

 

This also eliminated the brake arm from causing problem.

 

Last picture shows axle in as it should be, with washer in up against swing arm.

 

I am using an MKI swing arm.

 

I currently have the stock rear end back in and it works perfectly.

 

The one explanation I have thought of is as the axle is being torqued, the ring gear is being forced into the pinion gear just enough to cause binding.

 

Skydoc didn't have an explanation for this.

Any suggestions would be great.

 

Gary

[jasonm.]

You need to look at the FJR rear where the splines engage. There is a pressed in axle spacer. In this case it may not be the correct length to press against the left wheel bearing properly. Look at both rear drives in this area. I think you'll get the idea.

[dingy]

Are you referring to inside this area?

 

Should there be a spacer at bottom where grease is obscuring it?

 

 

 

Thank You,

 

Gary

[Squeeze]

Gary, look at #4 and # 32 in the Parts Sheet.

 

http://www.partshark.com/fiche_image_popup.asp?fveh=1156&section=43810&year=2003&make=YAMAHA&category=Motorcycles&dc=5364&name=DRIVE+SHAFT

 

If you can lock up the Final Drive by tightening down the rear Axle, there's something wrong in this Area. Maybe somebody overtightened the Axle in the Past and crushed a Collar. I've seen that.

 

[MiCarl]

Gary, sure looks to me like you're missing the spacer.

[jasonm.]

I don't think they would be missing. They are pressed in.But the reach to your wheel by these spacers may not match up...

[dingy]

It is the spacer that is missing that is causing the problem.

 

It does not appear to have been pressed in though. The outer bushing for the axle is still in rear end. It does not appear from the inside to have broken off . It looks like a machined surface.

 

The solution I am working on is to remove the pressed in spacer from a third spare rear end (not working venture one that is on bike now) and modify it.

 

It is correct ID, but length will need to be altered.

 

Thank you for pointing me in right direction.

 

1st picture shows Venture rear end internals with bearing and seal removed, 2nd picture shows FJR rear end internals as I got it.

 

Gary

 

 

[GigaWhiskey]

I am sure I missed something somewhere is some thread. Why a FJR rear versus a VMAX rear?

 

I hope this does not end up hijacking your thread. Sorry in advance.

[dingy]

FJR is essentially the same as a Vmax, same ratio.

 

Gary

[dingy]

It's now FJR equipped !!

 

I took spacer out of spare stock rear end and modified it.

 

Rear wheel spins freely now when torqued to 110 ft/lbs.

 

 

Thanks for help !!

 

Gary

[jasonm.]

glad I was correct and it could be remedied...

[Guest seuadr]

so is this a preformance upgrade or does it improve gas mileage?

[dingy]

so is this a preformance upgrade or does it improve gas mileage?

 

 

It makes the engine turn about 10% higher RPM's for the same MPH.

 

Increase the acceleration rate a bunch.

 

There is almost nothing I am doing to this bike that has anything to do with increasing MPG.

 

I have a Dodge truck that gets about 14 MPG, If the bike gets 35 MPG that will be just great.

 

Gary

[Leeway]

Great to hear! What modifications did the spacer require?

[dingy]

Great to hear! What modifications did the spacer require?

The FJR rear end I had did not come with the spacer it needed.

 

From the parts fiche it does not appear to be a press in like the Ventures use.

 

I had a spare venture rear end that had a spacer in it that was the proper ID, but overall length was a little long and OD of washer was a little big.

 

I have a variety of calipers, depth gauges and bore gauges.

 

I used the rear end that was known to be working OK, which was my original 83 rear end. I measured from face of female hub spline to the top of the spacer.

 

I then modified the donor spacer to match this height when sitting in FJR unit.

 

Gary