Should I rebuild it? Final Drive

[Tartan Terror]

Well a few months ago I traded my final drive to get a Drive with the Vmax gears. Long story short I am not happy with it and am sorry I changed. Its too far the other way so I decided to go back to the original. I purchased a rear from Pinwall that was on a 1999 that has 70K on it. My bike has 17K. Before I put it in should I reseal and rebuild it or at that much mileage are they still tight? I plan to powdercoat it in the winter as part of the firebike theme anyway. Maybe Ill just do it now. What are your thoughts? Just put it in or do the rear first?

 

Scotty

[flb_78]

Dang, you should have offered it for a straight across trade or a trade plus some cash for a low mileage unit here on the forum unless you were just wanting a 2nd final drive as a spare.

 

After reading about Red Rider's troubles with his unit at 85K miles, I think it would be wise to tear it down to reseal it and check for wear.

[Tartan Terror]

Thats how I got into this mess. I dont want to be off the road for another week or so waiting for them to cross in the mail. When I have it out I may sell the Vmax rear but I want it out and in in one day.

[V7Goose]

If the unit was not run dry there is no reason it should not last several hundreds of thousands of miles. I think you can see the ring gear teeth through the hole where the speedo sender mounts - if they all look smooth, I'd just bolt it on and start riding.

Goose

[Carbon_One]

What Goose says and then do the power coating in the winter. Powder coating will require ne seals anyhow.

larry

[Sylvester]

My final drive has 130,500+ miles. That should tell you something.

 

[RedRider]

The gears in mine still looked good. It was the nose bearing on the pinion that went out. It may in fact have been initially the tail ball bearing that died and then caused the nose bearing to go. Why? Don't know, but I have been thinking about it.

 

Possible causes:

1) Remounting the final drive after lubing the drive shaft, I may have tightened the 4 acorn nuts before tightening down the rear wheel axle nut. Thus causing deflection at the input of the pumpkin.

2) When filling the drive, a bubble of fluid formed across the fill hole, making it appear it was full. But it wasn't.

3) Hard riding in the mountains.

 

My guess is it was #1, although I thought I was always conscientious of the procedure.

 

Bottom line, the design is really solid and if properly maintained, it should last significantly longer than my 85k miles (began having trouble at about 70k). Therefore, a quick inspection of the gears thru the speedometer hole will tell you if the gears are in good shape. Check the pinion for any axial movement which would be allowed with bad bearings. Check the drain plug to see if there are any shavings (likely cleaned before you purchased the drive). Check the drive for gear lash (it is explained fairly well in the repair manual).

 

If all looks in good shape, you should be good to go. Rebuiling a rear drive is not an easy or inexpensive task. I checked.

 

RR

Edited July 27, 2010 by RedRider