450 R/T rear sprocket wobble & wheel alignment

[graeme]

PS,,,,,
If you use sealed bearings you don’t need the felt washers

[Paul1098]

Hi Paul,

The spacer 290 is between the wheel bearings and the sprocket carrier bearings. And yes, if there is play then the bearings have to be replaced in the hope that it will cure the problem! It is also possible that the bearings are loose in the housings. All this is dependent on the hub and sprocket carrier being the same as a normal 450 item...... I know that Eldert has an RT so if he reads this maybe he can confirm?


Cheers,

Colin

Would the spacer fall out when you remove the sprocket carrier from the wheel?

I'll check the fit of the bearings to the housing. Is there an equivalent SKF bearing or are these specials?

[Paul1098]

PS,,,,,
If you use sealed bearings you don’t need the felt washers

Felt washer is only on the brake side?

[themoudie]

Aye Paul,

The sprocket carrier in your 450 R/T appears to be the same as used in my '74 450 MKIII, if it uses two support bearings with a spacer between and another spacer on the inside of the carrier, as Graeme has described and the exploded diagram posted by Jordan shows. If you have only a single bearing sprocket carrier fitted in your 450 R/T hub, then I suspect that someone has built a "bitsa", or replaced bearings at an earlier date and done the job incorrectly, loosing the inner spacer in the process!

The bearings you require are not "Special", any good quality, deep ball bearing, measuring 20mm x 42mm x 12mm, with two rubber seals (6004 2RS), covering both sides of the bearing are suitable. Either standard clearance or C3 clearance bearings are fine.

Personally, I would use only bearings from a "High Quality Manufacturer".

As others have indicated the felt washer becomes redundant when using 2RS rubber sealed bearings. If you are in the UK, then I would suggest that Nigel Lacey's "Lacey Ducati" online shop, "Simply Bearings" online shop, or your local bearing factors are your best places to go for the bearings and Nigel's shop for a "missing" internal spacer.

So, to summarise, bearings #310 (2 x 6004 2RS) inserted from the left and the right hand sides of the sproket carrier #240, after heating the casting to approximately 100°C and putting the bearings in the freezer for a good hour. MAKE SURE THAT SPACER #295 GOES BETWEEN THE BEARINGS! Then insert spacer #290 into the inner face of the carrier, this can be tight and may benifit from being put in the freezer along with the bearings and varies depending upon wear to the spacer and the carrier. The 2 felt bearing protectors #280, can be ignored or removed, providing rubber sealed bearings are used and I cannot see any reason for not using this type of bearing.

If anybody thinks that I have made an error here, please say so and I will correct it. Thank you.

Hope this helps, good health, Bill

[Duccout]

Hi Paul,

Just to answer your earlier query: yes, the spacer 290 can easily fall out as it can be quite a loose fit. If yours is missing then you may have found the reason for your sprocket wobble!


Cheers,

Colin

[Paul1098]

I'll pull the rear wheel and check for the spacer once i'm back home.

SKF do a 6004 2RS bearing so i'll probably go with those.

[Paul1098]

All the spacers are in the sprocket carrier.

Bearings in the sprocket carrier can be moved from side to side so looks like they are worn and probably the main culprit.

The wheel bearing on the drum brake side is open and drum brake has the felt washer.
The wheel bearing on the sprocket side is an enclosed type with metal rather than rubber seal.
Wheel bearings rotate OK and no sideways movement can be felt.

On the drum side it looks like i'm missing part # 0170.77.210 which is described as a washer and i assume the felt washer rubs against.

Is it ok to run without this washer?

[Duccout]

I think that that washer is a shield to protect the bearing from dirt. Maybe you can find something to replace it, or change the bearing to a shielded one? I don't think that it is especially critical, the worst that can happen is that the bearing will wear out.

Cheers,


Colin

[Paul1098]

I think that that washer is a shield to protect the bearing from dirt. Maybe you can find something to replace it, or change the bearing to a shielded one? I don't think that it is especially critical, the worst that can happen is that the bearing will wear out.

Cheers,


Colim

I've just found a photo of the washer and it does look like it's there to protect the bearing rather than as a spacer.
Decided to order sealed wheel bearings at same time as the sprocket carrier bearings so I can ignore the washer and the felt discs.

[Jordan]

I'd be inclined to use rubber-sealed rather than metal-shielded bearings in wheels, because:

Unlike engine or gearbox shafts that rotate inside stationary housings, a wheel axle doesn't move and the hub rotates.
Sealed bearings have the rubber pressed into the outer race, and the sealing lips bear on the inner race, where the contact surfaces move more slowly.
Centrifugal force acting on the grease will tend to make it fling outwards, but it's retained because there's no gap at the outer circumference.
Conversely, shielded bearings generally have the shields pressed or clipped to the inner race and have a clearance gap at the outer circumference.
The grease could creep out of that gap, in theory.