Fork top and bottom bearing race insertion

[andy13]

Hi guys, I have a series 3 that I am starting to rebuild. My question is about the best and least expensive way to fit the new top and bottom fork bearing race and chrome ring. There are lots of tools out there to purchase, I will only need to use once. Suggestions greatly appreciated. Thanks

[Knowledge]

Are the existing top and bottom races bad? They can often be quite durable items, so I would not plan to replace them unless they actually need replacing as both can be tough to remove.

[andy13]

They are all scrap, including the chrome ring. So I am repalacing all of them, and they were an absolute pain to get out.

[HxPaul]

http://www.scooterrestorations.com/lamb ... -race-set/
I suppose you'll get the chrome ring from the same place.

[andy13]

Thanks guys. It is the best tool for the job that I am looking for advice.

[Warkton Tornado No.1]

As with anything that is old & made of ferrous materials, the best way to ease fitting, or re-fitting of the original bearing journals, is to ensure the frame housings for the bearings are clean & back to steel, with no trace of rust.

Any new journals should be checked for size against the original parts. It is no use relying on any new part being correct these days......

Fork/frame bearings are transition fits, so they rely upon needing considerable force to fit. The force required will be lessened with the forethought of freezing overnight.

Fitting should be far easier than the removal, as the components are far more easily pushed in than out as they do not rely on lengths of tube etc resting on a narrow shoulder to have force applied, largely on one side only, encouraging tipping out of true. That said, anything such as a journal should not be knocked in with a club hammer. A softer material such as a copper faced mallet, or a piece of wood will prevent damage.

I am unaware of any tools to assist, but the lower bearing is the toughest to fit. However, if I felt the need to have some method other than knocking the thing in nice & true, I would acquire a bearing with thrust capabilities (a deep groove ball bearing might do it, though a taper bearing certainly would) to draw the bearing into the frame via a substantial size of studding (M16 minimum)

A bearing used to pull things together decreases the effort needed by an incredible amount. My home made engine mount tool utilises deep groove ball bearings with a length of M16 studding & I have removed/replaced mounts dozens of times. Although I apply liberal amounts of a penetrating oil (WD40 is not a penetrating oil) I have never, ever had to apply heat! Quite why that is such a common practise is because without a bearing, friction is so difficult to overcome. There is a risk to using heat on engine mounts for their removal, especially if the mounts are only being transferred to another block, like was the case with the early SIL two hole/solid through mounts, still highly prized by some of us

Finally, using a Copaslip type compound can only help the process of fitting such bearings & make any subsequent removal far easier.

I hope this information helps......

[andy13]

Thanks, some very good information.

[dickie]

WT1 is absolutely correct about checking size. I've had variations of 0.5mm on brand new bottom races! Easily fixed, but i just tried to fit without checking before I started to investigate. No way is 0.5mm excess going in without splitting the tube.