Hello
I am working on a 1947 Norton 500T which I bought. A bike with a colourful past I think. My problem is that there was a lot of crank end float. I have stripped the engine and it seems to have self aligning bearing either side of the crank. It also has a ball bearing on In the primary side of the casing. Can anyone tell me why this is? I intend to take the bearing back to original specification with the roller bearings. Any advice would be welcome. Thanks for reading.Fran
Beware....
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Hello Michael They are…
Hello Michael
They are double row ball bearing. I have had a very informative d reply on the subject on this forum which is well worth a read. Thanks for your reply
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Main bearings.
Hi Fran,.
Your flywheels look like the 1948 onwards Hopwood type. These are wider and heavier than the 1947 ones, although the bearings are the same size for both.
I believe the double row self aligning bearings were used during the war years on 16H and Big 4 engines to allow a more loose tolerance so engine parts could be mixed and matched under adverse conditions. The 1948 engines use a lipped roller on each side of the wheels and a fixed single row ball bearing in the outer drive-side. Make sure you have got the correct centre spacer between the drive side bearings and shim as usual to get 5 thou end float. As Michael says, check the bearing fit and use Loctite bearing adhesive if you need too.
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Hello Richard That is an…
Hello Richard
That is an excellent reply and explains a lot. There are no shims at all on this crank and the float is huge. I have never shimmed a crank before so that should be fun! The only spacer between the bearings is the one with the notches in to allow the oil on to the bearing. I am presuming the shims will go behind the roller bearing up to the face of the crank?
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Main bearings.
Hi Fran,
Yes, that's correct with the shims against the flywheel faces and the spacer you mention is the correct one. When you fit the new bearings the end-float might not be so much. The con-rod little end needs to be central in the mouth of the crankcases, which is a bit of a faff as you will need to try the crank in the cases a few times to get the end-float and centrality set right. If the bearings are a good fit on the main-shafts you might need to tap the shafts from one side then the other to get a true measurement of the end-float.
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....you could be mistaking bearings loose in cases for end float.