Norton Mk3 crankshaft float, clearance, end play

I am ready to install rods, but thought it would be best confirm if any "centering" of the crankshaft is required.
Nothing seems to be mentioned in workshop manual.

I am used to keeping some honed out inner races that slip on the crank, bolt up, and make plans from there.
I dont find that part of Norton work on crank.
Shims better on outer race?
Shims better on crank behind inner race?
End play not an issue with MK3?

It depends how much float is has now and if you can be bothered setting it to the 0.010" to 0.015" spec.

They came out of the factory slapped together and out the door even if a spec (low/high) was added to the manual.
I followed Jim Comstocks recommendation and added shims under the main bearings (not behind the inners) to get 0.012". (0.029" from the factory)

The catch with that is, it is easier checked with dummy bearings.

searched and found forum info to jog my memory.
I think I have these outer race shims.
I now remember years ago checking Mk3 clearance on neighbors Mk3, split engine, heating case, dropping outer race , installing shims, installing outer race, bolt up, check again.

That is correct but a lot of work compared to dummy bearings of some sort.

The Old Britts shims if you have a set would work well but would imagine the crankshaft also changes dimension once the engine is up to temperature along with the cases.
The 0.010"/0.015" was good enough for me even if the engine had come from the factory with the best part of three times that. (low figure)

If those are the factory connecting rod bolts it does not hurt to check the bottom of the counterbore in the rod to see if the head is seating fully at the OD

Time Warp said:

It depends how much float is has now and if you can be bothered setting it to the 0.010" to 0.015" spec.

Click to expand...

That figure was for the single roller bearing.
When the factory began fitting the second roller this was increased to 0.010" - 0. 024".

L.A.B. said:

That figure was for the single roller bearing.
When the factory began fitting the second roller this was increased to 0.010" - 0. 024".

Click to expand...

I never mentioned the factory spec.
I set the crank as posted at 0.012" or mid way between what Jim Comstock posted for a stock (minimum .010") engine and race engine (minimum 0.015")

#
Shimming the crankshaft in general is only an option, just like shimming roller bearing layshafts, the drive side swing arm bush or tapered roller steering head bearings.
The engine will still run, the gearbox will still turn, and the bike will still go around corners with none of those items shimmed.

Easy if you can do those things, not the end of the world if you cannot.

Not enough pictures.
A jig for making stainless steel shims. (It needed the 4 jaw after this lot)

OD.


ID.

My mk2a had exactly 24thou float the whole time I owned/abused it
Never an issue