Crankshaft end float

I have recently dismantled the Primary chaincase to fix oil leaks on my 72 750 and decided to check the crankshaft end float.

It measures out at .70mm, which according to my manual is approximately 2x the limit.

I don't know the history of the engine and have not lifted the heads, but the engine runs well enough, I did not hear any knocking, not sure why the end float is so great, but could be due to previous owner reassembling engine without shimming (engine has been apart judging by silicone seal used on crankcase halves) or would the endfloat be caused by main bearings breaking up.

So my options are:
button it up and forget about it
Find someone in the UK who can rebuild engine to a good stock condition, without breaking my bank as I may not be keeping the bike longterm.

Comments and advice welcome

Charles

0.07 mm is approx 3 thou so just below the 5 thou min, have you got the decimal place wrong ?

Finding excessive end float is not uncommon, as long as it stays constant then its not a problem, 0.7mm would be 30 thou.

Kommando,

Yes you are right, the end float is .7mm not .07mm

I'll change the original post

Some manuals say .024 as the upper range. .7 mm, being .0275", is just outside. Whether that is a call for a teardown, I don't know. But it is so close that a call for a concensus is in order.

I would re-check and triple check for high accuracy of you procedure. Being just slightly out of spec in this regard may be just fine. If criusing at high RPM for extended periods.......well, it's your call.

850 and 750 Commando Workshop Manual. Technical Sata section ...subheading Crankshaft.
' Permissable end float : 0.005 - 0.015 inch (0.1270 - 0.0.3810 mm)'.
850 Electric Start Workshop Manual. .......
' Permissable end float : 0.010 - 0.024 inch (o.254 - 0.610 mm)'.
So I picked up the phone ......The Gentleman I talked with stated he had known of engines that had run successfully with 1/8 inch end float and others that ran very happily with 1/16 inch end float. However he stated it is not a good idea to run such end float with Mk3 electric start lumps as it causes problems and that he sets up all his and customers race motors to have 0.005 inch end float.
Of course drive chains and belts do not take to running on incorrectly aligned sprockets or pulleys as it causes wear and premature failures.........
Personally when employing roller bearings for both bearings on Dommys I always set end float to 0.012 inch and have a collection of different thickness 30mm bore shims with which to do so. I seem to remember that in Motor Cycle Shop in London decades ago there were shims for setting end float in one of the Norton spares drawers but they could well of come out of Shenstone on one of the spares buying trips..when new short stroke steel rods were being punted around the trade at £5 each and Shenstone still had a BIG bin full of them!! HAPPY DAYS!!