Seen an excellent '71 Roadster for sale with only 25000 miles. Owner advises that the top end was rebuilt and the bottom end was sound. Are these early 750's reliable without having the main bearings and layshaft bearings done or is that something I should factor in? Reading all the articles makes for scary reading that the gearbox could lock up unannounced... Also I am not sure if it is a combat engine but are they a no-go? Finally is the drum brake any good?
Thanks

FastFred wrote:Owner advises that the top end was rebuilt and the bottom end was sound.

But it could have had 'Superblend' bearings fitted years ago, unless the owner knows its full history?

FastFred wrote:Are these early 750's reliable without having the main bearings and layshaft bearings done or is that something I should factor in? Reading all the articles makes for scary reading that the gearbox could lock up unannounced...

Potentially any Commando (except for the Norvil new builds etc.) could still have the old style layshaft ball bearing fitted and is certainly something that needs checking unless it is known that a roller bearing or Hemmings ball bearing has been installed.

FastFred wrote:Also I am not sure if it is a combat engine but are they a no-go?

A '71 model wouldn't normally have the Combat engine, only the '72 models are likely to have been built as Combats.

FastFred wrote:Finally is the drum brake any good?

It isn't all that good, but adding the stiffening plate modification improves it, apparently.

Thanks L.A.B.

Can the layshaft brg be checked in position? I have stripped one many years ago but forgotten.

FastFred wrote:Can the layshaft brg be checked in position? I have stripped one many years ago but forgotten.

Yes, the bearing can be checked and if necessary changed without having to remove the gearbox. If you enter "layshaft bearing" into the search facility, then you should find plenty of information on how to do it.