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I am currently restoring a 73 Commando 750 Roadster One lobe on the camshaft is worn on an angle and the lifter is rounded as well. My question is when they converted from the combat back to the non combat configuration what parts of the engine were the same as the Combat engine ? or was this a complete makeover. Is it a different head to reduce the compression ratio or just a thicker gasket? And is the camshaft a standard 750 camshaft. This motor looks like it has the original roller bearings as when I removed them the cages stayed on the crank and I had to pull them off They are dissimilar to the Superblend bearings that were in my 850. I cant really tell from the literature that I have what Norton did with the 73 750
Thx
Jack
There were very few differ…
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There were very few differences between the Combat and stock motors. The Combat used a 2S cam - you can get your worn lobe redone by RGM for about £20 - they can also re-face the lifters.
The Combat used the same head (stamped with a 'C' at the top), albeit with some material shaved off to raise compression. The guys who built the motors wanted to shave a similar amount off the pushrods to maintain the correct geometry, but they were overuled by those 'who knew better'. In other words, the accountants, who didn't know better.
There were some changes to the crankcases too, however, they are easily modified - there are endless threads about breather locations, oil pick-ups, and so on.
Early Combats also used the early roller bearings, but as they caused so many problems, the Superblends were brought in to replace them.