Hi all, I bought a 73 Commando, my 5th Norton, matching engine, frame and gearbox numbers 220570. It was brought back into this country in '83 from, I presume, the US. Black barrels, head has H 6 teaped into it. There might be something before this though. To cut to the point, there's a LOT of side play in the camshaft. Must be a good quarter inch at least.. Funny thing is, the engine runs as sweet as a nut. anyone any info on camshaft side play?
I've included a couple of photos. Cheers!
73 750 commando
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200000 combat breather series/ cam bushes?
Well said.
IF it is missing the inner thrust washer, than you are in trouble
If this engine has the original 06-2600/01 bush/thrust washer, than he would do well to upgrade to the 850 style on the timing side. His cam washer could instead be missing the outer one? similar resulting slop.
Either one missing would account for 1.5mm extra end play. Again up to 1mm total is probably OK
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combat
The bike came with black barrels and the semi high compression RH6 head, It's an import, nos. 220507, and I wondered if it could possibly be a combat motor. one of the side panels has been resprayed, and in the sunlight is faintly visible, under the respray, the word Combat. It has the breather at the back of the crankcase l/h side..Any input would be greatly appreciated.
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Side panel decal
If it does have evidence of a "Combat" sticker on the side panel, then somebody has added it. The factory never fitted anything like that. Regardless of whether it was a Combat or not it just says "750 Commando" on the side panel.
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You have a nice looking bike. Later than mine.
The H6 seems to have a very faint "R" to the left. RH6 is a semi high compression 32mm port head,
Squish band is about .100" deep (semi combat)
see here: http://atlanticgreen.com/nhth.htm
I have a 73 220xxx engine/head a few hundred after yours, with a "5" that does not have the RH but the number is in the same spot. full squish band .120" deep. is standard compression 32mm ports.
Your cam, no NHT, should have over about .030" (3/4mm) of end play. 1/4" no way, no how......
Danger!!. I would have that engine out and on the bench asap.
Good luck