Don’t worry, no heresy committed. I was just trying to tell you that the inertia forces you think the camshaft has don’t really exist. Remember, the camshaft has the forces of the valve springs against it when a valve is open. Another thing to keep in mind is the camshaft is spinning at half the speed the crank shaft is. The chain isn’t really a weak point, just a maintenance item as said earlier.Thanks for your comments.
History - I built the engine using a bottom end - no heads - from eBay.
It had been cut out of the frame, mounts still attached!
I won't bore you with all the details but examination of the tensioner and chain surprised me as no signs of wear, looked new and when adjusted all the gap was above the tensioner locking bolt.
There was gouging damage to the case that suggests it had suffered a broken chain/tensioner previously - so the new parts made some sense.
I've run it for 600 miles since the rebuild and adjusted the cam chain 3 times as per Haynes manual.
As for the design aspect, I think the amount of space on this community devoted to the subject tells a story - it's not one of the cx's strengths.
Don't get me wrong, I'm very impressed with it, 50 bhp out of a 500cc, my bsa Firebird 650 was tuned and made less.
And when I stripped the cx the difference in technology blew me away - the BSA's were positively agricultural compared to the cx!
But one thing the pushroded BSA won on was the gear driven camshaft.
Cam chains and pushrods each have their own problems, the cx has both!
I apologize if I've committed heresy, I know the people in this community love their bikes and I don't want to offend anyone.
I shall press on with the additional tensioner adjuster bolt mod and post results - good or bad.
Cheers all and take care.
I've never seen a spring used there. I wonder if that lug in the center is from casting the blade? I suspect that the mold would have cast several pieces at the same time and the lug is where the channel was connected. Not sure about the two slots in either end.On close inspection the adjustable tensioner blade has two slots in either end.
View attachment 211717
Along with the thick lug in the centre it seems to me there is something missing - a piece of spring steel tensioned against the slots and pushing against the lug in the centre.
Seems to be designed and made to take a spring in the back.
Any thoughts on this?
When adjusting the cam chain as per manual it seems it's still a little slack on the spring tension alone - with this mod I can move the tensioner arm manually, it's not an additional locking bolt - only an adjustment aid.Not sure what you've gained with your addition, other than a redundant lock bolt on the tension adjuster. Slippage of the stock lock bolt has never been an issue. What performance change do you expect to see?