P11 knocking.

atmain

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Sep 27, 2011
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I have a P11 and it has an intermittent knock, i feel that it happens mainly under load early, then stops. Usually a double or triple knock. Happens in neutral also. Any ideas before I start to strip down. Cheers
 
“Knocking” is usually used to describe the noise of slack big ends.

Your intermittent nature could be due to big ends on the early stages of out of tolerance wear and / or related to oil pressure.

Before tearing it down, I’d hook up a temp oil pressure gauge and see if the knocking aligns with dips in pressure.

Cold thick oil and / or a worm pump, can cause a lag between increasing the revs and the oil pressure ‘catching up’.

Such a lag might therefore be indicating a worn pump. Might also be indicating big ends that are on the edge. Replacing the pump first would be the easiest way to eliminate one or t’other.
 
Last edited:
Alternator rotor is a good call…

A mate of mine bought a Daytona years ago, got it for an absolute bargain as we basically thought the horrible noise it emitted was due to a loose rotor, whereas the seller thought it was the big ends…

We were right !
 
If the nut retaining the rotor is loose it'll be obvious
But to check the actual rotor you need to clamp just the centre in a vice using packing on both sides
Then see if you can rotate it at all forward and backward
 
Alternator stator is fastened inside the outer primary cover on a P11. It is not mounted to the inner cover or drive side crank case. The chain would have to be exceedingly loose to hit the P11 primary cover. If the chain was that loose it would definitely knock on the bottom of the primary though just before it wadded up and locked up the engine. So yeah anything is possible.
 
Thanks for the input, had a rotor do that on my Commando sounded similar, fingers crossed.
 
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