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Noisy tappets


I know the Dommie doesn't have the quietest valve gear. But this morning I tried to find the source of the clatter on mine. I'm not convinced it's worse than others but...

With the timing cover off and plugs removed, when I kick it over slowly there are two points where the cam faces 180 degrees apart where there is a distinct "tick tock" from somewhere in the area of the camshaft. The cam chain is, if anything, a bit on the tight side so it isn't back lash in the cam chain. Do they all do this? I'd expect it to be quite quiet if it is turned slowly. I think it's always been there. Or for 10k+ miles. I don't see why the tappets should jump to make such a noise. It's turning slowly so it's not pushrods hitting the tunnel or anything like that.

To add to this - I suspect the reason Dommies clatter from the front of the engine is that the cast iron tappets ring like little bells...



Hi Dave remember that the rotation of the camshaft affects the timing chain tension. With the camshaft chain this tends to flick it against the tensioner which leads to a double ticking sound every 180* of crankshaft turn.

Another source of clicking can be the oil pump work drive gear pushing the crankshaft sideways. With a standard Dominator Ball / Roller bearing set-up this only really becomes noticeable if the the ball bearing is very worn. However with a twin roller crankshaft, it is more likely to happen.


Next time our bikes are together we can have  a  " who's bike has the loudest rattles" ,  comparison.


Could it be wear in the cam followers and their tunnels.  I once had a 99 that was quite noisy when first started, then the noise reduced once oil draining from the head reached the cam followers.   Relining the tunnels fixed that problem.  

I know that the valve train does not require very much oil, hence the factory hit or miss feed from the main return line, but lubricating the cam followers is in my opinion very important.  I have a flow controller pressure system, which gives a steady small supply of oil to the head.   No sticking my finger over the return outlet for me, no over oiling of the head and happy cam followers! 


Stethoscope ?  , No  lets get with it,  A  decibel counting phone app  to determine the winner.  And a usefull prize,   I will  provide (at great expense)  a set of new  foam earplugs  !.


That's why the exhaust system on a 650SS is extra noisy......!!  Without it all you would here are the rattles from the motor.  If you here a bike approaching that sounded like a skeleton street dancing in a steel dustbin, then you can expect a 650SS.  Have fun with noise tests ?  Howard  


Ah  ,I think I have hit a snag,  my siamese system and pattern cheroot  "silencer"  will  probably drown out the clatter  and give the highest reading ,  although I may have the quietist engine. One would think that high mileage would give the most wear ,but my money is on  dirty oil after seeing the state of the Atlas rings (son left to  do his own oil changes!).


I've tried all sorts and am none the wiser. Screwdriver, metal rod, plastic pipe,  beginning to think it might be cam bushes. A job for next winter I feel.


Hi Dave,

This is perfectly normal, it is where the camshaft changes from being driven by the gear train to the cam followers driving the camshaft. So although there is only a small amount of backlash in the gear train, it is this backlash that is changing from driving to driven.

My completely rebuilt engine with everything optimal made the same noise when turned over slowly.

Do not worry, ride and enjoy.



It's possible that one or the steel ends may have worked loose on a pushrod. This makes a loud rattle that get sworse over time as the end of the Aluminium pushrod is worn away by the movement of the steel end. This results in metalic looking oil and ultimately can cause damage to everything in your engine that needs oil. I know, as I've just finished stripping my engine after just 1500 miles, started with some new pushrods now one of them has ruined the engine even though I checked the tappets trying to eliminate them as a cause.


Thanks for the observations all. I think I'll leave it!  Clearances are spot on and stable. I'll keep an eye on them in case of push rod issues. Now to find some effective earplugs...


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