srx600 top end clicking

[srx ijk]

Hi all - my srx600 is now starting well and pulling strongly, but.... I have a top end noise which sounds just like bad tappet clearances but isn't (checked twice and clearances spot on).

Thoughts please on whether this could be piston slap or a cam chain/tensioner problem (both seem unlikely on a relatively low miles engine and the noise persists even when engine warmed up).

Anybody else had this problem?

thanks
Glyn

[Steve H]

Check that the decompressor lever isnt touching the rocker arm. Run the engine and hold the decompressor lever, if its moving then the cable needs adjusting.
Piston slap will be more evident when cold and clear when hot, if its bad you may hear it on part throttle when warm. Generally tends to be a lower frequency than tappet noise.
I would expect tensioner problems to result in a russling noise.
Rev counter cable could be another source if its damaged.
Exhaust gasket leaking ?

[srx ijk]

Hi Steve - just come across your reply - will check your recommendations. Many thanks!

[srx ijk]

Update - so with the engine running the decompressor lever doesn't move (but will oscillate backwards and forwards when pushed back against the cam), rev counter cable seems fine, exhaust stud nuts tight.
Agree with you re camchain rustling noise - it's not a constant noise - more like a tapping.
I'm beginning to think it's got to be piston slap (not audible at all when riding 20 mph or faster, but exactly same sound when stationary with engine cold or hot & at all engine speeds).
Also only became evident after over-wintering in the shed on first start up - and oddly not present at all last Autumn before hibernation.
I think it's head off time!

[Steve H]

I would have described piston slap more as a 'clack' rather than a 'click'.
What exhaust are you running ? if its the original steel item has a rust pinhole developed over the winter ?

[iansoady]

In my experience piston slap is worst when the engine is cold, and tends to be when it's lightly loaded rather than open throttle. But noises are so hard to isolate! I've always run my obsolete old clunkers with what used to be known as "racing clearances" ie nearly worn out. My ES2 had quite loud piston slap when cold but didn't burn any oil and went like the clappers.