Idle Transition Knock and Noise

Hi, I've got a 2004 Daytona 955i with 13,000 miles on the clock. It's developed noise at idle (a 'slight rattle' would be a good description); when the engine speed rises to to about 1700 rpm it emits one noticeable 'tap/knock' (akin to a ping-pong ball hitting a table), which can be easily heard and just felt through the bars, and the idle noise disappears; when the engine slows there is another 'tap/knock' at the same engine speed and the idle noise returns.

This occurs whether in neutral or in gear (both applying power and engine braking) and when the clutch is engaged or disengaged. I think, therefore, that the noise is purely a function of engine speed and not of torque or power.

My local triumph dealer were concerned about this during a recent service, but were unable to offer any suggestions as to the cause and, try as I might, I've only found one other person that's had the same problem but they didn't post the solution.

It has been suggested on another forum that it may be worn clutch tangs or final drive, which I will investigate, but if anyone has any other ideas I would be really grateful!

Many Thanks.

 

Thank you I've got her booked in to the garage to have the cam chain and tensioner checked and replaced if required - hopefully that should solve it and if not then I've got a few other avenues to investigate.

 

The garage have checked the cam chain and tensioner and found nothing wrong ... The investigation continues ...

 

Right - got a second opinion from another Triumph technician -Apparently the engine noise at idle not out of the ordinary for a 955i. It turns out that there is a solenoid controlled air valve under the tank (Not being a Triumph expert I can only assume this is SAI) - at 2000rpm (give or take) this valve operates which causes a knock along with the change in engine tone - again this is normal (and more noticeable on some engines than others).

Why on earth the original garage didn't mention this as a possibility (and saved a lot of hassle) I don't know - I even asked the guy about the possibility of it being an EGR valve or similar and he said that no such valve was fitted to a 955i! At least I have peace of mind now but I will most certainly be using a different garage in future.

Thank you everyone for your support and suggestions - I shall now try to track down the other post I found regarding these symptoms and reply!