Engine Chattering

[profwhb]

I am hearing a chattering (sometimes clattering) sound coming out of what seems to be the lower left front side of the engine on deceleration between 1800 and 1600 rpm.  Removal of the alternator housing and compensator showed no indications of damage or looseness.  All hardware appeared to be tight and in place in the primary gear case.  On reassembly, the sound remained.  It is only evident between 1800 and 1600 rpms on deceleration.  It is sometimes a chattering sound, but does become a more pronounced clattering sound as well. I am suspecting cam drive chain slap, but the guides would seem to preclude that possibility as they are fiber and not metal.  What I hear seems to be metal slapping metal.  Anybody run into this to date.  It has gotten worse in the last 200 or 300 miles.  Bike now has 20,600 miles on it.  Always ran synthetic, Super X tune, and installed an oil cooler at 2500 miles.  Motor mounts are good and I see no interference between the motor and other external hardware... 

[wytfut]

Wow... New one to me...

Your rpms specifics.... To me means something loose and the harmonics at those speeds riles it up.

First up..... As you sit on bike... Cam chains would be on your right side. Doesn't mean it isn't the problem, just means the sound is coming from the wrong side in your symptoms.

I've seen loose bolts in the tops of our heads.... I'd pull valve covers for a good look. Look at all of them...

Our starters coast along all the time....and thatd be right in the area that you hear.

And lastly tank slap against the frame can be very uncanny.... You said motor mounts are good, but at 20k, have they been changed out?

Ill think about it for more ideas.... And contact Jamie in the mean time....

Bruce

[Traveller]

Hi Bill,

While you had the primary cover off did you notice any metal or perhaps a grey metallic slurry? If you haven't already, you might want to drain the oil and perhaps even open the filter for inspection.

Just for information, the timing chain guide has a metal core under that hard rubber like surface.

Jamie

[profwhb]

Bruce,
Engine mounts were changed out a couple of times... adding the upgraded motor mount covers from SuperXParts reduced the vibration and I haven't had to replace any motor mounts since.  I changed out the oil when I evaluated the primary gearcase components and saw no sign of slurry or metal including the drain plugs.  I will do some more road analysis and see if I can better determine the exact location of the noise... especially as it relates to the location of the cam chain tensioners.  Is it possible the chain tensioner adjusting spring is getting weak or has failed on the front cylinder?
Thanks,
Bill

[wytfut]

Until you get inside .... it is a possibility....
I gotta admit..... something is definitely amiss....
I would think if that tensioner has failed it would run terrible, due to cam timing.... I'd think that it could easily jump time if the tensioner failed.   

If it were mine.... I'd have it on my lift... and be going over it with a fine tooth comb starting at the top end of the front cylinder, and working down....

curious.... at those RPM's... does it do it just sitting still?.... be a chance to get someone, or yourself down close to listen at those rpms?  ..... may help get it narrowed down?   I use a stethescope in my shop frequently when I get cornered with noises...

To get a "real" look at those tensioners... you're going to have to pull the head....  As pulling the bolt/nut from the side of the jug, is only going to show you the spring.... and not the actual tensioners condition  ...

this could be something simple/easy.... but its not looking that way so far...

 for more thought.... how is it running other than the noise.... probably won't make any difference, but just curious...

[Berlin Bob]

Just for shits and giggles.....tap on the exhaust covers.....

[wytfut]

Oh my Bob....
Thats absolutely wonderful.... Crossing my fingers...   I've heard that noise too
Thanx buddy