I've recently been hearing a light jingle jangle sound from down below, and was beginning to suspect the cam chain... a tinklely sound like gently shaking a set of keys...
First suspect,... the keys!.... nope, not the keys...
Second,... maybe I'm too lean and it's valve rattle... nope... I stepped up one on the pilot jet..
So I notice, it only comes at that float position,  not accelerating or decelerating,... right in that middle float area...
Must be the cam chain....
Then, I notice that if I get up to speed and pull in the clutch,... I can vary the throttle and the noise stays the same...
Not related to engine rpm....
Hmmm,.... Drivetrain?....

So I pulled the drive pulley cover and saw that the big pulley nut was no longer flat edge to the washer crimp.
Crank on the nut and it started to move before 25 ft pounds.  
I had to have a buddy come sit on the bike and hold the rear brake while I cranked her down.   I think I remember that it should be 85ft lbs.,... I cranked it to 95 or a 100ft lbs with a new dab of loc-tite just to be sure.

Test ride says,.. no noise,...Bingo!... pulley nut was making the noise...

So if your spurs are going jingle jangle,.. check that big ol' nut...

I have heard exactly that sound & since the keys hang on the left side, I thought,, well,, I guess I better pop that little cover off & see what kinda twisting it takes to get some more Tight outta that nut...thanks for the post.

What do you guys use to straighten out the fold in the lock washer?

I used a wood chisel.  It worked, but it put some gouges in the washer.

What do you use to re-bend the lock washer?  I used the same wood chisel and left a few small gouges in the pulley.  

My pulley was not loose, BTW.  I was just checking the torque since I had the bike torn down for some other maintenance.

I expect Ill be using a regular chisel, when that day comes.

If its layed over that tight, Digger, Im goin for the wood chisel just long enough to get it moved enough to get the clunky ol cold chisel in there.

I did the same as you Digger,....  
I have a special, bang about, wood chisel for just such jobs...

Not to hijack the thread, but Justin, years ago when I rode dual purpose bikes, we were on the trails. A friend's bike had the switch close to where our"s is. A branch or something grabbed his keychain and keys went everywhere  I have one key in the switch and one on the key ring in my pocket. Truth is much stranger, and more entertaining, than fiction

Just wanted to bump this post up again,... rather than post a separate update ...

Had the same sound come up again,... and... sure enough, the pulley was about a 1/4 turn backed off again...
Cranked it tight with everything I got this time... and "jingle jangle" went away...