Nice pics mate.
I'll give you the part no.s from "oemmotorparts" again & as I said these are genuine yamaha parts but not yamaha part no.s. It might be cheaper to buy from a yamaha or parts dealer, in which case you need yamaha part no.s (look on their microfiche & point @ the parts you need). Then I'll explain why I used genuine yamaha, then a few tips.
Go to "oemmotorparts" click on "yamaha" then "xtz660" then any year, theses parts are all the same.
In the clutch section you need:
no.2 key YA00245281
no.3 tab washer YA00243821
no.18 tab washer YA00243839
In the crankshaft piston section you need:
no.15 plate washer YA00241764
2x no.16 washer YA00120022
no.26 key YA00245262
no.29 tab washer YA00243729
You also need a new gasket (cut new 1 or buy an after market kit).
New oil & filter (your old 1 is full of swarf)
When I got this problem I read lots of fixes on the 'net. Some, with experience in racing, say the only fix is to fit a solid balancer drive gear from "slipstream" I don't know when they last tried genuine yam replacement parts & I believe yamaha fitted a "cush drive" for a reason, probably vibration. I can't remember if they mention washer no.15 which on mine was the cause of the problem.
Before I stripped my engine I had come to the conclusion part no.16 was too soft, I ordered a new 1 to use as a template so I could get new 1's made out of a harder metal. When it arrived, me & a blacksmith friend compared original with new. The original washer is plain in colour, has rounded edges & if you hang it from string & tap it with a screwdriver, the ringing doesn't last long. The new washer is mottled in colour (indicating it's been heat treated) has less rounded edges (indicating it's been machined) & in the ring test, it rang alot longer (indicating it's harder metal).
We came to the conclusion yamaha have already addressed this problem.
Washer no.15 was the cause of my problem, the original was warped by the stamping process that formed it, causing high spots that rub into washer no.16. I don't know if yamaha have addressed this, I flattened my original 1 on emery cloth stuck to plate glass. When you get your new 1, make sure it's FLAT ON BOTH SIDES! (If you use emery cloth, rotate the washer now & then to keep the sides parralell & make sure the washer's still thick enough to hold the nut off the crank boss when everything is assembled)
To undo & tighten the clutch center nut, I put the bike in 1st & stood on the rear brake, I also put a screwdriver through the back disk, to lock the rear wheel (THIS METHOD IS LIKELY TO DAMAGE YOUR CHAIN, use an old one or buy a clutch tool, IT'S YOUR CHOICE!)
To lock the crank, stuff cloth or leather between the balancer gears (official yamaha manual method) & make sure all 3 dots are inline when you reassemble.
Before you attach the clutch basket, you might like to file down any notches in it.
It might take 2 or 3 attempts @ replacing the clutch cover to get the clutch arm in the right place.
Torque settings:
Crankshaft nut 85 lbsft
Balance shaft nut 43 lbsft
Clutch center nut 65 lbsft
Good luck
Rick
