After the restoration: Cam Woes [page 3]

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Wednesday, Jan 8 2014 [25,724 miles]

right cylinder and piston
Right piston

Right piston

Right piston

I pulled the cylinder and piston from the right side of the bike. I measured the right cylinder and found that unlike the left it was slightly out of round. There was a .01mm difference between vertical and horizontal measurements at the top of the cylinder. There is also a 0.03mm difference between the ends of the cylinder and the middle.

Also, the fingernail test can feel some of the score marks that I can see on the left cylinder. I’ll be ordering 3rd oversize pistons and getting the cylinders bored to 73.5 mm.

tappets and cam
Left side tappets

Left side tappets

Left side tappets
right side tappets

right side tappets

right side tappets
right side cam

right side cam

right side cam

I pulled the tappets from both sides to take a look. The pictures tell the story. Both exhaust tappets are pitted. Both intake tappets are just starting to pit. Worse, the cam will have to be replaced. Again. The picture doesn’t show the damage very well but you can feel the wear with your finger. Large craters worth of wear. The cam will come out next.

Thursday, Jan 16 2014 [25,724 miles]

preparation
Drain oil

Drain oil

Drain oil
disconnect battery

disconnect battery

disconnect battery

I’ve finished the GS 6K service so can now get back to the R69S. I’m going to pull the cam withough removing the engine from the bike. I started by draining the oil. This was not strictly necessary, but I wanted to see if there were any metal bits on the magnetic plug or in the oil. Didn’t notice any. I also disconnected the battery.

remove generator and magneto
Remove front cover

Remove front cover

Remove front cover
remove advance and damping mass

remove advance and damping mass

remove advance and damping mass
remove generator and magneto bodies

remove generator and magneto bodies

remove generator and magneto bodies
Generator

Generator

Generator
removing magneto rotor

removing magneto rotor

removing magneto rotor

I pulled the front cover, the advance mechanism, and the R69S damping mass, first. Then, after disconnecting all wires I removed the magneto and generator bodies. I pulled the generator armature and placed it in the generator body for storage. I pulled the magneto rotor last, placing it in the magneto body.

remove timing case cover
Timing gear case cover

Timing gear case cover

Timing gear case cover
Pulling cover

Pulling cover

Pulling cover
Starting to move

Starting to move

Starting to move
Timing gear case cover w/breather

Timing gear case cover w/breather

Timing gear case cover w/breather

I used my Ed Korn all-in-one tool to pull the timing case cover.

Pulling the cam
timing gears

timing gears

timing gears
air impact

air impact

air impact
pulling the cam

pulling the cam

pulling the cam
Pulling the cam (2)

Pulling the cam (2)

Pulling the cam (2)

An air impact made loosening the cam retaining screws an easy job. Well, mostly easy. One of the four screws wasn’t in the best shape. It will be replaced. I don’t know if I damaged the slot in attempting to remove the cam now or if it was damaged when I installed the cam in ‘10.

cam condition
cam wear

cam wear

cam wear
chipped cam

chipped cam

chipped cam
timing gear wear

timing gear wear

timing gear wear

Ouch! Not only were the exhaust cam lobes shot, but a very small chunk of the cam was missing. Apparently that chunk wound up between cam and crank timing gear, causing much damage.

I’m taking parts and a parts list over to Brent’s next Tuesday to start the repair process.

 

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