I recently had the crankshaft of my 1966 Yamaha YL1 rebuilt by Roy’s Rides from Missouri. I’d suggest checking out the “Preferred Provider” page found on this blogs home page if you’re interested in more info on Roy’s Rides.
Back to the crankshaft, here are a couple of photos. Unfortunately I failed to take a “before” photo showing the crank before Roy did his magic. However, the parts Roy replaced are shown as well as the “after” photo below.
In the first components photo note the items circled in red. In the upper right one can see the one wrist pin (“gudgeon” pin for our UK cousins) Roy replaced due to wear. The other, original wrist pin was reused. The second red circle illustrates the bent connecting rod Roy discovered. If I recall correctly the bent rod was from the left cylinder, the one with the severely damaged piston. My guess is the rings snagged the transfer ports and caused the piston damage and bent the rod. That’s my theory anyway.
Roy also replaced the two main ball bearings, which were way beyond their prime.
Roy and I had several phone conversations regarding this project as he was concerned about several details, such as equal weight of the replacement connecting rods.
Great service and work on Roy’s part!
Finished Crank below…
Bent rod…yikes!
Exactly…
Do you now whats the rod length on the twin jet? center to center? THANKS
I am rebuilding a 1966 yamaha yl-1 100 as well. I was wondering if you could take some pictures of the battery box area. I bought the bike in pieces, and can’t figure out were the regulator goes.
Thx
Bob Martin