But mom, it followed me home! And I'm gonna build it right here!

Its not too cold so I go to the garage and pull the pistons off. WTF! No bearings around the wrist pin. I think must be not 256 rods right? Wrist pin measures just at .866" on both dial caliper and regular old school micrometer, sounds like 22mm to me and the rods are marked with cast in 256. Also how to ID piston? P1000933.JPG P1000932.JPG Heading back out for more playtime!
 
Needle bearings were only in the early production 70's, all 256 motors kept the big "small end of the rod" and just made the wrist pin and piston wrist pin bore bigger. A noted weak point of the early motors, the top of the rod is on the thin side. Run long and hard it can stretch and will eventually let daylight in. So measuring the small end of the rod or at least checking wrist pin fit/wiggle during top jobs is good practice.
 
I haven't checked the bore yet, but I'm expecting no surprises. Split the cases and everything looks really nice; shift dogs only show slight visible wear polish, the shift forks show minor wear on contact surfaces. Last night I ordered a bunch of necessary parts; gasket set, cam chain, seals and of course shiny stuff for the engine.P1000936.JPG P1000937.JPG P1000938.JPG P1000939.JPG P1000940.JPG P1000941.JPG Prolly restore in the works. And a question; Has anyone tried to put later tach into early housing, it looks to me that the tach is held into the housing with phillips screws?
john
 
Very nice John! I’m happy to see you’re moving right along with your project. You’re smart for splitting your cases. That’s something that everyone recommended for me to do and for some reason, that was my line in the sand that I decided not to cross. I wound up having to do several quick oil changes to flush sludge and debri out of my cases.
As long as you have your crank out, be sure to check the lead balance weights for looseness. They have come dislodged on some members bikes and locked up the motor. If they’re loose, there are ways to address that.
Nice work so far, I’m enjoying following your progress! :thumbsup:
 
P1000942.JPG P1000945.JPG
My "T-Guage" set only goes to 2.75" so I purchased a set to increase the range and the barrels measure 2.955" or in yamaspeak 75.057mm well under 75.1mm wear limit. Measured this in the kitchen with the wife's approval! Fancy that. Tomorrow the cylinders go to work for cleaning, bead blast, honing, cleaning again and then a spray with S100 corrosion protectant.
john
 
View attachment 154485 View attachment 154486
My "T-Guage" set only goes to 2.75" so I purchased a set to increase the range and the barrels measure 2.955" or in yamaspeak 75.057mm well under 75.1mm wear limit. Measured this in the kitchen with the wife's approval! Fancy that. Tomorrow the cylinders go to work for cleaning, bead blast, honing, cleaning again and then a spray with S100 corrosion protectant.
john

Very nice John! You’re moving right along with things. You have a nice machine shop near you? I had a really hard time finding one here in Phoenix.
 
you lucky boy...Santa came early eh !.:)......great Winter project ... good to hear that you've chosen restoration rather than another hack job. You've made a great start and a lot of progress already in a short space of time. I shall be following this project with interest .
 
I fixed the blast cabinet hose on my dime and then the compressor went down, no blasting tonite. The owner is fixing the compressor overnite so the business can function tomorrow, if not fixed, the backup unit can't handle the blasting load. Slows progress, oh well, stuff happens. Or maybe I can find something else that needs attention.
john
 
Bummer, about the compressor. But, sometimes, ya just gotta do what you can do, when you can do it. As anxious as you are about your "slow progress", it's not a race, it's a journey. And the destination is less important than what happens along the way. Wow. If I was a fortune cookie, I'd say something like "...the oxen are slow, but the Earth is patient..." :doh:
 
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