Cylinder numbers above the exhaust port?

[CarterB]

i just sold a supermoto to a corporate yamaha guy from atlanta. if i can find his contact info again i bet money he can explain this. i got some cylinders with the usual junk alignment but are stamped 00

 

[SurferSmurf]

i cant see the "0 0" being for allignment. why? when i machine parts at work that and the size is closer to the high or low limit of the tolerance we dont put a mark on the part. it just doesnt make sense. why would they mark what motors were better than others and then sell them. i would be more inclined to think that it has something to do with piston clearance rather than port match.

 

[Watcon]

Cylinder sizing

It's for piston sizing.. When they are finish honed, the next worken on the assembly lines knows exactly what size piston / ring combination to install. And there are slightly different sizes on the assembly line.

 

[SurferSmurf]

thats what i was thinking. after Hop-sing finishes the hone he marks it then Mee-soo can run and get the right size pistons from a shelf and assemble later and not have to make a measurement.

 

[Boris]

It's for piston sizing.. When they are finish honed, the next worken on the assembly lines knows exactly what size piston / ring combination to install. And there are slightly different sizes on the assembly line.

Stop playing the role of Myth Buster here.
I have 2 "00" cylinders that I hope to get top dollar for. :naughty:

 

[Matt_E]

It's for piston sizing.. When they are finish honed, the next worken on the assembly lines knows exactly what size piston / ring combination to install. And there are slightly different sizes on the assembly line.

Been saying it for years. :biggrin:

 

[SurferSmurf]

Stop playing the role of Myth Buster here.
I have 2 "00" cylinders that I hope to get top dollar for. :naughty:

i'll go along with whatever you say for a small cut. :biggrin:

 

[QJS]

That's the urban legend, anyhow. Can anyone tell me why Yamaha would go through the trouble and do this?

On the other hand, might Yamaha have reason to stamp the cylinders for specific piston/wall clearance so the right pistons/rings get installed?

I think the answer is pretty obvious from an economic standpoint alone.

This is correct, its called selective manufacturing.
Chris.

 

[bondra131]

Who gives a poop about perfect alignment?... if you don't like it, file it down. Or get a badass port job

 

[Half flip95]

Who gives a poop about perfect alignment?... if you don't like it, file it down. Or get a badass port job

Go ahead and post that in the thread on noobism