chriselmore_1
high on resin
- Location
- san jose ca
What do those numbers on top of the front exhaust port mean? Mine say 0 0 but have seen a bunch of other numbers on other cylinders
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Cylinder numbers above the exhaust port?
- Thread starter chriselmore_1
- Start date
#ZERO
Beach Bum
- Location
- Florida - U.S.A.
That's the sleeve port alignment with the cylinder casting and 00 is perfectly matched.
- Location
- Lake Havasu City, AZ USA
I thought this was "debunked" too, but i cant remember why? lol
Why would they care about marking which cylinders sleeves are lined up the best?
Why would they care about marking which cylinders sleeves are lined up the best?
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.
fulltilt429
Delta Dog
- Location
- Pleasanton, CA
I hope its not port match, mine says 18 & 12
- Location
- Lake Havasu City, AZ USA
It would have to have something to do with tolerance wouldn't it? The only think that seems to change between mass produced parts is the pistons and rings. You never get a set the same and all decent engine builders will need the pistons before they bore to suit.
I'm sure Yamaha have some sort of setup that drops the sleeve in perfectly every time, so unless the castings on the sleeves and cylinders changes a lots, I really don't see why it would be port alignment that those numbers represent.
I do know someone that has contacts within Yamaha Japan, so I will ask the question...
I'm sure Yamaha have some sort of setup that drops the sleeve in perfectly every time, so unless the castings on the sleeves and cylinders changes a lots, I really don't see why it would be port alignment that those numbers represent.
I do know someone that has contacts within Yamaha Japan, so I will ask the question...
Mile9c1
X-H2O.com
- Location
- Grand Rapids, MI
Was there a thread about it? I've had two Wetjet cylinders marked "00" and both had PERFECT port matching. No "yamaha" 61X cylinder I've ever seen has been as close. Coincidence? No way!
WaveDemon
Not Dead - Notable Member
- Location
- Hell, Florida
the zeros probably had less to do with the perfect matching than the fact that they were wetjet motors. I've seen and heard that wetjet matching is way better than standard yamaha.
shawn_NJ
Chasing waves.
- Location
- Daytona Beach
I have a 0 - 0 61x cylinder here at my house. The mystery of the numbers continues....
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Mile9c1
X-H2O.com
- Location
- Grand Rapids, MI
Mile9c1
X-H2O.com
- Location
- Grand Rapids, MI
Didn't Yamaha make them all? My guess is Wetjet said, "Hey Yamaha, we only want your '00' cylinders".
Mile9c1
X-H2O.com
- Location
- Grand Rapids, MI
There's no piston mark though.... if the markings represent something about the bore sizes, then it seems fitting that the pistons would also have to be marked in a special way, or they'd get mixed up. Yamaha marked the 66E and 66V pistons, I believe (GP800 and GP1200R engines). Those cylinders don't have sleeves, the cylinder bores are nicasil coated aluminum. I forget if the 66E cylinders were marked.
The Yamaha stock port mismatch is horrible! Whatever they did, it was anything but consistent.
cattledog
EH TEAM RACING
- Location
- toronto canada
my spare cylinders have the mystery 00 numbers, spooky what does this mean
So why mark them for sleeve match? What's the point?
OCD Solutions
Original, Clean and Dependable Solutions
- Location
- Rentz, GA
The 66E cylinders are marked just like the pistons.
I don't see the point of marking the mismatch unless it means there will be something done about it. Unless the sole reason is for grading and deciding who gets the cylinders, which is believable.
I don't see the point of marking the mismatch unless it means there will be something done about it. Unless the sole reason is for grading and deciding who gets the cylinders, which is believable.
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Dustin Mustangs
uʍop ǝpıs dn
- Location
- Holland, MI
- Location
- Houston/Galveston
I think you on to something there young man.
You would look at the transfers, not the exhaust.