Double Zero Cylinders

'Crockett

'Crockett

Freelance Smartass
I agree that for freeride or freestyle just port it and enjoy the benefits, however if you can find a "00" cylinder and not have to port it then you're $$ ahead. More money to spend on the latest freestyle widget from "Blam-damn-we're-bitchin" Racing inc. or who ever else is running a special of the month on dash mounted Carbon fiber Kleenex dispensers.

I say majority rules on this issue, 4 out of 5 people say they've seen a positive difference in the lower numbered cylinders.

It also may pose another interesting question: Since Wax was the lone disenter, Does this mean Yamaha hates Australia !


"oh no, we have velly many not good sirinder, I have idea, we stamp like good sirinder and send to Australia, they maybe so busy worry about snake, crock-o-dire and big god-zirra size sharks to not notice differ-lence"

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'Crockett

'Crockett

Freelance Smartass
The reasoning for the numbers ? . . . .Quality control

They probably have set limits as to just how bad a match it can be before being rejected. It's quite posible that they are graded and numbered before they even get the sleeves installed. A simple set of gages would be all that were needed.

They could go one step further and decide based on the grading which models get which cylinders or what percentage of good and bad get used per model.

I do not believe these cylnders are "die cast" they are most likely "Investment cast" and core shift is likely the cause of the differences

I'm convinced it is a grading system for the quality and accuracy of the castings. JMO
 
'Crockett

'Crockett

Freelance Smartass
I'm gonna back peddle a little bit here . . . . . anybody got a cylinder with both sleeves out ?

Measure both bores in the blank cylinder (without the sleeves) and see if the bores differ.

It would still indicate a grading system, but it may have more to do variances in the machining process and which sleeve would press in with the right tolerances.
 
blasterboy1980

blasterboy1980

It must go faster!
Location
Key West
When I raced in the limited sport class back in the day, We would use the
00's because they lined up nicely and you werent allowed to port the cylinder. It would give better flow, We had a limited blaster going 54/55 that was back in 97/98 with a stock water box.
Off topic here: A friend of my father's Bob did R&D for yamaha at the time. We got to ride the first Wave Venture ever made they were doing hull "G" stress test's on it in Satillite beach. We even raced it and got protested because they werent in production at the time. It was a dog though in the offshore it just plowed through the waves. We also got to mod a raider 1100before they came out they wanted to see how fast my dad could get one going just by porting nothing else. To make a long story short I was 14 at the time they let me race the damn thing in an off shore Pro-moto they didnt care, it was a test boat. My dad set it up for nothing but top end lightening switch power band. Needless to say I busted my knee up and busted my nose. However yamaha let us keep the boat I ended up breaking 3 of the 4 motor mounts so they some testing in while I raced. The raider hull was to unpredictable but it was a damn fast hull.
 
nikad58

nikad58

1974 YZ 701
Location
200 miles west of Havasu !
the only couch rider said:
we can blame this all on butch the parts whore..... he started this whole thing just so the value of the parts he has goes up
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LOL what I remember after many talks over this with everyone and anyone racing back in the early 90's is.. time/shift codes of the engine being put together.. nothing more nothing less.. i cant tell you how many cylinders we lined up and looked at 20+ and couldn't see anything that made sence.. lol the whore has spoke.. haha now the 007's were a secret !
 
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feartheride

feartheride

feartheride
Location
St.Catharines,On.Canada
Heres a bit of info for you.General Motors use to mark the pistons and cyl. with letters to fit the best size piston to the corrosponding bore. Too many numbers for that to be the case with yamaha though but the sleeve bore might be a theory
 
Matt_E

Matt_E

steals hub caps from cars
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at peace
At this point I would say that best sleeve lineup is pure coincidence on 00. Yamaha would have zero interest in marking how well the cylinder performs.

I am guessing that variances are due to the manufacturing process of the sleeves. I presume the port windows are machined as a last step. Any sloppyness will be introduced here.

Unless Yamaha was selling better matching cylinders for more money than the rest, I call BS on that.
 
'Crockett

'Crockett

Freelance Smartass
Matt_E said:
I am guessing that variances are due to the manufacturing process of the sleeves. I presume the port windows are machined as a last step. Any sloppiness will be introduced here.
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I'm sorry Matt, but from what I have seen personally, your presumption is incorrect . . . .

I have ported cylinders with mismatched "numbers". The port height and distance to the top of the cylinder on the sleeves themselves were comparable from one bore to the next. I know this to be a fact because I map them before porting.

The difference in the effective port window area was in the aluminum casting. That is to say, the aluminum intruded into the the window area of the sleeve.

I don't know any other way to put it, except that the sleeves were consistent, the castings were not, irregardless of what the stamped numbers may or may not actually mean.
 
Matt_E

Matt_E

steals hub caps from cars
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at peace
Very interesting - thanks.
I am not sure why the casting itself would be off. Unless their casting molds vary from one to the next.
 
'Crockett

'Crockett

Freelance Smartass
Matt_E said:
Very interesting - thanks.
I am not sure why the casting itself would be off. Unless their casting molds vary from one to the next.
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As I have mentioned several times,the cast parts themselves vary from one to the next do to core shift. In most forms of casting core shift is almost impossible to eliminate.These cylinders are most likely done with a "lost foam" investment casting technique which is better than the old procedure for sand casting, but still not without defects. They are developing and using new procedures involving ceramics to improve accuracy and reduce core shift, but we won't go into that because I don't think it applies here.

The molds themselves do not necessarily vary from one to the next but the end results do. There is movement of the cores which are the internal mold parts, usually the most intricate and delicate forms, during the pour or as suggested here, it can even be human error during set up, causing improper positioning between the mold and the core.

The foam cores themselves are injection molded and can have imperfections in them. An imperfection of this type, if missed during inspection, can be transfered to the final cast part as well.

At the risk of sounding callus, I will also say that these castings are mass produced by underpaid foundry workers who are just trying to make it through another shift . . . . . . not brain surgeons. :biggrin:

I hope this clarifies what I have been trying to explain . . . . . .
 
Matt_E

Matt_E

steals hub caps from cars
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at peace
Have you been paying attention?

This is most likely related to exact bore diameter to properly match piston size for clearance.
 
Matt_E

Matt_E

steals hub caps from cars
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at peace
:lmao:

Don't mess with the rocket man. ^^
 
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