Separating the MEN from the boys (carb)

[teddux]

Answer 2 questions without external linking; in your own words

1.) For which I have already given hints on,
Why is it easier to somewhat successfully modify the
Mikuni carburetor on a 850cc or similar, rather than on a 450cc?

2.) Instead of following the costly & time consuming guessing method by
trial & error, invent your own formula that WILL work on ALL Mikuni
carburetors used on ALL Suzuki series motorcycles.

i. for Pilot Jet size
ii. for MAIN Jet size
iii. for Needle Valve Diameter to Main Jet (needle jet) Clearance at
different rpm's

 

[Dave8338]

Answer 2 questions without external linking; in your own words

1.) For which I have already given hints on,
Why is it easier to somewhat successfully modify the
Mikuni carburetor on a 850cc or similar, rather than on a 450cc?

2.) Instead of following the costly & time consuming guessing method by
trial & error, invent your own formula that WILL work on ALL Mikuni
carburetors used on ALL Suzuki series motorcycles.

i. for Pilot Jet size
ii. for MAIN Jet size
iii. for Needle Valve Diameter to Main Jet (needle jet) Clearance at
different rpm's

1. The smaller the displacement the less room for errors in tuning.
2. Too many outside variables ie. pipes, pods, sea level, ambient temp (to some extent) engine tune (valve specks) cylinder head flow rate, constant vs variable rpms, I think you get the point.

Even though all bikes were built by the smae company, everything from casting density to machining tolerances vary from model to model, where they fall in the build cycle, and who had the final say as far as quality control was concerned.
Genuine carb tuning is engine specific and not a one size all approach.

 

[Ohioan]

1. What he said ^^^^

2. 42

 

[hampshirehog]

1.) For which I have already given hints on,
Why is it easier to somewhat successfully modify the
Mikuni carburetor on a 850cc or similar, rather than on a 450cc?

It isn't. It's usually easier to sort out slide carbs eg VMs than CVs but apart from that engine size makes no difference whatsoever (though a single will always be easier than a twin which in turn will always be easier than a 4, like for like).

2.)
Instead of following the costly & time consuming guessing method by
trial & error, invent your own formula that WILL work on ALL Mikuni
carburetors used on ALL Suzuki series motorcycles.

i. for Pilot Jet size
ii. for MAIN Jet size
iii. for Needle Valve Diameter to Main Jet (needle jet) Clearance at
different rpm's

As Ohioan said - 42 (we read the same book). Plus needle jet clearance (?) at different revs is irrelevant - revs have no part to play in needle jet tuning whatsoever. It's throttle opening that you're getting mistaken with and that equally applies to full bore at low revs and idle circuit only at high revs. Revs do come in to play when looking at velocity stacks and in 2-strokes but that adds another dimension.

 

[teddux]

Where are ALL the rest of "GURUS"?

Thank you, you ALL (who have participated) have my TOTAL RESPECT.

I rest my case.

ps. Anyone can make a spreadsheet.

 

[Guest]

I rest my case.

What case were you presenting? You didn't say.

 

[1_v8_merc]

You don't need to modify much of anything to go fast, when you have a Flux Capacitor!(like me)

 

[teddux]

What case were you presenting? You didn't say.

renobruce, i have learned in my field something called "discipline".
when a manual, regulation or manufacturer states something is NOT to be modified, i comply.
This is again, due to my occupational DISCIPLINE.

As you state that you are an "Aircraft Dispatcher", well, you need to learn that same "DISCIPLINE" or the FAA will have a field day with you.

Oh, sry, that is http://www.thegsresources.com/_forum/member.php?u=18160
but you all act the same, anywaze.

May you all have a SAFE & pleasant Easter, God BLESS!

 

[teddux]

You don't need to modify much of anything to go fast, when you have a Flux Capacitor!(like me)

lmfao, did you see my contribution in trade-a-plane?
Yes, MY other BIKE is a CESSNA!
Today's strip is inspired by Ted, who wrote us and said that this really works in real life. No, not the flux capacitor itself of course, but using this answer to make your boss leave you alone so you can concentrate on your work again! Thanks a lot Ted!! And we hope that your boss doesn't read this and you'll have to think of a new trick because of us...
I think it is save to say that almost everybody has watched at least one of the "Back to the Future" movies, so I assume everybody knows that the flux capacitor is the core component of Dr. Brown's time traveling De Lorean. Funny though that even though everybody knows what it is, nobody knows what it actually does. We all just know that it requires "1.21 gigawatts of electricity". So I guess it will take a while until they really start putting these things into Cessnas.

Tuesday, June 28, 2005

 

[Guest]

renobruce, i have learned in my field something called "discipline".
when a manual, regulation or manufacturer states something is NOT to be modified, i comply.
This is again, due to my occupational DISCIPLINE.

I seem to remember on my STOCK exhaust that it said not to modify it. Your exhaust by your own admission is GONE. Where is your discipline there?

Happy Easter, and God bless you, too!

 

[teddux]

I seem to remember on my STOCK exhaust that it said not to modify it. Your exhaust by your own admission is GONE. Where is your discipline there?

Happy Easter, and God bless you, too!

I have no discipline on an exhaust, where's MY "regulations" for that? And as I have said, this is NOT a street-worthy bike.

 

[TheCafeKid]

1. The smaller the displacement the less room for errors in tuning.
2. Too many outside variables ie. pipes, pods, sea level, ambient temp (to some extent) engine tune (valve specks) cylinder head flow rate, constant vs variable rpms, I think you get the point.

Even though all bikes were built by the smae company, everything from casting density to machining tolerances vary from model to model, where they fall in the build cycle, and who had the final say as far as quality control was concerned.
Genuine carb tuning is engine specific and not a one size all approach.

Could not have said it better Dave. The fact of the matter is that NO two motors, even off the same line are alike. Unless of course, all of them were built to blueprint tollerances and specifications, and even then, unless the materials used were ALSO manufactured to specific tolerances and verified as such, you'd still be looking at the possibility of at least SOME difference if you were attempting to tune to an exacting standard. If you work around aircraft, you of all people should know this.

The fact remains that even with the same model, from bone stock, we are dealing with 27+ year old motors, in bikes of the same age, and generally, with carburetors of the same age. There are so many many variables that come into play, not only in the motor, but in the carburetor itself (why, ive seen YOU even post on this board about emulsion tube or jet deterioration) What you suggest ( a formula for simple carb tuning) actually HAS been laid out. But even the designer of the formula, and subsequent jet kits et all, knew that these variables would come into play, and lay out in their instruction that this formula(S) is simply a baseline from which to tune to your specific needs/performance wants.

Even a blueprinted motor, unless EVERY SINGLE expansion rate, wear rate, etc is known, once fired, will never be the same. You're suggesting that carb tuning, or squeezing every ounce of power from a motor is an exacting science, when anyone worth their salt at it will tell you, while there is a science to it, its as much an art form, a guessing game, and a trial than anything else. Go seek out the pictures of Pops Yoshimura hand filing cams in prep for a race... Those came out of a machine or a mill, designed to do what Pops wanted, but the science can only do so much, the art must do the rest...

If what you believe were true, there would be no drag racing, because everyones bike would run the exact same trap time/speed at the track...

 

[teddux]

Thanks for all the responses, this was more a psychoanalysis and I have satisfied myself with who's who in here.
You should have noted that this was a question being answered by a question, to get people thinking before modifying a cv carb. They would eventually reach the part about the needle diameters. Possible, but not for mere garage mechanics. The stock cv carb NEEDLE is virtually STRAIGHT compared to a slide carb. Adjusting it is senseless and mere LUCK if at all semi-successful.

 

[TheCafeKid]

Thanks for all the responses, this was more a psychoanalysis and I have satisfied myself with who's who in here.
You should have noted that this was a question being answered by a question, to get people thinking before modifying a cv carb. They would eventually reach the part about the needle diameters. Possible, but not for mere garage mechanics. The stock cv carb NEEDLE is virtually STRAIGHT compared to a slide carb. Adjusting it is senseless and mere LUCK if at all semi-successful.

Which is why, myself and MANY others have stated that running a pod/pipe combo and attempting to jet it by hand using the stock needles is an effort in futility... What exactly was the point of your psych exam here?? Im still not sure I follow the logic behind it. Are you trying to convince yourself that you're smarter than everyone, or just trying to verify it?

 

[Turtleface]

Which is why, myself and MANY others have stated that running a pod/pipe combo and attempting to jet it by hand using the stock needles is an effort in futility... What exactly was the point of your psych exam here?? Im still not sure I follow the logic behind it. Are you trying to convince yourself that you're smarter than everyone, or just trying to verify it?

It's a whole lot of confirmation-bias, this psych exam. Dude seems to have a beef with some of the more technical forum members.

 

[tkent02]

It's a whole lot of confirmation-bias, this psych exam. Dude seems to have a beef with some of the more technical forum members.

All of them it seems.

I guess when one knows so much more than the rest of the forum put together, it's hard to be humble.

 

[Griffin]

All of them it seems.

I guess when one knows so much more than the rest of the forum put together, it's hard to be humble.

Particularly when one is an insufferable prick.

 

[tkent02]

Particularly when one is an insufferable prick.

I liked it better before your edit.

 

[Griffin]

I liked it better before your edit.

It's the kinder, gentler, GS Resources.

I liked it better too. It was more accurate.

 

[Nessism]

The stock cv carb NEEDLE is virtually STRAIGHT compared to a slide carb. Adjusting it is senseless and mere LUCK if at all semi-successful.

While it's true that the needle doesn't have much taper, shimming it 2mm has a very noticeable effect on the mixture of an otherwise stock system.