POLL: Best carbs for ported 701-760?

[DAG]

 

[waxhead]

This is what I have (oem 44’s) and having constant inconsistencies with the carbs. @McDog is trying to get me to try the oem 38’s , which I’m not knocking, but I bought a single 62t mani and I’m going with a new sbn46. Ive ran them before on previous motors with success, and the 38’s May hit harder or pull longer or be snappier, but I’ve run a single with success in the past... so I went that route. Oem 44s were not for my setup. That being said, I’ll have a complete dual 44 setup for sale sometime next week

I will buy it. There is nothing wrong with the stock 760 carbs and i run them on a heap of skis. They are an awesome and cheap upgrade over the stock 38s and I prefer them over the aftermarket 44 setup

 

[waxhead]

Somewhat related question but I think maybe @waxhead would have some insight. My understanding is that the "oem" 44 carbs from the Yamaha 760 are less desirable than "aftermarket" sbn44's (from Mikuni) because of something to do with the progression holes creates a partial throttle lean spot that is trickier to tune around than the "aftermarket" 44's or 46's. If that is the case, are the 44's that come with a 1200 tripple the same as what comes on a 760? (and is the lean spot thing actually true?)

Seems like if a guy wants something bigger than stock 38's those Yamaha 44's are by far the cheapest option, but I've heard mixed info about if they're any good.

Its very hard to make money selling 2nd hand carbs so of course new is going to be better. There is nothing at all wrong with the oem 44 and they are a great reliable bolt on. I would buy these over aftermarket 44 as they are cheaper for the same performance. if im going to buy aftermarket carbs im going to buy novi or 46 stock.

 

[ProSouth]

I will buy it. There is nothing wrong with the stock 760 carbs and i run them on a heap of skis. They are an awesome and cheap upgrade over the stock 38s and I prefer them over the aftermarket 44 setup

pm me your number and I’ll shoot you a text or call you when I’ve change my setup. They’re freshly rebuilt and will come with everything except reed cages

 

[Vortex]

But why spend the extra money for larger carbs just to restrict them!!!!!!

The reason would be the data shown on a flow bench. Novi carbs have a really strong signal strength to the main jet (taken from group k article). Oe carbs get more signal to the pilot jet. Imo this is why some tuners who recommend a/m 44s/46/48s say larger carbs hit harder. 3/8ths throttle the main jet hits.

 

[TheBuzzard]

Theoretically all you would have to do it on equalize airflow differences between small and large carburetors would be to slightly restrict the air inlet of the large carburetors.

There's a group k article where they talk about using duct tape to do that and got a lot better signal.

Another thing. A larger set of carburetors without the air inlet restricted would also in theory burn less not more gas. This is due to the Bernoulli effect, larger carb slows the air flow. The strength of the air flow signal will be substantially less. This is mentioned in mikuni manual, says something on the lines of "engine is lean at wide open and doesn't respond to jetting changes, cause: carburetor too large for engine."

Again in theory a resticted air inlet should mostly solve the issue.

My personal experience backs up those claims, however my novis are old and could have had other issues at play.

that's what the jetinetics tuneable filtration system does. its like an ocean pro vortex or blowsion tornado but you can adjust the cone up or down for the correct amount of air.

 

[aero92x]

46s it is, upgrading tapered 38s.
Braaap

 

[waxhead]

Any time your using an aircleaner to jet your carbs in its a huge FAIL. You putting on a more restrictive aircleaner to try and make your carbs work.

 

[egbrig]

So I've been off the forums for awhile but now I'm back and ready to go and call out.
What a load of crap, tuning with restricting air. All that means is you don't know what your doing. I've tested signal with Ed Brazina himself and I have my own flow bench 947cfm @ 28".
I personally like Harry Klemm, he is truely one of the best people you can meet and I love his Kwai two stroke bike. My personal findings don't match those of that article and after many years of running different carbs at pro level competition, I have come to some conclusions which I "try" to help my customers with.

One of the factors of TPE is real jetski setup info. Any idiot with a cnc can make parts, but setting up a package you need to know jetski's. Just cause you have a rope doesn't mean your a cowboy.
Voting on "which carbs" is a stupid means to a choice. Voting just means a bunch of people who don't know get to join the gang.
The question is: what is your setup, what is your riding style, what is your riding environment, what is your budget, what are you after==== the best or===== what you can afford.
I see all this talk, then go to a group ride and see a bunch of excuses as to why the guy with all the answers on this forum has his boat running like crap.

Find a builder and go with what he says. If he doesn't have a straight answer then he's just full of it.
Of course there will be different opinions. I would let WAX set up my 760 44's but not some "guy". I chose to start with 46's because I wanted to avoid the cheap guy who will screw up an entire package to save a few.

 

[Vortex]

Any time your using an aircleaner to jet your carbs in its a huge FAIL. You putting on a more restrictive aircleaner to try and make your carbs work.

I think you are missing the point, if the air inlet didn't matter everything would use the same air intake. No it's not gonna tune your motor for you and do some magic. Sheesh.

Many riders use the stock aircleaner for several reasons, that would be considered more restrictive than open elements. Or using a 1.5" filter instead of 3". Not talking about drastically restricting air flow.

The point is changing the air filter does change how it runs. If it didn't, then why does the mikuni manual recommend changing pop off springs when you go to open elements?

 

[Vortex]

So I've been off the forums for awhile but now I'm back and ready to go and call out.
What a load of crap, tuning with restricting air. All that means is you don't know what your doing. I've tested signal with Ed Brazina himself and I have my own flow bench 947cfm @ 28".
I personally like Harry Klemm, he is truely one of the best people you can meet and I love his Kwai two stroke bike. My personal findings don't match those of that article and after many years of running different carbs at pro level competition, I have come to some conclusions which I "try" to help my customers with.

One of the factors of TPE is real jetski setup info. Any idiot with a cnc can make parts, but setting up a package you need to know jetski's. Just cause you have a rope doesn't mean your a cowboy.
Voting on "which carbs" is a stupid means to a choice. Voting just means a bunch of people who don't know get to join the gang.
The question is: what is your setup, what is your riding style, what is your riding environment, what is your budget, what are you after==== the best or===== what you can afford.
I see all this talk, then go to a group ride and see a bunch of excuses as to why the guy with all the answers on this forum has his boat running like crap.

Find a builder and go with what he says. If he doesn't have a straight answer then he's just full of it.
Of course there will be different opinions. I would let WAX set up my 760 44's but not some "guy". I chose to start with 46's because I wanted to avoid the cheap guy who will screw up an entire package to save a few.

So you're saying Harry Klemm doesn't know what he's talking about? That's a bit harsh lol.

Have you ever worked with automotive carbs? You're supposed to adjust the idle mix with the air cleaner on (while observing a vacuum gauge.) No one does that out of laziness, but that recommendation is based on the same principle (Speed of airflow affects mixture in layman's terms)

Every part of the system matters, don't play me the fool for bringing up something that is often overlooked.

This is all in reference to the question of running much larger dual carbs(46, 48) on sub 760cc w/porting. On any other high outpit combo sure run the largest filters you can. As previously stated above, An engine can only consume so much air and fuel, the smaller air filter merely helps create higher air pressure to help pull fuel thru the Jets of a carb that's oversized for the application.

 

[Big Kahuna]

No, he said he found different results.... I think egbrig knows what he is talking about.

 

[egbrig]

Vortex, you are an angry person. Whats your real name or you going to hid behind an avitar. Your posts are harsh so, ok, who are you and what have you done to warrant any badge of expertise? Do you race, how long and at what level? Do you tune for others? If your going to make sure pointed fact sounding statements then say what your expertise is!

"helps create higher air pressure " WRONG! Lower pressure, you don't even have the physics right.

Where did I say "Harry Klemm doesn't know what he's talking about "? I'll say it again,
"My personal findings don't match those of that article" I performed same tests with Ed on his flow bench ( his pulls over 1000cfm @ 28").
Also that groupK test was done on a weak probably a SuperFlow 110 bench. THAT MAKES A DIFFERENCE! If you don't understand, you can even call me, then ask questions but don't comment as if you know whats what.
These are not AUTO carbs. The Physics is the same - but 2t vs. 4T air needs are different.

 

[egbrig]

BTW, Harry is one of the nicest people you can ever meet and I really enjoy when I get to talk to him in Havasu!

 

[Jr.]

So you're saying Harry Klemm doesn't know what he's talking about? That's a bit harsh lol.

Have you ever worked with automotive carbs? You're supposed to adjust the idle mix with the air cleaner on (while observing a vacuum gauge.) No one does that out of laziness, but that recommendation is based on the same principle (Speed of airflow affects mixture in layman's terms)

Every part of the system matters, don't play me the fool for bringing up something that is often overlooked.

This is all in reference to the question of running much larger dual carbs(46, 48) on sub 760cc w/porting. On any other high outpit combo sure run the largest filters you can. As previously stated above, An engine can only consume so much air and fuel, the smaller air filter merely helps create higher air pressure to help pull fuel thru the Jets of a carb that's oversized for the application.

He states he does not agree with Harry! And like wise I dont agree either! Doesnt mean Harry doesnt know what he is doing? In reality he is way smarter than most on these boards. I personally have my ideals to accomplish my goals .
Btw, I’m the builder of ProSouths motor package. I told him in the begining the oem 44’s would not work for him.
He is using this thread as a learning experiance.

Just like I dont agree with what your stating here! And I agree with Egbrig, you dont know what your doing. While in theory you are correct. Thats a back yard way to accomplish what all the best carb builders take years to develop.

 

[Vortex]

Vortex, you are an angry person. Whats your real name or you going to hid behind an avitar. Your posts are harsh so, ok, who are you and what have you done to warrant any badge of expertise? Do you race, how long and at what level? Do you tune for others? If your going to make sure pointed fact sounding statements then say what your expertise is!

"helps create higher air pressure " WRONG! Lower pressure, you don't even have the physics right.

Where did I say "Harry Klemm doesn't know what he's talking about "? I'll say it again,
"My personal findings don't match those of that article" I performed same tests with Ed on his flow bench ( his pulls over 1000cfm @ 28").
Also that groupK test was done on a weak probably a SuperFlow 110 bench. THAT MAKES A DIFFERENCE! If you don't understand, you can even call me, then ask questions but don't comment as if you know whats what.
These are not AUTO carbs. The Physics is the same - but 2t vs. 4T air needs are different.

Ok ok so I mixed up one detail and worded it backwards. The point was the type of air filter does change how the ski runs.

The Klemm article states he did in fact restrict the air filters with duct tape during testing larger carburetors and it produced a favorable change. You then said that very concept was a load of crap. I'm not intending for this to get heated, I'm an amateur racer and I'm sure you know something I don't.

If you would kindly refrain from asking for my personal info that would be cool, I'm actually quite friendly and I don't appreciate you assuming anything about my character.

 

[egbrig]

One of the biggest problems people face on such forums is anonymity. On many forums people claim facts, knowlege, expertise without having to back it up. They hide behind an imaginary persona. Why?

You didn't mix up one detail and word it backwards, you don't understand it that well. That's the truth.

I'll make it easy to understand. If this was MMA it would be easy, shut up get in the ring and put it to the test. NO HIDING.

I do know and have met most of the people in Jetskiing who have designed, developed, and proved in competition what works, how and why. So yes, personal info is who you are and what you know!

Things are changing for me and so now I will and get to call it out. My personal hero's in this sport, the Tim's, (Tynin, Judge) Hero, Bun, XS, ,,, Phil and Paul along with many more. When Phil Clemmons tells me a result I ask questions, I don't question his judgment because who he is and what he's done.

I've seen people argue with Tim Tynin about pipes and the guys arguing don't even know how a pipe works other than the very, very basic theory (really, they've never built a pipe) .
I have had conversations with some guys that developed GP 500 two stroke engines (If you don't know about the 500's then you don't understand the level of two strokes). I asked questions and gave my personal results and listened to the answers as to why I got what I got.
I don't want to be the "know it all" guy and there are a few smart guys on this forum but I'm over it. There is some really good info on this forum but if you don't know who's who, how can you get to the good info, how do you know who to trust, the guy who types the most but when you see them at an event they're stuff runs like crap, and is put together poorly.

Things don't need to "get heated". In fact when I go to Havasu, Kyle from Dasa is so much fun to hang out with, Zack from Power House is on my speed dial and Phil C.
is ahead of my girlfriend on my speed dail. I only have six people on it and two of them are competitors who disagree with me on engine design.

 

[Vortex]

Ok bro...the key facts I based my statements on were sourced and cited, from the mikuni manual (carb lean at wide open open and doesn't respond to jetting changes-carb too large for motor) and harry's article which discussed a straightforward way to attempt to deal with that issue. The thing I misworded was higher vacuum signal not air pressure, and yes I'm not an engineer or a physics professor, it doesn't take that qualification to know the smaller airway will produce higher vacuum.

Have you even tried to run 48s or similar carbs on sub 760cc motors? I have put the theory to the test, I used to run 4" elements and I switched to 2.5, and I did notice a slight increase of fuel consumption indicating better signal. Can I prove that with data, no, but you have no real numbers to do disprove that either so...

I've talked to one of Phillip clemmons' customers who wasnt happy with their engine and his way of handling that. So no one's perfect.

Have a nice day.

 

[Big Kahuna]

"Congrats to all of the P&P team riders for their excellent performance in Amateur Freestyle at this years IJSBA World Finals. Our riders took 2 of the top 3 spots and 5 of the top 7, against the best riders in the world. Great job guys! We are glad to have you riding for P&P!

Taylor Kress-Am World Champ
Ryan Doberstein-3rd
Iceman-5th
David Oski-6th
Daryl Winters-7th
Kelly Hieke-Landed 2 HUGE backflips in competition (new personal best for her in competition)!"

So you found 1 person that was not happy. Interesting. I am sure these guys are not happy either.

 

[Vortex]

They're probably not too thrilled by the balance of their bills from p&p lol . I know he's not cheap. Flatwater freestyle is a open your wallet class anyway, hell I don't even really like flatwater f/s i'm a racer after all.