Taper bored 38's on a 845cc Big Bore?

Matt_E

steals hub caps from cars
Site Supporter
Location
at peace
So your saying performance wise they are all pretty close??

Most people don't take the time to objectively compare different carb setups, tune them all to perfection, make sure everything else is equal, etc. I have yet to see such a test. So you get a bunch of opinion and brand loyalty.
My personal opinion is that if you've got a well tuned carb setup, there isn't all that much to gain by going to another well-tuned setup (unless you got a really chitty setup to begin with).
Also, a poorly tuned top dollar setup will be outperformed by a well-tuned set of stockers.
If you've got the money, the best setup is the one your engine builder recommends to run on the package he is building you, with the specs he tells you to run.
Personal experience.
My BlackJacks perform better than anything else I've had in the past, but this is on a Jetworks motor, set up by Art from the ground-up. And my prior carbs and motor setups were done by me (a hack), so it isn't really a fair comparison.
I don't know how other carbs would perform on my current setup, because I don't feel like messing with it. I trust the guy that I paid a bunch of money to build it for me.
 
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waxhead

wannabe backflipper
Location
gold coast
Very true words there Matt
I have seen so many skis with people claiming this and that and how crap one set of carbs are etc. Then riding it and tuning it and then they are all happy.
I think with bj carbs you get the setup art recommends and so because its close you are very happy with them.
You dont get that with novi or stock 46 so you they only go as good as the person tuning them.
As far as taper bore 38s I would refuse to tune some ones ski if they had taper bore 38s on them. They are so inconsistent and the fuel flow doesn't match the carb flow and so there are always weak spots in the carburation.
Best cheap carb set is still the oem 44s in my book. Other than that its novi all the way
 
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I think tuning a set of taperbored 38's is way different than tuning a set of 44's or larger carbs.

Wax maybe you don't work with too many taperbored 38' so you don't have it figured out yet.

I'm currently building a 771 for my 16 year old nephew and we are going to run the original 38's taperbored and the thin tube with the stock air box. I should know how they tune in a few weeks. I hope to remove the carbs only once to get it dialed in.
 
Very true words there Matt
I have seen so many skis with people claiming this and that and how crap one set of carbs are etc. Then riding it and tuning it and then they are all happy.
I think with bj carbs you get the setup art recommends and so because its close you are very happy with them.
You dont get that with novi or stock 46 so you they only go as good as the person tuning them.
As far as taper bore 38s I would refuse to tune some ones ski if they had taper bore 38s on them. They are so inconsistent and the fuel flow doesn't match the carb flow and so there are always weak spots in the carburation.
Best cheap carb set is still the oem 44s in my book. Other than that its novi all the way

Hmmmm... Thats funny I have a set of Jetworks Mod 38's and they are spot on... They came to me jetted by Art, I listened to his instructions on how to adjust the screws by how the boat reacts at various Rpm's and throttle positions and it took no time at all to set them up! I've had plenty of people ride my boat who have the same size motor and the bandwagon 44-46's with Rad Valves blah blah blah etc, and everyone of them have been impressed with his 38 Mod carbs. Little off topic but maybe people should take some advice from people like Art @ Jetworks, He wouldn't recommend a set of 38 Mod carbs to someone if he knew they didnt work and they wouldn't be happy with them. All that would do is kill his business and credibility.
 

WaveDemon

Not Dead - Notable Member
Location
Hell, Florida
Most people don't take the time to objectively compare different carb setups, tune them all to perfection, make sure everything else is equal, etc. I have yet to see such a test. So you get a bunch of opinion and brand loyalty.

The only time I can think of that this isn't true are with xmetal modified carbs (if you want to call them AM). There are times when even xmetal will use Full Spectrum carbs over their own.
 
sometimes i think about going back to a 701 with tapered 38s for surf ski in light hull. They make plenty of power,while not the most power,they certainly give wayyy more ride time proportional to the power made for surf usage.
 
Location
dfw
Mod the 38 if, you are up to your eyeballs in them and your time is worth nothing. An unmodified sbn44 flows more and is extremely easy to tune. They wont go much, if any, faster but will hit the pipe sooner and feel more responsive.
 
Still on my 701 !!! 4 years later with the addition of a PFP, TL , and MS109. Snappy power with 30 mile cruising range!
thats a setup ya dont see very often,props for doing something diff,dont think ive ever seen,pfp and 38s before. trade some power for some run time,nothing wrong with that
 

OCD Solutions

Original, Clean and Dependable Solutions
Location
Rentz, GA
sometimes i think about going back to a 701 with tapered 38s for surf ski in light hull. They make plenty of power,while not the most power,they certainly give wayyy more ride time proportional to the power made for surf usage.

Scott's already switched back to a 701 and I am gathering parts for another 760. Even an unported 701 with all the limited bolt-ons is a really fun surf ski.

As for better mileage with the 38's, I don't know about that. My wife seems to burn just as much fuel with her 760 with 38's as I do with my SS865 and 46's. She just putters around out past the bigger waves and never really gets on the throttle but she'll consistently take on 3.5 gallons to my 4.

So either the 38's aren't really that great or the maybe 46's are just as good.?.?.? Dunno.
 

Quinc

Buy a Superjet
Location
California
Scott's already switched back to a 701 and I am gathering parts for another 760. Even an unported 701 with all the limited bolt-ons is a really fun surf ski.

As for better mileage with the 38's, I don't know about that. My wife seems to burn just as much fuel with her 760 with 38's as I do with my SS865 and 46's. She just putters around out past the bigger waves and never really gets on the throttle but she'll consistently take on 3.5 gallons to my 4.

So either the 38's aren't really that great or the maybe 46's are just as good.?.?.? Dunno.

Must be that 40% fuel loss two strokes have.
 
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