Single carb on a 701

[kevbo]

Good info! I follow your arguments about single carbs. Is there any advantage of using a bigger pair of carbs on a smaller engine for blipping vs wot runs?

It is mainly about fuel draw. Individual inlets get a stronger signal than a shared manifold. A pair of 44s hit the pipe at 40% throttle while the single required 60% and didn't pull as hard. A larger single was about the same as the twin 44s but with the high speed lean out. I made sure that the N/S was larger than the main jet so there was no restriction there. Im not saying a big single cant work, just be aware of the possibly (expensive) problems. I never try to predict what the carb settings should be. I always start massively rich and lean from there. What I end up with seldom matches other peoples numbers.

 

[WB1994]

We chase boat wakes all summer, run 50:1and have single carbed 701s, 717s, 771s,964s,967s, and 1105s and havent siezed anything. These two in the picture get thrashed by lots of people all sumer. Hold them wide open or flatwater flip them. Give me your ski for a day and we could tune your single it no prob. Trying to talk someone through it never works. They all tune different.

 

[long beach local]

We chase boat wakes all summer, run 50:1and have single carbed 701s, 717s, 771s,964s,967s, and 1105s and havent siezed anything. These two in the picture get thrashed by lots of people all sumer. Hold them wide open or flatwater flip them. Give me your ski for a day and we could tune your single it no prob. Trying to talk someone through it never works. They all tune different.

View attachment 365076

Very Cool!!! Those arn`t cheapo turd motors either . What type of intake ,carb,reeds do you prefer ? how about baseline jetting , isnt the jetting similar on the exact same carb between 2 of the same size motors.

 

[High Speed Industries]

How many of you guys tune with a tach? I understand this is pretty useless for freestyle applications, but those of you going lean at full throttle should probably consider adding a tach to your toolbox. Looking at plugs and going by feel will only get you so far.

Carbs (and skis in general) are only as good as the guy (or girl) tuning them.

 

[flyHigh]

As you said for freestyle I haven't seen anyone doing it. It sounds good in theory but I was not able to go wto while staring on my chinpad(position of the tach) trying to read rpms and have my eyes opened for "traffic". I tried it a couple times that day since I inwasted 70$ in the tinytach. No chance at all. Maybe with a different tach (bigger and lit screen) or more skill. You can feel the rpms drop. I rely on sparkplugs, pistonwash and feeling. I would like to see a video of someone tuning a 60mph+ ski with a tach for peak rpm.

 

[Vortex]

You gotta get the commercial tiny tach that has max rpm recall function. Just make for damn sure the pump never comes unhooked when you're taking a reading

 

[MADMAT]

I bet ya if you go back in time single -vs- dual was one of the first threads ever on the X! LOL.

I want a single at some point....

 

[flyHigh]

You gotta get the commercial tiny tach that has max rpm recall function. Just make for damn sure the pump never comes unhooked when you're taking a reading

Well that sounds doable. I had my info's from the Group K carb tuning section and they stated rpm max is not everything. One should check the drop in rpm's after hitting max rpm and according to that drop you adjust the carbs. Seeing that drop of 150-300 rpm's while going wot did not work out for me at all. Do you use a tach to tune your carbs? If so how "successful" have you been? I could see myself doing it the way you described it.

 

[Vortex]

Well that sounds doable. I had my info's from the Group K carb tuning section and they stated rpm max is not everything. One should check the drop in rpm's after hitting max rpm and according to that drop you adjust the carbs. Seeing that drop of 150-300 rpm's while going wot did not work out for me at all. Do you use a tach to tune your carbs? If so how "successful" have you been? I could see myself doing it the way you described it.

Yes I use that tach to tune although I'm not a pro forum tuner lol. It helps for dialing in the high speed screw. I run 48s on a 727/735 now and I noticed significant difference in max rpm when the high speeds were changed only about 1/4 turn. I.never have had my tune exactly where I wanted it but I still have been top 3 in my racing class both times I went. Even got a moto win against Jordan Carrol who is a pro rider. He was on my ass the whole race lol. I still have a lot to learn I really am not trying to sound like I'm the shiz lol

 

[kevbo]

Usually, maximum low speed pull will be a mixture rich of peak rpm unless you are trying to use big pilots and small mains. You need glass smooth water to fine tune the main circuit at full throttle. For freestyle just tune for best response and max pull.

 

[650sx mod]

took it out tonight for the first time tonight seemed like the jetting was ok will need fine tuneing for sure though. both dual 48s have 110 low and 115 high and have the low speed adjustment screws 1 and a half turns out and high speed jet I believe is 2 turns out.

 

[Storbeck]

i have dual 48s on it and was expect what most people said with performance but so far it has been very snappy and good had a buddy ride it that has a single 48 on a 61x and he really cant tell a difference maybe part of that is the prop but so far so good

What were you describing in this post if you just now to it out for the first time with the dual 48's?

 

[motozachl]

We chase boat wakes all summer, run 50:1and have single carbed 701s, 717s, 771s,964s,967s, and 1105s and havent siezed anything. These two in the picture get thrashed by lots of people all sumer. Hold them wide open or flatwater flip them. Give me your ski for a day and we could tune your single it no prob. Trying to talk someone through it never works. They all tune different.

Man wish i had you down here in FL to help tune one of my setups

 

[650sx mod]

does anyone know anyone selling bar pads that are 4 inches tall and have a groove for a ratchet strap if you do and could pint me in that way would be awesome thanks.

 

[Vortex]

Try Showtime freestyle

 

[bored&stroked]

i have dual 48s on it and was expect what most people said with performance but so far it has been very snappy and good had a buddy ride it that has a single 48 on a 61x and he really cant tell a difference maybe part of that is the prop but so far so good

took it out tonight for the first time tonight seemed like the jetting was ok will need fine tuneing for sure though. both dual 48s have 110 low and 115 high and have the low speed adjustment screws 1 and a half turns out and high speed jet I believe is 2 turns out.

This makes no sense

 

[Quinc]

70$ in the tinytach. No chance at all. Maybe with a different tach (bigger and lit screen) or more skill. You can feel the rpms drop. I rely on sparkplugs, pistonwash and feeling. I would like to see a video of someone tuning a 60mph+ ski with a tach for peak rpm.

I tried getting a gps reading on my bob hull and at 52mph it tossed me off.

@Rdrttoy when you do rpm checks are you keeping the ski on the trailer?

 

[Half flip95]

my ski pulls 8300rpm at sea level, on the trailer, in the garage

 

[650sx mod]

I know its been a while since I have said anything on this thread but the weather has finally been warm enough to take it out and I love it. Always a couple kinks to figure out for a first timer builder for sure but everything I have worked out besides the battery hold down and I could use some help. I have a piece of star board that I shaped to the bottom of the hull the best I could then epoxy it Then screw in a RRP adjustable battery box. This came un glued from the bottom of the hull so I tried just a couple of pieces of fiberglass matts and resin just two strips it lasted much longer but eventually came undone again. I don't know if I am just doing this wrong or there is a special way to do this My next idea is to epoxy the bottom of the star board and Fiberglass it all in. I thought I could get a little input before I try this though. I have also heard that nothing really sticks to starboard which I believe is the issue. Any help is greatly appreciated. Thanks

 

[Haydenstanley123]

The single carb setup on a 62T based motor can be a challenge to get running correctly (46mm). I'm not saying it can't be done, but the smooth linear performance isn't there (welcome to tuning hell) and it can consume more fuel than duals. The best stock/lightly modified 62T setup would be to use the dual 38's. If you really want to run a single, get a 61X with a Wetjet (westcoast) manifold and a single 44.

Hey man do you know anything about the 61x wetjet carborators I’m having trouble with one right now