Superchicken wont hit max RPM

[WFO Speedracer]

the big pin and stx exhaust combo manages to push a giant stx hull so it seems like it should be able to work in a chicken.

Most were on STS hulls and the STS is the only model that had that exhaust system , the STS is a much smaller ski than the STX HULL , I have a few of both here , the STX 750 did have the big hull but a completely different exhaust system .

That big pin in the STX had 83 HP and the STX reportedly ran 48 MPH but that number sounds a bit on the high side to me 45 ish maybe.

The Seacouch is still going to have a lot more wetted surface area than the STX hull.

 

[Storbeck]

Most were on STS hulls and the STS is the only model that had that exhaust system , the STS is a much smaller ski than the STX HULL , I have a few of both here , the STX 750 did have the big hull but a completely different exhaust system .

That big pin in the STX had 83 HP and the STX reportedly ran 48 MPH but that number sounds a bit on the high side to me 45 ish maybe.

The Seacouch is still going to have a lot more wetted surface area than the STX hull.

Maybe we're not talking about the same exhaust?

I meant the big green thing. Used on 96 and 97 sts and 98 stx

 

[WFO Speedracer]

Yep same pipe , here is the one in my Seacouch it wraps around the back of the ski . Its very similar in design to a Coffman pipe for a TS or SC 650 .

 

[ClumpDigger]

Are you sure the stator in this thing is good, they can cause running issues that many people have mis- diagnosed as carb issues , the debacle with the 44 SBN tends to point me in that general direction , it should have run just fine with the 44 carb . I would double check the reeds and the stator .

I had a small pin 750 in mine years ago , truefully with the 650 exhaust on it it wasn't much faster than the 650 , the main difference is it didn't die out in turns like the it did with the 650 .

That Big pin , STS pipe combo in my experience is one on of the best running combos they ever made, it's a good 20 hp more than a 650 , you should be able to tell quite a difference in power. The thing is if the stator is bad it won't matter what carbs are on it, it will never run right and get full RPM's .

Yup at the beginning I ohms tested the stator, coil, trigger everything was good. Spark plug leads would jump a 1/2” gap on my spark tester. It isn’t breaking up it’s just like a generator and when you get the prop out of the water it opens up and then you get a speed boost for a half a second and then back to a generator. Reeds are great. I put the stubby cone on it yesterday it made a noticeable difference so I’m leaning towards over propped. Got a guy on here that is going to trade me props and go from there.

 

[ClumpDigger]

So I got 2 props laying around, one came with an X2 I bought and the other one I’m not even sure where it came from.

The one that says X2 on it is a skat trak “6” the other says something in cursive (malio?) and then the number 60. I’m guessing they’re the same pitch but I have no idea. would either of these be pitched lower than a 10/16?

 

[WFO Speedracer]

Mako impeller , they were sold through Kawasaki accessories division back in the day, yes it is most likely a 16 degree straight pitch .

They were actually pretty decent impellers. I would try one in there at this point what do you have to lose ?

You can always bend the rear blades a bit to up the pitch if you have to .

 

[fastgtfairlane]

You dont want to go that low on the other impeller. The hooker is a big hub impeller which takes up volume adding more load on the pump..which is why you can go lower on the leading edge. Id try that skat 16.

 

[kevbo]

The old straight 16s are too much load plus they cavitate and vibrate a lot more than cambered blades. A straight 15 is good on 650s and high port 750s. The 16s need a low port 750 or an SXR cylinder to get enough low end response.

 

[WFO Speedracer]

The old straight 16s are too much load plus they cavitate and vibrate a lot more than cambered blades. A straight 15 is good on 650s and high port 750s. The 16s need a low port 750 or an SXR cylinder to get enough low end response.

I would think you would run out of impeller and hit the rev limiter with a big pin and 15 degree straight pitch, maybe a 15.5 , he has the 16 , simple enough to try it and see , if it's too much load bend the rear blades upward a few mm's and take some pitch out or send it off and have it done , if I had that 16 degree in my hand I know what I would do .

 

[kevbo]

It mostly depends on the pipe with high port cylinders. That OEM pipe is long enough to pull more impeller load compared to an aftermarket pipe. If the pipe runs over 7000rpm, I always have to start reducing the load for decent response. Last year I could get new small hub 11-16 concords for $150. They are easy to cut and space for 650 pumps and driveshafts.

 

[WFO Speedracer]

I am interested to see what he come up with because I will be running basically the same setup in mine , for now it will probably get a small pin with that pipe because I have one available out of an ST 750 , I am going to build a big pin to go in it for later.

 

[ClumpDigger]

Thanks for the help guys I appreciate it. I got the pump out and put that mako prop in, it was in a lot better shape than the skat trak. Planning to head up to the lake tonight and silicone it back in for the weekend.

 

[ClumpDigger]

She rips with the mako 60 prop and a stubby pump cone. Thanks for all the help

 

[WFO Speedracer]

Anytime , by helping you I am helping myself lol .

 

[ClumpDigger]

Got to 42mph on phone gps and I started spilling my beer. Certified ripper.

 

[ClumpDigger]

Fire chicken update: I sent my 10/16 to get re- pitched to 9/15 (impros hooker) and that didn’t cut it either. Better than the 10/16 but didn’t accelerate or open up like the mako 60. I have another chicken with a SP 750 I’m going to throw it in there and see if she likes it or not.

43 mph seems to be the top speed, I saw 44 a couple times but I couldn’t get it to stay there so I don’t think it counts.

Gonna keep the mako 60 in it for a while, it’s a stupid fun boat with that prop in it and I’m tired of messing with silicone. On the bright side I can get the pump out in about 10 minutes now.

 

[WFO Speedracer]

Thanks for the update , now I will know where to start.

 

[123hi]

Great info! I was considering trying an 8/14 hooker but I might pass on it considering your findings

 

[ClumpDigger]

I did some more prop swapping in superchickens and added another superchicken to the mix. unfortuantly I didnt have my tiny tach with me so this was all seat of pants feel compared to the mako 60 prop that was in the 750bp chicken and a kawasaki STS 750 that i have a small pin swapped in using them as a kind of baseline.

New superchicken had a 750 sp stock CDK dual carbs stock SC650 pipe and a 13-18 solas impeller, didnt cavitate, accelerated pretty good but didnt reach max rpm imo (did not verify with tach but it you could tell) at one time i had this prop on a stock chicken with a pump stuffer and it did 39, i wanna say the 750sp did 36 or 37 with the 13-18. also not sure how much the 650 pipe was choking out the 750 with this set up.

ended up throwing a STS pipe on this 750 small pin with an XP waterbox and the rad dudes 2" exit and swapped a single mikuni SBN 44 (150 main 120pilot 80g spring, may be too rich) and swapped the 9/15 hooker on it with a stubby pump cone. i will say it is pretty close and the accleration is pretty good, it did slightly better than the big pin motor though im also questioning my jetting. i plan on putting the skat trak 16 i have laying around on this to cofirm if i am overpropped or its a carb tuning issue.

lastly i threw the 13-18 onto the 750bp chicken with a pump cone, so damn close but the mako 60 is still more fun. wouldnt hit max rpm and didnt rip like the mako 60 did. trying the mako 60 with the stock pump cone to see what that does vs the stubby. i wonder if 12-17 would be the ticket or if that pitch exists. The mako 60 will cavitate if you give her the beans at a low enough rpm though so shes not "perfect" but its the closest i got so far and rips the mid range real good.

will probably be selling a very lighly used 9/15 hooker and 13-18 solas in the near future stay tuned.

lakes are starting to get cold, trying the skat 16 with the 750sp this weekend but it will probably be the last swap of the year as i am out of props to try at that point.

 

[WFO Speedracer]

I did some more prop swapping in superchickens and added another superchicken to the mix. unfortuantly I didnt have my tiny tach with me so this was all seat of pants feel compared to the mako 60 prop that was in the 750bp chicken and a kawasaki STS 750 that i have a small pin swapped in using them as a kind of baseline.

New superchicken had a 750 sp stock CDK dual carbs stock SC650 pipe and a 13-18 solas impeller, didnt cavitate, accelerated pretty good but didnt reach max rpm imo (did not verify with tach but it you could tell) at one time i had this prop on a stock chicken with a pump stuffer and it did 39, i wanna say the 750sp did 36 or 37 with the 13-18. also not sure how much the 650 pipe was choking out the 750 with this set up.

ended up throwing a STS pipe on this 750 small pin with an XP waterbox and the rad dudes 2" exit and swapped a single mikuni SBN 44 (150 main 120pilot 80g spring, may be too rich) and swapped the 9/15 hooker on it with a stubby pump cone. i will say it is pretty close and the accleration is pretty good, it did slightly better than the big pin motor though im also questioning my jetting. i plan on putting the skat trak 16 i have laying around on this to cofirm if i am overpropped or its a carb tuning issue.

lastly i threw the 13-18 onto the 750bp chicken with a pump cone, so damn close but the mako 60 is still more fun. wouldnt hit max rpm and didnt rip like the mako 60 did. trying the mako 60 with the stock pump cone to see what that does vs the stubby. i wonder if 12-17 would be the ticket or if that pitch exists. The mako 60 will cavitate if you give her the beans at a low enough rpm though so shes not "perfect" but its the closest i got so far and rips the mid range real good.

will probably be selling a very lighly used 9/15 hooker and 13-18 solas in the near future stay tuned.

lakes are starting to get cold, trying the skat 16 with the 750sp this weekend but it will probably be the last swap of the year as i am out of props to try at that point.

Awesome, thanks for the updates