What should I change on my setup?

[Byerly]

I recently bought this superjet and it's not quite what I was expecting. It doesnt have that "umphh" that I was expecting. I am having a hard time doing any subs or 180 stabs. Ive been told to try a new impeller or a big single carb. I'm not expecting backflips but something that will maybe allow me to attepmt barrel rolls. I am installing footstraps this weekend just because I am waiting for winter to put my footholds in. What do you guys see that I could do to make it have more low end torque. Any information would be appreciated.

1994 SN Yamaha Superjet
701 62T engine
Ported Head 155 compression in each
Dual 38 carb with K&N Flame arrestors
Reed Assists
Factory B pipe with mod chamber
Factory Pipe Alum waterbox
MSD Enhancer
Wet Wolf outlet cone
Riva ride plate
Scoop intake
Aftermarket Impeller, not sure which one the guy before me installed
UMI handle pole
UMI center Pad
UMI Finger throttle
ODI Hand grips
Beef It Handpole Reinforcements
Hydro-Turf mats
Hydro-Turf chin pad
Dual primer
500g Bilge Pump
Rhino Lined Hull
Brand new Battery

 

[tor*p*do]

sounds like a good setup
check your impellor- it may be holding you back

 

[Sospikey]

Well, that should be plenty punch for the tricks you mention (by just looking at the mods). As with all motorsports; it isn't just about adding parts; one need to add the right mix of parts and set up the stuff right.
Well, here's what I would look at. Is it a pure 62t motor or a 61x cylinder? I'd check water routing for the pipe, check the set screws the head pipe. Check that the jetting has been changed out to match the pipe. The impeller (pitch and model) WILL have a big input in performance. "Ported head", I guess you mean milled head? 155 psi seems on the low side for a milled head, that seems more like stock compression.
About tricks; are you new to jetskis? It isn't just like you can hop on and barrel roll the sucker!

 

[zyxwvu44]

I have a very similar setup andine rips really well. Are your carbs jetted and tuned properly? Another big Thig could be the impeller. Before I changed mine it felt like I was burning out all the time instead of gripping the water and shooting away. Check carbs first cuz it could be free, then try a different impeller

Sent from my Nexus S using Tapatalk

 

[B_RAD_BALLA]

Have you checked your skill level? Maybe its not the ski and you need to learn how to do the tricks . its not as simple as buying a ski and being able to do tricks just sayin...

 

[EXPERIMENTAL]

hey, if you want some ummph, trade your current carb setup for some black jacks from art at jet works, good guy. I changed from dual 48mm riva pro series to dual 44,, black jacks. i told art my current setup and told him i wanted maximum bottom end. couldn't be happier with his products and the change in power

 

[NVJAY775]

I'm guessing jetting and carb adjustments, impeller, headpipe water screw adjustments, and a limited chamber instead of the mod chamber will help out the bottom end hit.

I think FP has jetting recommendations on their site.

Carb air screw adjustments may be found on a good thread here. I can't remember the name of thread unfortunately (hopefully somebody that remembers will chime in) but it's pretty dammm good info.

A limited chamber will hit a bit earlier than a mod chamber. Might be able to get a trade going with somebody on that. Although the mod will still hit pretty good, the limited will be a better set-up.

Your headpipe screw settings will help too. Your bottom and middle screws, when closed down, will help bottom end. The top screw can be anywhere from 1/8 turn open to a full turn open. I think... Lol! Pretty sure this will give you the most bottom end as well.

 

[Byerly]

I have been riding for about 3 years. I had no problem doing these tricks on my 750 sxi pro. I'll do some diggin and see what I can do. Thanks for all the input.

 

[Mark44]

Check impeller # and check the tuning on the carbs with a PET tach. Should have real good bottom end even with 38's, nothing wrong with those carbs on your platform. I would also bump up compression to say 180.

Mark44

 

[d_moss]

You said the hull is rhino lined? that would rob lots of power making all that drag. That would be like having carpet on the bottom of your hull..

 

[MADMAT]

13/16-3 prop

-2 on handle pole

185psi

The prop is the absolute most important part IMO. It has to be a 13/16-3mm for that set up. It will change your riding style completely.

I love my dual 38's and would never change them for that motor.

Also I prefer a bored 85mm exit nozzle over a short cone. I have tried em both ways on your set up and hated the short cones.

CHECK YOUR PROP! If its a 14/19..BYE BYE!

 

[MADMAT]

Oh and ditch the reed stuffers!

 

[Byerly]

All work and tuning was done by someone named zigler in wisconsin about 3 years ago. Any info about him? I appreciate all the info and will see what I can do myself and what I can't handle.

 

[D-Roc]

bore it to 83mm pistons, ada girdle head with 35cc domes, deck cylinder, port cylinder, port b-pipe, buy bigger carbs, get a TL setup, learn to tune all of these parts and then get a lighter setup. but before you do any of that, buy yourself a c-75 skat/tbm super cone setup and bore your nozzle to 85mm. It will take you some time and years as money allows which is good because you will have to learn to ride and keep your ski alive.

 

[Byerly]

All iv'e been able to find out about reed stuffers is that they are great for low and mid range. Why would I want to get rid of them? Is there a way to find the pitch on my impeller without removing it? I assume it requiers a special tool and I don't have it. Looks like its time to invest in some new tools.