HX Upgrade Recommendations

[daboostcreep]

I have a 96 HX that runs strong, but I'd like to do the most cost effective and smart modifications.

Take a look at the impeller. How bad is this, and how much improvement will I see from a sharpening? I really don't know much about the effects of this kind of damage on performance. Is there an impeller that comes highly recommended that justifies the difference between a $60 sharpening, and $260 for a new Solas? I will install a new wear ring regardless.

Please tell me what mods or a package of mods I should to to have a reliable, faster ski for recreational use. I want the ski to start everytime, and not die in 6 months of use. I also want to keep the cost low but the parts effective.

 

[Dr Honda]

any engine mod's will shorten it's life... but the best bang for your buck is a "Factory pipe" system. It will ad 20 HP to a 720 engine. And... they make an HX pipe.

As far as the impeller... that one is up to you. That impeller isn't in bad shape. I would just take a file to it, and clean up the rough edges. The leading, and trailing edge doesn't need to be sharp... but you do want a clean transition to minimize cavitation. BUT... a Solas, or Skat-Trak impeller will make some marked improvements. On an HX... I would recommend a Skat-Trak swirl. It will give you better acceleration, and out of the hole, while maintaining the same top speed.

 

[daboostcreep]

I like the idea of the factory pro exhaust, but ive read that it requires increasing the revs from 6900 to the 7600 range, and also requires some better octane than the 91.

Any truth? I like power under the curve also, not just topend. Suggestions beyond the exhaust?

 

[Spimothy Leary]

i believe factory exhaust requires 93, thats what I run (787 spec1)

my list would start with impeller, i have no opinion on which prop but if doc says swirl, then get a swirl until a hx junkie says differently.

sponsons will improve cornering, it will turn much harder .

exhaust WILL get improvements, but will probably shorten the life span but hard to prove that, I don't know about the jump to 7600 rpm's ... I run 7050 on my xp with spec1, never been anywhere near 7600.

flame arrestors and rejetting might get a tiny improvement, but not enough to get excited, but makes carb tuning easier

water injection maybe ? improves mid range .

 

[daboostcreep]

Im going to file the rough edges of the impeller today. Is shaving the head for a bit of increased compression a worthwhile thing to do at the $100 mark? Also, ive read that carbs from an 800 RAVE motor work great. Anyone done this?

 

[brock1]

i too have seen that the carbs from a 787 make a difference in power in the 720 but have never been fully sold on the idea my wife has a gsx with the 787 and i have been very tempted to pull the carbs off when she is not lookin and throw them on mine to see but have never got the balls to do it yet :blush:..mostly cuz of her

 

[daboostcreep]

Anyone have input on a head shave?

 

[Popsslowdog]

Not experienced with that on PWC's, but have done it on lots a other motors-mostly when gas didn't cost so much. Raising the compression pretty much commits you to permanent high octane fuel if you want your motor to last. Especially true with 2-cycles. You can get away with more heat and the occasional detonation with an iron motor and forged pistons, than with aluminum and other lightweight alloys.

I have an old chrome clad bore 2.4 li Mercury with 165 psi compression that I have kept alive for about 12-15 years. I MUST use only the best 93 oct pump gas I can find, add a good +7 points octane booster every time, and premix at 32:1 or I will get detonation. This gets really expensive, really quick!! (also have a 125 hp Nitrous setup on it)

These PWS Hotrodders can tell you the best way(s) to make power and keep your motor alive. Shaved heads is one way but the costs are pretty high. just some rambling thoughts from an old wrench turner.!

 

[Popsslowdog]

Not experienced with that on PWC's, but have done it on lots a other motors-mostly when gas didn't cost so much. Raising the compression pretty much commits you to permanent high octane fuel if you want your motor to last. Especially true with 2-cycles. You can get away with more heat and the occasional detonation with an iron motor and forged pistons, than with aluminum and other lightweight alloys.

I have an old chrome clad bore 2.4 li Mercury with 165 psi compression that I have kept alive for about 12-15 years. I MUST use only the best 93 oct pump gas I can find, add a good +7 points octane booster every time, and premix at 32:1 or I will get detonation. This gets really expensive, really quick!! (also have a 125 hp Nitrous setup on it)

These PWS Hotrodders can tell you the best way(s) to make power and keep your motor alive. Shaved heads is one way but the costs are pretty high. just some rambling thoughts from an old wrench turner.!

 

[Spimothy Leary]

i believe if you keep the domes under 185 (could be 175) then you can still run 93. too lazy to look it up but for some reason I remember that to be 43cc domes was the 'cutoff' i've never bothered with that, i'm about 4 mods away from needing to worry about higher compression

 

[daboostcreep]

i believe if you keep the domes under 185 (could be 175) then you can still run 93. too lazy to look it up but for some reason I remember that to be 43cc domes was the 'cutoff' i've never bothered with that, i'm about 4 mods away from needing to worry about higher compression

I'm tempted to just send the head to GroupK and let them shave it to run on 91, where is 87 is stock. I will always have a minimum or 91, and most likely run a mix of 1 gallon of 100 and 4 gallons of 91....shake, pour, and enjoy!!!!

You refer to being 4 mods away....what mods have you done to your HX if you have one? If not an HX, what engine mods have you done to your 720 if you have one??

 

[1MACGYVER]

This is mine, Factory pipe, high comp head (i run 98 octane premix), rev limiter, Worx sponsons and R&D intake grate.
Its a wild ride, such a simple little motor but so much fun

 

[Spimothy Leary]

I'm tempted to just send the head to GroupK and let them shave it to run on 91, where is 87 is stock. I will always have a minimum or 91, and most likely run a mix of 1 gallon of 100 and 4 gallons of 91....shake, pour, and enjoy!!!!

You refer to being 4 mods away....what mods have you done to your HX if you have one? If not an HX, what engine mods have you done to your 720 if you have one??

787 not 720 but same difference when it comes to mods
FA's/Spec1/Water Injection/Nozzles/Swirl/Finger Throttle

eventually it will include Novi's/XO/UMI/Stinger,
then I'll consider an aftermarket head..

 

[1MACGYVER]

Mods for the outside: Universal bars, UMI throttle, Sticky blacktip seat cover, hydroturf.


I forgot the solas prop, K&N filter and R&D intake manifold before.
I dont think theres much else to do

 

[mikidymac]

Some are going to disagree but from what you are looking for, reliable, easy to start and more power not just top end DO NOT buy a pipe. The pipe makes all of its power by spinning more rpm's and this will result in much more wear and a shorter engine life period. Crank bearing and especially seals will need to be inspected yearly. These pipes were designed for racing and not recreation use where they are operated at high rpm and speed constantly and this is the oposite of a recreation ski. The best bang for the buck that will give you everything you asked for is a Group K Sleeper kit. These guys build the most reliable endurance racing skis, check their record. They know what they are doing and it is an engineered and tested package that works. It sounds like you are alerady thinking about them for the head mod so just let them do the entire sleeper kit. One thing to remember is that you need to be starting with a solid engine so if it needs a rebuild you need to factor that into your budget.

Where in Cali are you?

 

[daboostcreep]

Some are going to disagree but from what you are looking for, reliable, easy to start and more power not just top end DO NOT buy a pipe. The pipe makes all of its power by spinning more rpm's and this will result in much more wear and a shorter engine life period. Crank bearing and especially seals will need to be inspected yearly. These pipes were designed for racing and not recreation use where they are operated at high rpm and speed constantly and this is the oposite of a recreation ski. The best bang for the buck that will give you everything you asked for is a Group K Sleeper kit. These guys build the most reliable endurance racing skis, check their record. They know what they are doing and it is an engineered and tested package that works. It sounds like you are alerady thinking about them for the head mod so just let them do the entire sleeper kit. One thing to remember is that you need to be starting with a solid engine so if it needs a rebuild you need to factor that into your budget.

Where in Cali are you?

Agreed, I want exactly what you said. The pipe seems like its a death sentence for a ski if its not setup perfect. I'm going the cheap and easy way first.

I've done the following:
Ordered new wear ring.
Sharpened stock impeller from what it was before, to what is seen below.
Replaced gray fuel lines

I would do the sleeper kit IF, the motor was needing a new topend. I can't justify pulling the cylinders without needing it. I'm considering rebuilding the stock carbs due to the removal of the stock gray fuel lines showing green slime inside. This leads me to believe that even though the ski is running fine, there may be something in the carburation missing that I'm not aware of because I've never know the difference. I'm assuming at best the filters are nearly plugged up. Should I simply rebuild the stock carbs, or should I get a set of stock 800 carbs?

 

[Spimothy Leary]

Agreed, I want exactly what you said. The pipe seems like its a death sentence for a ski if its not setup perfect. I'm going the cheap and easy way first.

I've done the following:
Ordered new wear ring.
Sharpened stock impeller from what it was before, to what is seen below.
Replaced gray fuel lines

I would do the sleeper kit IF, the motor was needing a new topend. I can't justify pulling the cylinders without needing it. I'm considering rebuilding the stock carbs due to the removal of the stock gray fuel lines showing green slime inside. This leads me to believe that even though the ski is running fine, there may be something in the carburation missing that I'm not aware of because I've never know the difference. I'm assuming at best the filters are nearly plugged up. Should I simply rebuild the stock carbs, or should I get a set of stock 800 carbs?

everything the droid said is accurate, agree that there is downside to a pipe but IMO a properly running pipe offers an impressive amount of performance, set that aside you can always add one later

sleeper kit , yes, do that only if you need a top end, don't get power hungry on a good running ski and take out good parts. By the time you need a top end you'll have a good idea if you like this ski as is or if you want more, and in the meantime you might look at other minor upgrades here and there.

YES keep the carbs and rebuild/clean them don't replace unless these are determined to be FUBAR, then replace. take a good look inside then determine if you want a rebuild, verify jets, all that stuff. if your not 100% comfortable you can send them out and sometimes save money since rebuild kits sometimes are not necessary if its just one bad thing, like say a filter and a diaphragm. all the more reason if your comfortable is just pull them get a good look and see what needs to be replaced,.

 

[scorpio67]

everything the droid said is accurate, agree that there is downside to a pipe but IMO a properly running pipe offers an impressive amount of performance, set that aside you can always add one later

sleeper kit , yes, do that only if you need a top end, don't get power hungry on a good running ski and take out good parts. By the time you need a top end you'll have a good idea if you like this ski as is or if you want more, and in the meantime you might look at other minor upgrades here and there.

YES keep the carbs and rebuild/clean them don't replace unless these are determined to be FUBAR, then replace. take a good look inside then determine if you want a rebuild, verify jets, all that stuff. if your not 100% comfortable you can send them out and sometimes save money since rebuild kits sometimes are not necessary if its just one bad thing, like say a filter and a diaphragm. all the more reason if your comfortable is just pull them get a good look and see what needs to be replaced,.

What kinds of things should you look for when inspecting carbs?? Are there actually visual signs of problems??

 

[daboostcreep]

I added the picture a few posts above to show the results of dremeling the stock impeller which was damaged as shown in first post. No bad for 15 minutes of time and the dremel tool and bits I already had! I'll keep the $100 roundtrip for sharpening in my pocket, and put it towards an aftermarket impeller down the road.

Anyone have instruction on how to install a primer kit on these carbs and remove the choke?

 

[daboostcreep]

So far I have done some refurbishing on the stock impeller, and replaced the wear ring. I also pulled the head and sent it out to GroupK to be cut.

Anyone know if the filters in the carbs can be replaced without needing to remove the carbs? Also, can it be done without needing to make any adjustments to pop-off and other stuff? I'll do it myself if its as simple as popping the cover, removing some gaskets and the diaphram and reversing the process. If its going to require setting anything, I'm going to skip. The reason I would be doing this is I replaced the stock gray lines and they were slime green inside.

 

[Spimothy Leary]

What kinds of things should you look for when inspecting carbs?? Are there actually visual signs of problems??

honestly I can't say, i have a very very experienced tuner with a garage full of tools in my ride group, we ride together 40 times a year, I simply hand my carbs to him and he tells me what I need, i've never had to learn carbs because i've always had an expert on "staff"

 

[1MACGYVER]

They disconnect quite easily, I became a pro at it before I rebuilt mine, I was disassembling them them every 2 rides and cleaning them. Main things to check are that the diaphrams are nice and tight not all stretched, clean the filters, do a pop off test (should be quite high on the hx 36-60psi) and drown it in carby cleaner. It easy on the bench but the chance of getting parts lost or screwing up the reassembly would be too great doing it in the ski

 

[kkeipe90]

hi i have a 96 hx that im installing a factory pipe i have everything done except the ewci rev limit/ module. im unsure witch wires need to be hooked to what. wondered if u could explain how u wired yours

 

[AdamXP800]

Keipe, start a new thread, don't dig up an old thread from the past.