300/440/550 js440 performance

[ntiguy85]

Would it be better to put an aftermarket exhaust and flame arrester on my 440 or a new impeller with a diff pitch for a little more get up and go? If so what pitch? I know with a new prop it won't give me more "power", but from what I've been reading it can help with more thrust. Mostly ill be doing just flat water recreational riding. Also if I want to put on a new set of bars do I need some sort of adapter for the new bars to fit?

 

[ntiguy85]

Oh yea its a 1977 and bone stock and im 190lb.

 

[screaming440]

i have always run a 15 or 15.5. there are some newer dual pich props but i've never used any of them so i don't know about them.

this is just like puttng a higher gear in a car. the bigger number will increse you speed to RPM but you will give up some bottom end.

since the prop is dependent on the mods you do it may be better to do the mods and ride it first. if the ski picks up some power and has good bottom end then pitch it up.

also the old 440s (pre 1982 i think) did not have a stainless pump sleeve in them. it is possable that your has been replaced but you should check it. if you don't have a sleeve it is likely the pump is all gouged up. this will eat up a ton of power. the poor mans fix for this was to use fiberglass body filler to fill the gouges. it worked good but did not last long. so the best thing to do is try and locate a sleeved pump if you don't already have one.

don't exspect a lot out of the mods you listed. if you want to pick up real power you got to get air through this motor. so most of your gains are going to come from porting and a bigger carb.

these are the short list of mods will get a 440 running like it should have:

44 mm bn carb and mani (stock carb off a 86 or later 550)
milled or am head
exhaust pipe and mani
am water box
prop

as for porting the rec skis we built back in the day usually had the ports cleaned up with the intake port lowered about 1.5 mm and the exhaust lifted about 2mm. you can go a lot bigger but this is where you will see the biggest gain. the skis i am ridding today have the ports opened up about 4mm but they are really loud and i have to run high $$ fuel and oil in them.

 

[fastgtfairlane]

i have a very nice solas 13/18 pitch 440 impeller i would make you a deal on.. i would also recommend boring the exit nozzle for more thrust will also pick up some on the low end

 

[screaming440]

i have a very nice solas 13/18 pitch 440 impeller i would make you a deal on.. i would also recommend boring the exit nozzle for more thrust will also pick up some on the low end

yeah that just didn't make the short list)

you can also put a nozzle wedge on it to make it plane faster and help keep the nose down when planed out. cleaning up the pump casting imperfections (aka pump porting aka pump bluprinting) is not that hard to do and helps a bunch too.

 

[Mobile Chernobyl]

I think the best performance mod for a 440 is getting a 550sx!

 

[fastgtfairlane]

agreed haha although most would simply say "buy a superjet"

 

[screaming440]

yep riding a SX IS almost as bad as a superjunk)

the JS is the only Jet Ski!

 

[ntiguy85]

thanks for the replies guys!! thats alot of stuff to do and alot of stuff to consider and money too haha! im having a hard time finding places that do mods to the old skis, or atleast advertising that they do mods like pump boring or blueprinting, boring exit nozzles, head mods, etc. is there somewhere that i could send the pump and head to or someone i could call to get prices and info for that kind of work?

screaming440 you mentioned an "am head and am water box", but with me new to this sport what exactly do you mean by that? of course i know what the parts are, but is "am" an acronym for a company? ive googled the heck out of it and havent found any info that refers to anything in the jet ski world haha.

fastgtfairlane what would you have to have for the solas 13/18? oh and if i lived in mooresville still it would be easy to find someone to do the work. there are 2 or 3 shops i know of in that town alone!!

 

[Mobile Chernobyl]

am on this site means after market.

For all you machining needs, such as nozzle boring and head milling, the user #Zero on here does very excellent work for a great price!

However, I lent my 440 out to a few people your weight, and you'll be hardpressed to make that thing much faster! I would look into the 650 conversions and just straight up drop a bigger engine in there! At the bare minimum try and find a JS550 motor or top end to do the 440/550 conversion! I just sold one to a guy doing that - you can find complete motors for aroudn $200 or less.

 

[screaming440]

am on this site means after market.

For all you machining needs, such as nozzle boring and head milling, the user #Zero on here does very excellent work for a great price!

However, I lent my 440 out to a few people your weight, and you'll be hardpressed to make that thing much faster! I would look into the 650 conversions and just straight up drop a bigger engine in there! At the bare minimum try and find a JS550 motor or top end to do the 440/550 conversion! I just sold one to a guy doing that - you can find complete motors for aroudn $200 or less.

no disrespect i just don't want anyone to be mislead. the truth is you can get all the power you need out of a 440 motor you just need to know how to do it. also i should say that i am a lot bigger than ntiguy85.

the 650/750 motor adds a ton of weight to the ski and only adds a little hp. my 440 will run circles around my twin carb 550/750 conversion. the 750 is putting out 75 hp my mild js motors are probably putting out 70 to 80 hp and the wild ones are 90+ hp.

 

[screaming440]

thanks for the replies guys!! thats alot of stuff to do and alot of stuff to consider and money too haha! im having a hard time finding places that do mods to the old skis, or atleast advertising that they do mods like pump boring or blueprinting, boring exit nozzles, head mods, etc. is there somewhere that i could send the pump and head to or someone i could call to get prices and info for that kind of work?

screaming440 you mentioned an "am head and am water box", but with me new to this sport what exactly do you mean by that? of course i know what the parts are, but is "am" an acronym for a company? ive googled the heck out of it and havent found any info that refers to anything in the jet ski world haha.

fastgtfairlane what would you have to have for the solas 13/18? oh and if i lived in mooresville still it would be easy to find someone to do the work. there are 2 or 3 shops i know of in that town alone!!

the best thing to do is look around for more skis that have the goodies on them and put all the best of 3 or 4 skis into one. if you look around you should be able to find them for 100 to 200 bucks.

group k still works on the old stuff but...

pump work is not that hard to do you just are cleaning up the vain area with a die grinder. if you look around here there should be some posts about using a ridge reamer to open up the nozzle. any automotive machine shop should be able to mill the head for you.

 

[Mobile Chernobyl]

no disrespect i just don't want anyone to be mislead. the truth is you can get all the power you need out of a 440 motor you just need to know how to do it. also i should say that i am a lot bigger than ntiguy85.

None taken lol. I know a guy who's trying to push 150hp++ on an 80's ford festiva that only weighs 1500 pounds or less now set up for autocross lol.

Is it possible to make a 440 fast? Yes certainly. I'm sure just as my buddy has with his festiva though - you spent a pretty penny getting 70hp out of your 440's! (if not, tell me the secret!)

 

[fastgtfairlane]

the key to a 440 with a lot of power is getting the rpms up.. porting, and serious tweaking from the exhaust with water tuning to pump tuning everything

 

[screaming440]

None taken lol. I know a guy who's trying to push 150hp++ on an 80's ford festiva that only weighs 1500 pounds or less now set up for autocross lol.

Is it possible to make a 440 fast? Yes certainly. I'm sure just as my buddy has with his festiva though - you spent a pretty penny getting 70hp out of your 440's! (if not, tell me the secret!)

it doesn't take a ton of cash to get these running good. read my first post in this thread. porting is where its at and i even gave away my porting secrets.

if you look i have posted about porting on the X "porting 101" i think it is called

 

[Mobile Chernobyl]

Cool - I will take a look! I have a 440 as well as my 550sx.

 

[screaming440]

here is the link:

http://www.x-h2o.com/threads/99155-porting-101-Re-good-idea

 

[kwakhead]

oh, heck yeh 550s and 440s will fly with the right work done. once you buy every mod possible for the 550/440 motors and hull, its all about TUNING, TUNING, TUNING!!!!! if you put too much power to the motor and you dont know how to properly put that power to the pump and tune the pump, than all the power is gone. my first 750 550 conversion ski i ever built, super powerfull, wouldnt move though lol, cavitated so much from all the power. and when you start putting on all the engine mods, ya gotta know how to jet ur carbs and even sometimes porting is needed! if you know your stuff, you can get all the power you need. heres a perfect example....
2000 kx85 85cc 2 stroke race bike, race tuned but pretty much stock, thats only 85cc's but it puts out 25hp
a stock js440 440cc's comes with 27 hp stock, but how does that pee wee 85cc race bike have pretty much the same power??? its alll about the way its built, the size of the engine doesnt play a huge role. but if your looking for a very powerfull and reliable ski that you can keep stock and get great power, 550/750 or 650 conversion, great power, and you can keep them pretty stock and reliable, not that if you know what your doing a 440 modded motor wont be reliable, they just definetly wont last as long with all the mods on them whereas you can just go with a 650 or 750 motor and keep it stock and get slightly more power, DEFINETLY more bottom end power, hands down.

 

[kwakhead]

im working on the first 550 backflip ski. right now lol. definetly not a 550 motor though, the hull has a 650 pump cavity too, rocker nose, 6 in shorter in the rear, reinforced, handle pole mounts at the front. modeling it after a foot rocket

 

[kwakhead]

just like your build chernoybl, your 550sx hull modernization build inspired me, check my thread, its posted, i didnt take the fiberglassing as far as you, but im running a 750 race motor, and 650 pump. mines for freestyle though.