Kawasaki js440 freestyle build.

[jetski9010]

I am building this ski for a buddy that started off as a friendly bet with another guy that has a 550. What started as a few cheap bolt on mods off ebay has now turned into an all out 440 that is being built for freestyle. I know what most people are saying why dont you just put a bigger motor in it but he has to keep the 440 because thats how the bet started. He bought this ski last summer for $200 and it was bone stock. This thing is an 85' and in really good shape and clean. Dont think anything in the engine was ever taken apart looks like its all from the factory. Even still had the pumice stone air filter haha.

So here is the list of parts I got for it.
Westcoast pipe
PJS waterbox
Westcoast flame arrestor
Lightweight jetnetics flywheel
lightwieght aluminum driveshaft
quick steer plate
umi straight bars
watercraft factory footholds
Group K porting
Group k shaved head
Group K worked over carb
PJS 16.0 prop (might give impros a call and see what he can do for me)

I just got it all apart the other night and send the motor parts to group k. Now I got to pull the old driveshaft out. I have a rebuild kit for that when I put the new shaft in and I am also going to fill it with oil instead of grease.
I will get some pics of the build up in the next few days. Not really sure what to expect from this ski because I dont think anyone ever built a 440 for low end but we will see how it turns out. Maybe it will be the first 440 to barrel roll haha.
For now we are just going to run it on pump gas but if I get a 38 sbn carb so I can rejet it we will switch it over to E85 fuel 105 octane like are sj's so we can bump the compression up to the 200-210 range.

 

[Foximus]

There are no 440s built for low end because the 440 pump doesnt work at low end.

Neither does low cc piston ports.....


I'm confused as to what the bet is....?

Enjoy.

 

[jetski9010]

well I have a plan A and plan B. First would be to try to run a 12-16 or 13-16 prop try to have the best of both worlds or plan B would be cut the pipe short and tune it for high end power and run a low pitch prop and let the engine rev up before it loads the pump up it would not make a good ski to ride around the lake all day on but would give you what you were looking for wave jumping.

 

[Polish jet pilot]

Bore the nozzle as much as you can, then maybe switch to a 550 pump...cheat your frined both cylinders look the same (440 and 550 ) ) )

 

[jetski9010]

I forgot to say that I sent the nozzle in to group k to get bored also. I thought of switching the cylinders to a 550 but I really want to see what a 440 that is all done up for wave jumping can do.

 

[Carbon Blaster]

Great build!
Will be a lot of fun, don't give up on the little 440 - if you do the right things it will be a surprising rocket in the surf.
By the look of the parts you already have or getting, your half way there.
Running the right intake grate will make a difference in loading up the pump down low.
Take your time shimming the pump so there is equal clearance between the prop & liner.
Twin carbs will help.
If you can find someone to mold reed valves directly into the crankcases will give you insaine low to mid punch.
Oil feed the bearing housing & light weight flywheel will be a mod you will feel on acceleration. If you can run Total-loss even better.
As awesome as the aluminium prop shaft sounds, keep it for flat water - YOU WILL bend it like a banana in the surf. When the pump hits the water after landing a wave, the water wants to stop the prop, the engine is still turning & the shaft bends.
Titanium is the ultimate or machine one from hollow stainless.
All the rest of the things you are doing is very cool!

 

[Foximus]

Thats pretty cool... but all that work to weld on and machine out new crank reed induction and you leave BN carbs? I think not sir!


Did you fill the intake port with epoxy and then machine a boost port down from it? Surely not using the transfers only?

 

[Carbon Blaster]

Thats pretty cool... but all that work to weld on and machine out new crank reed induction and you leave BN carbs? I think not sir!


Did you fill the intake port with epoxy and then machine a boost port down from it? Surely not using the transfers only?

The twin 38's work great on that motor with a little tweaking.
I had sand-casted plugs made that fill the old intake area but don't quite touch the piston, then machined 2 boost ports into the plugs and holes through back of piston

 

[jetski9010]

the bn carb is not on there for good in fact I might not even use it at all I just figured for $35 while its at group k why not.
As for the titanium shafts are they even out there or are you talking about getting one made? I had to pay a lot just for the aluminum shaft I got.

 

[Foximus]

aluminum shaft will be just fine.

 

[Carbon Blaster]

the bn carb is not on there for good in fact I might not even use it at all I just figured for $35 while its at group k why not.
As for the titanium shafts are they even out there or are you talking about getting one made? I had to pay a lot just for the aluminum shaft I got.

Jeff Jacobs use to run titanium shafts in his race ski, I think he would of had to have them made.
I ran an aluminium prop shaft on flat water for a season with no problems, but 3 in 2 months in the surf.
So at the end of the day it's your decision, can only tell you what happened to mine
If you haven't already got one, a good exhaust manifold (like PJS or similar) will help with your combination.
Good luck!

 

[orangefinger]

i think you should do fox mod and put 650 pump in save yourself the other hassle....

 

[Foximus]

i think you should do fox mod and put 650 pump in save yourself the other hassle....

Hrm... that has a nice ring to it.


:jester:

 

[jetski9010]

yea i have the matching westcoast mani for the pipe. What do you guys think about a intake grate for this thing. Right now I am just running the stock one with the center bar cutout.

 

[Carbon Blaster]

yea i have the matching westcoast mani for the pipe. What do you guys think about a intake grate for this thing. Right now I am just running the stock one with the center bar cutout.

Throw it at someone you don't like, they are crap, even with the centre bar cut out.
I'm trying to remember a good brand.... when I built mine it was 10 years ago & we sand casted our own intake grates & shaped the 2 blades in the shape of a teardrop for zero cavitation . Needs a a decent amount of scoop to load up the pump, losing top end isn't an issue for you as it's for the surf.
Blueprinting your pump will be a noticable difference as the oem castings are cavitation heaven.
You can run a closer head squish & slightly advance the timing, this will give you more mid-range punch for the surf, but beware of detonation if you hold it full throttle on flat water.

 

[Foximus]

I had a few different intake grates and found that the best was the really aggressive PJS one. However it needed to be sharpened and massaged in a few areas.

 

[jetski9010]

I got some pics of the ski build.

 

[jetski9010]

more

 

[BU1LD]

This is one of my 440 pumps that has been extrude honed!

Looks fu kin beautiful!!!

 

[jetski9010]

I got the footholds in the weekend and started turfing. They look really good. I will post pics soon.