Kawasaki js550 High compression head comparrison vs OEM

[@scrambler250r]

Just a heads up for anybody, Yes you can put the dual ring SX(reed valve motor)pistons in the older piston port 550s. Read on several forums & it's a great & easy upgrade!

[@9mmkahr]

you have a piston port? i have a 90 550sx PP with a few mods. compression is 110/125 so i'll be putting new pistons/ rings and an ocean pro head i just got off ebay

[@stock23]

Could you put a 550sx head on a js440

[@brads3111]

yes, you can. If you dont have an aftermarket exhaust yet. theres a killer deal on ebay for a kirker exhaust for only $90 it looks mint. get it

[@ronjackson1444]

Brad im from colorado springs and moved to FL. I havea 85 JS440 and have some questions about it. your videos have been helpful. thanks alot man. Do you just search for parts or do you know of any secret stashes i can look for thanks

[@brads3111]

ebay is always awesome but be very carefull, tons of people lie about what part it is and they also charge too much so you end up getting ripped off. They are really bad about ripping people off on carbs and intake manifolds. florida i know for a fact has people selling stuff on craigs.. Craigs is always a really good option but you have to be very patient. Everybody will ask too much for these parts but keep in mind their over 25 years old so how are they worth so much? Its because their crazy. i bough a full kerker exhasut and 440 motor with aftermarket head for $75 "craigs". I just bought a whole electrical system for $30 "craigs". I bought a aftermarket head for $40 "ebay". mariner waterbox for $25 "craigs" So take your time and it will pop up.. good luck

[@stock23]

I have a js440 and I want to get a high compression head but do you have to get bigger pistons

[@brads3111]

absolutely not. I would also consider getting new pistons and rings if you havent done so already. New pistons and rings will bring your original compression right up and give it more low end torque like you need.

[@stock23]

and do you know for sure that a 550 head will work on a 440

[@brads3111]

NATHAN DIBELLA a 550 head will work on a 440

[@brads3111]

brads3111 yes it will work. but honestly since your soo dead set on getting a head and since winter is rite around the corner. you can actually get a high performance 440 head that is way beyond bad ass off of ebay for under $60 and it will be an exzact fit like you want. if your willing to look around for up to 3 months you will find one for as cheap as $40 with free shipping.. theres a pjs head on ebay rite now for $50.. Personally i would get a 440 head for a 440 motor. That is what it was built for. Also as soon as you get a new head you need to put the head on a flat piece of glass to make sure that the head you have received is not warped. My original stock head was leaky and i could never figure out why until i put it on glass and it was severly warped. So i bought a high performance one. Good luck

[@grahambuchan4935]

Hey do you happen to know what the stock carb setup is?(jet positions) my one jetski got extremely hot when we test rode it and it barely had the power to get up on plane with my dad who is probably around average weight for a middle aged man

[@brads3111]

According to the 1976 manuel pilot screw is 1 5/16 low speed screw 1 1/16 high speed screw 1 5/16 hope this helps and sorry to get back to you i couldnt find my books

[@grahambuchan4935]

brads3111 thanks so much!! Is this for the round body bn44? Where are the pilot screws? I can only find low and high and mine is tore down alreday

[@brads3111]

if you have a stock js550 then the largest carb you will have is a 38mm mikuni carb. As far as i know Mikuni doesnt make a bn44 round body. they do make a square body bn44 which is stock for the js550sx.. I dont have the stock specs for a mikuni bn44 two screw carb.. you can google the stock recommendations but a big factor is altitude and performance mods. If you have a aftermarket pipe than you run richer in my experience. Higher altitude you run leaner. I live in denver so i run leaner but i have a pipe so i run richer. so mine runs about stock specs.. also you will just have to play with the carb at the dock. Remember if you aint smoke'n you aint two stroke'n. Meaning your ski needs to be smoking to be safe.

[@brads3111]

brads3111 by the way bn44 are the easiest to dial in. you only have to screws and never tune your ski unless its int the water

[@grahambuchan4935]

brads3111 ya i have a 44round on it its two screws on one side

[@brads3111]

are you talking about boring out the pistons to .5mm or are you talking about porting out the intake and exhaust ports? I only bored it out .5mm with that high comp head and twin ringed pistons your compression should at least hit 175psi with a copper head gasket and high comp head. good luck bud and throw some vids online and let us all check it out.

[@chrisburnsed6349]

brads3111 , you’ve put out a ton of false and left out a lot of info on this topic. I was the engine builder at R&R jet tech and built All of Harry Goatcher’s engines for 5 seasons so I know what I’m talking about. I knew you were full of shit when you called the squishband “a lip”and the rear cylinder the “bottom one”. I didn’t intend on coming off like a jerk but I can’t take all these people coming on KZbin and giving incorrect information. Please do not come in here putting out junk content. 175lbs of compression is very close to bone stock if your ski is fresh and honed correctly ringed and broken in correctly. A race head on a fresh hone and rings should be around 200-205lbs and would require a quality race fuel. Having two water outlets on any engine would be better as it allows more water in and out of the entire engine faster which is overall better for cooling. To say that two outlets would starve a cylinder of cooling is simply ridiculous. There is SOOOO much more that goes into making these engines fast. It’s a number of things combined working together that makes a fast Jetski or any engine for that matter. With a 2stroke while yes the head is an important part , it is actually the very last thing we looked at when finding power.

[@pickelljacob3491]

So all you need Is 440 jugs and u can put a 440 head. 550 jugs with 550 head.the bottom ends are pretty much the same. Don't be scared. Single rings have blow back. Use a double all the time. Doesn't matter whatever year the motor is. I made a sleeper looks like shit and rusted on the outside but inside brand new. Port your motor more power speed low end top end I recommend