Kawasaki JS 550 need advice

[rad1026]

my son came home with a JS 550 he got for free. It has very little compression so we can only get it started by putting oil in the top to build a little compression. I don't know what year it is. I have taken the head off and the cylinder off the bottom end. The pistons connecting rods are nice and tight on the crankshaft, no slop. The piston pin needle bearings look brand new. There is a little scuffing on the cylinder walls, nothing bad at all. So it looks like I just really need to hone the walls and do a top end kit. The pistons are stamped .040 which I'm assuming mean the engine has been bored over stock. The intake and exhaust ports look to be polished, the carb is Mikuni, is that a stock carb? I will get a manual this week, but tell me if I am on the right track. There are really no shops in town here that work on PWC other then the dealer and I don't want to go there for advice.

 

[timmyboy76]

Re: Kawasaki JS 550 need advice

an easy way to tell if motors' been opened up, is that you'll see paint missing on the head bolts and surrounding bolts. Also, there will be an unpainted base gasket too.

It sounds like ur on the right track. Was it the front or back piston that let go or both? With 1 over, you may need to "fatten" up the high speed setting, to compensate for the bore. If all looks good, then ya, hone it out and slap a piston or 2 in, and go at it. Go thru the mikuni (stock carb) and see what alls needed.

 

[rad1026]

Re: Kawasaki JS 550 need advice

I don't know if anything let go, this is a freebee and we really don't know the previous owner very well. There was no paint missing on any bolts so maybe it was all painted when they did the work. So you say 1 over, I'm assuming that means the .040 is basically one step over the original bore? So when I order pistons and rings I need to make sure I go with the .040 over stock. I know that is a basic question, sorry.

 

[timmyboy76]

Re: Kawasaki JS 550 need advice

not sure if i can post the link to ebay, but go there and type...js 550 pistons. You'll get a ton of "rebuild" kits, one particular, has all 4 "bores" that can be ordered with kit..150 buks too. Cant beat that.

 

[rad1026]

Re: Kawasaki JS 550 need advice

cool, I will check it out. Should I just buy a honing tool and do it myself?

 

[rad1026]

Re: Kawasaki JS 550 need advice

okay, i measured the bore before ordering any parts. Glad I did! The bore is 69mm not 75mm. Its a 440 isnt it? Is it even worth putting any money in to?

 

[Noltz]

Re: Kawasaki JS 550 need advice

I'd wait on the service manual before proceeding. I don't have access to specs but in motorcycle world it was common to put different jugs and pistons on the same bottom end for multiple displacements. For example the '99-02 SV650, was a factory big bore (with common bottom end) SV400 from Japan. It sounds like Kawi did the same thing here.

Get your manual, or call the dealership with your serial number. "I'm looking at purchasing this boat, but the decals have been removed. Can you tell me what this is supposed to be? And do you still stock parts for it if I need anything?"

 

[justtwistit]

A js440 and 550 jug will swap over. the openings in case has to be opened up a little for the 550 top end to fit, that is if it is a 440 bottom end.

 

[GA_Boater]

A js440 and 550 jug will swap over. the openings in case has to be opened up a little for the 550 top end to fit, that is if it is a 440 bottom end.

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