Thread: 1997 Kawasaki ZXI Tear Down
03-08-2014, 10:34 PM #1
1997 Kawasaki ZXI Tear Down
Hey all! New to the forums here. I am somewhat new to jet skis but I know my way around an engine esp two strokes. I purchased a SN Yamaha Superjet last summer and I got hooked. Well today I picked up a Kawasaki 750ZXI for $800 bucks trailer included (I felt this was a pretty good deal). It is in good shape, garage kept very clean ect.
Anyhow the girl wanted $1000 but we couldn't get it to start when I came to look at it and settled on $800. She said it ran fine last September and had it winterized and put in storage. Well when I showed up, they had a hose hooked up to the water line while the engine wasnt running. From my researching, i found this a big no no. Upon pulling the plugs they were covered in a creamy white gas/oil/water mix preventing ignition. I figured maybe a bad head gasket, but since they ran the hose without running the engine, I assume this pushed water past the gaskets and into the crank and head. Upon getting it home I removed the cylinder head and jug and found this.
As you can see there is clearly some water in this thing. I removed the motor and tore it down to the crank. I removed the pistons and cleaned/oiled the bearings. Once I split the cases, I cleaned all the gunk out of the case that I could and flushed the crank with premix multiple times until it looked like new. All the bearings look fine (this thing was never run with the water in the crank other than turning over a few times and it sat in there less than 4 hours). Upon my teardown, I found that this had a WSM top end rebuild kit. Judging by the nearly zero carbon build up on the pistons, I assume it was done recently. I plan to replace a bunch misc gaskets and put this thing back together but I have a few questions.
1)Is there any need to rebuild the bottom end because of what happened. The rods have no up and down play on the crank and the bearings seem perfectly fine.
2)Is there any need to rebuild the top end if the pistons look this new? Should I at the very least replace the piston rings and have the cylinders honed? The cylinder walls have no scoring but I dont see any of the cross thatching anymore.
3)Is there a gasket used between where the cases split? I only found a little bit of rtv sealant and want to confirm this is the correct way to seal them. Also do the cases need torqued to a certain spec when reattached to each other and anyone know what this is?
4)How in gods name do you get a torque wrench on the nuts that attached the jug to the cases? I used a 14mm wrench to get these off but how do I torque them down when I put it back on, there is not enough clearance to get a torque wrench in there.
5)Last thing, while spinning the impeller shaft with the engine out, I noticed the impeller is slightly rubbing on the steal ring it sits inside. I believe this is called a wear ring (that's what its called on a superjet). Anyhow, what causes this to rub and what do I gotta do to fix it? The impeller shows no sign of damage from debris or cavitation.
Sorry for the long winded post. I just wanted to get all of that out there so I can begin any steps needed to get this thing back on the water by summer. I plan on putting an oil injection block off kit as well as a crank drain block off kit before I re-intall. From what I hear, with these two items the ski is pretty damn reliable. If you guys could give me some guidance and help with my questions that would be awesome, thanks!
03-09-2014, 11:46 AM #2
Welcome aboard, Th3 VVAy!
Usually when water gets in a 2-stroke, all you do is remove the spark plugs and crank it to dry it enough for it to start. Then put the plugs back in and run it a while. The water will get blown out and everything is fine. No need for a complete teardown.
If you removed the pistons, you'll need to replace the circlips that hold them on. If you can put the rings back like they were, i.e. same grooves on the same pistons on the same cylinders, you're OK.
There is an anaerobic sealant that is used on the crankcase halves after they are cleaned.
6 mm crankcase: 69 INCH-pounds,
8 mm crankcase: 22 FOOT-pounds
cylinder base nuts: 25 FOOT-pounds
cylinder head nuts: 22 FOOT-pounds
Go to your local auto parts store and buy a box-end crow's foot socket to torque the cylinder base nuts. You may have to grind the socket to get it on some nuts.
The wear ring can get water under it, which causes corrosion. Corrosion forces the ring into contact with the impeller. If it's not too bad, you could just run it for a while. However, it will wear down the impeller. I don't think the wear rings can be replaced on the Kawasakis. You may be able to buy a replacement pump housing that has a replaceable wear ring. Some have a stainless wear ring, some use plastic.
If it were mine, I'd leave the oil pump on and just replace the hoses. The pumps don't fail, the hoses do. Good idea to remove the crankcase drain--unless you plan to run the hose with the engine off again!
03-09-2014, 11:55 AM #3
Welcome to the site, and the PWC addiction!
As I am sure you know, water in an engine is bad. It can / will cause rust and corrosion in a short time. "IF" it was only in there for a few hours like you say, I am sure you will be fine.
To answer your questions as best I can;
1) - no, like stated above you are probably OK. MAKE sure all bearings have no sign of rust, and roll smooth.
2) - again, probably not. It would not be a bad idea to replace the rings as technically you are not supposed to re-use rings once they have been removed from the cyl bore.
3) - be sure to use a specific "crank case sealer". We sell / prefer three bond 1211. There is a torque spec on the cases. I always strongly suggest getting a hop manual for your machine so you will have all needed procedures, and specs.
4) - there is a special tool called a crows foot for this purpose.
5) - again hard to say without seeing. Your wear ring may be swollen a little. Is this a salt water ski? A lot of times, it is just a little sand / dirt / grit in there that will make a little noise when you turn the shaft. I see this A LOT.
Hope this helps. On a side note, I have everything here you would need. Gaskets, crank seals, 1211 case sealer, rings, and even a shop manual.
Feel free to call the shop 608-743-1305 if I can help.
03-10-2014, 06:53 AM #4
Thanks for all the information guys. Steve, I appreciate the torque specs. Ill be getting a shop manual but haven't made it quite that far yet. The impeller is only glancing on one blade during a 360 degree spin. Its just enough to add a little resistance but can still be turned by hand, you guys think this will be alright for the season?
John, the bearings have no rust at all and roll freely. I will be ordering a gasket kit new rings and probably have the cylinders honed. I realize I probably didn't need to tear it down completely but being I knew nothing of the history of the ski I'm glad I did. I found the carbs were not even bolted down. All it took was a little wiggling and they popped off the gasket. Someone must have removed them and forgot to put the bolts back in? Anyhow, thanks for the pointers, maybe ill leave the oil injection on there. Should have it back together soon and ready for summer!
03-10-2014, 06:59 AM #5
If you hone the cylinders, you should definitely install new rings and break the engine in again.
Does it have the stock flame arrestor? The screws that hold the carbs on go through the flame arrestor, then through the carbs and into the manifold.
03-10-2014, 08:00 AM #6
Woops good call. Yes it did have the stock flame arrestor. I should have payed more attention when I was removing it. Those long bolts also secure the carbs (I'm an idiot). I don't know which ring goes where now. I was very meticulous when removing all nuts/bolts by labeling them and putting them in bags. But I unfortunatley didn't mark the rings so I definitely need to replace them and might as well hone the cylinder. What's required during break it, no bouncing off the limiter for the first few hours? Also, what is required when aligning the engine on install? How do I make sure the crank is perfectly inline with the impeller shaft? Thanks.
03-10-2014, 09:00 AM #7
Hello Th3VVay, to solve your torque problem purchase a digital torque adapter. They run about $40.00 on line. They attach to your socket or socket extender in your case and will allow for you to torque your nut/bolt. You will never use your plane torque wrench again. As to your engine questions .... great idea to break down case and check everything out. From your description, you will be able to clean everything up and reassemble the engine. I think IMO you got the problem before it could do any real damage. Replace the head gaskets. Good luck & Welcome to the hulk.
03-10-2014, 09:56 AM #8
Also the pistons have std stamped on them, I assume that means standard bore? Want to make sure I get the correct rings. What is the stock bore btw, I can measure the piston with my calipers to be sure?
03-10-2014, 01:57 PM #9
04-08-2014, 08:36 PM #10
Thanks for all the info guys. Got the ski back together today and motor installed. Cranked it over a few times before the battery died so I didn't get to hear it run ): I do have one more question though. When I pulled the motor I left the carb attached to the fuel and oil lines in the hull. Most of the oil from the oil injection line drained out somehow and collected in the bottom of the empty hull. If I just turn the engine over a bunch of times with the plugs out will this replenish the oil in the lines? I don't want to start it up on straight gasoline until the oil injection pump fills the oil line. The lines are clear so I can see there is nothing in them.
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