1994 Kawasaki JH750ss xi porpoising

[tragic]

hello all I just got this ski this season and dont know it's history but it is porpoising at high power setings anything over 4000rpm. I have turned the electric trim into a manual trim do to it did not work and have tried to set the trim at all different settings but it still porpoises. The only thing that does help is if it is full of gas and you lean way over the bars it can then go over 4000rpm but, if you hit a little wave it will start porpoising and will not stop till you slow down. Is this how all Kawasaki JH750ss xi ski are or is their somthing I can do to get it to stop porpoising?

 

[Jeff Walkowiak]

Re: Kawasaki JH750ss xi porpoising

Re: Kawasaki JH750ss xi porpoising

get the nozzle pointed down till it stops doing that.

 

[tragic]

Re: Kawasaki JH750ss xi porpoising

Re: Kawasaki JH750ss xi porpoising

thanks for the reply Jeff I have pointed it down and the nose still bobs up and down at fast speeds. Any other ideas ?

 

[Joe_the_boatman]

Re: Kawasaki JH750ss xi porpoising

Re: Kawasaki JH750ss xi porpoising

Mine doesn't do that (or at least I don't notice it). My trim is locked all the way up (i.e. - nose up). Any "cargo" up near the gas tank you could take out? Does it behave differently based on the level of gas?

 

[MikDee]

Re: Kawasaki JH750ss xi porpoising

Re: Kawasaki JH750ss xi porpoising

I had a 95' 750SSxi It did the same thing sometimes! It's an inherent characteristic, depending on distribution of the load, and different speeds, usually at WOT it flattened right out. I'm heavy, so I had to play with the trim alot, but it was the worst for me when fully trimmed out.

Be thankful thats your only problem, my 96' Yamaha Waveventure 1100 is like a bucking bronco in any kind of chop, the rougher it is, the worse it gets! It's nose heavy, and It'll pound you to death, get you soaked, and want to throw you off, unless you do no more then just enough speed to keep the nose up (about 20mph). The lake I ride on, is never calm either!

 

[tragic]

Re: Kawasaki JH750ss xi porpoising

Re: Kawasaki JH750ss xi porpoising

The ski acts best when full of gas and I lean over the bars to add weight to the front. I have tried to load the front of the ski with weigh but it will still "BUCK LIKE A BRONCO" when at 3/4 to full throttle and only gets worse as it gets faster. I am about 180 lbs and I have tryed all sorts of riding postions it starts porpoising sooner if I sit to the back of the ski. I have also trimmed the jet all the way down and it still bucked and also tyied it with the trim all the way up and could barely get it on plane but it still bucked on plane. I forgot to mention it is a 1994 kawasaki JH750 ss xi

JoeyPlumley I read in I boats forum that some people have shimmed their ride plates to make them more stable does yours have washers under it and is it the stock ride plate??

 

[Joe_the_boatman]

Re: Kawasaki JH750ss xi porpoising

Re: Kawasaki JH750ss xi porpoising

No washers underneath. Don't know if it's stock or not, here's a picture.

 

[tragic]

Re: 1994 Kawasaki JH750ss xi porpoising

thanks for the pics Joeyplumley that helps more than you think a pic is worth a thousand words. I compared your pic against my ski and it looks like my ride plate and yours are the same but mine looks like it might be bent if i put a ruler on it length wise or across it is dished in about a 1/8in. It also looks like your ride plate is lower in the front than mine. I am taking the ski to the water this weekend and I am going to try to shim it with washers to mach yours I will try to post results on monday.