What are pistons trying to tell me

[boneyard]

So I picked up my first ski about a month ago. 98 SXi pro. Popped the head today for inspection. What are my pistons telling me ?

Ski seems to run good. Could use more power for sure. Compression came in at 125 both cylinders.

 

[smoofers]

Seems somewhat lean. I'd also look at a hone and new rings. Your compression should be at least 150.

 

[boneyard]

My plugs are black after an hour of riding. Never fouled a plug before. But maybe that's just for the long no wake zone.

Cleaned it up. All stock A cylinder and A pistons, so I'm hoping I can ring it and clean it up bring it back up to 150+

 

[boneyard]

 

[Yami-Rider]

Looks about right to me, a little on the lean side.

 

[boneyard]

Thanks.

 

[user_error]

those pistons look about perfect to me. bore it out .5mm, new pistons, and it should be ready to rip again

 

[boneyard]

Slapping it back together for a few more weekends. Then taking it to a guy for machine work and custom port job. Along with some other mod to gain that low end

 

[Roseand]

Slapping it back together for a few more weekends. Then taking it to a guy for machine work and custom port job. Along with some other mod to gain that low end

"Custom port job"? Hopefully it's someone that's done 750 cylinders and isn't just experimenting on yours. Make sure it's a reputable porter familiar with your setup.

 

[boneyard]

Very reputable. Kawasaki are his thing. But thanks for lookin out. He will be talking the whole motor. Putting a degree wheel on getting it done right. I hope haha.

What I really wanted was to swap a 800 cylinder on there. But they go for crazy money

 

[Proformance1]

Just remember if your gauge is reading 125, it may be your gauge. mine reads 135 at 180 confirmed. A gauge is a standard to test to, a reference point. If you had checked it last year and it was 150 and now its 125 you would have an argument for a rebuild. dont just spend money based on the reading. Now if it has 300 hrs make sure to rebuild the crank and all.

 

[veedubs]

The best thing you can do is get a Factory Limited Pipe for the ski. It will make a huge difference.


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[boneyard]

The best thing you can do is get a Factory Limited Pipe for the ski. It will make a huge difference.


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What do you think the R&D pipe ( snail pipe ) I can get one for 400

 

[veedubs]

It's okay. My buddy has one on his and it's all top end power. The Factory pipe adds power everywhere. Plus you can tune it. There was a brand new one on eBay for $600. Hold out for the Factory pipe and you won't be disappointed.


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[boneyard]

Any of you guys out their run a dried out stock exhaust

 

[jim_ii]

I have a '99 Pro with a dried out stock exhaust (extra pisser overboard from the head before the water goes into the pipe). It helped somewhat on the power but not a huge improvement.

On our '98 Pro we have a milled stock head and the Factory Pipe. Unbelievable power difference compared to the '99. The Factory Pipe is the way to go!

Feel free to PM me if you have other questions on the Pro's.

 

[FlightPlanDan]

Agree. Factory pipes rock.
But they don't fix compression issues.