Thread: STXR Piston Carnage
01-11-2008, 02:21 PM #1
STXR Piston Carnage
These pics are from a 1200 sbt engine that was run for exactly 14 hours. All the oil lines are full and intact. When the eng was installed, the carbs were gone thru (they are all stock). No signs of it getting hot either. The mag and cent cyl have 120psi. The ski is a 04 STXR w/only 36 orig hrs. What yal think???
01-11-2008, 02:39 PM #2
I bet if you pull the carb from that cylinder you will find some garbage in there. That thing was leaning out and detonating for a long time.
Last edited by 800AMSOIL4U; 01-11-2008 at 02:41 PM.
01-11-2008, 04:08 PM #3
Looks like my ultra (which also had a SBT motor.) which run less than 20 hrs.
I agree, it was probably run lean.
However, mine was also missing a thrust washer on the crank???? Must have been a Friday?
01-11-2008, 05:00 PM #4
I vote lean. I bet the mechanical damage came as the piston was comming apart or mabe a pice of the ring. Do you happen to have aftermarket flame arrestors on it? Another place to look would be the carb base gaskets, and manifold gasket. You can have an air leak there and kill it.
01-11-2008, 06:19 PM #5
The carb is very clean. Carb and intake gask look fine.
It uses oem flame arrestor. Has a 165 main jet.
I wish I'd done a leak down test before I removed the cyl.
Can someone explain to me what the diaphram and needle on the back side of these carbs do. I'm not to familiar with these types of carbs kaw uses.
Last edited by JeffSki; 01-11-2008 at 06:44 PM.
01-11-2008, 06:23 PM #6
01-11-2008, 08:04 PM #7
Yea, for some reason, the PTO cylinder seems to go often on these engines.
I am in the process of having mine rebuilt at Sharp's Marine. I had to have the crank rebuilt, that cylinder honed, and a new piston.
I am also replacing the factory carbs because don't like the CV style carbs.
Here is my thread. It has been put on hold untill it warms up a bit.
01-11-2008, 08:46 PM #8
Last edited by btldigger; 01-11-2008 at 08:50 PM.
01-11-2008, 08:54 PM #9
Yea, I took that cap off, it's seated perfectly. What does that side of the carb do?
01-11-2008, 09:10 PM #10
There is a screw there under a cap. It adjusts the low speed circuit.
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