01 GTX RFI Dropped Cylinder

[Flysooner9]

Was riding my 01 GTX RFI this morning. Has been having an issue of fouling the rear spark plug after running strong for 45 min or so. Recently rebuilt the fuel injectors and replaced the rectifier to fix the 12V low problem it also had. So this morning similar deal. Ran greet for about 45 min then began to cut out a little and lose power. Although this time it died and would not restart.

beached it to throw in a fresh set of plugs to get back to the ramp since I figured they fouled again. Plugs werent fouled but i changed them Anyway. Still would not start. Motor cranks fine.

got home and did compression check. Rear cylinder that had the fouling issue had good compression but the front cylinder is toast, only about 30psi.

Long story to ask what would cause a cylinder to suddenly give up? Can it be related to it fouling the plugs previously? Haven’t opened it up yet to check for damage.

i figure the fact it cranks freely is a little bit of good news but I don’t want to jump in and change the cylinder and piston if it’s just going to happen again.

 

[mikidymac]

What did you do to “rebuild” the fuel injectors.
Typically it’s lack of fuel that ruins cylinders.

 

[Flysooner9]

What did you do to “rebuild” the fuel injectors.
Typically it’s lack of fuel that ruins cylinders.

rebuilt by fuel injector man.

 

[Flysooner9]

Pulled the piston. Any idea what would cause this? Don’t want it to happen again

 

[mikidymac]

Running lean like I said, either not enough fuel or oil or both.

 

[Flysooner9]

Running lean like I said, either not enough fuel or oil or both.

so this time around I’ll for sure replace the pump and filters. Anyway to ensure it’s getting enough oil?

 

[mikidymac]

Just make sure the oil pump is pumping and replace the small 3/32” oil lines from the pump to the intake.

 

[Flysooner9]

Just make sure the oil pump is pumping and replace the small 3/32” oil lines from the pump to the intake.

whats the best way to prime those lines if I change them? Also found my fuel filters were in horrible shape. Practically solid with sediment and crap. Surprised it even ran at all.

also can someone confirm that the GTX RFI doesn’t have an in line filter? Ski doesn’t have one and don’t see one in the shop manual diagram.

 

[mikidymac]

No inline.

Start the ski and let it idle while holding the oil pump lever wide open after you bleed the oil pump through the bleed screw.

 

[TxAg15]

That sucks man. I almost the EXACT same sequence of events happen on my 02 gtx rfi. Only when I took the cylinders off, found some scoring and lost a wrist pin bearing on the crank so I had to do a full rebuild.

I just primed the oil pump/oil lines by filling the supply hose with oil, then loosely fitting a 30mm socket over an extra plastic oil pump drive shaft I had laying around and driving it with a drill while holding the cable at WOT. Only took a minute or so before I saw little drops of oil coming out of the nozzles in the intake.