piston got a hole blown through it - Snowmobile Forum: Your #1 Snowmobile Forum

gradd · 11-29-2006, 01:48 AM

i just bought a 98 arctic cat thundercat 1000 from my boss and once i got it i put new plugs and fuel filter and cleaned the carbs.so i took it out today and was out out for mabe 10 minutes and it lost all power and then died. it wouldent pull over so i went to the clutch and then turned it over but herd the piston grinding in the cylinder so we popped out the plugs and the middle plug had piston fragments all over it so i towed it home and when i took it apart the piston had a hole in it and the rings were pritty much welded to the piston. the other two pistons are fine and i was wanting to know what happend to the middle piston? and why it happend? the sled just got a $500 tune up, im thinking they dident do anything to the mechanicals they were supposed to go over the whole thing. there were no new plugs and the anti freeze was not topped up just new sliders and belt. anyhelp would be great! and where can i get stock pistons for a good price? and how much will it cost aprox for cylinder rehoning?
thanks Gregg

**smallengineguy** · 11-29-2006, 07:11 AM

It leaned out. Either it had the wrong spark plug, or it was sucking air. Check the boot that the carb mounts to for cracks. As far as the cylinder goes, if it's Nickasil plated, you'll need to send it out to get bored/recoated. If the cylinder looks OK, just replace the piston. Regardless you're going to completely take the engine apart to get all the junk out of it.

mmrosshere · 11-29-2006, 08:28 AM

when you tear it down be sure to check all the intake gasket surfaces as well as the boots for the carbs. make sure as SEG said you clean everything out completly. Anything left in the bottom will find it's way back to the top of the piston. ya wouldn't want to go though this more than once.