stuckoncape

what happened, i was riding on a trail at somewhat slow speeds, when i got a chance to goose it i took the oppurtunity, this turned out to be a mistake. after about a 1/4 mile the sled died and would not start. When i took the spark plugs out i noticed one plug was missing the small tab on the bottom of the plug, and the compression was very low in that cylinder. Any thoughts?

smallengineguy

Remove the head and you'll find out.

__________________
1992 Ski Doo Mach 1 (SC-10/2 suspended) March '07 SF.com Sled of the Month! (Lost in fire 4-7-13)
1992 Ski Doo Mach 1 original
2006 Ski Doo MXZ 500SS
1999 Ski Doo Grand Touring

Webmaster Evergreen Valley Snowmobile Club
SledNH.com Moderator

smokingcrater

do you really want confirmation of what you know is true? It broke off, then wedged between the piston and cylinder. Most likely your piston and cylinder are both toast now.

__________________
1) 2000 Arctic cat ZR 700, which now thinks it is a 2001 ZR 600 EFI APV w/136" ripsaw. (for sale!)
2) 1995 Yamaha VMAX 600, which now thinks it is a Polaris! (Polaris x10 suspension, Polaris P85 clutch) (for sale!)
3) 2004 Yamaha Warrior
4) 2006 Yamaha Nytro

joshkidner

well it either burned off, or you have a plug that protruedes further than it should. also test compression @WOT. you likely toasted your piston and cylinder

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1987 chasis with 1985 597cc under the hood. Xtra-10, fox shocks, and a whole lotta speed!

nunrleft

Burned a hole in your piston and it burned off the tip of the plug at the same time. Too lean; dirty carbs or bad crank seal most likely.

stuckoncape

if this is the case toasted cylinder and piston, what can be done, is the engine trash or is it fixable?

Josh Kidner

I would guess about 200-250 in fixing it. You will need a new jug (cylinder) piston, rings, gaskets, and possibly a head, but not likely. Take the head off and take couple good pics of down in there (make sure piston is in bottom position so we can see all the damage)

stuckoncape

Thanks for responding, I would love to take some pictures but my machine is 300 miles away in northern maine. I won't be back up there until mid february. I am glad that it is something that is fixable, I really like that machine.

smallengineguy

Minimal labor, which is good. I can have my 617 top end apart in less than an hour.

__________________
1992 Ski Doo Mach 1 (SC-10/2 suspended) March '07 SF.com Sled of the Month! (Lost in fire 4-7-13)
1992 Ski Doo Mach 1 original
2006 Ski Doo MXZ 500SS
1999 Ski Doo Grand Touring

Webmaster Evergreen Valley Snowmobile Club
SledNH.com Moderator