[Rotax6615]

while riding the trails the other day my mach dropped down to 2 cylinders with a few backfires... compression test shows 150psi left cylinder 50 psi center cylinder and 150psi right cylinder...... hoping its just replaces rings and go, i noticed oil leaking at the front of the engine where the jugs bolt to the crank case.. is it possible im loosing compression there?

 

[smallengineguy]

It probably leaned out due to a dirty carb, etc. The "oil" you see is the unburnt fuel/oil seeping out because compression is too low to burn it. You'll probably need to hone the cylinder as well as get a top end gasket set for it. Pull it apart first and see what you're up against.

 

[Rotax6615]

pulled the head its ok...looks like a ring went.. scored the cylinder so i guess im doing a top end in it.. worried about any metal chunks from the ring going down into the crank how do u check that?

connor.

 

[smallengineguy]

When you remove the piston/cylinder, spray that side all down with carb cleaner and get a long magnet and stick it down into the crankcase and get the metal out. Compressed air will help with that also.

 

[BskidooC]

Your going to be S.O.l. on the aluminum off the cylinders but there probly isnt enough to worry about anyway. You can always split the cases and go through the bottom end. Your call.

 

[Rotax6615]

want to be sure so the bottom end dosnt let go after i put new cylinders and stuff...only one piston and cylinder is wrecked could i get away just replacing the center jug and piston?

 

[snowgoforever]

How many miles on the sled? If a few thousand or more, might as well do the whole top end. Unless you want to tare it down two more times in the next 1,000 miles.

 

[Rotax6615]

the sled has about 8000kms on it it was a new top end about 3 years ago.

 

[BskidooC]

Great compression on the other two. Unless theres something that you can visibly see wrong with the cylinders I would run them. Replace the rings just for the hell of it if the pistons are good. Rings are cheap and easy to replace....might as well.

 

[Rotax6615]

thats what i was thinking,.... what pistons do you guys recommend? ski-doo pistons are 200 per with rings.. weiscos are like 70 with rings and wristpins.. dont want to do this again anytime soon should i go with ski-doo? extra money but factory stuff

 

[Rotax6615]

ok, pulled jugs, went to remove the pistons (center first) got the one retainer clip out of the piston that holds the wrist pin in place went to remove the other clip from the other side and its MISSING! check the cylinder and sure as funn part of it is in bedded into the cylinder wall, so i guess the rest of the clip is in the crank some where! fml!! i guess im splitting the case, is there a "how to" on that? thinking i might take it to bondis engines.