Snowmobile World banner

1 - 7 of 7 Posts

·
Registered
Joined
·
374 Posts
Discussion Starter #1
Background information:  I picked up a '92 ski-doo formula plus x and put about 50 miles on it before it melted a piston (mag side).  I had the cylinder bored .010 over and used a new oem piston.  I pulled the carbs and they were fairly dirty so I cleaned them.  Jetting is stock.

I put it all back together and had it running.  Let it warm up good, rode it around the house twice and let it cool down.  Fired it up again and let it warm up good.  Rode it down to the lake and rode about 100 yards on the lake before it siezed.  I never exceeded ~35mph and rode less than a mile.

I pulled the head to reveal a nice vertical gouge right where the pin that aligns the ring rides.  There are a couple other areas where the piston lightly scraped the cylinder.  In its current position, I can slightly turn the crank so that the mag side piston will slide upward slightly but it won't really move.  It looks like the ring end-gap was set properly.

I could be wrong but I can see a gap in the other ring and cannot see the gap in the ring on the new piston.   Should I suggest to the dealer that he is responsible for the damage?

My other question is how do I remove the cylinder and piston from the engine.  The piston is siezed in the cylinder where I can't get to the wristpin.  Should I just pound the piston out with a peice of wood?

I snapped some pictures but they didn't turn out good.  When I pulled the plugs the PTO side (no problems with this side so far) was tan, the MAG side plug was charcoal.
 

·
Registered
Joined
·
42 Posts
Yes you can use a piece of wood and a mallet to get the piston out, a little oil probably would help it out also.  As far as the dealer responsibility is concerned, I have no idea if they would be responsible, unless they did the work, or gave you the wrong part.  I'm not really sure though.  Good luck.
 

·
Registered
Joined
·
374 Posts
Discussion Starter #3
I forgot to elaborate on the dealer portion.  I had the dealer bore the cylinder .010 and asked him specifically to check the ring-end gap.

It would be helpful if I had the pictures but my digital camera was acting up.  Apparently not all of the pictures I took were saved.  Stay away from the Kodak cameras, nothing but problems.  It takes good pictures, when it decides to turn on.
 

·
Registered
Joined
·
119 Posts
</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (JETRep @ Jan. 27 2002, 8:40pm)</td></tr><tr><td id="QUOTE">I put it all back together and had it running.  [/b][/quote]
Let me get this straight... You put it back together and now want to blame the dealer?
?
 

·
Registered
Joined
·
791 Posts
The way the first story sounds like you put it back together.  But when you put the rings in did you get them in the right place top ring lower ring there is a difference.  And did you use the pins in the pistons to keep the rings from turning or did you accidentaly push the pins in not knowing what there for .  The pin is probably pushed in holding the ring out on the end of the gap which worn and gouged the cylinder.
 

·
Registered
Joined
·
448 Posts
As with others, we don't know who rebuilt it.  My question, is the piston in the right way?  Arrow pointing forward?
 

·
Registered
Joined
·
374 Posts
Discussion Starter #7
Yes, the arrow was pointing outward.  I did the rebuild but the dealer did the boring.  I no longer believe he is at fault, however.  I think the cause of the seizure was not due to the carb itself unless I somehow missed a clog when cleaning them.  The reason I originally thought the dealer may be at fault was because I couldn't see the gap in the ring when it was in the cylinder while I could plainly see the gap in the good cylinder.  This time it seized up really good (last time it wasn't seized, just melted the piston).  I don't think it was simply jetted too lean on top because this seizure occurred when I was going no faster than 35mph, I was barely on the gas.

So I guess I need to look at fuel lines, filters, etc.  Is it possible that the brief wide-open run could have simply 'blown-out' the MAG side seal?  I don't have a compression or leak-down tester so I could test the cylinder after rebuilding it.  Looks like a compression tester will be my next purchase.
 
1 - 7 of 7 Posts
Top