1997 583 Rebuild - seeking advice - Snowmobile Forum: Your #1 Snowmobile Forum

Rookie 51 · 02-09-2013, 01:02 AM

Well after a few issues I seem to have a problem with 1997 Formula Z 583. When I bought it a few weeks ago, the compression was 120+ each side and now I just checked and PTO is 120+ and the Mag is 30

. I am going to retest tomorrow and tear into it and I wonder how far should I go (realizing I am not sure what is wrong).

Since I am going to take it apart how far would should I go with replacing things (pistons etc), should i just plan on a new top end on both sides or ??

mikemalibu · 02-09-2013, 01:42 AM

I think the best thing to do is tear it apart and find out what failed and WHY it failed. Nothing worse than putting the engine together only to have it burn down again 20 miles from nowere.

**RJ Gleason** · 02-09-2013, 07:26 AM

Three options as to why if burned the mag side.
1. clogged carb made it run lean
2. an air leak, either the crank seal or the carb flange
3. coolant in the cylinder.

Even the position of the damage to the piston can help to tell what caused it.

Rookie 51 · 02-09-2013, 08:09 AM

Thanks for the tips! I will likely be back with pictures in the next few days.

g1teg · 02-10-2013, 10:37 AM

I just recently bought the same sled, and my Mag side was at 30. I pulled the top end off and found that the ring had snapped, leaving a piece of it slamming around inside the chamber.

I replaced my pistons and overbored 0.20. Was all very easy (assuming you have a trustworthy shop for the boring). Very fun now that its running!

Rookie 51 · 02-10-2013, 11:05 AM

Well I got the top end apart yesterday, before I even turned a bolt I started to get some leads as to WHY (oil in antifreeze jug). Then after getting the top end apart there was some definate scoring along the walls on the mag side, so the decision has been made that i am going to replace pistions and go 0.10 or 0.20 over (depending on what deals I find on parts).

Here is the question - what could cause this? I have read that the ususal cause is Rotary Valave seals. Any ideas, tips or tricks on cause or replacing the rotary valave seals?

**RJ Gleason** · 02-10-2013, 03:44 PM

Rotary valve seal or bad O-ring will allow coolant into the cylinder.
Considering the age of the engine, I'd replace every seal just to be safe.

Rookie 51 · 02-10-2013, 06:08 PM

Thanks RJ, that is what I was thinking. I was trying to avoid splitting the crank case but the more I read it seems the best thing to do.

Rookie 51 · 03-09-2013, 09:13 AM

Just wanted to say thanks to all who replied and help me through (directly and indirectly) my mid season rebuild. I still have some minor idle issues to work out but I have had a blast in my first 3 hours.