I bought an '04 Trail. It has the 550F in it. (BTW- The 550F is a 544cc Liberty engine.)
Anyway - I did much research before buying it. All the negative reports are dizzying. If you look for the updates on the engine, you can tell if it has had the recalls done on it. If it has the updates, ask if it has been rebuilt. If it's been rebuilt, AND has the updates, you may want to take a chance like I did.
Mine had about 700 miles on the rebuild when I bought it (almost 6k on the speedo, rental sled...). I put about 1000 miles on it last season. I have been careful with the jetting, and have watched the top end VERY closely. The piston wash indicates I am running it rich still... better safe than sorry. You're not going to win any races with the 550F, but it's been uber-reliable for me so far. Never had overheating issues either, even on 35 degree (F) days.
2004 Polaris Trail RMK 136
1997 Ski Doo Summit 500
2000 Arctic Cat ZL550 ESR (in NY)
2000 Arctic Cat 440 Panther (sold)
1980 Arctic Cat Jag 3000 F/C (in NY)
"If it ain't broke, take it apart and find out why!"
Last edited by rgoers; 12-05-2011 at 03:06 PM.