Rotax 500, 600, 700, 800 Top End Installation

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Published 2021-01-01
This is the installation of a top end on the x93 series Rotax twin in Ski Doo snowmobiles. The head on the 793(800) is slightly different but specs and patterns are the same. I also discuss and explain base gasket thickness and its effects.

All Comments (21)
  • I always bolt the exhaust manigold to the cylinders and intall them as a pair. It keeps them true to each other. Also the base gasket should have a thin film of anerobic gasket sealer on both sides to alleviate the coolant eventually deterating the paper gasket. This is per Bombardier service manual. I was a service tech for Skidoo for 42 yrs......got in on the 2001 piston recall ,where I rebuilt 40-50 of these during that snow season in Montana.
  • @keitheberle5703
    excellent video,great explanation of base gasket effecting the port timing !
  • @doobyboy21
    I always use Wiseco circlips I can actually push them in with my fingers without the need of a flat head screwdriver ! They are the easiest ones to push in !
  • @Lehmerable
    You make that cylinder installation look so easy, I'm not sure why I'm having trouble getting the cylinder to slide past the first ring.
  • @runpuppyfpv5744
    I have one of the engines on my drakart it runs good but im sure its ready for a new top end any suggestions on a place to get the parts ?
  • @Letsgotojail
    Would this be the same as the 87 ski doo 503? I Have an old stratos thats only got 65 psi in the cylinders. Runs but wont move.
  • Just got my bass gasket and my old one did not have holes in the middle This new base gasket has 8 holes Does that matter ? It’s a double gasket 0.8 mm
  • Thanks for the video Mac, I learned a lot. Do you know if this engine has the nikasil coating in the cylinders or a good old fashioned cast iron sleeve? I have a 2002 Rotax 600 which I am guessing would be the same as yours and need to do a top end and possibly some cylinder work. Thanks, Jon
  • @kevinlyon7303
    Would the process in this video be the same process when i rebuild my 2008 Ski-doo Summit X 800R 154" RevXp? Or is it different?
  • @SWATT101
    Put red locktite on the exhaust bolts...the bottom ones are a bit of a pain to get at if they fall out
  • @swektmaico
    The oiled assembly has been replaced by dry assembly mostly these days. There will be oil coming with the gas.
  • I’ve replace this cylinder base gasket 2 times now and still wants to seep out? I’ve tighten in a kris cross patter at 21foot pound
  • What year is your motor? I have a 600 ho swap in my 800 but don’t know what year it is and I need a cylinder
  • @Joe-wy2bn
    Looks like a top end rebuild kit for my machine, the pistons are available in three different sizes. How do I choose? Thanks!
  • @beerman2for1
    i got a quick question for you Mac. Just got finished rebuilding the top end on my 2001 mxz 700 deglazed and freshened up the cylinders new pistons, rings and gasket kit. they are single ring pistons and my question is is there a top and bottom to the rings? i tried to start it and felt like no compression tore it back down and both rings are stuck in the ring lands im stumped. cylinders and pistons seem to be okay.