Hey guys! First post here since I just picked up my first Yamaha sled the other day. Got myself a 04 viper mountain 4300 miles and this things clean! Pretty rare sled where I live, at least I’ve never seen one in Maine. What’s everyone’s experience with these? Compression seems a little low 100-110-110 I’m thinking it’s either from from the mileage or the compression tester I used wasn’t very accurate. What’s everyone’s thoughts? I’m gonna try a different tester and see what I get. Anyways it runs real good I think it’s gonna be a fun sled! 
Vincent
New member
Those sleds have staggering domes in the head , so one will always be lower then the other two. Also if the sled has sat around for awhile the compression numbers will sometimes read low, t I'll you rack up some mileage on it and the rings reseat. Mine went from 110 to 125psi after the first 500 kms of riding
And yes, gauge to gauge numbers can vary, so well worth a try
And yes, gauge to gauge numbers can vary, so well worth a try
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just run it. the compression is a bit lower than usual but from the milage and age of the sled, it has sat quite a bit. once you start running it, it should be fine. i would pull and clean the power valves, repack the speedo bearing and check all the idler wheels/bearings so that you will have less issues during your riding season.
congrats on the sled and welcome to ty!
congrats on the sled and welcome to ty!
super1c
Super Moderator
Numbers are fine. X2 above! Run it.
Thanks everyone! I knew the number of the cylinder closest to the belt was supposed to be a little lower but they all seemed down there. Anyway I got a few cracks on the exhaust to fix and new carbides to install, along with a few other things then I can finally get to riding! (Once we get some real snow)
fullcoda
Member
Also from Maine, 2005 sx mountain viper. Great sleds. Lots of fun