The hyfax is the long nylon (plastic) bars that run along the bottom of the rear suspension. The metal clips in the windows of your track run on the hyfax. If they are worn thin, of you can see the rail through the bottom of them, then you need to replace them. They are usually around $10 each. You may be able to slide them out through a window in the track, if not, you will need to remove the rear suspension (skid) and change them that way. Or, bring it to a shop and have them do it... if you remove the skid you will need to readjust the track tension, and that is a whole new thread.
melt all the snow out of it first (heated shop) and then take it for a run, might just be the trake hitting ice build up
and check all the above also
you can lift the ass end and turn the track to also see were it is coming from
A forum community dedicated to snowmobile owners and enthusiasts. Come join the discussion about performance, racing, troubleshooting, trails, maintenance, riding tips, modifications, classifieds, gear, and more!