grinding noise over 80?

insaneSXR

insaneSXR

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Joined
Oct 16, 2004
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Age
41
Location
Ontario, Canada
well i just put my sled back toghther and took it out for its first ride of the season. added 96 studs, dropped 1 tooth from the top gear added one tooth to the bottom gear, and changed all axle and jack shaft bearings. sled runs great through the trails now but the problem is that as soon as i get over 80km and let off the throttle i can hear a slight grinding noise untill the sled starts to slow down again. no noises at all in the trails its only when i get over 80. any thoughts?
sorry for the long winded explination
 
are you holdin in the brake? cuz when you hold in the brake it makes that noise... check your brake and see if its rubbing
 
your sled goes over 80kph???? damn i better check mine over then ..... lol just kidding ... make sure those studs aren't hittin anything ... then double check the sprocket alignment on the sled and make sure they are perfectly in line.... do this by chedcking the chain visually or pull the chain off and put a straight edge against the sprockets and make sure there is no gap. Then reset the chain tension.... if that isn't it, CAREFULLY run it on a stand and see if you can locate the noise that way.
 
insaneSXR said:
well i just put my sled back toghther and took it out for its first ride of the season. added 96 studs, dropped 1 tooth from the top gear added one tooth to the bottom gear, and changed all axle and jack shaft bearings. sled runs great through the trails now but the problem is that as soon as i get over 80km and let off the throttle i can hear a slight grinding noise untill the sled starts to slow down again. no noises at all in the trails its only when i get over 80. any thoughts?
sorry for the long winded explination
Click to expand...
track tension could be too loose.
 
well i brought it back into the garage and took it appart again. sprockets are lined up on a straight edge, chain tentioner is finger tight according to the manual, i have the track tightened so that it only sags about 3/4 of an inch and i couldent find any holes in the tunnel or the front heat exchanger. the studs are 1.075 the max that woodys recomends for my sled. so i put it all back together and took it out for another ride. same thing. let off the throttle at anything over 80 and hear the grinding. do you think there would be any problem with the larger bottom sprocket?
thanks
 
I overlooked an idler wheel bearing that was doing the exact same thing. Mine was tight, no play, but it would howl/grind when I let the throttle off at 70km.
 
are you sure that you got everything correctly lined up in the chaincase when you put it all back together? Big spacer on behind top gear, small spacer behind bottom gear. The shouldered side of the bottom gear goes towards the driveshaft. Alignment is very important. See if there are a lot of shavings on your chaincase dipstick, that would be a sure sign something isn't right in there.
 
nope the dip stick comes out clean. i guess ill have to pull the suspention again this weekend and channge the bearings. hey greg how did you figure out what bearing was bad? or did you just change them all?
 
insaneSXR said:
nope the dip stick comes out clean. i guess ill have to pull the suspention again this weekend and channge the bearings. hey greg how did you figure out what bearing was bad? or did you just change them all?
Click to expand...
just spin them by hand. if they feel rough, turn real hard or turn really easy they are shot.
 
insaneSXR said:
nope the dip stick comes out clean. i guess ill have to pull the suspention again this weekend and channge the bearings. hey greg how did you figure out what bearing was bad? or did you just change them all?
Click to expand...

I actually lifted the back up and ran it at 40mph and used a mechanics stethoscope; I put the tip on each bolt head and I could hear it crystal clear.

You can get the stethoscopes at auto supply places for around $10.00.
 
thanks the princess auto book is like the bible at work. im going to have to bring the sled back into the garage this weekend. i hope santa delivers to garages. lol
 
well i found the problem last night. wasent a bearing problem at all. it was a bearing installer stupidity problem. when i put the peices that hold the clutch side jackshaft bearing back toghther i put the bolts in backwards. which is why it would only grind over 80. because thats when the secondary would shift out far enough to hit the bolts.DAMIT!!! now if you excuse me im going to go stick my head in the sand
 
think of those bolts as an 80 KMPH governor.....



I've often wondered if those bolts would be ok with nuts to the clutch side. The nuts are a pain to hang on to when removing (if you don't take off the airbox first)...

I won't try it...

glad you found the noise..
 
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