Yeti belt sliding off the sprockets AND tensioner wheel

coryf89 · Feb 1, 2019

what happened with my set up today? rode for an hour nicely and coming back on the trail I could hear a "bzzzttttttt" sound. turns out the belt tried coming off of the sprockets, almost chewed through my 4th clear plastic cover, and also seems to be popped off the tensioner roller too. did the belt stretch or did I not have the tension set tight enough?

2017 yeti 129 with the 28mm belt kit.

coryf89 · Feb 1, 2019

byeatts · Feb 1, 2019

coryf89 said:
what happened with my set up today? rode for an hour nicely and coming back on the trail I could hear a "bzzzttttttt" sound. turns out the belt tried coming off of the sprockets, almost chewed through my 4th clear plastic cover, and also seems to be popped off the tensioner roller too. did the belt stretch or did I not have the tension set tight enough?

2017 yeti 129 with the 28mm belt kit.

There is a upgrade with a floating jackshaft bearing modification available to align the belt pulleys, Go to Yeti dealer they are the only ones who have the alignment tool. unless ewer belt was wore out. thats also assuming ewe have everything tensioned properly and in perfect condition.

coryf89 · Feb 1, 2019

pretty sure everything is damn near perfect and this is a next to new belt that ive got on. closest dealer is over an hour away. I will call tomorrow and see if they can perform that sort of alignment.

bighuckpunk · Feb 1, 2019

On my first ride the nut backed off the tensioner pulley bearings. It didn’t come loose but was about 10ft/lbs off.
How many hours on your rig?
Did you wear out a bearing?
Is the nut and both pulley bolts tight?
Did the bearing holder bolts come loose?
If you have an alignment problem you can check with a 12” ruler across both pulleys, they should be perfectly aligned. If you do need the new bearing/holder, that is a service bulletin situation and I think the labor/parts/belt is free of charge.

chumbilly1 · Feb 2, 2019

Im thinking bearing failure. You have been posting/riding kit for a while right? If alignment was off it would have been a problem a long time ago. Just saying.

tillbuilt · Feb 2, 2019

If you have had a few seasons of trouble free belt life, something has failed. Check: bearings, and tunnel damage from impact. Your jack and drive shafts are out of alignment causing the belt to walk off. If you have it aligned, it will walk off again, unless you find the actual component that has failed.

coryf89 · Feb 2, 2019

Should this tensioner roller shaft be able to go in and out 1/4”?

58 hours on this kit. Original bearings. Bearings seem fine.

My tensioner roller nut was a tad loose and one Allen head screw seems to popped out. Tightened everything. New belt. Gonna try again today.

coryf89 · Feb 2, 2019

byeatts · Feb 2, 2019

coryf89 said:

obviously assure bearings and everything is in good condition, The problem with carbon is as they lay up the tunnel no two are exact. We have seen a few that were on the edge as far as alignment and with any normal wear they now walk the belt. Your Yeti dealer can install alignment jig and see whats happening,You failed to provide the hrs on that kit and belt replacement intervals? also check axle for any deflection ,,All Yetis now come with the floating bearing.

coryf89 · Feb 2, 2019

58 hours I said in the last post. Belt replacement is averaging 10-15 hours before it breaks due to something coming loose.

What’s the trick to taking this piece off?

And should this shaft between the wheels be different spacing on each end on the hex part?

I think the problem was just the tensioner bolt coming a little loose.

coryf89 · Feb 2, 2019

the bearings seem to roll smoothly and theres no up and down play that I can feel in them. I will check alignment shortly here and report back.

byeatts · Feb 2, 2019

coryf89 said:
58 hours I said in the last post. Belt replacement is averaging 10-15 hours before it breaks due to something coming loose.

What’s the trick to taking this piece off?

And should this shaft between the wheels be different spacing on each end on the hex part?

I think the problem was just the tensioner bolt coming a little loose.

You have an alignment issue. The belt should look new at 58 hrs. The tensioning bolt has a lock nut to prevent backing off, I assume it was tightened?

coryf89 · Feb 2, 2019

wow, ive been through 4 belts. all from different issues though. its getting expensive at $100+ per belt.

yes the tensioner nut was tightened. maybe not enough I guess... weird as I tend to tighten stuff too much if anything. it wasnt loose and about to pop off to the point where the tensioner could wobble in and out though. was still "tight" but only enough that a 2 year old could of loosened it with the ratchet.

once I smashed against a rock so hard I damaged the lower sprocket and destroyed that black housing as well as the clear cover... dented and bent sprocket caused a belt to die.

once the lower sprocket randomly came loose, caused a belt to die.

I cant remember the other one.

now this issue. I will check alignment with a straightedge and then call the dealer and see what they can do for me, if anything. im pretty sure the dealer 1 hour away wont be able to help, they couldnt last year... just middle man parts really. the next competent one is 2.5 hours away. great.

the tensioner roller nut coming fairly loose wouldnt of caused this eh? going to use blue loctite on them all next time thats for sure.

will keep you guys updated.

thanks.

tillbuilt · Feb 2, 2019

coryf89 said:
58 hours I said in the last post. Belt replacement is averaging 10-15 hours before it breaks due to something coming loose.

What’s the trick to taking this piece off?

And should this shaft between the wheels be different spacing on each end on the hex part?

I think the problem was just the tensioner bolt coming a little loose.

You need the Yeti pullers to remove the Jack and Drive shafts. Watch the Yeti YouTube videos for instructions on how to pull the shafts.

Your drivers on the axle shaft are definitely out of place just by looking you can tell that one driver on the left side is over about a quarter inch out of spec. There are measurements for the drivers I can email them to you if you’d like.

I have never seen a tensioner lock nut come loose on a Yeti. It was either not torqued to 45 ft pounds correctly or it’s been on and off so much that the lock of the nut is worn out and needs to be replaced.

Sent from my iPhone using Tapatalk

coryf89 · Feb 2, 2019

not to remove the shafts just to remove that plastic piece so I can see whats going on behind it and why the tensioner stud is able to rock in and out a significant amount.

what causes them to come out of alignment like that and whats the fix for it? I imagine itll make sense if I seen it all taken apart.

I watched that video, seems like not much isnt happening without that special tool. even then, I cant align it myself without the tool can I? seems like it needs to go to a dealer and that doesnt sound cheap, especially after a $2200 motor rebuild!

I will PM you. thanks.

byeatts · Feb 2, 2019

coryf89 said:
not to remove the shafts just to remove that plastic piece so I can see whats going on behind it and why the tensioner stud is able to rock in and out a significant amount.

what causes them to come out of alignment like that and whats the fix for it? I imagine itll make sense if I seen it all taken apart.

I watched that video, seems like not much isnt happening without that special tool. even then, I cant align it myself without the tool can I? seems like it needs to go to a dealer and that doesnt sound cheap, especially after a $2200 motor rebuild!

I will PM you. thanks.

Ewe differently tossed in some more info. Assuming everything was perfect and belts are not lasting then its likely an alignment issue. hitting rocks or loose bolts, over tension the belt or too loose will all cause issues . and has nothing to do with alignment, When everything is perfect and belt runs true they will show little if any wear at 58 hrs.Put it back together and run on stand and see if belt runs even of both gears or if its trying to walk.

coryf89 · Feb 2, 2019

ok, something definitely isnt lined up. I put a new belt on, tightened everything, made the tensioner pretty tight. could barely flex the belt the width of that red thing with both thumbs. it walked off within 80 seconds of idiling on the stand, started shredding my brand new belt already damnit.

whats the exact way to diagnose this at home and what is the correction for it other than to stick a straight edge between both gears? or is this strictly a dealer only fix?

also, check out this video... does it seem super rattly and like it vibrates and clatters a lot at idle/low rpm? when I gave it some gas it seemed to straighten out and not be so loud, but at idle, with track off the ground it sure sounded rough. also is kind of hard to spin the track when its off the ground... I thought it would freewheel a lot smoother thats for sure. is that normal?

https://youtu.be/EZhHXwU3IG4

bighuckpunk · Feb 3, 2019

You can lay a straight edge against the flat sides of the two gears for inspection. This will prove if you are out of alignment but it won't tell you if you are in perfect in alignment. You need the tool for that.
And again, this my be a free repair due to the service bulletin about the gear alignment issue.
In your vid it looks like the belt is hanging off the side of the lower pulley, the belts should line up exactly the same with the edges of the pulleys.
You got this!

coryf89 · Feb 3, 2019

bighuckpunk said:
You can lay a straight edge against the flat sides of the two gears for inspection. This will prove if you are out of alignment but it won't tell you if you are in perfect in alignment. You need the tool for that.
And again, this my be a free repair due to the service bulletin about the gear alignment issue.
In your vid it looks like the belt is hanging off the side of the lower pulley, the belts should line up exactly the same with the edges of the pulleys.
You got this!

thanks man!

I cant find this service bulletin anywhere.. can you point me in the right direction please?

I got the specs on what they driver shaft distances should be. going to tinker with it tonight.

just curious... why do I need that tool to press the shaft out....wouldnt a hammer with a piece of wood do the same? or is the carbon fibre setup something you dont wanna be banging on with a hammer?

you guys say to replace bearings every so often, like every year, as if its a super easy task... but that also seems like you need that press tool to pop the bearings off. do you all own that tool or am I missing something here?

Yeti belt sliding off the sprockets AND tensioner wheel

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