Hi all, picked up a used 800 EX, and got a replacement OEM belt as a spare, but I have no idea how hard the previous owners were on it. It appears that there is a min mm of service for the belt, but after searching the internet and these forums I can't seem to find it anywhere.

Can anyone tell me the minimum mm the belt can be at before needing to be replaced? And if it's jerky to start/sides of belt look shiny, it's time to replace it as well?

I don't know if this applies to the 2021 ZForce 800EX, but on my 2023 ZForce 800 the minimum belt width shown in the service manual is 33.5mm. The Belt is equivalent to an Ultimax UA485, so you might find the specs on it to see what the original width is and how much wear is permitted before replacement is needed.

As for the jerky starts and shiny belt, I can relate.  On my last trip out my GF put mine in a ditch and tried to power her way out, generating some belt smoke before I could stop her. Since then mine has been jerky on starts.  I haven't examined the belt or replaced it yet though.  I did have it dealer serviced after that trip and they didn't mention anything about belt wear or possible replacement, although they found a few other minor items to fix.  From what I've found, in many cases the wear on the belt from abuse like this often diminishes with a bit more use and wear.  I'm going to let mine go for at least one other week long UTV trip and see how it goes.  If it doesn't improve a bit I'll probably replace my belt.

[2015 Z Force 800 53/Trail EPS]

I don't know if this applies to the 2021 ZForce 800EX, but on my 2023 ZForce 800 the minimum belt width shown in the service manual is 33.5mm. The Belt is equivalent to an Ultimax UA485, so you might find the specs on it to see what the original width is and how much wear is permitted before replacement is needed.

As for the jerky starts and shiny belt, I can relate.  On my last trip out my GF put mine in a ditch and tried to power her way out, generating some belt smoke before I could stop her. Since then mine has been jerky on starts.  I haven't examined the belt or replaced it yet though.  I did have it dealer serviced after that trip and they didn't mention anything about belt wear or possible replacement, although they found a few other minor items to fix.  From what I've found, in many cases the wear on the belt from abuse like this often diminishes with a bit more use and wear.  I'm going to let mine go for at least one other week long UTV trip and see how it goes.  If it doesn't improve a bit I'll probably replace my belt.

Smoking the belt ensures it's now not only glazed and has burned compounds, but will start coming apart right at the worst time. Do yourself a favor and change it before the trip and use the old one as a spare after scotch-briting the glazed areas.

Smoking the belt ensures it's now not only glazed and has burned compounds, but will start coming apart right at the worst time. Do yourself a favor and change it before the trip and use the old one as a spare after scotch-briting the glazed areas.

That's the plan.  Have the new belt in hand and just waiting on the arrival of some of the additional tools needed.  Doesn't look like it's a "fix by the side of the trail" sort of repair though, so I'm not sure just how useful having a spare belt handy can be.  I thought about roughing up the old belt surface and also wonder how useful belt dressing might be.  I use it on the V-belt drive on my tiller with good results.  I remember my Dad used bees wax on the drive belts on his sawmill to keep them from slipping.

[2015 Z Force 800 53/Trail EPS]

Smoking the belt ensures it's now not only glazed and has burned compounds, but will start coming apart right at the worst time. Do yourself a favor and change it before the trip and use the old one as a spare after scotch-briting the glazed areas.

That's the plan.  Have the new belt in hand and just waiting on the arrival of some of the additional tools needed.  Doesn't look like it's a "fix by the side of the trail" sort of repair though, so I'm not sure just how useful having a spare belt handy can be.  I thought about roughing up the old belt surface and also wonder how useful belt dressing might be.  I use it on the V-belt drive on my tiller with good results.  I remember my Dad used bees wax on the drive belts on his sawmill to keep them from slipping.

Put nothing on a CVT drive belt. Pulleys are not fixed like standard v-belt pulleys. You can clear some of the glaze but the burned rubber runs deep and flexing it cracks it into pieces in time. No, I sure wouldn't want to do a trail-side belt change on one of these...and I'm sure my wife wouldn't be amused either. Better to take a tow strap and be pulled back in. I keep a 15-footer under my seat.

No, I sure wouldn't want to do a trail-side belt change on one of these...and I'm sure my wife wouldn't be amused either. Better to take a tow strap and be pulled back in. I keep a 15-footer under my seat.

Good to know but it kind of negates keeping the old belt as a spare.  If I should replace the existing belt and not try putting any more trail time on it keeping it back in the shop as a spare, then when or why would the spare ever get used?  LOL  Seems a bit like carrying around a flat spare tire - just in case it might be needed on the road.

Life without a little bit of risk is boring.  Luckily the guy I off-road with carries a tow strap - I carry the air pump and cooler full of drinks.

[2015 Z Force 800 53/Trail EPS]

Carrying a burned belt for a spare is also a bit crazy...lol. As much PITA as it is to change one on these it better be a good one.

Carrying a burned belt for a spare is also a bit crazy...lol. As much PITA as it is to change one on these it better be a good one.

That's my thinking as well!  I popped the cover off to examine my belt - one bolt is a bit of a bear to get to!  All I saw on the belt was a small area about 1-1/2 to 2" long that had a bit of a shine to it - nothing really bad.  I scuffed it up a bit and put everything back together.  We'll see how it does on the next trip out, and/or if my GF shines up the rest of the belt with her "more power Scotty" style of driving.

[2015 Z Force 800 53/Trail EPS]

Carrying a burned belt for a spare is also a bit crazy...lol. As much PITA as it is to change one on these it better be a good one.

That's my thinking as well!  I popped the cover off to examine my belt - one bolt is a bit of a bear to get to!  All I saw on the belt was a small area about 1-1/2 to 2" long that had a bit of a shine to it - nothing really bad.  I scuffed it up a bit and put everything back together.  We'll see how it does on the next trip out, and/or if my GF shines up the rest of the belt with her "more power Scotty" style of driving.

I don't know if this applies to the 2021 ZForce 800EX, but on my 2023 ZForce 800 the minimum belt width shown in the service manual is 33.5mm. The Belt is equivalent to an Ultimax UA485, so you might find the specs on it to see what the original width is and how much wear is permitted before replacement is needed.

As for the jerky starts and shiny belt, I can relate.  On my last trip out my GF put mine in a ditch and tried to power her way out, generating some belt smoke before I could stop her. Since then mine has been jerky on starts.  I haven't examined the belt or replaced it yet though.  I did have it dealer serviced after that trip and they didn't mention anything about belt wear or possible replacement, although they found a few other minor items to fix.  From what I've found, in many cases the wear on the belt from abuse like this often diminishes with a bit more use and wear.  I'm going to let mine go for at least one other week long UTV trip and see how it goes.  If it doesn't improve a bit I'll probably replace my belt.

Smoking the belt ensures it's now not only glazed and has burned compounds, but will start coming apart right at the worst time. Do yourself a favor and change it before the trip and use the old one as a spare after scotch-briting the glazed areas.

Have you noticed a new vibration?  On a snowmobile, smoking the belt will often give it an "hour glass" where the primary sheave closed and slipped on the belt.  The hour glass will cause vibration and is tough on the sheaves.  When you have the original belt in hand, pull it between your thumb and index finger. If it is hour glass'd, don't even keep it for a spare.