ARO Chaincase chain and tensioner wear after two years

Anyone else running their second season on an ARO? I've got between 750 and 900 miles on my 2018 snow check. I've completely wore out the factory chain and the tensioner roller. The factory sprockets look good to keep going.

Anyone else already replaced theirs? Or maybe you're on your 3rd set?
 

AK1000

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Oct 16, 2008
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Same 2018 Snowcheck ARO 137. A Lot of chain stretch(cheap chains) but rollers and sprockets all still good.
Chain lube every other ride, and lots of deep snow!
 
Nov 28, 2007
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TheARO primary chain slider setup is a total afterthought go to a 15 front sprocket and 18 on the secondary shaft flip the slider upside down and cut the whole back section beyond the frame cross tube off .
Grind the slider to a low profile and call it a day — the chain will barely touch sliders and just clear the track. Without the revers flex you take out 50% of the chainwear and free up preciouse hp —on top of it it will bring your kit right up tight to the bike for best weight transfer. This works on Yamaha not sure about other brands , but would guess it is the same. If the chain is to tight drop the rear of the bike a bit till it fits.
 
Mar 10, 2011
20
5
3
Aro chain slider

Did the same on my 2014 ktm but dont need the middle slider it just misses the cross bar .I havent rode yet need to order 18 tooth sprocket for chain case hope to get and try this weekend thanks for the advice :face-icon-small-coo
 

CATSLEDMAN1

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KTM ARO chain case mod




follow up on vega 350 doing the chain case mod.
1. 2013 ktm sx450/520 with 2019 ARO kit
2. removed chain shoe and put 15 tooth on bike and 18 on ARO
3. put 17tooth top 18 bottom in chain case
4. we made a bushing for the shoe removed to be the tensioner in the chain case because the round wheel on the chain vibrates and makes noise.
5 stock chains with no links changed
6.this gives a track run out of about 14.3 inches , works

Test ride in spring snow. Noticeable relief of effort to spin the track when unloading, quiet and really cut down on kit vibration by ? maybe 70%
For sure a power gain but it was hero snow so hard to tell. Let off the gas, bikes coasts, wouldn't do that before, able to ride tight woods without wanting to flame out or kill the motor on a bike with a high first gear.
Great mod for the work involved. A mystery why these kits don't come this way from Polaris ?



 

BendBrapp

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Nov 11, 2015
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Snowchecked a 129 ARO LE for next season. I’m curious if the updates address any of this? I have focused at making my MHST as efficient as possible over the years. One thing is for sure, replacing the stock chains immediately!
 

GKR

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Nov 26, 2007
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If a guy wanted to run a 14 tooth countershaft gear to keep ratios where I want them would it clear the chain slider cross shaft? That would be with an 18 tooth on the jackshaft? My idea is run 14/18 in jackshaft and 17/17 in chaincase which gets me closer to my current ratio. If I run 15/18 as suggested in this thread I will be effectively gearing up more than I want to.

Current gearing- 13/17 to 17/18 = 0.722 (swapped stock ARO chaincase gears)
Recommended above- 15/18 to 17/18 = 0.786 requires purchase of two gears
My idea (if it clears)- 14-18 to 17/17 - 0.777 only need 14T countershaft gear.

Original ARO gearing was - 13/17 to 18/17 = .810 which was too high
 

CATSLEDMAN1

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Aro

sprockets on ARO have different splines than the splined kits and I believe the last year of RAW.

14 t on KTM would not clear the aluminum cross bushing, but if you remade a steel version with smaller diameter cross bushing I believe you could run the 14 on KTM.

From feed back from people riding and looking at 2020 TS kits, same plastic chain guide as 2018-2019 ARO. I can't say for positive that these mods would be exactly the same on the 2020 models.
 

CATSLEDMAN1

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and another thing

as far as track efficiency on the ARO, one draw back is the fat little top idler wheels, They rub on the drive lugs. On the 16-17 older TS kit and the ARO you will gain some more track efficiency if you machine the wheels narrower or make skinny aluminum wheels. We have done both, and its noticeable when you have the track off the ground and turning it by hand.
 

YZ426F

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Nov 26, 2007
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TheARO primary chain slider setup is a total afterthought go to a 15 front sprocket and 18 on the secondary shaft flip the slider upside down and cut the whole back section beyond the frame cross tube off .
Grind the slider to a low profile and call it a day — the chain will barely touch sliders and just clear the track. Without the revers flex you take out 50% of the chainwear and free up preciouse hp —on top of it it will bring your kit right up tight to the bike for best weight transfer. This works on Yamaha not sure about other brands , but would guess it is the same. If the chain is to tight drop the rear of the bike a bit till it fits.
First, thank you for the info.
Question about this mod, are you using the TSS or a fixed strut?
 

jrlastofthebreed

It seemed like a good idea at the time
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Oct 24, 2016
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Coeur d'Alene ID
KTM ARO chain case mod




follow up on vega 350 doing the chain case mod.
1. 2013 ktm sx450/520 with 2019 ARO kit
2. removed chain shoe and put 15 tooth on bike and 18 on ARO
3. put 17tooth top 18 bottom in chain case
4. we made a bushing for the shoe removed to be the tensioner in the chain case because the round wheel on the chain vibrates and makes noise.
5 stock chains with no links changed
6.this gives a track run out of about 14.3 inches , works

Test ride in spring snow. Noticeable relief of effort to spin the track when unloading, quiet and really cut down on kit vibration by ? maybe 70%
For sure a power gain but it was hero snow so hard to tell. Let off the gas, bikes coasts, wouldn't do that before, able to ride tight woods without wanting to flame out or kill the motor on a bike with a high first gear.
Great mod for the work involved. A mystery why these kits don't come this way from Polaris ?



You got any pics?
 
I've been thinking about the chain case mod discussed above and was wondering if anyone has tried doing the 15-18 primary to 17-17 in chain case... Would this put the gearing closer to stock while at the same time remove unwanted drag and bring the kit closer to the bike? Or would the gearing be way too tall?
 

CATSLEDMAN1

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when I change over to my Riot, I will take some pic of the idler wheels if they haven't change them, and mod to the frame to run the 15/18 sprocket combination. I have searched to snowmobile parts but have not found a suitable narrow wheel replacement for the top idler wheels, so just had to make some, kind of a pain.
 

sledhappy

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Nov 23, 2008
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TheARO primary chain slider setup is a total afterthought go to a 15 front sprocket and 18 on the secondary shaft flip the slider upside down and cut the whole back section beyond the frame cross tube off .
Grind the slider to a low profile and call it a day — the chain will barely touch sliders and just clear the track. Without the revers flex you take out 50% of the chainwear and free up preciouse hp —on top of it it will bring your kit right up tight to the bike for best weight transfer. This works on Yamaha not sure about other brands , but would guess it is the same. If the chain is to tight drop the rear of the bike a bit till it fits.
i just picked up a 19 ARO. I will be looking into this
 
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