Is the chaincase a weak spot?

[TrivanovicRobert]

I have a 19 alpha 154 thats starting to have a few kms on her. I know BDX makes steel chaincase gears and claim the aluminum one is an issue. Is anyone actually having problem with them? I change my oil multiple times a season so it stays nice and fresh inside oil wise. Anything to be concerned about?

 

[IDspud]

I stumped my chain case and shattered the bottom last year with 3500 miles on, rode about 15 miles dry chain back to the trailer.
I was amazed at how good my aluminum gear looked both when it drained and especially after the ride back out.
I’ve broken a steel king cat sprocket with less miles than the aluminum, but that was also from punching a Boulder into it.

 

[Vern]

I’ve never seen a report of an actual failure from the aluminum gear. Just people freaking out cuz the oil gets shiny.

 

[kiliki]

I’ve never seen a report of an actual failure from the aluminum gear. Just people freaking out cuz the oil gets shiny.

This^^^ super easy to change the oil too.

 

[hansenmac]

1700 miles on mine and no problems. i change before the season and thats it.

 

[bjd68]

2000 kms on my 18 cat, no issues change oil about every 500 kms

 

[Teth-Air]

Many of my Cat customers that buy a TKI belt drive conversion tell me they broke the chaincase and only a few complain about the aluminum gear as the failed point. Usually a stump or a rock. They are quite venerable compared to other brands it seems.

 

[slyrydr]

because of the "rolled" chaincase to accommodate the lowered drive shaft, the chaincase and brake both hang down lower than other sleds....a good belly protection plate pretty much takes care of the problem.....loading on a trailer can catch the drive shaft bubbles also

 

[IDspud]

Got a favorite?

 

[TrivanovicRobert]

Glad to hear it seems like they are pretty solid. Ill just change the oil often and keep going. I haven't heard of anyone directly loosing a chain case either from a failure just wanted to check

 

[IDspud]

Don’t tell anyone I have a 2015 with 5600 miles running original chain case hardware and oil.

 

[boondocker97]

Don’t tell anyone I have a 2015 with 5600 miles running original chain case hardware and oil.

My 2014 made it about 450 miles haha.

Fewer problems in general with the 2016+ gears and chains when they switched to the Borg Warner parts.

 

[hansenmac]

I put an aluminum protector over my chaincase and it does have a good dent in it now so im glad i put on.

 

[madmax]

Aside from damaging the chaincase/gear/chain on a rock or stump, they are very durable a so long as the chain is adjusted correctly. There have been issues with the stock auto tensioner failing.

 

[Clarke673]

My take. The DESIGN of the cat case in relation to the retrofit into the Yamaha chassis making the 2 stroke YAMAHA design faulty.

Look to same chassis but Yamaha with a 4 stroke. Pretty sure they are different. Heavy? Yep. Definatly not a week spot though for big power. .my 2 belt drive polsris sleds scare the f out of me. Love cases

Sent from my SM-N981U using Tapatalk

 

[bgraff1]

ive seen enough of the chains fail (2012-2015) that i dont even give them time to break before replacing them with a TKI or C3 belt drive. towed out a couple sleds because of exploded cases. trips ruined and your lucky if you dont need a chopper. belt blows just change it out and continue on with life. i understand this isnt the norm though

 

[sno*jet]

im a fan of the belt too but ive been riding since the 80s and never seen one of these catastrophic chain failures people talk about. not doubting they happen i just dont think they happen that often. i see no need to put a manual adjuster on these newer cats either. sounds like the early proclimbs had an issue. the newer ones have drain plugs, so make sure you change it when the sight glass looks like its full of JB weld instead of oil. shop around for insurance, it isnt that much. i will let them buy me a belt drive someday if that rock happens. sure, it wont cover a chopper ride, neither does my medical insurance. living life on the edge i guess.

 

[bgraff1]

im a fan of the belt too but ive been riding since the 80s and never seen one of these catastrophic chain failures people talk about. not doubting they happen i just dont think they happen that often. i see no need to put a manual adjuster on these newer cats either. sounds like the early proclimbs had an issue. the newer ones have drain plugs, so make sure you change it when the sight glass looks like its full of JB weld instead of oil. shop around for insurance, it isnt that much. i will let them buy me a belt drive someday if that rock happens. sure, it wont cover a chopper ride, neither does my medical insurance. living life on the edge i guess.

here is one that i was involved with. main chain broke, took out the top/bottom gears and then both inner and outer cases. normally find a chain, gears and limp it back but this being a 4s it also took out the engine oil tank (attached to the chaincase) so it could not be run. took 860hp worth of sleds to tow this out of the hills. 220hp 2s attached to a 320hp 4s attached to a 320hp 4s finally attached to the dead sled. the belts that needed to be replaced plus the parts to repair and the loss of a day of riding easily paid for a belt drive. again, i know its not the norm but ive seen it enough that 1200$ is cheap insurance, cheaper if you find a used one. like anything in life its up to the end user to determine if the pros outweigh the cons and then live with the decision made.

 

[sno*jet]

^ i see your point for sure, but for me $1200 isnt cheap insurance, $200 i could do. also covered if it's stolen. i dont think these stock 800 cats are having chain breakage issues like the old ones may have, and high horsepower 4 strokes. I'll get a belt drive for sure if something takes mine out someday. Kinda had my sights settled on a TKI.

 

[boondocker97]

IMO what happens to the Cat chain cases that blow that are not a result of impact damage:

They are made of magnesium. Magnesium has a much higher rate of thermal expansion than aluminum. Magnesium expansion coefficients vary widely depending on the alloy, but lets say you pick one in the middle of the range. I haven't measured how far apart the jack shaft and track shaft are C-C in the sleds, but for argument sake assume 18". Put that together and that 18" distance increases by up to 1/16" unrestrained with a temperature swing of 100-150 degrees F (can't remember what I used years ago when I calc'ed this). That means there would have to be enough slack in the chain for it to increase it's length by 1/8" (1/16" up and back down). So imagine it's 0 degrees on a cold morning, the chain has worn into that aluminum lower sprocket a little, and that auto tensioner gets one more click tighter that it was on the edge about before. Now fire the sled up and start riding, deep snow starts covering over the hood vents, underhood temps rise, chaincase starts expanding, aluminum lower gear starts expanding, and you hit the other side of a creek crossing with the track under full load with a fiddle-string tight chain...

Now the numbers are probably a little different here and there, but that's the concept. This also demonstrates why you have to leave a belt drive belt loose, and it gets tighter after everything heats up. Cat's fix after 2015 was to put a stronger chain in that doesn't break as easy. It seems to work, but doesn't really address the root problem.