Upper Chaincase Bearing - Cato-strophic Failure

[jross2828]

Hey All!

2014 ZR7000 guy here. Has anyone seen a failure this extreme with the upper bearing? Unfortunately replacing this bearing wasn't on my radar (obviously is now.) I was right around the 7000 mile mark. Chaincase Oil was changed every other season. The reason I'm bringing this up to you smart fellas is the chaincase clearly failed here.

At first I thought I was experiencing belt slip. I rode 285 miles while it was 38 degrees or so the other day (from Escanaba area to the Soo). About 30 miles from the Soo I thought I noticed the belt was slipping. I haven't ever had issues with the sled and the belt was newer but I chocked it up to riding hard on an extremely warm day. I swapped back to my old belt and it rode just fine the rest of the way to the Soo. Next day I took off and made it about 30 miles before my day turned bad. Experienced the same issue but knew things were bad this time.

After getting home and pulling the chaincase apart the whole chaincase cracked. Metal shavings behind the case and inside and bearings laying in the bottom of the case. Did my bearing fail here or is there something else more sinister that took place? What are everyone's thoughts on the status of my chains/gears? It doesn't look they were totally destroyed, I see some markings on the reverse chain. Is there any way my secondary or jackshaft was damaged with the way the case broke and caused the jackshaft to be out of alignment?

Thankfully this was the last ride for the season so I have some time to come up with a solid plan.

 

[STAIN]

I have seen worse, just 2 weeks ago!
shaft is most likely ok
I would not use the chain or gears after they have been subjected to that much metal debris.
while you are in there, weld the tensioner wheel bolts, upgrade the upper gear bushing and install an updated left side lower shaft bearing.
This is also a good time to do any other updates ( track, shock service, idler wheels, hyfax ) you may need done. It all has to come out to change that inner case.

 

[Sevey]

Sorry to hear about your woes.

Like the above comment - case will need a complete overhaul. Way too much debris.

Curious - did the cover make it? or did it get cracked as well?

MS

 

[ksiesel]

If I were tackling that failure, I’d be putting a 17+ chaincase housing in with a secondary shaft from 17+.

This will eliminate the wobble bearing and update your parts the stronger and more proven designs. The suggestions about addressing the chain tensioner, top gear bushing, and drive shaft bearings are good ones while you are there.

 

[jross2828]

I have seen worse, just 2 weeks ago!
shaft is most likely ok
I would not use the chain or gears after they have been subjected to that much metal debris.
while you are in there, weld the tensioner wheel bolts, upgrade the upper gear bushing and install an updated left side lower shaft bearing.
This is also a good time to do any other updates ( track, shock service, idler wheels, hyfax ) you may need done. It all has to come out to change that inner case.

Thanks for helping me realize I'm not alone. I was already planning on moving to dupont sliders for next season and idler wheels definitely need replaced.

 

[jross2828]

Sorry to hear about your woes.

Like the above comment - case will need a complete overhaul. Way too much debris.

Curious - did the cover make it? or did it get cracked as well?

MS

Cover actually made it but there were several tabs already broken towards the top that I would have to silicone each time I re-installed. Sounds like those tabs breaking are pretty common with the incorrect torque so I had planned on replacing it anyways. Now will be the time!

 

[jross2828]

If I were tackling that failure, I’d be putting a 17+ chaincase housing in with a secondary shaft from 17+.

This will eliminate the wobble bearing and update your parts the stronger and more proven designs. The suggestions about addressing the chain tensioner, top gear bushing, and drive shaft bearings are good ones while you are there.

I've seen a few recommendations from others on this. Is there a good FAQ/thread you know of tackling the upgrade? I wouldn't think it's all completely plug and play.

 

[jross2828]

If I were tackling that failure, I’d be putting a 17+ chaincase housing in with a secondary shaft from 17+.

This will eliminate the wobble bearing and update your parts the stronger and more proven designs. The suggestions about addressing the chain tensioner, top gear bushing, and drive shaft bearings are good ones while you are there.

Also, do you know if the ZR and Viper chaincase are identical? From a drawing perspective they look the same but it seems that one of the chains may be 2 links longer? Only reason I'm asking is depending on who you're buying from Cat and Yam parts can be quite a bit different in price. Also may consider buying something used depending on how many miles the sled had on it before being parted out.

 

[STAIN]

The cases are the same. The gearing is different in 2014. I would run the Yamaha 21-41 gearing.

If I were tackling that failure, I’d be putting a 17+ chaincase housing in with a secondary shaft from 17+.

The only problem with this approach on a CAT is that to do this you also need a new secondary clutch as the splines are different. If you have the money, the shaft, bearing AND clutch upgrade would be worth it as the newer CAT secondary is better than what they ran in 2014.

 

[jross2828]

The cases are the same. The gearing is different in 2014. I would run the Yamaha 21-41 gearing.

The only problem with this approach on a CAT is that to do this you also need a new secondary clutch as the splines are different. If you have the money, the shaft, bearing AND clutch upgrade would be worth it as the newer CAT secondary is better than what they ran in 2014.

Forgive my lack of knowledge but upgrading to a new Secondary wouldn't require a change with the primary, right?

If I decided to stick with the 14' setup I could run an entire Yamaha chaincase with Yamaha gearing and Cat Jackshaft as long as mine is ok, right? Only confirming because the yamaha prices are much cheaper from Partzilla for example. The recommendation is to run the FAG bearings, right?

If I decided to go the 17'+ route I would need either a Cat or Yamaha Chaincase, gears etc. Is the Yamaha and Cat jackshaft universal? I know the clutches and gearing are nearly the only differences between the sleds. What are the chances of finding a used secondary to make the upgrade?

If you and a few others think it's totally worth it to move the the 17+ setup I'll definitely consider it. The parts may be cheaper anyways aside from needing the new jackshaft and secondary change.

 

[STAIN]

new Secondary wouldn't require a change with the primary, right?

You can run the existing primary OR buy a Yamaha shaft and run the Yamaha secondary AND Yamaha primary

What are the chances of finding a used secondary to make the upgrade?

I am not sure, I did not research that but maybe you can find a used one.

If I decided to stick with the 14' setup I could run an entire Yamaha chaincase with Yamaha gearing and Cat Jackshaft as long as mine is ok, right?

correct

Is the Yamaha and Cat jackshaft universal?

no

the yamaha prices are much cheaper from Partzilla for example

I found the best prices at Boats.net. You may need to enter the part numbers in the search bar on that site to get them to come up as they don't seem to have a section for snowmobiles BUT sell all Yamaha parts. I saved @$300 vs Babbits......

 

[STAIN]

here is the order list I had. 2016 case. The upper bearing not included.

Order Items​	Ordered	Shipped	Total Price
8JP-E7143-00-00 - GEAR, REVERSE PINI	1	1	$65.94
8JP-E724A-00-00 - REVERSE WHEEL ASSY	1	1	$81.26
8JP-E761A-00-00 - SHAFT, 1	1	1	$13.08
8JP-E7692-00-00 - SPROCKET, DRIVE	1	1	$75.06
8JP-E769A-40-00 - DRIVE SPROCKET, 24T	1	1	$89.21
8JP-E8125-00-00 - SHAFT, SHIFT	1	1	$13.16
8JP-E8501-00-00 - FORK, SHIFT 1	1	1	$77.76
8JP-E8615-00-00 - DAMPER, RUBBER	0	0	$0.00
8JP-F196E-00-00 - FRAME, UNDER 2	1	1	$21.05
8JP-G7548-00-00 - SPROCKET, CHAIN DR	1	1	$30.40
8JP-G7587-00-00 - SPROCKET, CHAIN DRIVEN, 50T	0	0	$0.00
8JP-RA434-00-00 - WASHER, 3	3	3	$3.84
8JP-RA440-00-00 - WASHER, 1.00X1.562	1	1	$3.94
8JP-RA444-00-00 - WASHER, 12X26X1	2	2	$5.08
8JP-RA809-00-00 - BUSH, 12	2	2	$3.00
8JP-RAC03-00-00 - CIRCLIP, 4	1	1	$2.34
8JP-RAC04-00-00 - CIRCLIP, 5	0	0	$0.00
8JP-RAD12-00-00 - SPRING, 1	0	0	$0.00
8JP-RAH11-00-00 - CIRCLIP, 5	2	2	$1.98
8JP-RAM01-00-00 - CHAIN, BWA 13	1	1	$132.81
8JP-RAM02-00-00 - CHAIN, REX 11	1	1	$93.67
8JP-G754A-11-00 - CHAIN CASE ASSY	1	1	$211.13
8JP-G754B-10-00 - HOUSING CAP ASSY	1	1	$194.99

 

[74Nitro]

here is the order list I had. 2016 case. The upper bearing not included.

Order Items​	Ordered	Shipped	Total Price
8JP-E7143-00-00 - GEAR, REVERSE PINI	1	1	$65.94
8JP-E724A-00-00 - REVERSE WHEEL ASSY	1	1	$81.26
8JP-E761A-00-00 - SHAFT, 1	1	1	$13.08
8JP-E7692-00-00 - SPROCKET, DRIVE	1	1	$75.06
8JP-E769A-40-00 - DRIVE SPROCKET, 24T	1	1	$89.21
8JP-E8125-00-00 - SHAFT, SHIFT	1	1	$13.16
8JP-E8501-00-00 - FORK, SHIFT 1	1	1	$77.76
8JP-E8615-00-00 - DAMPER, RUBBER	0	0	$0.00
8JP-F196E-00-00 - FRAME, UNDER 2	1	1	$21.05
8JP-G7548-00-00 - SPROCKET, CHAIN DR	1	1	$30.40
8JP-G7587-00-00 - SPROCKET, CHAIN DRIVEN, 50T	0	0	$0.00
8JP-RA434-00-00 - WASHER, 3	3	3	$3.84
8JP-RA440-00-00 - WASHER, 1.00X1.562	1	1	$3.94
8JP-RA444-00-00 - WASHER, 12X26X1	2	2	$5.08
8JP-RA809-00-00 - BUSH, 12	2	2	$3.00
8JP-RAC03-00-00 - CIRCLIP, 4	1	1	$2.34
8JP-RAC04-00-00 - CIRCLIP, 5	0	0	$0.00
8JP-RAD12-00-00 - SPRING, 1	0	0	$0.00
8JP-RAH11-00-00 - CIRCLIP, 5	2	2	$1.98
8JP-RAM01-00-00 - CHAIN, BWA 13	1	1	$132.81
8JP-RAM02-00-00 - CHAIN, REX 11	1	1	$93.67
8JP-G754A-11-00 - CHAIN CASE ASSY	1	1	$211.13
8JP-G754B-10-00 - HOUSING CAP ASSY	1	1	$194.99

Stain, do you think he needs all of that. Looks like he caught it when it failed.
I've seen a few bad chain cases, I inspect every part to decide if it can or can't be re-used.

 

[STAIN]

Stain, do you think he needs all of that. Looks like he caught it when it failed.
I've seen a few bad chain cases, I inspect every part to decide if it can or can't be re-used.

Probably not, the one I had was DESTROYED. I had to cut the reverse chain off and it bent the shift fork rods.
I put that up mainly for a price comparison to other sites like Partzilla and a guide to what may be needed. I probably would not re-use the gears or chain if the case was full of metal.

 

[jross2828]

Stain, do you think he needs all of that. Looks like he caught it when it failed.
I've seen a few bad chain cases, I inspect every part to decide if it can or can't be re-used.

This is where I'm at slightly. I think it's worth it to upgrade chains since they really aren't that expensive although they seem to be ok. The gears look pretty dang good. It would be pretty tough for those to get bent out of shape and they don't have any weird markings, all of their teeth etc. I'm debating on whether to run with them or not but I think the chains may be a non-negotiable.