Advice on where to start - Secondary/Chaincase

S

Silver Bullet

New member
Joined
Feb 1, 2005
Messages
72
Location
Appleton, WI
I recently got my 1998 600 SX back going again after catching a ring on the exhaust port. I ended up putting in a new complete engine. I love how light this sled is compared to my 700 SRX.

Today, I took it out and it was strong right from the begining. I went about 40 miles or so when I was going down a straight-away about 70 mph. I started to approach a cross street so I let off the gas and started to apply brake, but nothing, no brakes. I was coasting toward the street and fast there was no resistance at all. There was a sled that was stopped waiting for cars to pass. I just missed them went across the road into the ditch and up the other side of the embankment missed two trees and came to rest in a field. I was lucky no cars were coming. I immediately thanked The Man Upstairs and changed my shorts. I could start it, but it would not engage. I thought maybe i broke a belt or something. but I still should have been able to stop.

I couldn't move the sled so a very nice couple brought me to my truck about 5-7 miles down the trail. I got the sled home and started to look at what happend.

The shaft in the secondary looks to have shifted to the outside about 1". I can rotate the secondary and the shaft from the secondary rotates. I can see the key and a collar on the inlet side of the chaincase and both those rotate with the shaft, obviously the track is not turning. I checked and the chaincase has oil in it. The dipstick did not have any metal shavings on it when I checked. There is also no visable damage to the chaincase. The sled I can move back and forth on the trailer and the track moves.

I'm just wondering where I should start on this one. I don't have much experience with the chaincase and secondary. Any ideas or help would be greatly appreciated.

Thanks,

Silverbullet
 
Sounds like you broke a chain. Takes about 20 minutes to tear apart and put back together. Biggest part will be seeing if anything else got hurt, and getting the parts.
 
The 'shifted to the outside about 1 inch' part makes me raise an eyebrow. You need to open up the caincase at any rate.

Possibilities, starting with my best guess ;)! :
1 Broken driveshaft. Especially if it made no racket before it stopped working
2 Striped gear
3 Broken chain
4 Broken Jack shaft

2, 3 and 4 should have made a hell of a racket before they broke or when you were coasting without brakes. My money is on drive shaft, but I only have 5 cents.
 
I missed the 1" part (Darn speed reading). Driveshaft will be a little more involved, but still isn't a bad job if it didn't tear anything else up. Time to pull the can and dump the chaincase cover.
 
Time to open the chaincase and see what's going on here. I'm going to say the top gear came off, that would be the only way the shaft would come out like that. But Crewchief is probably right.
 
sleddineinar said:
I'm going to say the top gear came off, that would be the only way the shaft would come out like that.
Click to expand...

I thought that to originally, but can you imagine the noise that would make, never mind that it would probably lock the whole case up and the track along with it unless the case exploded. That's why the 1" thing has me puzzled....I wonder if the secondary is shifted out part way......

I kinda like guessing on some of these problems..... ;)!
 
Thanks guys,

I won't have time to start to pull things tonight - I have to travel for work, but my next opportunity I'll pull the can, drain the chain case and see what is up. Honestly, I can say if there was a loud bang or not. At that point I was in panic mode and trying not to hit something or someone.

I'm sure I'll have more questions as I find out more information on the cause of this failure.

Thanks again - A lot of great people on this site!
 
OK - I was able to get home this afternoon and pull the can and the cover on the chaincase before I was frozen. When i pulled the chain case the sprokets looked good, the chain looked good. The bolt holding the secondary shaft in place was off and the oil had it attached to the bearing that resides in the cover of the chaincase. The shaft had shifted out of the gear because the bolt had come off. I removed the top gear and the splines look ok. There is some discoloration marks on the secondary shaft in a pattern that looks like the outer bearing may have some play/chatter.

I guess my plan now is to change the bearing in the chaincase cover and put things back together (TIGHT). I have a question on the torque specification on that thin bolt? Also what gear lube weight should I use in the chaincase. What tension should I have on the chain and how do I check that? I plan on lock-tighting that bolt as well. i don't want this ever to happen again.

Any other ideas, What about the inner bearing should I change it that shaft rotated very freely. Haven't had any issues beyond this with clutching.

Thanks for the help,
Kevin
 
i'M pretty sure the marks you see are from when they cut the splines on the shaft. If you pull the gear you will see what I mean. Mine had that too and I thought the same thing at first and then realized what it was.
 
Yes, the nut unscrewed and the shaft shifted toward the secondary which didn't allow the top gear to turn and allowed the track to spin freely. I am certain the bolt should have had loctite put on. I am the second owner and I have never had chaincase apart. I didn't need to.

I took the cover inside for a closer look at the outer bearing. It is very smooth no axial movement or catches. I will probably keep this bearing on. What type/color of loctite do you recommend for the nut holding on the top gear to the shaft?

I found out through other threads that the torque spec should be 43 ftlb. My father-in-law mentioned beside loctite I should probably stake the nut once its torqued.

Thanks very much for your guys help - that's why I love this place!
 
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I've never thread locked that nut but blue should be fine. Make sure the nut, washer, sprocket surfaces are not burred and that the shaft is fully seated in the case. The bearing behind the secondary should have two set screws in the collar that lock it to the shaft. Make sure you tighten the nut before you tighten up those set screws (little light loc-tite is good on these as well).
 
I got it fixed last night! I reinstalled the nut/washer with loctite 290 (green and wicking type) and torqued to 43 ftlbs per the specifications. I also checked the lower nut at 35 ftlbs to make sure. I also staked the nuts to prevent vibration from backing them off. Put the chain on and tensioned finger tight and back-off a 1/8 of a turn. Chain deflection of about 1/4". Filled the chaincase with 8.5 oz of synthetic 75W-90 Mobile 1. I took it around the yard and back up on the trailer for the next ride.

Thanks everyone for their help!
 
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