Chain Case - how hot is too hot?

M

Mills

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May 2, 2003
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637
Age
55
Location
Elk Mound, Wisconsin
I have a '99SX 600. Last winter I tore it apart and put all new bearings in the sled from front to back and fixed alll the things that had gone bad over the last 8K+ miles. When I am out riding now the chain case gets so hot I can't touch it for more than a second or two without buring my hand. I don't remeber it ever getting this hot in the past. Chain case has new bearings, new gears, new chain and fresh oil. I also put in new jack shaft bearings and new drive shaft bearings. I have checked the oil level and it is ok. I don't see any oil seaping out of the bearings on the tunnel side. The only thing that I can think of is that I put the parking brake back on the sled during the rebuild and one of the shoes is touching the rotor. could this be the problem? Could i have put anything on backwards that is causing some binding or rubbing someplace? Any suggestions of where to look or other things to check would be much appreciated.
 
hey mills, how have you been? is you chain possibly too tight? Otherwise I would look for the brakes pads like you said. how are the trails out your way?
 
Mills said:
I have a '99SX 600. Last winter I tore it apart and put all new bearings in the sled from front to back and fixed alll the things that had gone bad over the last 8K+ miles. When I am out riding now the chain case gets so hot I can't touch it for more than a second or two without buring my hand. I don't remeber it ever getting this hot in the past. Chain case has new bearings, new gears, new chain and fresh oil. I also put in new jack shaft bearings and new drive shaft bearings. I have checked the oil level and it is ok. I don't see any oil seaping out of the bearings on the tunnel side. The only thing that I can think of is that I put the parking brake back on the sled during the rebuild and one of the shoes is touching the rotor. could this be the problem? Could i have put anything on backwards that is causing some binding or rubbing someplace? Any suggestions of where to look or other things to check would be much appreciated.
Click to expand...
Take the cover off again & take a look inside...put a straight edge across the top the the bottom & see if they are plumed...see if there is metal shaving or some type of ware on the inner case wall & cover wall...adjust chain with cover off...what weight oil you run...I run amsoil full-syn ATF
 
I am going to have to take the cover off and look over everything inside like you said. I have always used Mobil synthetic 80-90 wt oil and never had a problem in the past.
Mills
 
Yep I changed the one in the cover too.
Huh, you may be onto something there. When I put it in I had to use a block of wood and hammer to drive it in. I wonder if I didn't get it seated properly and the face of the gear is rubbing on the OD race?
I guess the only way to find out is to take the cover off and check things out again.
Mills
 
thats what the wood block was used for, it doesnt allow to much direct force on the bearing, he is using the block between the hammer and bearing. i would definately check the alignment and tension of the chain.
 
Thanks, the wood block may work most of the time but the proper way to set a bearing is to use a press and pushing on the outside race only(unless it's going on a shaft). I have used a hammer and a socket or piece of pipe to accomplish the same thing. Point is, you should never press a bearing in using anything that 'may' load the inside race, even if it is a wood block, you're playing with fire. Hell, even a bench vice and socket are a better option.
 
When you have it apart, check the bottom gear to make sure it isn't on backwards. I did this the first time I changed gears, brought the Mountain Max to a halt in a hurry when the chain broke and piled up. I'd run a couple hundred kms before it happened and if it broke the chain, it was probably making a lot of heat as well.
 
THanks for all the suggestions as to what the problem might be. It is going to be a little while before I get to it because my ladder quit before I did when I was putting put the Christmas lights and I ended up breaking my tibia inside my knee joint. When I do figure it out I will post the cause of the problem.
Mills
 
Found the problem!

I found the problem. to make a long story short the spring on the bottom side of the parking brake mount broke right at the "perch" where it is supposed to sit in. The parking brake then rotated over so that one of the shoes made contact with the rotor which in turn created all the heat. I fixed the problem and haven't had a hot chain case since. It must have been doing this for some time because the parking brake shoe was wore at such an angle that it looked like it was sitting in the correct orientation and wasn't rubbing on the rotor. I found the problem by having another SXR owner take some pictures of the brake and chain case area and then compared them to my sled.
Mills
 
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