Chaincase chain failure

R

rx1jim

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Joined
Feb 17, 2008
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925
Location
Poughquag, NY
On the last ride, I heard and felt what I thought was the "ratcheting" or slipping of the track on my 2000 SRX. After checking the track adjustment with no change I decided it was the drive chain slipping/skipping. Just before the ride, I had just removed, cleaned, inspected and the chaincase. I am sure I had adjusted the chain to the proper tension. I checked the chain tension and sure enough it was very loose. i tightened it up and rode back to the hotel. Opened up the chaincase in the parking lot of the hotel I was staying at, took the chaincase apart, cleaned everything, reassembled it, put in fresh lube and rode another 300 miles. I just checked the chain tension today and it was loose again. I disassembled the chaincase and inspected the chain, WOW, it is a lot longer than a spare chain I have. I also found small pieces of the chain in the bottom of the chaincase. I am changing all of the bearings in the chaincase and the chain along with giving everything a good cleaning. The chain which failed (wore out) has 12,000 miles on it BUT the chaincase oil was always changed every season ( every 1500 - 2000 miles), sometimes twice a season. I have always used the chaincase lube from Spectro or Amsoil. I may start using a 75-80W synthetic gear lube for extra protection.

Has anyone else had a chain "stretch" this much so quickly?? The adjuster bolt went from having 1" extending from the chaincase to 0" in 600 miles. At least I got lucky and the chain did not break, that would have broken the chaincase for sure.
 

I had my bottom bearing go out in my 02 VIPER.. Rode it home took a look under the hood and saw one of the bearings on top of my motor...I knew I was screwed...I replaced every bearing in it and the driveshaft one too...I use ATF in mine when I replaced it but have been hearing alot of different opinions on what to use...No problems so far...knock on wood...A friend of mine just had his lower bearing go out on his Polaris and he uses that amsoil stuff...Of corse we were Ice fishing about 3 miles out on Lake Erie and had tow it back on a plastic sled...
 
YOUR LUCKY YOU CAUGHT THIS. THEY LET GO AND ITS LIKE A BOMB GOING OFF. NOW DID YOU POST WHAT CHAIN (link) THIS WAS AND WHAT GEARING . THEY DO GET WORN. 3:16 (yammie tony)
 
Ya sure you are not adjusting the chain too tight, Not trying to offend you or any thing just a thought.
 
Yammie, I have been running the stock gearing and the stock chain. I have been tightening the adjustment bolt finger tight than backing it off 1/2 turn. Given the consistent regulat maintenance I have performing on the chaincase, I was expecting the chain to last a lot longer than 12,000 miles. No big deal, I have a spare chain with only 1700 miles on it and the link center to center distance measures well within tolerance. I am going back to using 75-80W gear lube, staying away from the low viscosity chaincase lube.
 
I just read through the SRX shop manual and it states to replace the chaincase sprockets WITH a new chain as a set. I'll have to use the sprockets which were being run with my spare chain. The bill for the replacement parts is going to be steep, about $100 for the lower sprocket, $50 for the upper sprocket and $140 for the chain, $290, ouch!!!!!!!! I am replacing the two chaincase seals and the 3 bearings. FYI, the upper and lower chaincase bearings are model no. 6205 bearings with only one rubber seal, the seal faces INTO the chaincase. The bearing in the chaincase cover is a 6204 without any seals. i pack the bearings with synthetic grease upon assembly to make sure they don't run dry giving the chaincase lube time to work into the bearings. Almost assembled and ready to go!!
 
CAN I MAKE A SUGGESTION TO YA JIM. WHEN YOU GET FINGER TITE, DON,T BACK IT 1/2 TURN, INSTEAD GET YOUR 12 mm AND GO 1/2 TURN TIGHT. THIS IS WHAT I DO AND HAVE HAD NO ISSUES ON TWO SRX,s BOTH RACED AND RADER RUNED AND A 1995 VMAX 4 800 THATS GRASS RACED. CONSISITENT HARD HOLE SHOTS. NOW, SHURE YOU MIGHT NEED A NEW CHAIN. 3:16 (yammie tony)
 
Tony - Are you suggesting 1/2 a turn tighter after finger tight. No disrespect but this would be a very tight setup. Finger tight then back off 1/8 turn. This would be correct for a chain that has already been broken in. When you pull off the case after say 800 of 1000 miles the chain will be just right with a little play. Remember if you are installing a brand new chain it will stretch and should be adjusted after its broken in.
 
12,000 miles

I'd say 12,000 miles is fantastic for a chain. If your sled has 12,000 miles on it you are definately more anal retentive than me to buy both new gears and a new chain. If it were me I'd inspect the gears for damage when the chain was coming apart. If no damage I'd look for a good used chain in the 2,000-4,000 mile range, throw it in there and run it. Just curious....are you changing the bearing on the speedo pick-up side??? I'd change that one LONG before touching the one in the chain case cover.

Madmatt
 
MAC, CORRECT. TAKE CHAIN IN FINGER TIGHT UNTIL YOU CAN,T ANYMORE. OK, THAN GO 1/8 TO 1/2 MORE WITH 12mm. CHAIN WILL BE SPOT ON. I HAD NO ISSUES DOING THIS FOR YEARS. NOW NO I AM NOT SAYING ADDING SOCKET ON ADJUSTER AND CLICK AWAY, JUST COMPENSATE FOR SLACK YOU WILL GET BACK JUST BY TIGHTING THINGS BACK UP. 3:16 (yammie tony)
 
You said you inspected everything, but I have experience of chain failure when a bearing goes out on the driveshaft. If you keep getting loose, something is wrong other than the chain. Search for jackshaft or driveshaft bearing failure, something wrong with the tensioner, or a source for mechanical looseness causing the stretch.
 
I amend my above statement with "as long as the chain isn't some cheapo aftermarket junk". I would definately search for something else wrong in your setup.
 
MadMatt, yes, I replaced the speedo side drive axle bearing 3000 miles ago. I may take a bit of flack for admitting to this, but I take the speedo side bearing out every 500 to 600 miles, pop off the rubber seal, clean out the old grease and accumulated water and repack it with synthetic grease. This practice should allow that bearing to live for many, many thousand miles.

Mustang, prior to the last ride when this chain stretched out, I had the entire chaincase apart. All three bearings were removed, cleaned and inspected. They were all in new condition. I grit blasted and powder coated the chaincase and cover. Reassembled it with new oil seals and fresh Amsoil chaincase lube. I set the tension on the chain prior to putting the cover on to be sure it was correct. I am sure the bearings were fine. I now have the chaincase apart again, all the bearings are in the same condition although all three will be replaced with new units since they were running in chaincase oil which was filled with fine metal particles.

The chain is definitely gone, there are several plates or links which have broken and the are small pieces of the links in the bottom of the chaincase. The gears are definiely worn. The pattern of chain is worn into the sprockets.

I agree with going the used route. I am looking for a chain and gear set with a max of 2000 miles in it. A friend of mine may have a set for me. I am just glad the chain did not come apart during a speed run. That could have been serious!

It turns out my spare chain (a chain from a second SRX which I am rebuilding) is a 68 link chain. Can I use the 68 link chain with the stock gear set: 23T drive sprocket, 38T driven sprocket? I also have a 22T drive sprocket.
 
Maybe the gears aren't aligned right? If you had them off maybe there is a shim missing or installed backwards. Not trying to imply any lack of mechanical skill, we all do things then realize later it was a simple overlooked thing we did.

I'm grasping at straws here, but there is a major issue if the chains are stretching. You gotta figure that out because chain failure can be painful in the pocketbook not to mention potentially hazardous. My chain lasted over 9000 miles and only failed because the lower bearing allowed all my oil to leak out.
 
OK, I was able to find some used chaincase parts (I bought a complete chaincase from NYSRX, Terrific TY member!!!!) The chaincase had slightly less than 1800 miles on it. Although the outside of the case was pretty grundgy, the internal parts were clean and measured well within the wear specs. I reassembled the chaincase, packing the bearings with synthetic grease to prevent the from running dry until the lube circultated. The chaincase is now in excellent condition, filled it with synthetic 75-80W gear lube. Ready to load the sleds up for a 4 day trip this week (conditions and weather permitting). While I was in the chaincase area, I installed a stainless steel braided brake line which I had custom made, refilled and bled the brake system. The stainless line gives a firmer feel to the brake and looks better too!!

When I have some time, I am going to clean, powder coat and get the spare chaincase built and put on the shelf so it will be ready.

Next on my list will be to get a primary and secondary clutch so ZI can rebuld them for spares.
 
I always adjust the tension with the cover off and snug it up finger tight till you can only get about 1/2" deflection in the chain, bassically if you push hard on the inside of the chain it should come about 1/8" from touching the chaincase. I found doing this is the only way im 100% on the tension.
 
Concept, I tension and check the chain the same way, with the cover off. I tighten up the chain tension, rotate the track a revolution, check it again, then put the cover on.
 
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