Polaris broken lower gear bolt/chain case destruction

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rvrbum4

New member
Well it had to happen to me! My son's '03 ProX 600 (no longer have) grenaded the chain and chain case a few years back at the fault of a broken lower gear bolt. After all properly repaired it ran fine. The next year curiosity got the best of me so I pulled the cover and sure enough the head of the bolt was broken again!! At least I caught it this time. I installed new bolt, loctite, torqued properly and it was ok the rest of the year. This year I bought an '03 700 Classic Touring with 2k miles, like new. Within 250 miles and of course the first day of a 6 day trip in Northern Wis, broken bolt and grenaded chain case again!! At -20 degrees, I patched up the chain case with JB weld and RTV sealant and rode 3 more days before it began to bleed gear lube badly enough to just park it. Well this time I'm a little smarter. I'm gonna drill and tap it to 3/8" bolt and hopefully do away with my achilles heel. Well my son has an '05 700 RMK now and I thought all is good until I looked up part numbers and found that his sled uses the same little crappy 5/16" bolt that is so well known for letting go. I guess I will be proactive and drill and tap that one to 3/8" too before it lets go! On the flip side I had an "02 600 xcsp that used the same bolt and no issues in 6,000+ miles.
Question: I just bought an '06 Fusion and the lower gear bolt in that is a different part number, anyone know if it is larger or just a different number?
Recommendation: Check your Po-Po's part number for the lower gear bolt. If it's 7517979 I'd be checkin it out or your just playing Russian Roulette!
 
9

900cc

New member
You can also put three washers in between the large washer and the axle to create some room for the gear to float. This way if there is any flex or hard loads on the chain and gears it does not put as much stress on the bolt head. Snocross racers do this.
 
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mikedrh

Member
If the chain is in line and all the bearings are locked (or pressed) on right there is no need to use a bigger bolt.

If you never pound on your machine drilling it out to a 3/8" bolt probably won't hurt.

Have done it myself but, if you launch off a snowbank and land at full throttle to shoot a nice roost you may just twist the end of the driveshaft off. Polaris made that with 5/16" bolt so the shaft had more meat on it. I've twisted shafts off that had the original 5/16" bolt also.
 
indy_500

indy_500

Well-known member
mikedrh said:
If the chain is in line and all the bearings are locked (or pressed) on right there is no need to use a bigger bolt.

If you never pound on your machine drilling it out to a 3/8" bolt probably won't hurt.

Have done it myself but, if you launch off a snowbank and land at full throttle to shoot a nice roost you may just twist the end of the driveshaft off. Polaris made that with 5/16" bolt so the shaft had more meat on it. I've twisted shafts off that had the original 5/16" bolt also.
Click to expand...
My 5/16" bolt broke at 2000 miles. Drilled/Tapped to 3/8" Sold the sled with 8500 hard ridden miles with the original 3/8" bolt i put in at 2k miles.
 
indy_500

indy_500

Well-known member
reiley99 said:
what a slipper gear?
Click to expand...

It's almost like a spring loaded/clutch activated gear for when you launch off a jump and you go to land, you're track is spinning at a different speed than when you're going to land so it has some give.
 
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reiley99

New member
so kinda like a slipper clutch on a street bike so you dont lock up the rear tire when down shifting to fast.
 
indy_500

indy_500

Well-known member
reiley99 said:
so kinda like a slipper clutch on a street bike so you dont lock up the rear tire when down shifting to fast.
Click to expand...

Ya same concept. I just found out about these bad boys a year ago didn't know they had them, seems pretty sweet!

3/8" bolt red loctite 19 ft lbs been doing this to every sled i've owned for the past 4 years no issues for me. Done this to evolved gen II and edge chassis sleds.
 
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kraven700

Member
Add to all of the above;

With both sprockets bolted down, and the chain off, place a steel straight edge across the sprockets to see if they're in line, if not, shim accordingly . I use valve spring shims intended for car engines, they usually have a 1" I.D. and are available in a variety of thicknesses from SUMMIT RACING and other sources.

Before final assembly, use BRAKE CLEAN and air pressure to clean out the threaded hole in the drive-shaft.

Apply RED Loc-tite, and leave in a HEATED garage overnight so the Loc-Tite will cure
 
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sean34590577

New member
3 2005 indy 500 xc/sps all broke chain case bolt. mine did it at 700 miles,then again at 1400. put 3/8 bolt in,no more problems. Just bought the 14 indy 600 hoping they have that problem fixed
 
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rvrbum4

New member
Changed to 3/8 bolt and so far so good. Son's rmk is getting changed tomorrow.
Back to my original comment and question, does anyone know what size bolt is used in the lower gear on a 06 600 fusion?
 
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