Watch your rubbers!

[slimjim2525]

Well, I went on my Quebec trip for 17 days. I parked my 2018 Sidewinder in the garage, and when I got back there was a small puddle of gear oil on the left side of the sled. I was like WTF? I unscrewed the check bolt on the chaincase cover and nothing. Tore it apart, inspected both covers, and they looked good. So, now I'm really like WTF. I look at the rubber magnet and its sticking out a millimeter. I get my finger nail behind it, and it slips right out another 5mm before I meet resistance. So, now it makes sense that there was gear oil on the left side of the sled, and nothing by the chaincase cover. It was traveling through the driveshaft. Inside of the driveshaft was all gear oil. Not sure what happened to the rubber, but I got lucky, all the gears looked fine.

 

[Turboflash]

Yes, seen it and there were posts about this. Need to degrease it well and use some kind of gasket sealer when installing it.
Thanks.

 

[KnappAttack]

The rubber plug that holds the magnets can get hard and brittle over time, it doesn't want to hold the magnets anymore also. I believe it depends on the chain case oil being used. I had a 21 Thundercat in this winter that the owner changed the track on himself. He noticed his speedo wasn't the least bit accurate. As it turns out he had a dealer mechanic friend helping him in the shop and the magnets fell out of the rubber plugs and they didn't get them orientated correctly when they put the magnets back in the rubber plug, they have to be positive, negative, positive, negative etc. He had me pull the chain case to determine what was going on and I found the rubber plug was hard and it wouldn't hold the magnets in anymore and the magnets were actually rubbing on the chain case cover. The reason the speed was off is because they did not have the orientation of the magnets in the plug properly after they had fallen out of the crappy old rubber plug... I had to put a new rubber plug in it because the old one was so just hard and brittle. The new rubber plug was much softer and sealed the driveshaft fine along with holding the magnets in properly.

I've never noticed the rubber plug get that hard before and not want to seal or hold the magnets like that. When I service these chain cases, I use genuine Polaris synthetic chain case oil in them, and I don't think that hardens the rubber plug like some of these oils do that people use in them. I know many people use gear lube and other different oils, it must be the reason for the rubber plug changing, not wanting to seal and hold the magnets properly. Of all the machines I've serviced year after year, I've never seen the plug get like this using the Polaris blue synthetic chain case lube going all the way back to the 17 model sleds. So the 21 I had in here this winter has defiantly been using a different lube in the case to make that plug get hard, brittle & crappy like that and need replaced so early.

 

[STAIN]

when they put the magnets back in the rubber plug, they have to be positive, negative, positive, negative etc.

I did not know this, I have a friend who's ZR 7000 speedo is way off and I bet this is the reason.

 

[Sevey]

When i reinstalled mine when the drive shaft was out - i installed it with high temp silicone to seal it. It has worked so far with no issues.
MS

 

[slimjim2525]

When i reinstalled mine when the drive shaft was out - i installed it with high temp silicone to seal it. It has worked so far with no issues.
MS

This is what I will be doing going forward. I had Amsoil chaincase fluid in there. Took Knapps advice and ordered Polaris. Will check my 25 winder when I service it.

 

[Sevey]

Funny - have used Amsoil chaincase oil in it for years and never had an issue. The drive shaft has been out a few times and replaced due to their issues - so I have had to knock the plug our and reinstall it several times - no issue with the rubber hardening. Going on 8 yrs and close to 20,000km.

Do watch the magnets - each magnet can pull out or be be pushed in - perhaps too deep. I make sure they are all even before reinstall.
MS

 

[KRK1]

I didn't check my rubber once. My daughter's 34 years old now!

 

[Motorhead]

I had a few fall out when I did my oil changes per the book, on my bought new 2017! First oil change was at 500 miles and the second oil change was at 1100 - 1200 miles! Back then I was using oils that my Yamaha dealer recommended! So what I found on my second oil change was a few of those small rubber magnets had fallen out, I think as I pulled the chain case cover off? Why did they do this? My theory back then, was because of all the aluminum shavings in my chain case oil, the oil was full of aluminum sludge in that lower casing area, caused by chain stretch and the too small diameter of the 21t gear, which caused the chain to wear a chunk out of that post! I may be wrong about why and how this happened, but I will say a tune with an added 22t gear stopped that damage from occurring! Had it continued to wear, it would have worn through and then of course a worse problem! Changed that chain out at 5500 miles whereas there was no threads left on adjusting bolt, and still on my second chain with 13,000 now, but need much maintenance before next season, like chain, 22t, track, shock refresh, on and on! So now that I read this, I shall add checking on theses rubbers, to my long list! Also stopped using the Yamaha gear oil after that, and went to a full synthetic 75-90. Only had that problem that once when a few of those rubbers fell out!!

 

[KnappAttack]

I had a few fall out when I did my oil changes per the book, on my bought new 2017! First oil change was at 500 miles and the second oil change was at 1100 - 1200 miles! Back then I was using oils that my Yamaha dealer recommended! So what I found on my second oil change was a few of those small rubber magnets had fallen out, I think as I pulled the chain case cover off? Why did they do this? My theory back then, was because of all the aluminum shavings in my chain case oil, the oil was full of aluminum sludge in that lower casing area, caused by chain stretch and the too small diameter of the 21t gear, which caused the chain to wear a chunk out of that post! I may be wrong about why and how this happened, but I will say a tune with an added 22t gear stopped that damage from occurring! Had it continued to wear, it would have worn through and then of course a worse problem! Changed that chain out at 5500 miles whereas there was no threads left on adjusting bolt, and still on my second chain with 13,000 now, but need much maintenance before next season, like chain, 22t, track, shock refresh, on and on! So now that I read this, I shall add checking on theses rubbers, to my long list! Also stopped using the Yamaha gear oil after that, and went to a full synthetic 75-90. Only had that problem that once when a few of those rubbers fell out!!

I'm pretty certain the owner of the Thundercat I had in here earlier this season was using Arctic Cat chain lube. Its the only machine I've ever noticed that had the magnets come out of the rubber plug and have had that plug turn hard like it did. I could have fixed the magnet pole positions into proper order and sent it on its way, but I didnt feel comfortable that the plug was going to hold the magnets and seal the shaft up like it was supposed to, so felt that the plug had to be replaced. IMO it's the oil being used that affects the rubber plugs ability to seal and hold the magnets. It was defiantly hard rubber on that 21 Thundercat. I'm guessing some oils will harden and affect the rubber plug, where other chain case oils don't or at least do it to a lesser degree.

 

[slimjim2525]

Just checked the old rubber plug. Hard like a hockey puck. New rubber magnet coming today, and will compare.

 

[slimjim2525]

New plug didn't arrive. Will be here Monday. Are the magnets already in the plug, or are they separate and need to put them in the plug?

 

[KnappAttack]

Magnets are already in the plug.