Clearing the air on stub shaft bearing

[Fords4life]

Last season i stated using a standard clearance bearing was a cure all for me and clutch chatter,I WAS WRONG ON USING THESE BEARINGS!! yes i am a big enough man to admitt this, bearing #63072rsjem SKF here is what happened to me last season and i dont think it was just old murphy on my shoulder why im saying this, first my riot 9000 installed this bearing with green retaining compound with fresh apex clutch from thunder products tested hard with it working with dave from hurricane getting my hi elevation tunes dialed in, 1100 miles on clutch and cracks formed between puck slider towers, so i installed a tapp shortly after clutch started vibrate'n and gyrating, broken stub shaft, next my 2017 sw rtx installed same bearing number ran this sled on trails with 240hp tune started getting excessive primary clutch heat..200 plus degrees, pulled bearing installed stock bearing back in and heat gone, when both bearings were pulled the grease had " boiled" out, sorry so long winded..but the japs have the extra slop for a reason! Sorry to all.

 

[KnappAttack]

Lakercr and I are both running standard clearance bearings without issue and a lot of miles on them. His bearing cured the noisy Yamaha Primary, mine did not. We both have gone to TAPP primaries since, but neither of us had had any issues or heat like this. They are not SKF bearings but a KML 6307-2RDQE6 that he sourced in Canada and sent me to test as his quieted the primary so well.

 

[Sevey]

Last season i stated using a standard clearance bearing was a cure all for me and clutch chatter,I WAS WRONG ON USING THESE BEARINGS!! yes i am a big enough man to admitt this, bearing #63072rsjem SKF here is what happened to me last season and i dont think it was just old murphy on my shoulder why im saying this, first my riot 9000 installed this bearing with green retaining compound with fresh apex clutch from thunder products tested hard with it working with dave from hurricane getting my hi elevation tunes dialed in, 1100 miles on clutch and cracks formed between puck slider towers, so i installed a tapp shortly after clutch started vibrate'n and gyrating, broken stub shaft, next my 2017 sw rtx installed same bearing number ran this sled on trails with 240hp tune started getting excessive primary clutch heat..200 plus degrees, pulled bearing installed stock bearing back in and heat gone, when both bearings were pulled the grease had " boiled" out, sorry so long winded..but the japs have the extra slop for a reason! Sorry to all.

Years ago when i changed my Nytros i looked into sourcing another bearing - because at the time the Koyo through Yamaha was not available - back order. When i told the guy at the bearing shop the rpm and possible heat exposure of the bearing - he had nothing that came close to those specs. Stayed the course with the oem. I had even called koyo and they did not carry that bearing as a regular item. It was a specialty bearing just for Yamaha by the looks of things.

Thanks for sharing.
MS

 

[Upstater57]

Yamaha has been using its own bearing sizes for years. Good example is the crank bearings on vintage SRX's. Rebuilding those cranks is an adventure in finding replacement bearings. Not surprised to read about modern Yamaha bearings also being somewhat proprietary.

 

[74Nitro]

I usually use the Yamaha bearing for this application, but a couple of years ago I used a high quality bearing in 2 or 3 other sleds and haven't had an issue that I'm aware of.