OEM countershaft sprockets?

[MANIAC998]

Hey guys, I just replaced my chain & sprockets with aftermarket equivelent equipment, and noticed that the countershaft sprocket doesn't have the "ring" of rubber bonded to it like a stock OEM does. I did a search and didn't come up with anything, so I thought I'd ask you guys. Why is it on there from the factory? Is it for vibrations purposes? And if so, for rider comfort or for bike longevity? And lastly, why isn't it also on the rear sprocket? Send me your thoughts!!! Maniac

[KJ790]

What bike are you talking about? I don't think I have seen a ring of rubber on any stock sprocket before.

[MANIAC998]

'06 WR450 Yamaha, but my previous Suzuki DRZ had it too. What bike are you on?

[miweber929]

Ring is for sound deadening as every little bit the can quiet on the drivetrain they can have on the engine.

I'd imagine since the smaller one rotates faster and is a direct connection to the transmission, it's basically a stethoscope into the gear noise. There was some talk on the XR650L forum when I had mine that the chain sort of rode on the rubber to help vibration but once you run something 50-100 miles metal beats rubber so anything that touched had long since worn away.

Run both aftermarket and OEM on many different bikes and it's definitely quieter with a stock one, but is it enough to care about? Not in my book.

Ymmv, however.

Mike

[MANIAC998]

Why in the world did this thread get moved? It's not like my Yamaha is the only one that has rubber bonded to the countershaft sprocket. Almost all bikes come with this from the factory, and I wanted to know why. I thought, who better to ask then the experts at the engineering side of ThumperTalk. Could someone explain why this got moved?

[GuyGraham]

as said, its for noise reduction

don't even give it a second thought - you won't notice any difference

[MANIAC998]

Still asking why this thread got moved? Thanks for the replies, as this is what I expected. But I was trying to ask from an Engineering standpoint, but I guess I'll never know, now that this thread got moved for no apparent reason. Thanks

[byggd]

Might want to PM one of the mods with your question.

[MANIAC998]

Thanks byggd. I guess I'll give that a try. Maniac

[YamaLink]

That is odd considering the original post made no mention of Yamaha. Maybe it was moved because your signature or profile lists a WRF?

[MANIAC998]

I know! They just moved it for no apparent reason! It's not even like Yamaha's are the only ones that use the rubber molded to the countershaft sprocket. They all do it!!! So I try to ask "why" from an Enginnering standpoint, and it gets moved here?! Maniac