XR400 Front Sprocket

I decided to replace my chain and sprockets as I noticed some wear on the rear sprocket. When I pulled the front sprocket the back side was worn pretty badly from the chain. It ate into it a good 3/32! What would cause this? Is this normal after 2 years of riding? I was expecting an even amount of wear on the teeth but the chain really was tearing it up.

By the way, I bought Primary Drive sprockets (from Rocky Mountain ATV) to replace the stockers with. The back went on fine, but the front wouldn't even slide on the shaft. I double checked the part number and this is made for the XR400. Now I'm a little worried about the chain and rear sprocket. Has anyone tried these yet? I'm going to try and return the front and get something else.



i cant comment on the new sproks

but as far as uneven wear, you need to double check that you snail adjusters are spot on. i've heard that they are not to precise. if the rear wheel is tweaked a little left or right then you'll notice uneven rear sprocket wear.

a lot of factors play into chain and sprocket life. but two years doesn't seem like a bad number.

Rotate the front sprocket, 1 spline at a time, 360*, til you find a point at which those in the sprocket and those on the shaft align so that it will slide on.

I've bought several Primary Drive sprockets and they all fit fine.

Mine is like that too, and I compared it to my brothers and his is like that too. I think it might be from mud pushing the chain away from the engine. I eyed the chain and it looks strait and I had measured from the pivot bolt to the axle before (not lately) and my snail adjustors were pretty close.

My primary drive front sprocket fits ok, but the back is a pain since its hard to get centered.


Rocky Mountain is checking into it. I noticed the part number on the package is 36215 and on the invoice it's 36215B. So maybe it's different.

I replaced the front sprocket on my wife's XR200 and it went on as easily as the original did. I think it was a Primary Drive also (that was last winter).

I'll let you know what I figure out. I was reading some other posts about sprockets and Sunstar kept coming up as recommended. Another guy says the cheap sprockets will eat your shafts and to buy either Honda's, Sunstar or Renthal front sprockets.


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