ATC90 Rear Sprocket- what do I need?

[Frankencelery]

Last night I got around to changing the wheel bearings and rear sprocket in my 90. Unfortunately the rear sprocket doesn't match the old one. Check this out:

http://kottum.mystarband.net/3ww/ATC90Sprockets.jpg

The left one is the original, and the right one is the new one I bought 6 months ago that said "all years". Technically this is a US90, so maybe that's the problem. I wasn't able to decipher the serial number down to the exact year, but it's either a '72 or '73.

The reason it doesn't fit is because the carrier halves are supposed to touch each other and they do on the old one, but the new sprocket is much thicker and they don't come together properly. Clearly there's a mismatch.

Anyway, does anyone know where I can get either the correct sprocket, or the carrier part (mine is in pretty rough shape) that goes with the new sprocket I bought?

[atctim]

it should work - the new one has only 4 slots (which is all the OEM uses) but the OEM has 8 slots. I think there were extra slots put in to rotate it once they wore out.. Put it back together and it will fit.

[Frankencelery]

Sorry for not stating the obvious. I know it doesn't fit because I already tried to put it together, and the two halves are supposed to come together and they're 1/8" or more apart. If I were to try to put the bolts through and pull the halves together, it would bend the carrier halves completely out of shape.

[SWIGIN]

you should of got a 1 peice sprocket from dennis kirk....they are great

there has to be a way to get it to work

[SWIGIN]

you should of got a 1 peice sprocket from dennis kirk....they are great

there has to be a way to get it to work

[atctim]

are you saying that the outer "carriers" are not coming together tightly? The only thing holding them apart is the rubber "stoppers" that give the sprocket it's cushion. Put it together, then tighten down the 4 bolts / nuts slowly and equally and see if that pulls the gap together. I think I understand what you are saying, but I might still be unclear to the problem.

[Howdy]

I have used this style sprocket before. Never had much problem. I do know the inner part of the original sprocket is thinner than the replacement one. They do this to lower the manufacturing cost and for strength. If you need or want a orginial style sprocket or complete set let me know. I should have a few good used ones at the shop.
Howdy

[Frankencelery]

There's two major problems:

1. If you look closely at the original sprocket, it is indented and thinner in the center. Also, all 8 of the rectangular openings are open towards the inside. The replacement has 4 that are open for the rubber shock bumpers and the other 4 are closed. Which brings me to #2.

2. The "carrier" halves are molded so that they are raised in a pattern starting from the center and radiating out towards the bolt holes. Someone is selling ONE of these on Ebay. Check out the URL so you can see the picture.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=4646939100

Notice that the way the part around the bolt holes is raised? The only way that will fit into the sprocket is if all four of the openings are open towards the inside of the sprocket.

[Frankencelery]

Oh, and I tried Denniskirk. No such animal for my year.

[SWIGIN]

Oh, and I tried Denniskirk. No such animal for my year.

thats odd...i bought them there before...must have stoped selling them

heres a blury pic of mine..its for a newer 110 but its mostly solid and can be redrilled to fit about anything....like a 200x hub and axle like this

[Frankencelery]

Thanks Howdy. I bought a used set complete on Ebay. It was for a 1978, but I think my new sprocket will work. If it doesn't work out, I'll let you know.