Hi guys,

I have just started my rebuild of my 'new to me' MC21 SE.

I have bought a Rental rear sprocket to replace the manky one currently fitted.

The existing sprocket has threaded lugs on it that locate in to the cush rubbers.

The threaded lugs have a 21mm nut on the back of them, but don't actually seem to be threaded into the sprocket, and they really don't want to come out.

What is the process for removing / and fitting those to the Renthal sprocket, or do i but new ones separately? If so, where from, as i can't seem to find any?

Any help much appreciated.

Cheers,
Max

Hello "maxhouse", and welcome to NSR-WORLD.

Press the threaded collars out of the OEM sprocket, and into the Renthal. I'm not really sure why they have a hex on!
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Andy.
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Andy wrote:Hello "maxhouse", and welcome to NSR-WORLD.

Press the threaded collars out of the OEM sprocket, and into the Renthal. I'm not really sure why they have a hex on!

Thanks very much for the speedy reply Andy.

Do you need to apply heat or use a proper press? I have tried pressing them out using a vice and they don't want to budge. It is strange as they do turn OK using the nut on the back?

Also, I assume this means that if i want to swap rear sprockets at the track, i would need to pre-equip my rears with these collars?

Thanks again.

Max

Yeah, you just need to be a bit firm with them! They'll pop out OK, but you do need a decent vice.
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Andy.
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Your other option is to get 1 or 2 mc18 sprocket carriers, cheap enough on that there auction, instead of the lugs being pressed into the sprocket, they screw into the carrier with a nice big allen key, making it much easier to change sprockets, this is what i do, with no probs. give it a go see how much easier it is.
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I used an appropriately sized socket as a drift and tapped them out of old ones before. Works a charm.

Lesviffer750 wrote:Your other option is to get 1 or 2 mc18 sprocket carriers, cheap enough on that there auction, instead of the lugs being pressed into the sprocket, they screw into the carrier with a nice big allen key, making it much easier to change sprockets, this is what i do, with no probs. give it a go see how much easier it is.

this sounds like a very good idea, i'll get hunting on (not)said auction site.

Cheers,
Max

nxrsr20 wrote:I used an appropriately sized socket as a drift and tapped them out of old ones before. Works a charm.

I will try this too.

They did seem very firm though, i'll man up a bit and give it a bit more welly.

Thanks for the advice.

Max

Lesviffer750 wrote:Your other option is to get 1 or 2 mc18 sprocket carriers, cheap enough on that there auction, instead of the lugs being pressed into the sprocket, they screw into the carrier with a nice big allen key, making it much easier to change sprockets, this is what i do, with no probs. give it a go see how much easier it is.

I haven't had any luck finding an MC18 sprocket carrier for sale, but I have found an MC16 carrier. Do they fit the MC21 wheel and sprockets do you guys know?

It seems the sprocket fits to carrier with nuts/bolts, rather than being pressed, so would do the job if it does fit.

Otherwise does anyone have an MC18 sprocket carrier they can part with?

Cheers,
Max

The MC16 is very different.

If you're really struggling, send us your sprockets, and for a token charge we can press the threaded collars out, and back into the Renthal.

Just to be clear, you need to press them out, not try to hammer/punch them out.
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Andy.
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Andy wrote:The MC16 is very different.

If you're really struggling, send us your sprockets, and for a token charge we can press the threaded collars out, and back into the Renthal.

Just to be clear, you need to press them out, not try to hammer/punch them out.

Thanks for the kind offer Andy.

I don't have a bearing press, so had previously tried using a large vice and sockets as a drfit to try to press them out.

I did't give it too much welly at the time, as I wasn't sure if they could/should be pressed out, and i didn't want to damage anything.

I'll give it another go. If they don't budge, i will send them to you.

Thanks very much.
Max

They should come out using a couple of sockets and a good [heavy duty] vice.
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Andy wrote:The MC16 is very different.

If you're really struggling, send us your sprockets, and for a token charge we can press the threaded collars out, and back into the Renthal.

Hi Andy,

I had another go with the sockets and vice last night and still no luck, so i would like to post them to you if that is still OK.

Can you please let me know your address for delivery and also the the cost for the work and how you would like payment?

You also have PM.

Many thanks,
Max