Installing a CS Sprocket

I've got a 99 YZ400. I want to gear down for woods riding and ordered a 13T CS sprocket after reading a lot of the gearing posts here. Anyone have any advice on making the install easier?

1) I know the keeper on the nut is one of those bent flange arrangments. After straightening these how hard will it be to break the nut loose? What's the best way to hold it still? engine compression? apply rear brake?

I figure it should be any easy job but if any of you all have lessons learned the hard way lets hear them!

The answer to question 1 is that it may be quite difficult without an impact wrench.

If you do have an impact wrench, either electric or air, DO NOT put the bike in gear to remove the nut. That subjects the trans to a lot of unnecessary abuse. Just hold it by holding the rear wheel (with the chain on).

If no impact wrench is available, the best trick is to put the bike in 4th or 5th gear and place a hammer handle or other piece of sturdy hardwood or plastic through the spokes of the rear wheel so that it lays across the swing arm. Then crank away with as big a breaker bar as you have access to and a good fitting socket.

It's a normal right-hand thread, BTW.

Gray, doesn't that put a lot of unnecessary strain on the spokes?

Greyracer, I knew you'd come through, thanks. I was worried about the trans abuse and the handle idea is priceless. It had crossed my mind to wonder if it was a reverse thread but a little spacial visualization showed that lh threads would be uneccessary, thanks for the confirmation.

But you do bring up another question, What size is the nut? Come to think of it I may not have the correct socket size...

Greyracer, I knew you'd come through, thanks. I was worried about the trans abuse and the handle idea is priceless. It had crossed my mind to wonder if it was a reverse thread but a little spacial visualization showed that lh threads would be uneccessary, thanks for the confirmation.

But you do bring up another question, What size is the nut? Come to think of it I may not have the correct socket size...

I think it is like a 1-1/16" or whatever that converts into metric

Use an impact and have someone hold the rear brake for you

I just had my wife sit on the bike in first gear and with the rear brake on, the nut came right off. I wouldn't put anything against the spokes.

Gray, doesn't that put a lot of unnecessary strain on the spokes?
It's unecessary if you have an impact wrench. The strain on the spokes is minimal if you keep the board as near the rim as possible. It's a very old trick with a long history of not breaking spokes. If you want to minimize it further, find a point in the rear sprocket that you can slide a bar across the swing arm without touching any spokes at all.

I always soak the nut down with PB Blaster or liquid wrench a couple hours before I try to remove it. They normally come right off without much fuss.

ok gray, back to install, the plate that you bend over the nut, I just tighten the nut up snug and bend that plate over, but bending that plate over seems to be a BITCH, so is there any tricks?

Breaking the countershaft nut...

Take the rear wheel off, loop the drive chain on top of swingarm and then under (right around where the axle would slide in). Then vicegrip the chain to the swingarm (put one end of the grip in the swingarm axle slot) and the other on the chain and clamp. Remember, you wrapped the chain around the end of the swingarm so clamp on the opposite side of where the chain will be pulling.

Now the countershaft is held securely. Remove the countershaft nut.

To install, reverse the chain wrapping procedure.

Use an old chain if you are iffy about clamping your expensive x-ring chain.

It will hold 100%. No sweat.

Sic

The torque is 55 ft/lb.

It works best to turn an edge of the locking washer up a little before you install it. Then, you can reach straight in to it with a pair of Channel-Lock pliers and fold it over one of the flats on the nut. If you've already got it on, and the pliers won't catch the edge, sneak a chisel point in between the sprocket and washer and lift it up some.

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