Front sprocket removal tips


21 replies to this topic
  • OREGONMX

Posted July 14, 2008 - 03:05 PM

#1

So I just bought new chain and sprockets. I have only tried to remove a front sprocket once before and I eventually had to take it to the dealer to have them use a pneumatic wrench on it because I couldn’t do it. I don’t have one of those but I have a pretty big torque wrench this time around that might give me better leverage. What’s the best way to get the front sprocket off of a 2006 YZ250 and what size is that bolt?

Any tips would be greatly appreciated. Thanks

  • andrzej

Posted July 14, 2008 - 03:27 PM

#2

I just took the sprocket off my '06 YZ250 lat week (blew the crank and had to pull the bottom end).

But I took it off using an impact wrench (pneumatic). That's the easy way. If you're going to do your own wrenching, then investing in a compressor and some impact tools is worth the money and doesn't cost all that much.

Don't forget to bend the lock tabs flat first!

  • bikedude127

Posted July 14, 2008 - 03:29 PM

#3

I believe its a 32 mm.. And it can be tough unless you have an air wrench.. I have, in the past, just put it in gear and have someone apply the rear brake.. Once you get the socket on the nut, bang the end of your ratchet/breaker bar with a hammer.. Not suggested with a torque wrench though, good way to break it... You may be able to get her free that way..

Good luck

  • rusky

Posted July 14, 2008 - 03:30 PM

#4

a good way of doing it is to stick a wrench in between the chain and sproket so it will lock everything up and if you have a friend have him step on the rear brake while the bike is in gear. Then use some muscle on that nut :thumbsup:

  • WAMXP1MP

Posted July 14, 2008 - 03:51 PM

#5

I just use an electric impact wrench on it works good and is cheapier then pnumatic tools setup.

  • OREGONMX

Posted July 14, 2008 - 04:22 PM

#6

I do have a compressor. It's only a small 5 gallon one- would that work? A pneumatic impact driver is only $20 at Harbor Freight. Do I just put it in gear and loosen it up? How about tightening it back up? I don't want to F anything up.

  • techmc

Posted July 14, 2008 - 08:06 PM

#7

just finished taking off my frnt sprket on my 06, bent tabs back out and got my 32mm socket on my impact and went for it. It took a little longer than the last time to break it free,(with it in gear) but it got it done. I use an Craftsman electric impact also and it uses impact to tighten & loosen nuts and bolts instead of raw power, just like using a hand held impact with a hammer, but a lot faster. Just put the juice to it and it'll come off eventually!


Techmc

  • andrzej

Posted July 15, 2008 - 05:32 AM

#8

I do have a compressor. It's only a small 5 gallon one- would that work? A pneumatic impact driver is only $20 at Harbor Freight. Do I just put it in gear and loosen it up? How about tightening it back up? I don't want to F anything up.


Even a small compressor should work fine. Air impact wrenches don't use that much air (cfm).

As for putting it back, I would use a torque wrench and tighten it to specs according to the service manual. Always best to stick to factory specs for nut/bolt torques.

  • pard

Posted July 15, 2008 - 08:44 AM

#9

Anti-sieze,anti-sieze,anti-sieze

  • Matt_W

Posted July 15, 2008 - 08:45 AM

#10

I've used two methods that both work;

1) Wedge something between the teeth of the sprocket and the end of the swingarm, like a big wrench.

2) Buy a clutch/fly wheel holder tool. They are relatively cheap at $35 and can be used for a lot of different applications, such as holding the front sprocket while you take the nut off.

Also remember that leverage is your friend. I always have a 4 foot piece of metal conduit pipe on hand for high torque applications. I have a good compressor and impact wrench, but I still prefer good old fashioned leverage (and conduit is cheap by comparison). Put your ratchet on the nut and then slide the pipe over the end of the ratchet, and use the opposite end of the pipe to rotate the ratchet.

The leverage/conduit trick works only if you're working on something that you can stop from spinning. In the example above, you still need something to stop the sprocket from spinning. When you can't figure out how to stop it from spinning, then the brute force impact wrench is the only option.

I use the leverage/conduit trick for the rear axle nut, steering head nut, clutch nut and sprocket nut.

  • Luigic81

Posted July 15, 2008 - 08:51 PM

#11

I've used two methods that both work;

1) Wedge something between the teeth of the sprocket and the end of the swingarm, like a big wrench.

2) Buy a clutch/fly wheel holder tool. They are relatively cheap at $35 and can be used for a lot of different applications, such as holding the front sprocket while you take the nut off.

Also remember that leverage is your friend. I always have a 4 foot piece of metal conduit pipe on hand for high torque applications. I have a good compressor and impact wrench, but I still prefer good old fashioned leverage (and conduit is cheap by comparison). Put your ratchet on the nut and then slide the pipe over the end of the ratchet, and use the opposite end of the pipe to rotate the ratchet.

The leverage/conduit trick works only if you're working on something that you can stop from spinning. In the example above, you still need something to stop the sprocket from spinning. When you can't figure out how to stop it from spinning, then the brute force impact wrench is the only option.

I use the leverage/conduit trick for the rear axle nut, steering head nut, clutch nut and sprocket nut.


+1 rope in the spark plug hole trick, and I use a 2 foot open ended wrench as leverage on my socket driver

  • BRM

Posted July 15, 2008 - 10:47 PM

#12

I believe its a 32 mm.. And it can be tough unless you have an air wrench.. I have, in the past, just put it in gear and have someone apply the rear brake.. Once you get the socket on the nut, bang the end of your ratchet/breaker bar with a hammer.. Not suggested with a torque wrench though, good way to break it... You may be able to get her free that way..

Good luck


That is how I do it also. Give it a spray of WD40 the night before and it will come straight off.
It does not have to be that tight when you put it on.
Proof is a couple of weeks ago I replaced the bottom end............long story short I only hand tightened the front sprocket nut and did'nt bend the tabs either.
Ran it in on the Saturday. 4 + hours of hard trails up through the local hills on the Sunday. Tuesday talking with a mate he mentions that he has a new front sprocket for his bike and then it twigs:bonk: I could'nt remember putting a socket on the countershaft sprocket nut.
Sure enough go home that night and it is still in place.:thumbsup:
Man this bike must love me:ride:
Thanks Budda

  • Gani_riders

Posted July 16, 2008 - 10:39 AM

#13

Its a 30mm for sure i just did it 2 days ago

  • OREGONMX

Posted July 16, 2008 - 11:54 AM

#14

I don't mean to beat a dead horse here people- but I want to make this as painless as possible. I just bought a pneumatic impact driver today. I know I need to bend the tabs back and put the bike in gear. Should I have the rear wheel on the ground to provide a little more resistance or can I just put it in gear, keep it on the stand and remove the nut with the impact driver?

Yes, it would seem I am borderline retarded so the more step-by-step instructions I can get the better.- HA!

Thanks for all your tips- and FYI, on my 2006 YZ250 at least, it is a 32 mm nut- not 30.

  • shrubitup

Posted July 16, 2008 - 12:41 PM

#15

leave it on the ground for maximum resistance.:thumbsup:

I'm gonna do mine this weekend. I'm planning on PBBlaster, rope down the cylinder, my new 32mm socket, and electrical conduit as my breaker bar. Wish me luck!!

  • BRM

Posted July 16, 2008 - 02:10 PM

#16

Its a 30mm for sure i just did it 2 days ago


wrong... 32mm:bonk:

  • Gani_riders

Posted July 16, 2008 - 07:28 PM

#17

hmm apparently that was another revolutionary change through the years on the yz's... a 30mm to 32mm nut on the drive shaft lmao

  • OREGONMX

Posted July 17, 2008 - 09:37 PM

#18

So I got the thing off and it was pretty easy. I read every post on this subject after searching and everybody has a different answer. I noticed many people wanting a step-by-step "idiots" guide so here is what I did.


This is for the next guy who searches for how to do this.

I have a 2006 YZ250
I used a 1/2 inch drive pneumatic impact driver that I bought at harbor frieght tools for $22.99
The front sprocket bolt is a 32mm (I bought the socket at sears for $8.00)

The bike had both tires, sprockets and chain on it like normal
I left the bike in NEUTRAL
I took the bike off the stand and instead used the triangle stand.
Both wheels were touching the ground and providing resistance so I could get the bolt off
I bent back the metal tabbed washer with a hammer and a screw driver so I could get the socket on the bolt
I put the impact driver to the bolt (righty tighty, lefty loosey) and it came right off.

Hopefully that will help the next person.
Thanks for all the tips

  • rparobi

Posted June 14, 2009 - 11:25 PM

#19

Whats wrong with getting someone to apply the rear brake while you undo the nut, works for me every time , and there is also less of a chance of damaging your gearbox from the pounding force transmitted through your gearbox from the impact wrench.

  • ajd187

Posted June 15, 2009 - 05:44 AM

#20

I leave it in neutral, hold the rear brake, and use an impact. Works every time.





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