Get yer front sprocket off !

[Vitesse39]

As you may have guessed I'm trying to get the front sprocket off to change an oil seal (don't like oil dripping on to rear tyre ;) ).
As you know the sprocketis on a splinded shaft and held on by a nut which is on very tightly. This is the nut I can get off.
The 'F:censored:K it with haynes' book says put it in gear and that will stop the output shaft turning (yeah right), so I've got the bike up on the rear paddock stand with a bar through the rear wheel aswell so it won't turn.

I'm using a proper sochet with a breaker bar to try to turn the nut but don't want to put too much strain on the chain and knacker that up.
I have tried giving the end of the breaker bar a good wack to shock the nut into turning but no joy and the sochet starts to slip off and begin to mash the shape of the nut up.

Before I could get a bloke with a pneumatic gun to do it in 2 sec flat, but there must be a way with out one..........any ideas ????????

:scratchchin::scratchchin::scratchchin::scratchchin::scratchchin::scratchchin::scratchchin:

[Incorrigible]

If you've go the bike in top there won't be that much pressure on the chain

However, if you're trying your hardest with a breaker bar, that doesn't sound right. It's not a left hand thread is it ??

[Vitesse39]

I'm fairly sure it's a standard thread, but of course last time it was done up with 'blokes gun' again.

[dern]

Incorrigible said:

If you've go the bike in top there won't be that much pressure on the chain

If you're using the engine to provide resistance and the back wheel is free then there won't be any pressure on the chain. If you're locking off the back wheel with a bar to provide resistance then in won't matter what gear you're in surely?

If the former doesn't work (engine still turns over even when in gear) and you decide to lock the back wheel off then I can't believe that you will be able to muster as much force on the chain as the engine would.

I would definitely double-check the thread direction though as Incorrigible suggested.

Mark

[fergus]

double check that the lock tab is not folded over. The thread should be a standard one (i.e. right hand thread).

Your best bet is to use an impact wrench on it. If a breaker bar is not shfting it, then it must be torqued up pretty tight. They tend to tighten themselves anyway due to the load on the chain/outputshaft. If you can't get an impact wrench on it, try one of those impact driver things that you hit with a hammer to shock it (assuming you can get one with a 3/8 or 1/2 inch drive to fit a 32mm (?) mm odd socket. If you don't have done of these, try getting old socket that is larger than the o.d. of the output shft and placing it on the end of the socket and then hitting it. This sometimes shocks the threads and allows you to then undo the nut. Howeverr, make sure that you won't damage the gearbox internals from pushing in the output shaft if you choose this route. Personally, I'd go down to a local tyre shop, get them to whip it off, tighten it with your hand tools (fitting the security tab again), ride home whilst not accelerating too hard, then take it off at home with the breaker bar.

Remember to fold back the security tab when you've finished!

Good luck.

[Incorrigible]

dern said:

If you're using the engine to provide resistance and the back wheel is free then there won't be any pressure on the chain. If you're locking off the back wheel with a bar to provide resistance then in won't matter what gear you're in surely?

I have no idea what my brain was doing when I wrote that

Complete bollox, sorry. Dern is spot on

[s2ooz]

I just got a 3rd party to keep the foot on the rear brake, thats stops the rear wheel turning..

[Vitesse39]

I have just found out that this nut should only be at 94lbft of torque........let's just say it is currently way over !
I have also been assured that it isn't a reverse thread (thanks 'On Yer Bike'), so I can go home tonight and attempt to remove the rest of the skin from my knuckles.