Castellated clutch nut removal

[buxtonmick]

Righto, now I'm getting stuck into my project and, like someone said somewhere "an old motorbike is like a box of chocolates..."  Apart from two scored cylinders from broken rings and two snapped exhaust studs (any tips and/or ideas welcome), I've now got to the clutch removal bit.  I've got the tool to fit the nut but will it move?  Nowt.  So before I try anything of my own invention does anyone have the knack to this, namely, how to hold the centre from turning?

Cheers, Mick.

[Seamus]

May be wrong, but the centre drives the gearbox. So put it in gear and put the chain round the drive sprocket. Lock the chain using a screwdriver through the links and a bit of wood between the motor and the screwdriver, this should hold while you undo the centre nut. Take care where the motor is being loaded from the wood.

Worked for me on the 750

[UKROBK7]

I agree, on the 750 I have done that.  If the engine is out of the frame you will have to lock the drive sprocket using the chain method but I have found that the tool etc that you use to lock the chain can bend as the chain is quite narrow to get anything decent through it. 

Having done that:

Check to make sure lock washer is undone completely (mine had one of the ears broken off short and was difficult to see that it was still locked up).
Put it into gear
Use a breaker bar or good T bar on the special tool (I ground an old socket down to fit)
Give the end of the bar a sharp belt with copper mallet!  The impact will free it better than just putting pressure on the bar.

Or, if you are a bit more professional use a rattle gun!

If the engine is apart I think you will have to come up with an idea to hold the mainshaft safely without damaging the gears.

Rob

[buxtonmick]

Thanks for the help folks - I knew there was something not quite right!  The thing still won't move though, the clutch slips.  i've left penetrating oil on it and I'll have another go at weekend.  Aaargh!!!!

[UKROBK7]

I don't understand the clutch slipping bit.  If I am correct (not often according to my wife!) the nut is on the mainshaft.  When you put it in gear the mainshaft is connected via the layshaft (countershaft) to the drive sprocket.  So when its in gear and you are trying to undo the nut with the sprocket jammed the clutch doesn't come into it (unless as I said, I am wrong!).  I have had a look at the parts diagram for the 400 but can't see what the problem might be.

Rob

[buxtonmick]

Hi Rob, Thanks for your help. I've got the engine on the bench so maybe I haven't got the gear to engage - I'll have another try at weekend.

Cheers, Mick.

[buxtonmick]

Er, it does unscrew anticlockwise...?

[Seamus]

As far as I know it is a normal thread. Just make sure that you have put it in gear (use 1st). Check by ensuring that the sprocket turns when you turn the engine over.
I have one to remove over the weekend, so I may have a bit more experience next week and could add to this .

[470four]

http://cgi.ebay.co.uk/Honda-CB400-FOUR-FOUR-400-4-CLUTCH-TOOL-SOCKET-hj-/260791697247?pt=UK_Motorcycle_Parts&hash=item3cb8657f5f#ht_500wt_1156

Broken rings usually caused by overrevving/too much throttle hand? 

Did my clutch many years back, remember it being straight-forward tho? Seems to be one of those jobs where it can be a nightmare or real easy...

[buxtonmick]

470four; Reading the manual, it simply says "unscrew the castellated nut" - well I used the tool that you link to and ended up bending the 'prongs'!  The nut eventually came off using heat and a drift after soaking with penetrating fluid for a couple of days - anyone know where I can get a new one?

[UKROBK7]

From Dave Silvers -

[470four]

470four; Reading the manual, it simply says "unscrew the castellated nut" - well I used the tool that you link to and ended up bending the 'prongs'!  The nut eventually came off using heat and a drift after soaking with penetrating fluid for a couple of days - anyone know where I can get a new one?

Ouch!  Seems a modded socket would be better longterm then being steel rather than alloy...

As above - David Silver will be able to sort you out with a new one  

[exvalvesetdabbler]

To lock the drive train I usually stuff the end of my leather trouser belt in the teeth of the gear on the outside of the clutch basket.