Removing the magneto sprocket/ATD on Dominator

Heat the extractor up with a blow torch trying to keep most of the heat to the centre. To avoid overheating the tiny springs I would dismantle as much of the unit as I could, certainly the springs can be unhooked and taken off, and, I think, the bob-weights might be able to be slid off their spindles too. When you have the unit spitting hot (spit on fingertip will sizzle when touching the unit) tap gently sideways all the way round the unit with a small hammer at the same time as holding the centre nut with mole grips and wriggling the whole unit strongly and pulling at the same time. Obviously the centre nut should be fully loosened before starting the above procedure....Good Luck.....Les

PS...You may wish to try doing it cold first, you could be lucky, but resort to the heat method if this initial attempt fails....Les

PPS...It will also be better if you loosen the magneto and adjust to get the most slack on the magneto chain...This will allow more wiggling room. You will have to tighten the mag nuts back up slightly to hold the mag in position whilst doing the extraction....The top two will do.....Les

You may have read this elsewhere, but, if you succeed, replace the bottom mag nut with a BSA long sleeve nut. Removal, and replacement, of the mag will be much easier.

Previously les_howard wrote:

Heat the extractor up with a blow torch trying to keep most of the heat to the centre. To avoid overheating the tiny springs I would dismantle as much of the unit as I could, certainly the springs can be unhooked and taken off, and, I think, the bob-weights might be able to be slid off their spindles too. When you have the unit spitting hot (spit on fingertip will sizzle when touching the unit) tap gently sideways all the way round the unit with a small hammer at the same time as holding the centre nut with mole grips and wriggling the whole unit strongly and pulling at the same time. Obviously the centre nut should be fully loosened before starting the above procedure....Good Luck.....Les

PS...You may wish to try doing it cold first, you could be lucky, but resort to the heat method if this initial attempt fails....Les

PPS...It will also be better if you loosen the magneto and adjust to get the most slack on the magneto chain...This will allow more wiggling room. You will have to tighten the mag nuts back up slightly to hold the mag in position whilst doing the extraction....The top two will do.....Les

Not sure if this helps? The mag drive chain on my 99 has a removable link fitted. If yours is the same you could get away without having to struggle with the mag bolts.

Also it might be possible to ease the A/R off using a pair of suitable wedges behind the A/R. Gently tap them in and let them gently push the A/R along the taper until it loosens enough to pull it off manually. Keep us up to date....John

My Dommie's PO replaced the self extractor. Now it has a bolt to hold it in place. When the bolt is out the inside body has a thread and a separate extractor is used to remove it. My guess is that it was tapped in situ (or why did he bother?). But at least it is a reliable way to remove it.

There isn't a lot of room for a gear puller but that's what had to be used on earlier bikes. The handbooks illustrate a hooked bar to remove the sprocket without wrecking the alloy behind. I wonder if anyone has one and does it work? It is supposed to push the end of the shaft as it pulls behind the sprocket.

I remember having this problem on a Velo maybe 30 years ago. I removed all the mag fastening nuts so that the gear auto advance was against the crankcase. I hammered on the centre of the shaft with a centre punch and it released. I may have hammered on the nut partially screwed on, I don't remember. Don't hit hard enough to crack anything.

Just thought of another way:

The method will use a slide hammer...these can be bought for about a tenner. You will have to make up the attachment with a strip of mild steel about 8"-12" long and about 20-25mm wide.

1) Drill a hole in the centre to enable it to fit to the bottom of the slide hammer shaft.

2) At each end using a vice and hammer, bend over the strip to form "L" shaped tabs to hook behind the AR unit each side of its diameter.

3) Then bend the strip to form a large triangle shape so the centre hole is at the apex to form a puller that the slide hammer can pull against.

You can then use the slide hammer to directly jar off the AR unit, noting that once again initial attempts might need the heat treatment should it not come off cold......I'm pretty sure this will work though.

If however the unit is really stubborn and the puller slides off the back of the AR unit, drill the steel strip on both sides just above the unit to accept a long 10mm bolt with nut. This can be tightened up to stop the puller arms spreading apart and thus lock the bent ends behind the unit.This will enable even harder thumps with the slide hammer to be implemented.

http://www.ebay.co.uk/itm/Slide-Hammer-Dent-Puller-Set-5-Pce-Piece-460-MM-380625-/171501273854?hash=item27ee45c2fe:g:7GMAAOSwcu5UPTff

Lots more available similar

Les

Hi Dan....I have just remembered something VERY IMPORTANT!!!!

I should have stressed that great care is also needed when trying to remove the drive mechanism from a K2F mag....the steel drive input shaft is only fixed into the mag armature by being cast into the front brass section of it, so it is "relatively" easy to pull or break away the shaft when pulling the drive sprocket, cog or AR unit off in this manner...even though there is the front bearing holding it inside the case. The built-in self extractor pushes against the end of the shaft so wont pull it out of the armature. (note: the input shaft does not go right through the armature...just fixed into the front of it as said).

Unfortunately any levering or detached pulling or tugging method is going to exert this potential damaging force....so here I am ...shooting down what I have just suggested, but I don't want you to damage your mag!

With embarrassment I do not now recommended the slide hammer....or any other levering method either.......I can hear you groaning.....sorry

I think to be safe you will need to hitch up a conventional beam extractor with two or three legs to pull on the AR unit and push onto the centre of the loose nut, perhaps tapping the centre bolt when good force has been built up. The biggest problem is the lack of space behind the unit for the legs so you may well have to make one up to suit but better you do this than damage the mag's armature which is a REAL possibility (don't ask how I know!)....Heating really does make a big difference with this type of problem so would strongly advise this if initial mild attempts are fruitless.

VERY sorry for perhaps giving bad advise earlier

Les