So I'm dismantling the engine of the B33 barn find I have. I'm having trouble removing the magneto drive pninion center nut. Everytime I take a spanner to loosen it...the entire cam gears rotate with it. One of the fella's in the garage said to stick a spanner in the teeth of one of the cam gears to stop it rotating when I try to loosen the nut but that sounds a sure-fire way to knacker the gears themselves.
In the Haynes manual, it says just use a spanner to loosen it....and then use a special tool (no.61-1903) to extract the pninion itself. No chance of me getting to that pninion with this gear and nut in the way though...
Put the bike in gear, sit on the seat with one foot on the rear brake, remove the nut. The pinion gear sits on a taper. You need an extractor, 61-1903, that threads into the center of the gear. Snug up the bolt in the center of the extractor but don't over tighten. The bolt doesn't remove the gear, a light tap on the end of the bolt will break the hold on the taper. If you use the bolt to remove the gear you will mushroom the end of the magneto pinion.
Cheers boomer, unfortunately the engine is already removed and laying on a work bench...so no chance of me placing the bike in gear and removing it that way. Good tips for pninion Removal though. Perhaps sticking an old wooden Broom handle between the CAM gears like Larry suggested might work without arsing up the teeth on the gears..