Heavy Twins

So being a newbie to the qwerks and wonders of classic bikes...

The DSN lists lots of piston changes.  But Haynes notes that the barrel height changed in 1960.  Higher and lower compression pistons continued but the high ratio went up and the low compression pistons now gave CR nearly as high as the high compr

The speedo drive on my '58 99 only seems to be engaged in the rear wheel gear when I unscrew it from the speedo and gently pull it. When screwed in and engaged in the speedo it isn't engaged.

Any clever tips for a leaking screw in petrol tap ? I bought new good quality Taps with the rubber and metal washers but no mater what I do they still `weep` . It looks like the petrol is finding a way down the threads.

I had posted about my silencer which was hanging loose because the bolts had vibrated themselves off the bike and it was hanging loose. 

I am restoring a Norton Dominator 1955 88 Deluxe

Can anyone help me? I have an oil pressure problem on my 1949 Norton Dominator model 7. When I start the engine cold the pressure goes up to 100 Lbs. When the engine is hot the pressure drops to 10 Lbs and sometimes even 0 Lbs. I use SAE50 oil.

job for this weekend.
When I undo the throttle I won't end up with pieces disappearing into space never to be found again? Is it a straightforward process?  Any tricks?

thanks
'61 99 Dommie DL

Hi as my bike was rebuilt with an Avonaire fairing, my front forks are very hard - side car weight
springs were added and without the fairing, it tends to crash around on our bumpy potholed roads.

I'm trying to ID this works fuel tank...could it be from one of the Domi Racers.....