Hi Henri..there were various patterns of cam spindles..some marked for fitment, some not. Early ones were drilled all the way through and then the hole was sealed with lead solder on completion of machining.
There are other odd features as well...I have never got to the bottom of this question but I have been told the inlet and exhaust spindles (when marked at least) were subjected to different heat treatment. While there is obviously a reason for them being marked I am at a loss to explain it definitively...they appear to work under identical operating conditions...
The timing side bearing can be removed by heating the crankcase thoroughly to approx 100 degrees (not less but a little more is ok) and then using a hammer and parallel punch to carefully drift it out (through the holes provided in the crankcase) taking care to drive it out as squarely as possible. With the case heated it may actually fall out if you drop the casing face down onto a piece of flat wood of appropriate dimensions.
Always heat the cases when removing and replacing bearings and spindles etc. to avoid damage to the case and subsequent loss of fit.
If the parts are to be reused avoid applying any direct heat to them, heat the cases indirectly, from behind for instance...Ian
email (option): ian@wright52.plus.com
Yes..100 degrees C...The spirals aren't 'handed'..there is no apparent difference between the spindles...Ian
email (option): ian@wright52.plus.com
The easiest way to remove anything like bearings and shafts from crankcases is to thoroughly degrease them (I mean thoroughly or you'll be in trouble!!) open the windows in the house and switch on the extractor fan over the oven and put the cases in the oven for about 20 minutes, the good thing about putting them in the oven is you cannot really damage the cases with the heat, if it has a glass door keep checking until the bearing has fallen out, then you can remove the circlip (with oven gloves on) and the last bearing should fall out, if you have the new bearings it would be wise to put them in while it is still hot, they should just drop in just to save you repeating the process. If you want the shafts out they should still need a light drifting to remove them 
email (option): davmax@ntlworld.com
Putting the bearings in a sealed plastic bag and placing them in the freezer for a few hours before fitting also makes the job even easier...Ian
email (option): ian@wright52.plus.com
I use a propane torch for all the ones I do..The reason I mention 'indirect' heating is that the temperature is sufficient with that type of torch to affect the temper of hardened components if carelessly or inadvertantly applied to them for too long.
In every case, however, it is possible to heat the surrounding casing 'indirectly'..allowing heat transfer to do the job and with that method damaging temperatures will not be reached in the steel components...Ian
email (option): ian@wright52.plus.com