Atlas oil pump and starting queries

I think I would just try it.  But back the timing to 28.  Mixture could be a bit rich , slides could be a bit low. Try a couple of turns on the throttle stops.  The low pressure return feed could be restricted a bit if needed. 

Unless your Atlas has been fitted with the much later conrods, with oil bleed holes on the top shoulder, big-end shells with holes in them should not be a problem.  If you fit 6 start oil gears to the earlier Atlas engines you end up with a win / lose situation. The extra oil pressure is handy at low engine speeds and the oil filter will impede the return slightly which helps push oil up the low pressure return feed to the rockers. The downside being the oil pressure release valve will tend to kick off sooner with higher revs and dump lots of the excess oil into the timing cover.

You probably will need to adjust the ignition timing to 28* BTDC.

What size Monobloc Carbs have you fitted? A 1963 Atlas should be sporting a couple of 389s with much larger main jets. Probably 360 main jets with an air filter, larger without. A pair of smaller 376 carbs with 250 jets would struggle to breathe.  See attachment which shows suggested carbs and settings for various Norton Models.

That revcounter cable will not survive .  

Many times this has been condenser in the magneto, or a break down in the winding's. Once the machine has been layed up for many years this is highly likely.

Some Manxman and Atlas Big bore pipes  were  bent inwards to give space for the r/c cable, I have a set on my Atlas but I also have the 90 degree set up. I still think I would run it for a while with the current set up. If is smokes a lot and does not clear up after its run in then  think again. Another option might be just fit the larger capacity pump with 3 start gear set (which could be already fitted)and maybe get the oil pressure reading checked to see its enough. It may be possible to take off the head/barrels and look at the drilled rods ,apply oil at pressure to the crank end and see what transpires. I love an experiment !.

Holger

As Al suggests it sounds like a case of the above. I had this with my 650SS and my 500 Dommie, both of which would regularly get me 20 miles from here and then develop a misfire, stop, and wouldn’t re-start. The condensers on a K2F had a limited life, and heat seems to provoke their failure mode. Replacements sometimes aren’t up to snuff and can also fail. I went Lucas Rita and then finding them sensitive to battery voltage ultimately fitted modern BTH mags, which are fit and forget. They cost about what I believe a recon of a K2F would cost if it needed a rewind and was done right. I decided to bite the bullet and eliminate an old mag and an old charging system as variables. I have BTHs on a 650SS, a standard-ish 88 and now an 88SS and they’ve been really good. OTOH, if it’s sparking when hot the starting problem is probably not the mag, although only swapping it out would tell you for sure.
 

Re the six start pump I would agree with Bob and try it with the scrolled rockers and low pressure feed. My 650 had the plain rocker shafts but the low pressure feed, so, I suspect, a mixture of low pressure and higher pressure parts. After a valve guide came loose and the others were v worn (at which point I discovered the plain rocker shafts) I obtained a head with good guides, put scrolled rocker shafts in, retained the low pressure style feed with what I suspect is a high pressure pump, and it has been fine. I read somewhere that John Hudson, no less, stated that this arrangement, six start pump and low pressure feed to head, was OK, so I tried it.

Excess carbon on the piston could be worn valve guides - I had to have mine done on all three bikes.I’m hoping that the scrolled spindles will mean more oil mist around the head and less wear on the guides, but time will tell.

Phil

A very useful document. I’ve often wished there was more info about the alteration to make to these jetting figures when fitting air filters, as this information is hard to come by.

I think Al Oz was correct to suggest the condenser being the culprit if poor hot starting.

The answer to that is the 'easy cap'  from Brightspark.

http://brightsparkmagnetos.com/easycap/index.htm#:~:text=Universal%20EasyCaps%3A%20The%20%27Universal%27%20EasyCap%20is%20an%20ignition,be%20shaped%20to%20fit%20wherever%20the%20space%20permits.

I had the same problem on my 16h, but not any more.

And what's this with a she motorcycle?