1965 Atlas rocker spindles

The rockers are fed via a pipe banjo in the return feed to tank.

Thanks Guys. Confirmed what i needed to know, and useful information for the future.

Ian

Previously wrote:

The first Atlas engines, from 1963 on,had scrolled spindles with flats that were positioned facing the spark plugs. ie. inwards.

The Atlas rockers and spindles then changed twice. Firstduring 1965 and and another in 1966. First the rockers were shortened in length, in 1965,to allow chunkier bosses to mount the scrolled spindles. The flat were still kept facing inwards. The following year, the spindles were changed to plain withthe small flats now facing outwards. This change, in 1966, coincided with the arrival of the 6 speed oil pump gearing and pressure feed to the rockers.

As a general rule, by 1966,the barrelshad also lost their spigots and the cylinder head bolts (next to the plugs) changed from 5/16" to 3/8" . These cylinder heads should be sporting the plain spindles. Heads with thethinner 5/16"head boltsought to have scrolled spindles.

The problem faced with many Atlas owners is the history oftheir engine after nearly 50years of service. In that time there is a very good chance ofan earlycylinder head receivingplain spindles as an upgrade including a pressurisedrocker oilfeed or just the spindles alone.

After 40 years of owning quite a fewNorton 750 bikesIalways suggest that the spindle flats are fitted facing towards the rocker covers.ie. outwards irrespective of the type of spindle. The scrolled spindles tend to wear out the rockers more quickly so the flow of oil is not going to be hindered.

The most common mistake, thatpeople make, is to upgrade their engines to pressurised rocker oil feed without checking that the cylinder head has plain spindles. If scrolled spindles are left in place then a very smoky engine canresult.

Thanks for the reply last week Phil. I do have scrolled rocker spindles and i cant remember which way the flats were facing. If i put the spindles in with the flats facing outwards the oil hole in the spindle will not line up with the hole in the rocker arm, instead the oil will have to flow around the groove in the spindle to get to the rocker arm. Is this OK ? I have worked on several Nortons in my time and as far as i know have always put the flats facing outwards, it just that this time i happened to pick up a different manual as i was checking some rebuild settings. The book was Norton Dominator Twins by W.C.Haycraft and it states 1955-1965 Flats facing inwards. All my Other manuals say the opposite. My fault for reading the manual !

Thanks for the reply last week Phil. I do have scrolled rocker spindles and i cant remember which way the flats were facing. If i put the spindles in with the flats facing outwards the oil hole in the spindle will not line up with the hole in the rocker arm, instead the oil will have to flow around the groove in the spindle to get to the rocker arm. Is this OK ? I have worked on several Nortons in my time and as far as i know have always put the flats facing outwards, it just that this time i happened to pick up a different manual as i was checking some rebuild settings. The book was Norton Dominator Twins by W.C.Haycraft and it states 1955-1965 Flats facing inwards. All my Other manuals say the opposite. My fault for reading the manual !

Previously wrote:

Well slap my hand for getting that Atlas production date wrong by a few months!!! 1962 it is for export models and 1963/64 for the UK unless you were lucky enough to get one of the 62 registered bikes used by the UK dealers to promote the first models.

The book, Norton Dominator Twins by W.C.Haycraft is actually a very useful reference tool and contains more accurate detail than quite a few other publications. But........only covers bikes up to 1965. I have the 1973 revised edition, with the Green cover, but even that does not appear to mention later bikes or give specifications for them.

John Hudson ( Norton Factory engineer for many years)noticed that the rocker spindles on many of theMercury 650 Nortons did not have oil feed holes that aligned correctly but reckoned that oil would still be able to circulate if a) it was clean. ie regularly changed and b) was preferably a multigrade like a 20/50. his preference was Castrol GTX which I believe in the 1970s got upgraded to a 15/50.

He also recommended thatwhen servicing the head (valve seat etc)the oil feed holes by the spindles plates should be checked and cleaned.

Thanks for the help Phil, very useful. This forum is invaluable.