rocker spindle alignment

Commando spindles are plain and the hole is positioned forward for the exhausts and rearward for the inlets. Why? Does it matter on the inlets?

If the spindles are aligned "backwards" you will have too much oil delivered to the rocker boxes - to the point where oil will fill the boxes faster than it drains through the VERY small drain holes. Oil then fills the box so that the level is above the valve guide. The guides/seals cannot deal with being submerged in oil and considerable oil burning is the result. The oil will overflow back into the crankcase but the guides/seals remain submerged because the drain holes at the bottom of the rocker box are overwhelmed.

I solved an oil burning problem with my '73 when I discovered that the company who sold me the bike - and bragged on the "totally rebuilt engine" had installed the spindles backwards...

I have a set of plain rocker spindles with no flat. are these usable in the MK3?

seattle##gs said:

Commando spindles are plain and the hole is positioned forward for the exhausts and rearward for the inlets. Why? Does it matter on the inlets?

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It does mater equally on in and ex.
When the shaft hole faces the valve, the oil must lube the whole shaft prior to leaking out toward the ball end of the rocker. This is proper and adequate lube for the ball end.
If installed with the hole(&flat) pointing toward the ball end, it starves the rocker of pressure feed and the oil takes the path of least resistance and blows out the ball end.
kill the rockers
kill the rockers
kill the rockers
Extra oil in the intake area is only a secondary indicator...often followed with smoke

I would be extremely hesitant to use the bogus shafts you have

The MK3 manual tells me to position the hole towards the ball end ON THE INLET ONLY. The exhaust is positioned towards the adjuster. I have watched the rockers while its running and the oil is gushing out the ends of the rockers. I would have guessed that if the hole on the exhaust is positioned towards the adjuster because of oil pressure reasons it would be the same for the inlet. The manual tells me different (with no reason supplied). Is the manual wrong?

NOW FOR A TANGENT...once the spindle is worn,oil will flow freely out the ends of the rockers which would change the path and pressure of the oil flow. I will guess that 90% of Nortons on the road are running worn or very worn rocker spindles. I have three sets and most are worn at least .001 and unevenly. To replace or not to replace? I believe most Nortons could chug along quite happily for many miles in this condition but its less than perfect. (perfect as described by Norton engineers). I will bet almost no one replaces the spindles. They are about $35 apiece and rockers are about $250 apiece from Andover Norton. So what happens while running worn spindles and possibly worn rockers? More valve clatter?

seattle##gs said:

The MK3 manual tells me to position the hole towards the ball end ON THE INLET ONLY.

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http://britmoto.com/manuals/Manuals/850_man.pdf
Section C8,

2."Engage a rocker spindle into the cylinder head with the flat facing rearwards on the inlet side and forwards on the exhaust....
.
.
.

6. Align the rocker spindle as shown in Fig. C7.
Note : Flat on spindle faces away from centre of head, towards rocker cover."

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LES beat me to it

I see. It would have been clearer if the manual had used the terms "ball end" and "adjuster end". No confusion with that.

seattle##gs said:

I have a set of plain rocker spindles with no flat. are these usable in the MK3?

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I had a set too , coming from a 650 , and as you I want to know , they seem to be fit between the scrolled (3 start pump) and the plain with flat (definitly 6 start pump ), but ..........! may be dynodave could chime ........

The scrolled rocker pinion was used on the Atlas and earlier bikes with the feed from a tee in the oil return line. There was very little pressure.

If you use the scrolled pinion with high pressure feed [from the timing chest] then you will flood the head with oil just like you will if the rocker pinions with the flats are turned the wrong way.

Worn rocker arm shafts and rockers don't make extra noise but they do reduce the oil available to the crank.

Hi Jim, thanks for that , but what about those non-scrolled , so plain , but with no flats ??
we have a friend here with a 650 who got them ....?

I would not use a plain spindle with no flats.

Plain spindles with no flats seems (consensus) to be a tempory version in the beginning before the later featherbed twins finalized on the ones with the flat as a oil dispersal area without permitting a direct path to the rocker ball passage.
I myself, would not use plain shafts either in any motor of mine or on a customers engine.

Just a thought, what did Norton do when they inserted double speed oil pump worm mid 1966?

Bernhard said:

Just a thought, what did Norton do when they inserted double speed oil pump worm mid 1966?

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That was done at the time they went to high pressure oiling to the head. The 3 start gear did not deliver enough oil for both the crank and the head.

At first they went to plain rocker shafts and then they replaced those with shafts with the flat.