oil flooding inlet valves

Problem Solved,undersize rocker spindles leaking excessive oil flooding valve stem seals
thank you rohan ,dyno dave and others
i ordered new spindles and guess what ?

the straight/plain rocker spindles fitted appeared to be correct if a little worn.

i measured new spindle and it was 5/1000 bigger (as per recommended diam .4985 in)

the old spindles are undersize all over,not just where worn.

instant fix,smoke gone

the norton manual (1970s manual) says flats towards the valves but this prevents oil going along tappet to pushrod

i have fitted spindles with flat facing inwards to centre of head and working fine.

thanks again for your help.

merry xmas from Rod in Sydney

domiracer22 said:

The norton manual (1970s manual) says flats towards the valves but this prevents oil going along tappet to pushrod

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The holes being out of line is what's intended so the flats should face outwards, AWAY from the head.

domiracer22 said:

the norton manual (1970s manual) says flats towards the valves but this prevents oil going along tappet to pushrod

i have fitted spindles with flat facing inwards to centre of head and working fine.

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:shock:
Flat facing away from ball end DOES NOT stop lube of the ball end.
You have created 4 constant leaks to your HP oiling system and helped to starve the rocker shafts of oil. :roll:
Well maybe just 3, since one valve is always engaged and rocker is seated in the pushrod.

dynodave said:

Sounds like his OPV is is not contributing to his flooding. A seized OPV has yielded over 150psi. The opposite may be true...If anything the internal parts of the OPV are missing and you would have a lower pressure. Most OPV I've tested have opened 55-65psi and as rpm goes up the pressure does also...it does not limit the absolute pressure but only aids in limiting the amount of over pressure. It can often hit 75 but does not go to 150+...
When the oil is hot the OPV would almost never function.

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Here is a scenario that I experienced when I fitted double speed oil pump and Commando rocker feed – the pipe of the Commando rocker feed kept blowing off :!: :shock:
Cure, remove and clean OPV
There must have been an lot of oil pressure to do that :!:

Bernhard said:

the pipe of the Commando rocker feed kept blowing off :!: :shock:
Cure, remove and clean OPV

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"kept blowing off" ? why more than once?
A properly assembled line can easily stand 150PSI :!:
It's a reoccurring topic for the newbee's at my tech sessions for the last 25 years
correct grade of nylon and assembled with NOheat

However that does not stop the bling bling crowd from putting stainless braided.
I've been given a stainless braided set up (free) but refuse to use it.

re; “"kept blowing off" ? why more than once?
A properly assembled line can easily stand 150PSI :!:”

I got through no less than THREE oil pipe lines from Norton spares agents before someone told me what the problem was-so I disagree with the 150PSI :!:

Typical industrial hydraulic hose is assembled to operate happily with over 3000 psi.
Not that Nortons use anything like industrial hose or fittings, OR those sort of pressures.

The stock Commando plastic oil line to the head seems pretty bulletproof - but they do age,
and the plastic can just simply fracture. Then its time for a new one....

You guys need to quantify/explain/show what sort of hoses you are/were using,
or this is just another p*ss*ng match.
DD, show one of these hoses you claim you can make, with testimonials from happy customers . ?

Bernhard said:

re; “"kept blowing off" ? why more than once?
A properly assembled line can easily stand 150PSI :!:”

I got through no less than THREE oil pipe lines from Norton spares agents before someone told me what the problem was-so I disagree with the 150PSI :!:

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One of my lines:
I was going to a friends for thanksgiving diner and it was sure cold. 50W oil 25deg F., I fired up the combat with a handle bar mounted oil pressure gauge off the the end of the LH rocker line. Gauge full scale was 11 bar (150psi) wham.... pegged the gauge full scale. did not pop the line off, did not invert the crank seal. Idled it further and low reved till warm enough to ride. Last ride of that year!!!

I will concede that the pressure rating are very temperature dependent, since the "plastic" lines are black nylon 11 anything else would be vastly inferior. I never found anything close enough to even bother a try. Black seems to have the best ratings over clear or colors. I've tested several manufacturers to find the best one. Even during this test of black ones, the spread was more than I would have expected.
I have only seen one commando ever loose the oil line. Once we repiped it, it never failed again and that was 10-15 years ago. I only use oem (norton factory) fittings. A repiping is under $3. 1ea 9.5-10" piece and 1ea 24.5" piece all put together in the same plane so you don't have to twist the fitting. Done many for club members.
Hold the line in a flareing tool
pound in the fitting cold..use a plastic mallet--- critical do no use any heat ---make sure they are all in the same plane before pounding in.

The original Model 7 dommies for 1949 had an oil pressure gauge in the tank, full scale reading is 160 psi.
The official Owners Handbook notes that pressures over 100 psi can be seen with cold oil,
hence the oil gauge's high full scale capability.
And thats without any 6 start gears on the oilpump...

The other side to that is that once warm, with a well used motor, the readings on the gauge can be abysmally low.
It was said the gauge was removed for all later models, the low readings scared owners !

thanks dave,

happy new year

my dominracer 750 came with non scrolled rocker spindles and 6 start oil pump gears and

the oil feed to rockers is from timing case banjo bolt

New oil gauge showing operating 2000rpm oil pressure 40psi cold ( Sydney summer 25 C/90F) and 20 to 10 when hot

yes i have put compressed air up and down oil drain n works correctly

yes bike has timed breather

the original non scrolled plain rocker spindles were manufactured undersize allowing oil to flood inlet rockers and hence oil bypassing valve stem seals

new spindles provided instant fix ,no smoke.

with flats correctly fitted towards valves no smoke and plugs running light grey

thank you cheers rod

domiracer22 said:

thanks Rohan,

the 1962 dominator had original oil tank with 6 start gears on oil pump and oil feed to the head is from timing cover

i believe the oil flooding inlets situation was OK before fitting this oil tank as i purchased domiracer with manx style tank already fitted .

the bike was only ridden on country roads with no idling

and i live in Sydney and city traffic dictates idling .

it is possible problem was there since originally built, and has never been good in the oiling dept.


wih valve covers off and warm engine 1200rpm there is continual oil flowing/escaping from both sides between shaft and rocker shafts

clearances seem ok

i tried reducing flow rate by reducing 3 banjo bolts orifices from 2.5mm to .7mm but no difference

i have photos if i can work out how to post them

cheers rod

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have you made sure the drain oilways that run down the back of the cylinder head and barrel and then runs into the timing side space its does get blocked in the elbow in the crankcase bottom just under the back of the barrel on the right-hand side oilway and they get covered up by the fiber washer under the valve spring bottom cup has the oilway is next to it, check all these oilways has they drain any build up of oil from the inlet side try pipe clears and a long 3/16th drill bit and have a poke about good luck with it all

Interesting she quotes the third post,
IGNORES the subsequent 12 posts where you find the cure to the problem,
and is after the fact going to help you fix what you have already found as the fault :lol: :lol: :lol: :lol: :lol:

Any Idea what is the source of those undersize rocker shafts?
are they home made? Soft steel?
Can you catch metal with a file?
An oem shaft is very hard and a file will skate off and not catch metal.