Rocker Spindles Too Short

thunderbolt · Dec 22, 2017

I am rebuilding the head on my MK2 Commando. When I went to refit the rocker spindles which I purchased from RGM I found that when pushed right home they were .070" inside the surface of the head where the side plates bolt on to hold them in place.

This means in my opinion that the spindles would be able to rotate and cut off the oil supply to the rocker arms as the end plate with the two sprags in it would not locate in the slot in the end of the spindle.

I've come up with two possible solutions which are:

1. Fit a washer made to order in the blind hole where the far end of the rocker spindle fits therefore causing the spindle to not go in as far and therefore locate with the end plate correctly.

2. Use some Loctite Bearing Mount to locate the spindle in its correct position.

Thoughts please and any other solutions I haven't thought of.
Cheers Don

rivera · Dec 22, 2017

There are one piece rocker spindle covers out there with a better locating sprag of solid aluminium at the back.
e.g.:
http://www.hollandnortonworks.eu/im...134_tuimelaar_as_afdekplaatjes.JPG?1470999761

They reach deeper than the original flimsy ones. A washer in the blind hole also works well, did this on my Commando.

SteveBorland · Dec 22, 2017

thunderbolt said:
I am rebuilding the head on my MK2 Commando. When I went to refit the rocker spindles which I purchased from RGM I found that when pushed right home they were .070" inside the surface of the head where the side plates bolt on to hold them in place.

This means in my opinion that the spindles would be able to rotate and cut off the oil supply to the rocker arms as the end plate with the two sprags in it would not locate in the slot in the end of the spindle.

I've come up with two possible solutions which are:

1. Fit a washer made to order in the blind hole where the far end of the rocker spindle fits therefore causing the spindle to not go in as far and therefore locate with the end plate correctly.

2. Use some Loctite Bearing Mount to locate the spindle in its correct position.

Thoughts please and any other solutions I haven't thought of.
Cheers Don

Firstly, have you spoken to RGM about this? My experience has always been that they are very helpful.
Secondly, I do not see any problems using a spacer or washer, I think this is preferable to Locktite, especially when you come to remove them again. If the spindles do rotate though, you will end up with too much oil, not too little

grandpaul · Dec 22, 2017

The way to install them is to press them in only far enough to allow full purchase by the nibs on the inside end plate.

lcrken · Dec 22, 2017

grandpaul said:
The way to install them is to press them in only far enough to allow full purchase by the nibs on the inside end plate.

Yep. That's how I've always done it. If they get loose enough, I supposes it's possible they could rotate, and you'd get more oil in the top end, and probably start to smoke more, but I've never had that happen. I have worked on heads where the shafts were loose enough to remove easily without heat, presumably because previous mechanics had ignored the factory directions and removed and installed them multiple times without heating the head first. So maybe in those cases it might have been a good idea to limit their depth with a spacer/washer, but it never occurred to me at the time.

That's one of the beauties of working on Nortons, always something new to worry about

Ken

Stephen Hill · Dec 22, 2017

I agree with Grandpaul, push the spindles in so the locating tabs on the covers sit fully engaged in the slot. I would not "push them right home". This assumes the spindles are a good interference fit in the bore. If they are a sliding fit, subject to floating in and out, then your idea of a spacer is a good one.
I have never been impressed with the stock stamped, multi-plate covers. I used the one piece stainless covers with machined locating tabs from Rocky Point Cycle: http://www.rockypointcycle.com
Big improvement: fewer bits, fewer gaskets, more positive location in the spindle, better looking.

Stephen Hill

thunderbolt · Dec 23, 2017

Thanks guys for the replies. I got it wrong thinking the oil flow would be disrupted if the spindles turned in the head. Got that fixed in MY head now. This situation developed because the spindles were extremely tight in the head and difficult to remove. I had to heat the head hotter than I would have liked and use a puller to get them out. A lot of effort was required.

So I borrowed a 1/2" reamer (not adjustable) and reamed all four bores for the spindles to fit. This made the spindles a sliding fit in the bores. There was no movement or play laterally but I could fit and remove the spindles by hand easily enough.

I have been on the RGM website and they have a kit with a single stainless steel plate with a grub screw that screws in and locates the spindle so that it cannot move. I have decided to obtain one of these kits and use it to solve my issues.

Thanks
Don

madass140 · Dec 23, 2017

GULP!!

Danno · Dec 23, 2017

I have a hard time wrapping my head around why the axial position of the spindles would have anything to do with varying oil flow to the spindles and rockers. The relief and oilway are inside the rocker and the oil has the same clearance through which to escape and drain down the pushrod tunnels or rear oil drain hole. Why would the position of the relief and hole make any difference?

thunderbolt · Dec 23, 2017

Danno said:
I have a hard time wrapping my head around why the axial position of the spindles would have anything to do with varying oil flow to the spindles and rockers. The relief and oilway are inside the rocker and the oil has the same clearance through which to escape and drain down the pushrod tunnels or rear oil drain hole. Why would the position of the relief and hole make any difference?

That is precisely why the workshop manual tells you to face the rocker spindle oil hole away from the centre of the cylinder head. Other wise with the motor installed on a forward leaning angle and the oil hole facing to the centre of the head there would be too much oil in the head area which would lead to smoking exhaust. It's all documented by Mick Hemmings who is rather more knowledgeable than myself.

thunderbolt · Dec 23, 2017

madass140 said:
GULP!!

GULP!!!!!!!!!!!!!!

robs ss · Dec 23, 2017

Does the Commando have a similar arrangement to the earlier, vertical twins - in that a "flat" on the spindle has to face inward (toward the spark plug) in order that oil is fed (via the flat) to the rocker arm "ball" which engages with the pushrod?
If so - is this RGM kit suitable for earlier twins?
You will have guessed that I too don't have good shrink on my spindles (650ss)
Thunderbolt, my guess is Madass's Gulp is that you removed valuable shrink
Cheers
Rob

Danno · Dec 23, 2017

ludwig said:
Unfix it .
Oil flow CAN be blocked by a turning spinde ..

How? The oil delivery hole is recessed and the oil escapes and drains via the clearance between the spindle and the rocker. What's there to block it?

Danno · Dec 23, 2017

thunderbolt said:
That is precisely why the workshop manual tells you to face the rocker spindle oil hole away from the centre of the cylinder head. Other wise with the motor installed on a forward leaning angle and the oil hole facing to the centre of the head there would be too much oil in the head area which would lead to smoking exhaust. It's all documented by Mick Hemmings who is rather more knowledgeable than myself.

By that, shouldn't the spindles ALL face the flats rearward?

Danno · Dec 23, 2017

Not saying the location of the flats is meaningless, I just can't see how the position would make any difference. Oil comes straight from the pump to the spindles and drains out the ends of the rockers onto the thrust washers and quieting spring. How can the position of the spindle affect that? How can the amount of drain oil in the head vary when the supply is pressurized and delivered the same when the engine is running?

Madnorton · Dec 23, 2017

Think of what is acting on the spindle and the forces involved - all becomes clear, fit them correctly.

MexicoMike · Dec 23, 2017

FROM PERSONAL EXPERIENCE - If the spindles are installed in the wrong orientation, you will have too much oil in the rocker boxes which will result in oil pooling in the boxes, above the level of the oil seals because the oil cannot drain from the box as fast as it comes in until it overflows the box. So basically the valve guide and seal will remain constantly submerged in oil. Valve guide oil seals cannot handle that and you will get a LOT of oil past the seals/guides into the combustion chamber.

My Commando came from a prominent, well known purveyor of used Nortons ("Bike is in perfect condition!" per the business owner) with the spindles improperly oriented and the resulting oil smoke/consumption. Correctly orienting the spindles corrected the issue.

splatt · Dec 23, 2017

Danno said:
How? The oil delivery hole is recessed and the oil escapes and drains via the clearance between the spindle and the rocker. What's there to block it?

There won't be any oil to drain past the rocker and shaft because there wont be any oil getting there, once the shaft rotates it blocks off the oil supply to the rocker. Oil comes from banjo bolt in middle through drilling to notch in rocker shaft ,located by stupid little tab to stop it rotating.
Basically Mr Thunderbolt , you wrecked your head, its still useable but not as designed ,there appears to be plenty of others out there with loose spindles

YukoNorton · Dec 23, 2017

Although slightly off topic of the too short spindles, but related to loose spindles, it made me wonder about oversize (.001" or .002") spindles,as there must be a market for them; a quick search found some members' solutions from 2011:
https://www.accessnorton.com/NortonCommando/fixes-for-loose-rocker-arm-spindles.10450/ "
I have fixed them two ways.
First and probably the best was to make oversized spindles and ream the holes. The rocker then needs to be honed to fit. I have made new spindles from aluminum bronze and found they wear better than steel. I have also repaired them with thin-walled aluminum bronze bushings. Touchy process." Jim

and

"Simillar to what Jim did, I have had Commando spindles hard chromed to a slight oversize, and then honed the rockers to fit. In my case, the fit wasn't so loose as to require reaming the head or making bushings, and not much honing was needed." Ken

thunderbolt · Dec 23, 2017

splatt said:
There won't be any oil to drain past the rocker and shaft because there wont be any oil getting there, once the shaft rotates it blocks off the oil supply to the rocker. Oil comes from banjo bolt in middle through drilling to notch in rocker shaft ,located by stupid little tab to stop it rotating.
Basically Mr Thunderbolt , you wrecked your head, its still useable but not as designed ,there appears to be plenty of others out there with loose spindles

Very easy to be critical mate. You're not here in my workshop. I've seen wrecked heads after speedway blowups and this is not a wrecked head. I am the sort of person that wants the spindles located positively, not just pushing them into the head until they are level and then hoping for the next 30,000 kms they stay there and don't move. There is no play in the spindles in the head when cold, maybe a modest amount when everything is warmed up, but with the RGM mod they will not move at all. When Roger did the test on this modification he purposely ground the spindle under size so it would be loose in the head. He then ground two flats on the spindle so he could turn it when in place in the head and the new side plate tightened up. The modification locked the spindle in position to the point where he could not rotate/move the spindle at all using a spanner on the flats. I would rather have a spindle locked in position like this supporting my rocker arms than a spindle that can float around possibly.

Cheers
Don

Rocker Spindles Too Short

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