14CS warped rocker cover

Information relating to the Matchless G2 or AJS Model 14 250cc Lightweight
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mattward
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14CS warped rocker cover

Post by mattward »

Hi All,

I searched and searched and could not find anything about this one. I am in the process of restoring a 1960 14CS, and when I went to attach the rocker cover today, all was not quite right... I had purchased the cover last year as a shell from a relatively local source hoping it would be all good as the trader is generally pretty on to it. My first mistake, was not checking its fit on the motors head. Anyhoo, long story short today when I went to fit it Ic ould only get some of the bolts to 'take' as I tried to fix on the cover. I tried all sorts of things, before finally thinking it may be a bit warped.

So out comes the piece of glass and wet and dry to see what I was dealing with. I gave it a few rotations before I realised it was severely rocking. When I was fitting it to the head I was on the tappet cover side of the frame and hadn't noticed the issue too clearly. So I have attached some pictures to show the amount of warp I have.

Does anyone think this cover may be worth saving?

Should I try grinding the bas flat? its about 3mm gap at present.

Should I maybe get the high points built up?

Should I find another cover and write this one off as a tribute to gods of lightweights?

I would appreciate any thoughts or comments, obviously the cover is knackered as it is...

Cheers in advance
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Andy51
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Re: 14CS warped rocker cover

Post by Andy51 »

I have a spare lightweight rocker cover, PM me if you want it. Andy
SPRIDDLER
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Re: 14CS warped rocker cover

Post by SPRIDDLER »

That's a strange one.
I don't know how easy it would be to find another in NZ if you don't take up Andy's generous offer but it's clearly unusable as it is.
I reckon a replacement would be best.
However, if I was totally stumped in getting a good replacement I'd first try to pull it down square to a piece of steel with nuts and bolts in all the holes. However, it probably wouldn't retain its new flatness when the bolts were released and there's also the risk of fracturing the casting. I doubt that heating it would help to retain its flatness.
As a last resort I'd have it milled down flat and fit two gaskets if necessary, or if they weren't sufficient to take up the 'lost' material gap I'd have an alloy spacer laser cut by providing a gasket as a template. Even if you mill it flat (or build up the underside) it seems from your photo that at least one bolt hole wouldn't be aligned vertically with the threaded hole in the cyl head.
Matt rocker cover 2.jpg
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Rangy65
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Re: 14CS warped rocker cover

Post by Rangy65 »

Hi you have the wrong cover. G2 & M14 didn't get a valve lifter until much later and the cover in your pictures shows a valve lifter hole.

The Club spares scheme has some S/H covers that are correct.

PM me if you want want as spares is shut for the week due to Annual leave.

Cheers

Steve
John Jarrett
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Re: 14CS warped rocker cover

Post by John Jarrett »

Steve,
If it's for a 14CS or G2CS it would have a valve lifter.
John
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mattward
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Re: 14CS warped rocker cover

Post by mattward »

Steve,

The rocker cover is correct design, as listed in parts book. The 14CS is quite different to the 14 and the later 14CSR's being that it was originally designed with high compression piston which lead to needing the release valve to be able to kick it over, the same as the Model 8 (which I also have, the first basket I restored). I also picked up from the forum here that the later model lightweights had rocker covers without the oiling ports above the rocker arms, which seems a bit bizarre to me, but hey.

Thanks for having a look. I still for the life of me cannot work out how this cover has become sooooo distorted.

Neville, I will take Andy up on his kind offer if the cover he has works out to be the correct version, he's going to dig it out for a look. I have found one other online if push comes to shove... The holes for the bolts are so out of line (on second thought), I don't think even a grind or reconstitute would rescue this here mongrel...

Cheers
Matt
mdt-son
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Re: 14CS warped rocker cover

Post by mdt-son »

mattward wrote: Sun Jul 02, 2023 10:50 pm Thanks for having a look. I still for the life of me cannot work out how this cover has become sooooo distorted.
Matt,
I guess someone ran the rocker box with insufficient or partly missing clamping bolts (threads in the cylinder head frequently strip out).

G2CS and CSR spares are available, if not plentiful. This one is not worth saving. Trying to weld it will likely distort it even more.

- Knut
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mattward
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Re: 14CS warped rocker cover

Post by mattward »

Hi All, I managed to find another flat rocker cover on Ebay, for a good price from USA, I think the Matchles G2CS was quite popular over those ways. The rocker cover above has joined the collection of parts hanging on the "you what" wall...
Cheers
Matt
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jackstringer
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Re: 14CS warped rocker cover

Post by jackstringer »

Glad to hear you managed to get the bike together.

I wondered if a heat cycle in an oven could help it relax back into shape, or at least warm it up and clamp it down to see if it will flatten out a bit.

Back in the day I remember most of us would buy a spare engine complete and that would be what you used for spares or have that engine on the bench to repair once fixed it would go in the bike. My issue is often these days you have lots of breakers that split a working engine up so they can make more selling all the bits this is ok if you only need a LH case etc but you now have the risk that knackered parts sneak in or parts that worked as a pair but now they aren't together they wont fit other things. Anything that doesn't sell quickly ends up in a misc box and eventually it's at the Autojumble in a box and unless you take a person who knows thier parts there is a chance they will end up in the bin.
mdt-son
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Re: 14CS warped rocker cover

Post by mdt-son »

So true, Jack, but it's still possible to buy complete engines. Not too long ago a complete G2CS engine was advertised on Fleebay, not for hand money of course.

The irregular shape of the rocker box makes it highly unlikeley it can be restored by heat to become flat again.

- Knut
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