I had this on an old tacho some years ago, the screech was horrendous. I removed the clock and sprayed some ACF50 through the bulb orifice. (My thought at the time was if it doesn't cure it, its buggered anyway)... Anyway it worked a treat and it ran on the bike for a few years with no issues. I eventually had it and the speedo rebuilt and its been great for about 10+ years.

The rule of thumb is you DON'T spray anything into magnetic speedos/tachos... but if your prepared to have it rebuilt, then what is the loss?

Hi Bernie.

Taken from the Amal catalogue.

M21 Home and Export settings, for 1955-1960

Carb number 376/88 1957-1960 (or 376/23 - 1955-1956 - settings are all the same, so don't know what changed)
Bore 1 1/16
Main Jet: 250
Pilot Jet: 30
Needle Jet: 106
needle position: 2
Throttle Valve: 376/0605 (#5 cutaway for 376 carb)



Interestingly, the AA order model bikes, stuck with a 276 right till the end of production - god only knows why!!

As above, right hand thread. 5/16ww from memory.

get one of these when you come to re-time it: https://www.themagnetoguys.co.uk/magneto-static-timing-light

Worth every penny, spent ages when I was younger helping my father time his magneto, did mine the other day and it was a piece of cake. DTI down the plug hole, timed to 7.5mm down, tightened it up and sorted. Easy.

"Driven", make a very good assembly lube (grease), I put it on Cams, pistons, big end and timing side journals,  anything really that's a metal to metal contact. (don't put anything on the rings, piston skirts only).

Normal engine oil will run off by the time you come to start the bike (If your not getting it back together and running in a short space of time), I've also used Morris Competition assembly oil, its like treacle and very messy - its good stuff though, the Driven stuff is tidier and doesn't drip.


https://www.ebay.co.uk/itm/135678181579?_skw=driven+assembly+lube&itmmeta=01JSPSXE4JMX49QE52NTEBZ754&hash=item1f970cc0cb:g:jwEAAOSwYQViwYCs&itmprp=enc%3AAQAKAAAA8FkggFvd1GGDu0w3yXCmi1dmFnxF6NNaFAPqkxpCVpphFotN32%2BZyBZ1d0bLQteZJyccIv%2F1c299lsfZgLwGB4UKZ5sWQXdSoRpAgrOPZz8pPfq5Zur2FYB6YMhmP%2BEmE%2FC2vYecidlJEPOjyzfQvbN0Os1z7UOPwNTagGEif9zEQdmW8izdd%2BaOS%2BKBB5sha8p8w8dbl2AXnDD3nlg71PnGYswo8AZXixB6mNoLyFXugRdBkcSs1d9vNHMSz7yGLwRdZT4OO6jlS6Di6veA6bCks5Noi3UTjl9nDnruETMQbVkrqZR8zUU%2FM0AqknEhOQ%3D%3D%7Ctkp%3ABFBMuOL12c1l

This will see you through a few motor builds.

Quote from: BrummieJon on 23 April, 2025, 13:24:47Tried fitting the seal this morning, failed.... I tries chamfering the edges of the engine casing apeture, lots of lube and I still couldn't push it home... I think the dimensions are correct but the engine casing does not seem deep enough to house the already tin and flimsy oil seal supplied... Ive distorted it now... Not sure where to go now, try a new seal or out it back together as it was and accept the oil leak.

Heat the case up with a paint stripper gun set on high, take your time with it, get plenty of heat in there. The seal (and by the sounds of it you need another new one now) will pop in without any effort.

Anyone that's done an A65 gearbox oil seal will tell you how much of a P.I.T.A they are to do, damage the outer edge and your increasing the chances of a leak. I always heat mine up and they go straight in without fuss.

If you know the dimensions, (ID of the crank case and OD of the cush adapter) you can order an SKF or similar oil seal for probably less money from Simply Bearings, also it'll be far better quality than whats typically available for British bikes.

Whilst your rockers are accessible,have a look at cleaning the oil holes in the rockers, this will mean taking them out. They should feed oil which comes off the rocker spindle, through a hole and out of the tip/ball. If you have decent oil flow, just like the big ends, the oil should form a blanked between the cup and ball so you don't get wear. Also it should help reduce any clatter. Since your getting this kind of wear, it would lead me to think that these rockers have their little oil feeds blocked up.

Just seen who the seller is, which confirms what I was thinking.

There can't be many of these with an A10 engine and based on Sandbach Cheshire. If I am correct (I moved from Cheshire 8 years ago, and probably last time I saw such bike was even longer).

However if it is the same bike that I remember, previous owner (
And friend (now RIP). It would have been in very good mechanical condition and the mag would have been rebuilt (by the same learned person that built the engine). So it would be a good bike. I can't remember if the bike started out as. B31 or B33, but following some engine problems if I remember right, a common friend built an A10 engine for him. It will be a great riders bike and in lovely condition.

Ok, not original and I can't speak for who owned it between my friends ownership of many years and the current owner who had it since he passed.

Srm used to use their own springs and they are very good. They now sell the Hepolite ones, same with the cams. The cams are good quality,  however I was lucky enough to be building two engines with two new cams at the same time. One of the cams had a larger base circle and overall diameter on the lobe (though the lift was correct) it didn't fit one of the engines, but there was enough clearance in the other. So I could mix and match.

The springs work which I bought for the second engine and haven't been an issue (yet) though they were not a good fit in the lower retainer. I did check for coil bound and they seemed fine.

Old springs often look fine but can be weak or randomly break. When one breaks you'll find a flapping noise. Keep an eye out for some old terrys springs or get the srm race springs (which will be fine).

The original 3 spring Cush drive needs to be in A1 condition for it to work well. It was by far inferior to the 4spring setup which proceeded it and where by the clutch hub was mounted integral to the basket to prevent twist and wobble.

If the Cush drive isn't in A1 condition and you have an engine which is capable of providing some good torque then the clutch will start to slip. The Triumph solution with the T140 was to fit heavier springs. Having tried the heavier springs on an A65, you need strong hands to work it.

The arc kit has the ring gear on the outboard side of the clutch. Personally I would rather have it at the back of the clutch to put the driven area in line with the bearing to prevent twist on the basket. However I understand that for simplicity and preventing modification to the crank case, it was fitted outboard.

68 models still use bsc/BSF threads. Unified threads didn't start until 69.

Yes. The 12° advance makes it the noticeable difference between that (6Ca) and the 4CA points cam which was changed due to rogue sparks.

Quote from: idie on 10 June, 2024, 11:32:18
Your photo shows a single but you are referring to a twin
Which one?  Last time I saw damage like that was when the piston hit the valves.⁷

What photo shows a single? The head is clearly from a unit twin.

Since your getting failings on the inlet side, are the pushrods fitted correctly and in the right positions? Have you got the rockers in the right places (though it should be obvious if you haven't). What valve clearances are you using?

Secret is not to buy anything that comes from India. As spares resources are increasing the quality of most spares is also diminishing. NOS parts isn't always the go to, often NOS could be parts that weren't in tolerance then got stuck in a parts bin for re-finishing. Often probably didn't. However it is now often one of the best resources for new spares. Often reconditioning old or having something made by a reputable company from a 1st world country is the way to do it.

Buy cheap... buy twice.

Try getting yourself a new trip knob. I find the extended ones work best and don't fowl the rubber binnacle. Pull the old one out and the new one, should push straight in, might need a little twist to find its home position