Inlet Manifold - Anglian THS

[Keith Beach]

Does length matter when it comes to inlet manifolds ? !

I've got a THS with Amal 626 carb (see attached photo).

I thought I had read in the distant past that the Anglian had an extension to the manifold that went some distance down into the barrel but that many people sawed these off. Mine doesn't have any such extension.

Dick F recently showed me his inlet manifold and I realised that it was noticeably longer than mine (no end of potential material for jokes in this post !). My manifold is approx 2 1/2 inches in total length including flanges and about 2 1/8 excluding them. I didn't measure Dick's. I doubt that mine is original. Looking at photos of other Anglians suggests to me that Dick's is typical of Anglian manifolds.

So questions:

What was the purpose of the extension and what is the implication of removing it ?

What are the implications of a shorter or longer inlet manifold ?

Is mine too short ?

I'd value your comments.

best wishes

Keith

[Sprocket]

No but size does !

Hello,
As Anglian Barrels have become harder to find people have used Challenger Barrels, not so good for the job but they work. Only problem the Manifold tube (inner) will not fit so cut it off !! (well it will fit untill the last 1/2 inch then it jams) If you want to know if you have a Challenger or an Anglian Barrel pop an Anglian Maifold tube in, if it goes right home to the flange you are on a winner.

The TGS had the Exhaust through the frame, which clashed with the Carb, so the Manifold was off-set to the right, some more than others, so some longer tubes, some shorter tubes.

Longer Manifold tube = Better pull low down.
Shorterr Manifold tube =Better top end.

Only my view but get a Villiers S23/5, (I think it is without looking) drill and tap it in the side to fit a tick-over screw. Sit back and enjoy your Bike, I did.

Only problem is finding the Villiers Carb. The Tiger Cub boys have found out about them, and they like them too !

Please note I managed that with out one innuendo !!!!!!!!!

[Rob]

Here is the drawing for the inlet manifold as fitted to ALL Anglians (but bet someone proves me wrong!).

Also, the liner drawing for a THS. You can now play 'spot the barrel!

Regarding carbs, my Anglian starts and runs very well on an S25 but several Anglian owners have told me Amals are better. I shall experiment. The later S25's came with the tickover screw fitted if you can find one. Seems they are also in demand for Ariel trials bikes too!

Funny that, back in the day everyone threw the Villiers away and fitted Amals including Don Smith! Glad I kept a few!

[Keith Beach]

Rob and Sprocket, thank you for your comments (if a second similar reply from me should appear then apologies; I thought I had posted one earlier but it seems to have disappeared into the ether).

Looking at the factory drawings of the Anglian manifold it looks as if mine is standard after all. I read with interest about the reason for the right hand offset. I had wondered.

I think I probably have got a Challenger barrel. A while back someone more knowledgeable than I suggested the porting on mine was designed for scrambling. I then had two options by way of reply - either to stay quiet and look intelligent or be honest, say I didn't know much about porting and then put it on my list of things to learn more about. I opted for the latter. I haven't started that bit of my education yet but my Anglian does feel like what I imagine a Challenger barrel to feel. i.e. it sings along happily at the top end, feels like it wants to be raced and is less happy at the bottom end. I remember Dick, that you thought it was a bit flat at low revs when you tried it.

I cannot confidentally understand the cylinder liner drawings eg are the 40 and 42 figures on the bottom left diagram degrees ? But I need to take the barrel off and having a look and/or try an original manifold with extension if I can find one, so as to get a definite answer as to what barrel I've got. I might in any case try a longer manifold just to play around and see the impact on the bottom end.

If I've got a Challenger barrel and Anglian ones are now difficult to get hold of can I (perhaps being naive here) get my existing barrel relined and with Anglian porting ? unless someone reading this has a good alloy Anglian square barrel. I notice that Richard Deal sells Anglian barrels but I dont think they are originals or copies of originals are they ? I'd prefer to keep to "true" originals.

Interestingly Rob a few Anglian riders have told me they prefer a Villiers carb on their Anglians. Ive only tried Amal ones so don't know and guess it might be down to personal choice. What I do know is that I am under awed by the quality of Amal carbs.

Anyway my thanks to both of you for your comments and advice.

best wishes

Keith

[Sprocket]

Anglian

Hello Keith,

Paragraph five of your post, "strongly" suggest you purchase nothing at this point !

Maybe a good idea to make the AGM, always sound advice to be had their.

I intend to take my Anglian, if only to see Druids reaction as I intend to give it a bit of a polish.

Regards Rob.

[Keith Beach]

Sounds like good advice to me. I never rush at buying anything nowadays. I enjoy the cogitation and the learning curve therein.

I do intend coming up to Kidlington for the AGM.

best wishes

Keith

[Rob]

I'm just looking at a Challenger liner drawing and there is very little difference with the THS.

I also took a port rubbing of Dick's barrel and the ports in that are bigger than the Challenger's! Also, the bottom part of the liner at the transfer ports has been completely cut away. This bike was built by the late Reg May and judging by the riders they had at Comerford's, there must have been a bit of works input. Dick's barrel is stamped up M36/EXA, a TFS part number but also fitted to the TGS so it began life as a trials barrel.

Dick's bike performs about the same as mine so I don't think it makes much difference. However, I have just done port rubbings on MDS and TES barrels and they are both very different to each other. I will try and dig out a Challenger barrel and do the same with that.

Think we all need to get out more!

[druid]

Anglian barrel

Gents,
I may be wrong, and often am, but I think that the Challenger and Anglian liners are the same. I have the drawings but it's too cold to go looking for them at the moment. The changes were the inlet manifold, carburettor, exhaust and sometimes the CR. Some Anglians had a decompression plate at the head joint.
I believe the long tube manifold was probably to increase gas velocity at low revs, again I may be wrong.
As for Sprocket, the well known rivet polisher, you can expect the normal Druid response if you turn up with something shiny.

Druid

[Dick F]

Anglian barrel

Hi Keith,
As I said after trying your bike and as the chap we know who done the rebuilt said the extension tube had been reduced, and on bringing mine round to your house we could see that difference.

But as you are mainly using it for Road/ green lane riding there is not a lot of point in changing it, my TFS has a s25 and the same is on my TES

As Rob said we have tried each others bikes and there is not a lot of difference at all, and my TFS runs just as well on the S25.

Just ride the B....y thing mate! and get that gearing up higher and have some fun

[Keith Beach]

Cheers Tricky. I'll be interested to see whether Challenger and Anglian porting is similar though as he and his Greeves man thought it had porting for a scrambler. Im going to get myself a teach yourself about porting book ! I reckon I should think about bringing it up to the AGM (the bike that is - not a book on 2 stroke tuning).

[Don Morley]

Anglian Inlet Manifolds

Hi keith,

You really ought to get yourself copies of the articles I did in LL on the Anglians a few years ago! But to answer your question firstly you must realise the barrel porting is VERY different between what generally (And I have to say unfortunatly) are all known as being 'Challenger' type barrels.

Hence though they might all look the same as seen from the outside, there are in fact as you might expect fairly major differences between those cylinders designed for Scrambling, or those for Road Racing, and even those intended for ISDT use, or especially those cast and ported to give maximum bottom end and mid range power (rather than outright revs) as should be fitted to our TFS and Anglian trials bikes.

Put simply its horses for courses, and the ONE sure way to check if a Challenger type barrel is indeed a trials one is to offer up a genuine Anglian (or TFS) inlet manifold stub too it. I.E. A manifold WITH a long cylinder side extension which should fit right down into the inside of the barrel.

If the barrel is not a genuine trials Anglian or TFS component this propper manifold will not in fact fit, quite simply because the pipe to flange and barrel porting angles are all wrong, indeed it is impossible to even make it fit. Hence sadly nowadays people hide this fact by sawing the extension off.

So if you can beg or borrow a genuine Anglia inlet manifold and the extension stub will not fit into your cylinder barrel it does mean someone over the years has fitted the wrong top end to your bike, and hidden the favt by sawing the inlet manifolds internal extension off.

Not that this is a massive disaster, especially for road rather than trials use, where for instance the scrambles barrel works very well, and more so if you also do a few easilly done retrospective porting mods as you can then finnish up with a set up several of Greeves's works riders used to use.

That said though, if you have a road race barrel you will find it next to useless in torque terms if your bike is also fitted with a silencer, and this brings me finally to your asking if the various inlet manifold lengths are critical and or why?

Well actually not as critical (in my view) as you might think BUT it is important to remember Greeves knew what they were doing when they designed the TFS (Longer) and Anglian (Shorter) inlet manifolds. And perhaps more importantly they came to those angles and measurements via many hours of engine testing running on a BHP test rig.

Hence the actual Anglian manifold lengths and smaller internal diameter tubing they finally chose gave our engines MAXIMUM low down and mid range torque figures coupled to a far better and more useful rev range than such as a standard Villiers top end. I.E. They knew what they were doing!

The actual Anglian manifold dimensions thus should be 4 5/16" in total length with 2 1/8" of this total fitting down deep inside the cylinder barrel. Hope that answers your questions. Best wishes, Don Morley

[Sprocket]

Anglians

Oh Druid, afraid it`s got to be done, rude not to! And lets face it you would hate to miss the opportunity of a good Barracking, and at my expence too.

Now to get back on tack, It is I`m sure general knowledge that I know the "Square route of sod-all, which is sod all" however something came back to me which I shoud have remembered. If you take an Anglian Barrel, and a Scramble Barrel, turn them side ways (or get on your knees beside the bikes
and look at the angle/face, of the casting that the Carb bolts on.
Now on the Trails Barrel, the bottom of the casting face sticks out more, and the top goes in more, the angle of the face is at about 15 degrees.If you were to bolt a Carb onto it (with no curved Manifold) the thing is falling over, so much so that the float will not function correctly .
Now take the Scramble Barrel, the bottom of the face only sticks out a little,and the top goes in a very little, the face is at about 5 degrees,
bolt the 3/8 spacer and a Carb on, Perfect ! Well you have to keep tickling the bu**er when starting.

From that, it makes sence that the inlet port angle has to be steeper on the Trials Barrel, and less on the Scramble Barrel.

No Sh*t Sherlock! And Druid best have your tinted visor handy !

[druid]

Anglian inlet manifold

Gents,
I have Challenger (MX and ISDT) plus Anglian barrels but I can't be bothered to measure them, sorry.
What I will say is that the LINER is the same from memory. Not the barrel or any other part.
I'm talking from drawings. I hear what Don is saying but the liners were machined from master boards on a pantograph and it wouldn't have been that easy to change them. We're talking production barrels here not works ones.
If pushed I will drag out the drawings and check, or even worse do a port drawing but only if really pushed.

Druid

[Keith Beach]

Anglian Inlet Manifold/Porting

Thanks as always Don for your detailed comments and advice. From the dimensions you give for the inlet manifold and from the drawings that Rob posted I think I have the correct length, shorter, Anglian manifold. Except of course I don't have the extension stub into the barrel ! I am going to take your and Sprocket's advice and try and borrow or buy an Anglian or TFS manifold with extension and see if this fits. Do you know off the top of your head the LL nos of your articles you refer to ?

I read with interest your comment Sprocket on the angle of the casting the carb bolts on and this being about 15 degrees on the trials barrel and 5 degrees on the scrambler. Add and I understood why this should be ! On a quick visual just now mine is about 15 and certainly not 5.

But I think the medium term task is for me to learn more about porting and to then take the barrel off to have a look and get others to as well and see what's been done inside during its history. I ought to see if I can get it along to the AGM so others can have a look/go.

Cheers

Keith

[Dick F]

Anglian barrel

Its all sounding a barrel of fun now Keith