4 valve ES2

A friend sent me this photo of an ES2 cylinder head converted to 4 valves.
He doesn't know where the photo came from, and I cannot find anything like it on the internet.
Someone somewhere must recognise it, and perhaps can tell some background to it, who did the work, and what the intended use was.

Under the head is an old English motorcycle news paper, so most likely it' is the work of some English ES2 enthusiast.

Snotzo said:

and what the intended use was

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Indeed, that's the main question surely? That's an awful lot of work. And it can't be used in Classic / Historic classes as far as I am aware?

Funny, went to all that work and didn't introduce any downdraught (you can't see anything of the top of the inlet tract in the photo )
2 valves on the inlet may be warranted, but I doubt any value on the exhaust. You can see the port size reduction which is evidently beneficial on the Fullauto head.
My work on my Dad's 500cc Model 50 show the single's athsma is inlet related, not exhaust.
A good example of smart ES2 work is Australia's Geoff Clatworthy's ES4 - good downdraught, 2 spark plugs (high dome on high comp piston masks the flame front and slow the burn with one plug)
Cheers
Rob

Neat looking build.

What is that that looks like an additional linkage on the bottom side of the gear lever?

robs ss said:

2 valves on the inlet may be warranted, but I doubt any value on the exhaust. You can see the port size reduction which is evidently beneficial on the Fullauto head.

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Yes, its a bit of a mystery why Norton stuck with about equal sized valves for soooo long.
Other makers figured out long ago that bigger inlet valves gave more go,
and the exhaust valves didn't need to be equally as big.

Wonder what the 4 valve head above uses for valve rockers ?

I've seen the earlier ES3 in action, and it didn't have that lower linkage on the gearshift.
It goes below the frame line too, and is not exhaust related.
= ???

I'm not sure either, other than to observe that I think is is a cable rather than linkage.
Cheers
Rob

Quickshifter linkage?

Glen

Could be - maybe it gives quicker shifts by hand.
Someone with a stiff ankle maybe ?

I wonder if its connected somehow to the ignition, so that it cuts the ignition when you touch the gearlever. ?
Not the most obvious of functioning though.

Would this bike usually have a fairing ?
It may be somewhat disconnected from its intended purpose when the fairing is removed ?

Shots with fairing...

Actually, if you look at the LH shot it shows the cable going to the rear brake. My guess is what we could see in the RH closeup is the extension of a shaft from the brake pedal operating the cable.
Why go from left to right? Maybe something to to with shortness of cable (if all on left) giving problems with swingarm movement?
Cheers
Rob

Has this bike been setup with left side shifter, and right side brake ?
We are getting down to the nitty gritty of it, methinks..

Diverging somewhat from 4 valve ES2's though !

Rohan said:

Could be - maybe it gives quicker shifts by hand.
?

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I'm thinking Quickshifter as in the electric version. On modern bikes they are electronic, however electric quickshifter cutouts have been used on hill climb machines and some other race bikes for many years.

I have one of the electronic versions on order for the Thruxton.

With the straight electric style the ignition is cut for a split second when the gear pedal is depressed. This allows for a full throttle , clutchless shift. Sounds like it would be really hard on the gearbox, but apparently it's not so bad.

Might not want to try it with a regular AMC box, but that looks to be a TTI box, very tough.


Glen

Rohan said:

Has this bike been setup with left side shifter, and right side brake ?
We are getting down to the nitty gritty of it, methinks..

Diverging somewhat from 4 valve ES2's though !

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I think that's it. He has a shaft running through connecting the LH lever to the gearchange and the RH lever is operating the rear brake via the looped around cable. A very, very neat set up!

Fast Eddie said:

Rohan said:

Has this bike been setup with left side shifter, and right side brake ?
We are getting down to the nitty gritty of it, methinks..

Diverging somewhat from 4 valve ES2's though !

Click to expand...

I think that's it. He has a shaft running through connecting the LH lever to the gearchange and the RH lever is operating the rear brake via the looped around cable. A very, very neat set up!

Click to expand...

Yes you are right (Rob, Rohan and Nigel)

Too bad. I like the idea of an ES2 with a quick shifter 8)

Gken

I am enamored with the oil Lines!

Slick

S' agit t-il d' une ES4 ?

ballacraine

ballacraine
Actually ES2 (I believe Model 50 head) heavily modified hence Geoff Clatworthy uses the term ES4 - it had a predecessor, ES3
Cheers
Rob

Re: 4 valve ES2 and others

Hello,
My name is Geoff Clatworthy. I have built (with the assistance of others), a number of Australian ES2 racers now known as ES1, 2,3 and 4. The photos's elsewhere on these posts are of "ES3" (long stroke) with the obviously welded/modified inlet manifold, and "ES4" short stroke, both with the cross over gearchange linkage through the 3/4" s/a pivot bolt.
No quick shift other than the quality set up of the 5 speed TT Industries boxes and Bob Newby clutches (and rider skill).
Happy to answer not too long questions should I be able to assist. I have spent 40 years developing these bikes and don't believe that there is a lot more to be gained. I standard ES2 is claimed to have produced 28bhp (rear wheel?), where my modified iron ES1 produced 46bhp, ES2 and 3 between 49 and 51bhp and ES4 considerably more. They weigh about 238lb with fairings and oil without fuel; with performance reflecting the power to weight advantage over a Manx and some excelelnt riders Chris Anderson, Mike Soderland and Ian Lovell.
I believe the 4 valve ES2 to be an exercise constructed for the amusement of a clever English enginner utilising some speedway components and not intended for racing.
Kind regards from OZ - Clappers.

Geoff, we look forward to seeing some pics of the combustion chamber and the cams in your ES4.
If that is not asking too much - ie on the secret list ?! Those are impressive numbers indeed...
Jist curious...

I haven't sorted out yet as to how ro post photos on this site.

Anyone can extract good reliable performance from one of these motors starting with patience and a little effort. Weight:BHP advatage will see a well set up machine (sound chassis geometry/brakes/gear ratios) lap with OHC motors and twins of the same capacity. A bit more effort and time (and the same cost as other options); will see a good one at the front.

The combustion chamber on the LS motors are essentially hemispered with piston crowns to match at least for a squish portion (0.027"). Rather high comp on methanol. All twin plug heads except for the first iron motor (ES1). Around 0.425" valve lift with short duration cams. Pressed up steel crank, modified main bearing arrangement. Think the valve sizes are something like 48/44mm.

The SS has a compact bath tub design with large well disiplined squish areas providing a small compact chamber (flat dome after the last squish) - 14:1 comp. Rocker ratios 1.52/1.48:1. Roller followers although flat followers were utilised initially and possibly unneccessarily discarded. Lifts 0.610"/0.560". Cams modified to incorporate slotted gear wheels and cam carriers for fine adjustment of the timing. One piece crank on large needle roller mains. 2.1" B.E. redisigned oil pump. Ti rod. Custom pistons and valves. Dellorto SS1 carb.

Geoff