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4 valve ES2

Norton Models (not Commando or P11)

4 valve ES2

Postby Snotzo » Wed Dec 07, 2016 2:02 am

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.

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Re: 4 valve ES2

Postby Fast Eddie » Wed Dec 07, 2016 2:07 am

Snotzo wrote: and what the intended use was


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?
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Re: 4 valve ES2

Postby robs ss » Wed Dec 07, 2016 3:59 am

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)
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Re: 4 valve ES2

Postby Fast Eddie » Wed Dec 07, 2016 6:46 am

Neat looking build.

What is that that looks like an additional linkage on the bottom side of the gear lever?
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Re: 4 valve ES2

Postby Rohan » Wed Dec 07, 2016 3:21 pm

robs ss wrote: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.


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.
= ???

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Re: 4 valve ES2

Postby robs ss » Wed Dec 07, 2016 3:27 pm

I'm not sure either, other than to observe that I think is is a cable rather than linkage.
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Re: 4 valve ES2

Postby worntorn » Thu Dec 08, 2016 6:58 am

Quickshifter linkage?

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Re: 4 valve ES2

Postby Rohan » Thu Dec 08, 2016 7:58 am

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 ?

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Re: 4 valve ES2

Postby robs ss » Thu Dec 08, 2016 1:08 pm

Shots with fairing...
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Re: 4 valve ES2

Postby robs ss » Thu Dec 08, 2016 2:34 pm

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?
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Re: 4 valve ES2

Postby Rohan » Thu Dec 08, 2016 2:48 pm

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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Re: 4 valve ES2

Postby worntorn » Thu Dec 08, 2016 5:29 pm

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


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.


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Re: 4 valve ES2

Postby Fast Eddie » Thu Dec 08, 2016 9:10 pm

Rohan wrote: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 !


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!
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Re: 4 valve ES2

Postby worntorn » Thu Dec 08, 2016 11:38 pm

Fast Eddie wrote:
Rohan wrote: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 !


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!


Yes you are right (Rob, Rohan and Nigel)

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

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Last edited by worntorn on Fri Dec 09, 2016 9:42 am, edited 1 time in total.

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Re: 4 valve ES2

Postby texasSlick » Fri Dec 09, 2016 5:59 am

I am enamored with the oil Lines!

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The Second Law (of thermodynamics) rules.
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