FullAuto Heads Update

Another item on my wish list is more meat around the ports for reshaping. I know that the FA head already has some more meat than stock heads but it should be maximized as much as possible - all the way out to the head bolts. The Norton will never realize its full potential until it incorperates the best flowing 2 valve pushrod port shape ever designed - the HD XR750 D ports. With more material to work with - the FA head could actually get very close and then you would see HP figures never before achieved.
 
I would never buy a Fullauto head to use on a road bike. You can buy a lot of Japanese for that price. But road racing is different. The greatest joy of my life is having a shoot-out on a race track against another guy who has a similar bike. In Victoria, there is a guy who has a Minnovation Seeley Commando 750. My mate blew him off at Broadford with an RZ350 Yamaka which is almost as fast as a TR3 production racer. Doing that effectively means nothing. But doing it with a similar bike actually means something to me. Even a go against a bevel 900cc Ducati would be good.
I am trying to organise a ride day at Winton for early next year. It ends up as a race to see who stays in front the longest. 'Small things amuse small minds' ?
 
Hortons Norton said:
www.cycleworld.com

Motorcycle Airflow Specialist Jerry Branch Was Driven By Curiosity

The late Jerry Branch was an airflow wizard, a self-taught genius who earned the respect of many inside and outside the sport of motorcycling.
www.cycleworld.com www.cycleworld.com
Click to expand...
So is the take away from that article for this audience supposed to be... 32mm intake ports on Norton heads is hoggin' them out?

I guess I need to recalibrate my butt dyno. I have two Norton heads. One is a stock Commando 750 head and the other is a ported P11 head (Atlas?). The Stock Commando head has 30mm intake ports. The P11 head has 31mm intake ports, and was ported by Fred Barlow. Short story version is after using both on the same motor, the ported head works a lot better literally everywhere as long as I don't short shift and try to go 20MPH in 3rd gear pulling up a hill. Unfortunately, my bike is a one-off, so not much to compare it to. I think the motor would work fine with a head that had 32mm intake ports, but I'm talking out my rear end, because I've never had 32mm ports on it. Currently my intake manifolds are reshaped and blended from 35mm to 31mm. I would just open the 31mm end up to 32mm and see how it goes. .5mm with a dremel and finished up with sandpaper. Damn it! The guys with the straight jacket are coming and I need to hide.
 
Let's go back in time...


www.accessnorton.com

Head flow testing.

This quote comes from way back up the thread, posted in March..... I am new and if there is advice on cam selection on here I did not find it yet, so here goes...the quote: 'I spent some time on the flowbench this evening playing with the Fullauto head that is going on my bike. I installed a...
www.accessnorton.com www.accessnorton.com

www.accessnorton.com

Head flow testing.

This quote comes from way back up the thread, posted in March..... I am new and if there is advice on cam selection on here I did not find it yet, so here goes...the quote: 'I spent some time on the flowbench this evening playing with the Fullauto head that is going on my bike. I installed a...
www.accessnorton.com www.accessnorton.com

www.accessnorton.com

Head flow testing.

Knut, This will be done on your rh10. I know exactly how to get there now. Hey Jim, It appears there are at least two norwegians waiting in anticipatuion for a performing head :-) Were you referring to my cylinder head or Kvinnhering's in your recent posting ? Anyway, bottom end rebuild...
www.accessnorton.com www.accessnorton.com
 
And this is what Jim did with my FA head. These are great heads.

comnoz said:
So now that I identified a problem with my prior velocity readings and corrected them -here is the flow tests with the 1.5mm oversize intake and a little work in the valve guide and bowl area.

Nice improvement for a steetbike running a .400 lift cam.
Click to expand...

Flow
FullAuto Heads Update


Velocity
FullAuto Heads Update
 
From the air filter to the end of the exhaust it needs to work together, I don't know anything really when talking about high performance tuning. But I have heard people talk about valve overlap, cam timing, port size, and about 20 other things, lol but it would take me a lifetime around this stuff to understand it fully. This was not meant to say your wrong or that it did not help your bike. I spent a few days at Bonneville in 2006 and Jerry Branch was in the pits, when he was talking to a couple of very experienced V-twin engine builders, one of them had his shop right next to Branch-O'Keefe. I knew very little of what they were discussing but it was fun and the stories he could tell were fun. But velocity is very important!
 
Hortons Norton said:
From the air filter to the end of the exhaust it needs to work together, I don't know anything really when talking about high performance tuning. But I have heard people talk about valve overlap, cam timing, port size, and about 20 other things, lol but it would take me a lifetime around this stuff to understand it fully. This was not meant to say your wrong or that it did not help your bike. I spent a few days at Bonneville in 2006 and Jerry Branch was in the pits, when he was talking to a couple of very experienced V-twin engine builders, one of them had his shop right next to Branch-O'Keefe. I knew very little of what they were discussing but it was fun and the stories he could tell were fun. But velocity is very important!
Click to expand...

It's all good. Being wrong here is my superpower.

Fred Barlow was a BSA guy from what I have read but based on how my motor runs he knew what he was doing with a Norton head as well. Phil Radford said he was the guy at the time. It's not hogged out, just cleaned up (insert bowl work and other key technical phrases here). It was not a bolt on and go process. I had to put many years of motorcycle ownership and mad scientist tuning experience to the test to make it work. The head work was done in the late 1980's. I had no knowledge of Jim Comstock, or Full Auto heads at the time. I hang my head in shame and will take my keyboard and go stand in the corner now.
 
Fred Barlow was in the BSA comp dept and worked on the 1966 Titanium framed B44's. The secret to a good power output from the B44 is not a hogged out inlet port but instead working on the top of the port about 2" in to open this out just enough so even with a shallow inlet angle the incoming charge when going into the chamber is more vertical than on a standard head. This reduces the amount of incoming charge going straight out the still closing exhaust valve. Stan Millard took a different approach, he milled out the inlet port out nearly down to the guide and then welded back in a steeply downward angled inlet port. Stan's was the more radical solution with the biggest gains with a straight port but if you work within the standard head with angled port the working of the top of the port works.

Be interesting to see if the Norton head worked on by Fred had this opening out above the valve to steepen the direction of the incoming charge, he surely would have used the technique in his BSA days.
 
Fred Barlow probably learnt his stuff at a similar time to John Hudson (The late Mr Norton). John said he didn't favour big valves or ports, but improving shape around the valve bowl to gain maximum flow with the original sizes.

About the time I learnt this, I had in my hand an ex Thruxton fully hemisphered BIG valve short stroke head. However, in between Thruxton and me it had been to the Norton Experimental shop and through the hands of John Baker. So when I measured it had 34mm ports. Can't work said the naysayers, it's all I've got says I. I feared they might be right, who was this John Baker guy anyway?

So I fitted it to the 850 Mk3 bottom end with Omega pistons and a pair 36mm Mk1 Concentrics on a 'home made' manifold and proceeded to out drag every 750/850 Norton and most big twins I exited corners with! It pulled like a train from 3500 upwards to 6800!

I now run a standard Fullauto, on a short stroke 750, it has 32mm ports and works with 34mm or 36mm Mikunis on a 'home made' manifold. As we know it also has clever inlet ports and D exhaust ports.

I have no idea how the two engines compare due to passage of time between riding them, but it pulls like a train from 4000 to around 7500.

Both worked, different approach!
 
jseng1 said:
Another item on my wish list is more meat around the ports for reshaping. I know that the FA head already has some more meat than stock heads but it should be maximized as much as possible - all the way out to the head bolts. The Norton will never realize its full potential until it incorperates the best flowing 2 valve pushrod port shape ever designed - the HD XR750 D ports. With more material to work with - the FA head could actually get very close and then you would see HP figures never before achieved.
Click to expand...
From reading about the XR alloy engine, it was designed for racing and making a lot of power in a high rpm band (7-8 k revs) that would destroy a standard Norton. Flat track racing uses flat out high revving power, that's what makes it exciting to watch.
The alloy xr750 engine is oversquare and designed to handle those revs as a racebike, that is, run a few hours, rebuild then run a few hours again.
So I'm not sure that much of the Harley info transposes well onto a long stroke, low and midrange torque engine which has a tendency to explode when pushed to higher revs or when held for awhile at 6500.
That type of port design could be useful on a complete aftermarket short stroke engine build. This would be an engine with zero original Norton parts or even original Norton design. You would want stronger crank and cases, better valve train and better cooling would be nice as even standard Nortons run quite hot.
I think the numbers in that market would be very tiny, as in fingers on one hand tiny.
It would be a fun experiment though!
Glen
 
Last edited:
kommando said:
Fred Barlow was in the BSA comp dept and worked on the 1966 Titanium framed B44's. The secret to a good power output from the B44 is not a hogged out inlet port but instead working on the top of the port about 2" in to open this out just enough so even with a shallow inlet angle the incoming charge when going into the chamber is more vertical than on a standard head. This reduces the amount of incoming charge going straight out the still closing exhaust valve. Stan Millard took a different approach, he milled out the inlet port out nearly down to the guide and then welded back in a steeply downward angled inlet port. Stan's was the more radical solution with the biggest gains with a straight port but if you work within the standard head with angled port the working of the top of the port works.

Be interesting to see if the Norton head worked on by Fred had this opening out above the valve to steepen the direction of the incoming charge, he surely would have used the technique in his BSA days.
Click to expand...
In my case Mr. Barlow's port work is for a straight up Norton motor. I know this is a Commando forum. I keep thinking my engine is basically the same other than the intake downdraft being steeper on a Commando mounted Norton motor. Somewhere along the line I started thinking a motor is a motor and the same rules apply to all old pushrod motors that the common man can get his hands on.

If I had the balls to take that FBS head off my motor, it could be looked at closer. Last time I had it off, I had to put inserts in it for studs because the studs were pulling out. That head is getting fragile like and old man's skin on the top of the hands gets. If I take it off one thing is going to lead to another, and before I know it, I'll be $4K US deeper upside down on that bike. If I manage to stay healthy, it'll come off next year. I'd like to take some more weight off the rotating and reciprocating mass while I can still ride. I don't mind losing a little torque to improve how quick a motor spins up. Old school thinking?
 
Last edited:
Comparing the side view of HD XR750 port to the FA port in the illustration below shows that they are very similar. The big difference is that the HD port is wider - especially around the guides. We aleady have the FA port for stock Nortons. Modifying it wider would be for higher performance and race bikes including all out 750 short strokes and bore/strokes up to 1000cc. There should be enough material at the sides of the ports to allow for modification and presently there isn't enough to realize the Nortons full potential for an all out racer.

FullAuto Heads Update


The video below shows a 1st step towards a higher performance FA head. Its as far as you'd want to go for a hot cafe bike. But you could go a lot further for an all out racer.

 
Last edited:
Steve had to start with stock heads and didn't have the option/advantage of the raised FA port floor but he did the best he could with what was available to him - mainly reangling the guides for bigger valves - then blending the ports to suit. Some will argue about the port size but a lot of his heads made it to the winner's circles. My preference is to start with small 28.5mm port Atlas heads and raise/widen them while paying close attention to the Axtell port shape which already has so many hours of development invested and proven on the dirt tracks - up to 74HP for an all out long stroke 750.
 
Last edited:
I think inlet port size is related to the rev range over which the motor operates and the cam and exhaust system you use. With a Commando motor, it is probably always better to seek more midrange power and raise the gearing as you go. If you want more acceleration, using more and closer gear ratios can help. The fastest motors are those which can rev higher to develop more power. But a motor which is like that suits the straight parts of a race circuit better. You cannot have it both ways. Either your motor pulls like a train, or it develops more power at high revs. With my bike, If I keep the revs between 5,500 and 7000 and race change with the close box, it is quite fast enough. But you need to be able to do that at every point in corners. If you come out of the corners faster, you will be faster towards the ends of the straights. What really stuffs me is if I get a bad start and not all of the guys in front of me go towards the outside of the corners.
You wil note that the major advances with two stroke motors have been about improving torque In the old days when coming out of corners, you had to get the two stroke upright and pointed before you gave it the berries. In that video I posted about the Mike Hailwood Trophy race at Goodwood, there were TZ 350 Yamahas - no reed valves or controlled exhaust ports..
Getting the steering geometry right is critical. If you cannot gas the bike hard in the middle of a corner, you will be too slow.
 
acotrel said:
I think inlet port size is related to the rev range over which the motor operates and the cam and exhaust system you use. With a Commando motor, it is probably always better to seek more midrange power and raise the gearing as you go. If you want more acceleration, using more and closer gear ratios can help. The fastest motors are those which can rev higher to develop more power. But a motor which is like that suits the straight parts of a race circuit better. You cannot have it both ways. Either your motor pulls like a train, or it develops more power at high revs. With my bike, If I keep the revs between 5,500 and 7000 and race change with the close box, it is quite fast enough. But you need to be able to do that at every point in corners. If you come out of the corners faster, you will be faster towards the ends of the straights. What really stuffs me is if I get a bad start and not all of the guys in front of me go towards the outside of the corners.
You wil note that the major advances with two stroke motors have been about improving torque In the old days when coming out of corners, you had to get the two stroke upright and pointed before you gave it the berries. In that video I posted about the Mike Hailwood Trophy race at Goodwood, there were TZ 350 Yamahas - no reed valves or controlled exhaust ports..
Getting the steering geometry right is critical. If you cannot gas the bike hard in the middle of a corner, you will be too slow.
Click to expand...
Other than a tenuous link in the first sentence, I'm really struggling to see that this post has anything to do with the thread title - FullAuto Heads Update.
 
Hi,

Replacement Commando heads are getting really hard to find. John at STS is trying to fill this void by making available a new head that is an improvement over the the original Fullauto head.

The market for this is in fact a bolt on head and not the highest performance head that could possibly be made. Make a high HP engine and now you have to consider a gear box that can handle the abuse. Then a final drive that can deal with it as well. Reliability will be suffering the more power you make

Those that are willing to go down this path are few. Most everyone just want their bikes to be reliable, friendly and something they can enjoy for a few hundred miles a week....or month, as time to spend on the bike is not as plentiful as it used to be.

I for one think that this new head development is awesome. Yet another part made available to keep our Commandos on the road. Hats off to John for the time and money he is investing in something that is most definitely filling a void.

Matt
 
cNw said:
Hi,

Replacement Commando heads are getting really hard to find. John at STS is trying to fill this void by making available a new head that is an improvement over the the original Fullauto head.

The market for this is in fact a bolt on head and not the highest performance head that could possibly be made. Make a high HP engine and now you have to consider a gear box that can handle the abuse. Then a final drive that can deal with it as well. Reliability will be suffering the more power you make

Those that are willing to go down this path are few. Most everyone just want their bikes to be reliable, friendly and something they can enjoy for a few hundred miles a week....or month, as time to spend on the bike is not as plentiful as it used to be.

I for one think that this new head development is awesome. Yet another part made available to keep our Commandos on the road. Hats off to John for the time and money he is investing in something that is most definitely filling a void.

Matt
Click to expand...
The last time I raced, I only got one good start and I ended up in front. I was afraid of speading the Norton gearbox. - If you do that on the start line, you can easily be hit from behind.
That was the reason I sold my TZ350 Yamaha to buy the 6 speed TTI box.
 
Last edited:

Similar threads

Yakatak
Fullauto Head...5/16" Stud Issue.
Replies
4
Views
545
Yakatak
Yakatak
G81 Can Cycle
FullAuto heads back in production
2
Replies
25
Views
2,603
Blewdy Yaink
Blewdy Yaink
cNw
Fullauto/STS heads
Replies
1
Views
642
cNw
cNw
S
  • Locked
Fullauto head on a 750
2
Replies
20
Views
2,267
MichaelB
MichaelB
Blewdy Yaink
  • Locked
Technical Details on the New FullAuto Commando Cylinder Head from STS, in the US.
2 3
Replies
54
Views
7,524
Brooking 850
Brooking 850
Back
Top