Big valves or small valves

Schwany said:

When you say "one of my 750 valve jobs" are you talking about work you do for yourself, or are you actually doing valve jobs and port work on Norton heads as a service?

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I can do it but I don't presently offer it as a service. I developed a different technique that does not require a mill in hopes that a few do it yourselfers would give it a try. The advantage is that you can accurately locate the tappet contact point on the end of the valve stem. You have to fashion a few cutters and you need a lathe for that. See the vid.




Welding in an alum tube so you can reangle and install a 1/2" guide. Reangling cuts through the OD of the tube but it works out fine.


What I still need is someone who can get inside the port near the valve seat area with a pencil welder that has enough zap to weld the 1/2 round tube near the valve seat so I can finish off the raised port floors (starting with 28.5mm ports). So far no one can do it.

Al remember this post? As your quoting Percy beating Ago I would assume not!
Chris​

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• #61

Once again Al
Both feet.
Well read, reserched?
Just plain wrong!
It's documented (Jack Shermans) that they never had a crankshaft break!
The North is a road based engine.
The MV is designed as a gp race bike.
It weighed 260lbs made 78bhp
The Daytona Percy rode weighed 292lbs !

Keep walking through everything!

Ps just for your information. Percys bike was a 4 speed!

# it was a four speed# it was a four speed# Honest it was!

Chris said:

Al remember this post? As your quoting Percy beating Ago I would assume not![/HEADING][/HEADING]
[HEADING=3][HEADING=3]Chris​

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JoinedJan 21, 2008Messages1,362

• Apr 28, 2020
• Add bookmark
• #61

Once again Al
Both feet.
Well read, reserched?
Just plain wrong!
It's documented (Jack Shermans) that they never had a crankshaft break!
The North is a road based engine.
The MV is designed as a gp race bike.
It weighed 260lbs made 78bhp
The Daytona Percy rode weighed 292lbs !

Keep walking through everything!

Ps just for your information. Percys bike was a 4 speed!

# it was a four speed# it was a four speed# Honest it was!

Click to expand...

All I can say is that Percy must have been a desperate rider, or Ago was having a bad day. Or both.

If bigger valves gives better throttle response, that would be good. With the heavy crank, the 850 motor tends to spin up at the same rate regardless of the gearing. It you want good acceleration, you need close ratio gears and high overall gearing. A four speed close ratio box is good enough, but a clutch start puts you behind the eight ball. My bike jumps quickly enough off the start with four speeds close, If I rev the tits off it on the start line. But if I start with lower revs, it is hopeless because of the poor throttle response. The TTI box has much thicker shafts than a Norton box. When the heavy crank is spinning high, nothing stops it. With close ratios, and high overall gearing, an up-change at 7000 RPM gives excellent acceleration

Sorry all I shouldn't rise but!
Ago lapped everyone except Percy so he definitely wasn't having a bad day!

Percy was a very very good racer.
Desperate!! WT* is that about.

jseng1 said:

What I still need is someone who can get inside the port near the valve seat area with a pencil welder that has enough zap to weld the 1/2 round tube near the valve seat so I can finish off the raised port floors (starting with 28.5mm ports). So far no one can do it.

Click to expand...

Hi Jim, have you considered remote laser welding?


- Knut

mdt-son said:

Hi Jim, have you considered remote laser welding?

http://www.jlps.gr.jp/jlmn/assets/4ce2fcfe791f000564c5c92feba826fb.pdf#:~:text=One%20of%20the%20emerging%20joining%20technologies%2C%20remote%20laser,energy%20consump-%20tion%20and%20lower%20cost%20%5B8%2C%209%5D.

- Knut

Click to expand...

Practically speaking - who offers this service and does it work on thick aluminum?

acotrel said:

All I can say is that Percy must have been a desperate rider, or Ago was having a bad day. Or both.

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This is hilarious !
"Percy must have been a desparate rider" oh god

Well now I know.
All I needed to beat Yvonne Duhamel was some desperation.
I've been desperate lots of times, like when my cartopper fishing boat overturned, for example.
I remember nearly drowning and being pretty shaken up.
Turns out I would have been faster than Ago right then!

Glen

Wasn't that race supposed to have happened at Spa in Belgium ? The circuit might have suited the bike. In Australia, most of our race circuits are short and tight except for Phillip Island and Bathurst. Sometimes a large race circuit can level the field.

@jseng

Yes usually it's very suitable for deep penetration thick gauge material.
Mostly depending on the wave length of the used laser (gas, fibre, Diode etc).
I'm still amazed that neither in the greater bay area or as well long beach area that no capable TIG welder can be found as it didn't used to be like that.
I mean after all it's not rocket science and not even G6 aluminum ability is needed.
O tempora, o mores.

Kind regards Christian

jseng1 said:

Practically speaking - who offers this service and does it work on thick aluminum?

Click to expand...

jseng1 said:

Practically speaking - who offers this service and does it work on thick aluminum?

Click to expand...

All my previous exposure to laser welding was in weapons systems manufacturing. That was all done by automated robots, and wasn't something that would have worked for the Norton port welding. But it was also almost 20 years ago, and I was curious what the current state of the art is. Turns out there is now hand held laser welding equipment available that might actually be applicable to welding in ports. Or maybe not. In any case, I ran across some interesting sites that explain what is currently available and what it can be used for. Plenty more info available for the price of a bit of search time.




Quite a few Chinese sites out there also selling hand held laser welders.

Still, I'm not sure any of them can get into the Norton port and make decent welds on the thicker parts of the castings. Looks like they are mostly used on fairly thin materials.

It would be tempting to try one out on normal shop welding tasks, but sales prices in the $15,000 and up range will keep me from experimenting with it.

Ken

jseng1 said:

Practically speaking - who offers this service and does it work on thick aluminum?

Click to expand...

Jim, I think this technology is promising enough that you should call some of the vendors / agents. They usually have demo sites and the operators of those machines will know limit capabilities of the equipment. Another lead is John A. Macken. He is the "father" of remote laser welding. I am sure you can dig out his address. He lives in California.

In 2015, limit part thickness for RLW was 4mm, but today? The technology is evolving fast.

-Knut

I've talked to some expert welders and sent the head off to someone who said they could do it - but they couldn't. Supposedly here are people out there who can do it but until I find someone who has actually been able to get 1" deep inside a 1" diameter port - I'm stuck. There are pencil welders that could get inside the port but they don't generate enough heat to do the job because of the thickness of the alum.

jseng1 said:

I've talked to some expert welders and sent the head off to someone who said they could do it - but they couldn't. Supposedly here are people out there who can do it but until I find someone who has actually been able to get 1" deep inside a 1" diameter port - I'm stuck. There are pencil welders that could get inside the port but they don't generate enough heat to do the job because of the thickness of the alum.

Click to expand...

And I'm sure you've also already looked at more far out possibilities, like metal spray or other deposition technologies. It would appear that they all suffer from the same issue, the size of the equipment and the tight access to a small port. Sounds like new patterns and castings are the only realistic way to get what you're looking for. I'm still waiting for that big lottery win so I can finance the effort. For the moment, it looks like big valves and some port mods to a Fullauto head is about as good as it gets right now.

Ken

There is one guy here in Australia who makes cylinder heads for single cylinder motors. He carves the inlet ports out of the solid by hand.

Yes the FA head is a very good place to start.

Back to big valves. Here's a few winning bikes with big valves.

Ron Woods winning flat tracker with AMA factory big valve head (3mm oversize intakes I think). Alex Jorgensen and others riding.




Dave Watson's 1000cc roadracer with 5mm oversize intake and 3mm oversize exhaust valves (Maney stage 3). Gary Twaites riding.



Ken Canaga's monoshock 920 that took 3rd at Willow Springs against a field of air cooled monoshock Ducatis. The last Norton to get on the AMA podium approx 1990 with Rob Tuluie riding. Pretty sure it had big valves - Ken can tell us.

Hello All.
Here is what I found with converting Norton cylinder heads:
750- heads with 1/2" outer guide diameter:
For re- angling you have to bore the guide bore with the new angle which opens the bore to about 14,5 or 15mm. I always use standard 850 bronce guides and turn them down (between centres) to the suitable diameter. So you never are in need of special guides, you can always use 850guides and turn them down. The bigger intake valve would be 41mm. The exhaust is left with 33mm, because you simply don't get bigger valves into the bore.
750- heads converted for use in 850 (or bigger) engines:
Both valves have to be re- angled depending on size with different angles. This is also quite an easy job. Additionally you have to re- position the outer 4 bolt bores to suit the 850 hole pattern. This is what Steve Maney did .
850- heads converted to for bigger valves.
This is a very complex job. I cut a thread (M16x1, M17x1 or M18x1) and turn suitable flanged bushes with a suitable outer thread with a 8mm Bore. This hole is used for matching the valve shaft with the adjustment screws. The plug is inserted into the threaded guide- bore and locked with a high temperature valve locker (similar to loctite, but it withstands temperatures up to 1100°C. It's some American stuff.
It's very easy to do a big valve conversion for standard sized 750 valve guides. I have done quite a few big valve conversions now. Here is one I did for Yves van Heers from Belgium.
It was a Fullauto- head, which had the big advantage to have 1/2" guides as standard. I thinks Yves turned out to be 15mm outer diameter.
Certainly it would be a big advantage to have floor- raised intake- ports. In this case you certainly also have to raise the roof of tha port. But this makes things difficult, you have to weld. There is a guy near me who does laser- welding. But I guess, it will be rather expensive.
Best Regards
Klaus

@acotrel
If the guy is in the Perth/freemantle area than I Met him in some occasions (5acxs cnc center very nice).

@jseng1
In still puzzled that there is nobody capable to do such a job.
I'm not saying that for publicities sake or as a bragging effort, but i do on quite some occasions floor raising (welding as well as JB weld in intakes) on tt500's and with the right long neck nozzle a commando Port should be no issue, considering that I reach in as much as 2-3".
Same goes for the guide holes. I'm quite sure on could close completely the original bore and redrill on semi virgin aluminum.
As for the mini torches (think by weld craft( there are some that go up to 120-140 Amos, so with some preheating in Port welding should be possible.
As for reshaping the port through welding, it just occured to me, there must be some capable weldors over in your neck of the woods as it is somewhat common practice with hog's.

Kind regards Christian

jseng1 said:

Yes the FA head is a very good place to start.

Back to big valves. Here's a few winning bikes with big valves.

Ron Woods winning flat tracker with AMA factory big valve head (3mm oversize intakes I think). Alex Jorgensen and others riding.

Dave Watson's 1000cc roadracer with 5mm oversize intake and 3mm oversize exhaust valves (Maney stage 3). Gary Twaites riding.

Ken Canaga's monoshock 920 that took 3rd at Willow Springs against a field of air cooled monoshock Ducatis. The last Norton to get on the AMA podium approx 1990 with Rob Tuluie riding. Pretty sure it had big valves - Ken can tell us.

Click to expand...

You are correct on the date, Jim. The race was the AMA National in 1990, and Rob was 3rd in the Pro Twins GP2 class. You can tell from the picture below that we were pretty excited about it.

The engine was a 920 cc with a standard short stroke 750 head with the original 1.625" intakes and 1.302" exhausts and a little work on the port and seat areas.



Ken