1950 NORTON "BIG 4" going for Land SPeed Record ?

Hello from South Texas!

Thank you all for taking the time to post all of your knowledge on this site. Your knowledge has been a big insight for me lately. Thank you again.

*** I will state this from the begining... I am a Norton NUBE and I am posting this build on another forum so sorry if that bothers some people but I am trying to gather as much knowledge as possible.

Yes, you read that right, I am building a 1950 Big 4 (596cc) to run at the Bonneville Salt Flats this August. This is the first Brit bike I have owned and I know nothing about them other than I need to buy some different tools and this engine is like a large Briggs and Stratton to me.

This will be the third year racing at the flats. Usually I run a 99cc Kawasaki based "lay down" bike however this year I am wanting to try an older bike. I'm sure most of you would agree that a Big 4 would be one of the last bikes to use for a speed record however, this is the only bike I own that is old enough to run in the Vintage class.

If any of you have any information, experience, or just some comments that you want to throw my way, please do. I will continue to post my updates here. I will be filming the entire adventure from start to finish so all of you can follow along.

Will also be making an updated page on my website (www.motorcyclesandart.com) of what parts are needed and information that I am looking for. Maybe you all can help me when and where you can. Once again, I know nothing about these old Brit bikes as I am a two stroke guy.

More videos to come on the plan and progress.

Have a rad day! -- Casey

LINK TO FIRST VIDEO

Welcome.

The Big '4' (4+) HP was the RAC's (Royal Automobile Club's) formula for horsepower rating and not a measure of actual power output.

"h.p. = (D2 x n)/2.5
where D = the diameter of the cylinder in inches [1" = 25.4mm], and n = the number of cylinders"

(The original Big 4 was 82 x 120, 633cc) .

Wow. Interesting idea. After watching your video, I'm assuming you only plan to run the AMA (Bonneville Motorcycle Speed Trials) meet, since SCTA doesn't have a class for Production frame with Vintage Fuel engine. There is no current record in the 650 P-VF class, so plenty of opportunity. Sounds like a fun adventure. What fuel do you plan on running, just some sort of gas mix that you don't have to buy from the fuel truck at the meet, or are you looking at alcohol, nitro or nitrous? Given the stock carb and exhaust restrictions, there's not much to be gained from just alcohol or a gas/alcohol mix, but definitely some possibilities for nitro, or even better, nitrous. But it sounds to me like you're not looking to get into that level of effort for this bike. Please keep us informed as you proceed with the project.

Ken

Big massive respect Casey !

Looking forward to following this thread.

Carry on…

motorcyclesandart.com said:

Hello from South Texas!

Thank you all for taking the time to post all of your knowledge on this site. Your knowledge has been a big insight for me lately. Thank you again.

*** I will state this from the begining... I am a Norton NUBE and I am posting this build on another forum so sorry if that bothers some people but I am trying to gather as much knowledge as possible.

Yes, you read that right, I am building a 1950 Big 4 (596cc) to run at the Bonneville Salt Flats this August. This is the first Brit bike I have owned and I know nothing about them other than I need to buy some different tools and this engine is like a large Briggs and Stratton to me.

This will be the third year racing at the flats. Usually I run a 99cc Kawasaki based "lay down" bike however this year I am wanting to try an older bike. I'm sure most of you would agree that a Big 4 would be one of the last bikes to use for a speed record however, this is the only bike I own that is old enough to run in the Vintage class.

If any of you have any information, experience, or just some comments that you want to throw my way, please do. I will continue to post my updates here. I will be filming the entire adventure from start to finish so all of you can follow along.

Will also be making an updated page on my website (www.motorcyclesandart.com) of what parts are needed and information that I am looking for. Maybe you all can help me when and where you can. Once again, I know nothing about these old Brit bikes as I am a two stroke guy.

More videos to come on the plan and progress.

Have a rad day! -- Casey

LINK TO FIRST VIDEO

Click to expand...

I love your project
What sort of speed are you hoping to achieve?

You may be ahead of the game already but there is a good post, link below, on making the Big 4's little brother go faster. Similar work may apply the Big 4?

L.A.B. said:

Welcome.

The Big '4' (4+) HP was the RAC's (Royal Automobile Club's) formula for horsepower rating and not a measure of actual power output.

RAC Horsepower

"h.p. = (D2 x n)/2.5
where D = the diameter of the cylinder in inches [1" = 25.4mm], and n = the number of cylinders"

(The original Big 4 was 82 x 120, 633cc) .

Click to expand...

Thank you for the welcome and thank you for that explanation. I wish horsepower was that easy!

lcrken said:

Wow. Interesting idea. After watching your video, I'm assuming you only plan to run the AMA (Bonneville Motorcycle Speed Trials) meet, since SCTA doesn't have a class for Production frame with Vintage Fuel engine. There is no current record in the 650 P-VF class, so plenty of opportunity. Sounds like a fun adventure. What fuel do you plan on running, just some sort of gas mix that you don't have to buy from the fuel truck at the meet, or are you looking at alcohol, nitro or nitrous? Given the stock carb and exhaust restrictions, there's not much to be gained from just alcohol or a gas/alcohol mix, but definitely some possibilities for nitro, or even better, nitrous. But it sounds to me like you're not looking to get into that level of effort for this bike. Please keep us informed as you proceed with the project.

Ken

Click to expand...

Hi Ken. Thanks for reaching out.

As far as fuel, I will be doing calculations on compression ration and ambient heat and choose the level of octane from there.

If I can raise the CR from the 4.5:1 to around 7:1 (This CR ratio was found to be best in the Harley KR race bikes), I will probably run 89 - 93 octane. Once again, punch the numbers and mix fuel.

Low compression and low RPMs are not great to use with meth or eth. Takes too long to burn plus a handful of other reasons.

I have thought about running some nitro at the end of the week if all goes well.

Yes, I will be running AMA. If you notice in the 650 P-VF, I can run a different carburetor (VF class) however I have to run the factory exhaust (P class).

Thanks for checking in. I will keep you all posted.

Fast Eddie said:

Big massive respect Casey !

Looking forward to following this thread.

Carry on…

Click to expand...

Thank you Sir. I shall carry on.

baz said:

I love your project
What sort of speed are you hoping to achieve?

Click to expand...

Thank you Sir.

As far as speed, I really do not know what to expect. From what I have researched, these flywheels do not like to go above 5k RPM. Some people in the past have milled down the wheels and fitted steel bands around them to keep the cast iron from exploding.

I do not think I will have time to do this so the RPM will be limited to <5K.

I would like to see it go above 91.37mph. Wonder how many will know who's record time that is. Hint... It is in a car.

Thank you again!

ntst8 said:

You may be ahead of the game already but there is a good post, link below, on making the Big 4's little brother go faster. Similar work may apply the Big 4?

Vintage Norton Motorcycles

being a pictorial archive of these unapproachable machines

www.vintagenorton.com

Click to expand...

Yes Sir! Thank you for suggesting that. In fact, that article is what got me thinking about building this bike instead of just having in sit in the living room.

Please feel free to reach out if you find any other side valve/ flathead race info.

Have a great day!

The only other article i still have is by Nigel Fox, but that came from the the VintageNorton website as well.
I sold my 16H a month or two back and cleaned out the cupboard at the same time.
Great project, hope all goes well.

Do you know why I had to buy a gallon of ATF and a gallon of Acetone?
The answer is in the video....

I've heard acetone and ATF works ok a penetrant
But for rust removal I use ordinary food grade citric acid granules
Put a kilo in say 8 gallons of water I use a plastic dustbin
Dunk the components in the solution over night and the next day you can wash the rust off
If I were you I'd take the head and barrel off and put the whole lot in citric acid
Then clean it up and see what you've got
The primary chain is very slack because it needs adjusting you pivot the gearbox back to do this
You are going to have to completely strip that engine anyway to check the big end and main bearings
I'm not sure how you plan to tune that engine but I'd expect you will lightening the crank and re balancing
So you may aswel get into it
Good luck with it
Cheers

Your last successful kicking over may not have turned the engine but just a slipping clutch, or you turned it over and left the inlet valve open and moisture got it. If its only been seized for a few months then it should break free with no damage but it can take days of leaving the ATF/Acetone and then each day trying to turn it over for 15 mins and then leaving it 24 hrs before trying for another 15 mins. The nut on the end of the crank will take some torque before any threads get damaged. All that debris looks to be old carbon flaking off due to the ATF/Acetone, nothing exceptional for a bike that old and a side valve.

And as Baz suggests citric acid will remove the rust once the engine is free to spin.

This book may help It has a lot of info for "Back in the day" performance increases for side valve and big singles. Check e-bay if you don't find contact me and I'll lone it to you.

Someones done a fake Brooklands supercharged Zundap .

Id think STEEL FLYWHEELS , and a Super Charger might not be to bad.
The heads not got excessive length in the ports , which'd roast it from heat transfer .

With this the big call would be getting the exhaust out .
It might even be possable to double the std. cylinder charge . Whaa Hoo .

Methanol fuel for cooling ?

Theresabit of info around on em . The Overhead Valve is just a passing phase . The side Valve will return , Quote from my tuning side valve manual .

Course , Supercharged and converted to I.o.E. / ' F ' Head , would be best . As you could run Three Inch Valves ! ,

Oh Dear .

See if you can find any information written by Laurence Hartley .