PWK Carb

[Billybream]

Sluggo
Thanks for the advice and information, sourced viton o ring for the flange and stainless steel braided fuel lines.
Just awaiting new inline fuel filter before its first run out.

[Sluggo]

Billy, I am sure you will be pleased, please update with feedback, Any support needed, feel free to reach out either here or PM.

**NOTE** For some reason admin relocated this topic, looks like we are in Amal carb section now which kind of make sense...
-----------------------------------------------UPDATE FROM JRC----------------------------------------------
Hello Doug,

Thank you for the input regarding the JRC Superior carburetor. There are some folks out there who already have their minds made up. If we can educate a few of them we would be happy to do so. Our PWK carburetor has recently been updated to the Powerjet style. I have attached a recent new release we sent out be email. Available bore sizes and mounting styles are listed: https://mailchi.mp/9ab2c6a3be5a/jrc-superior-britflow-carburetor-updates?e=140ab0d3de

Those unfamiliar with carburetor tuning seem to be the ones with the most complaints. Followed closely by the purist who would never fit one just because it was not factory. When we know the application we pre-jet the product to avoid much of the bothersome tuning experience. The cheap products online are like you said of unknown quality. Many are fitted with odd size jets and jet carriers. This makes tuning almost impossible.

 We will put out some articles soon on the subject.

Regards,
Nick Willcutt


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JRC Engineering Inc
3110 Indian Ave Ste E
Perris, California 92571
USA
jrcengineering.com
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(Here is the text of the eBlast, Pix should be linkable, if not ask and Ill post them, as you can see these are a newer version and offer some great features)

The JRC Superior Britflow carburetor is intended to be a direct replacement for the factory supplied carburetor.

Why replace the stock carburetor with a JRC Superior?
Here are a few reasons:

Price - Our carburetor is an economical alternative to the OEM carburetor.

Performance - In dyno testing our carburetor was shown to increase horsepower and fuel economy. We have the data if you would like to see for yourself.

Safety - Our carburetor does not leak when "choked" for starting. So no fuel dribbling down the side of the carb. The flat slide design prevents throttle valve sticking. The bodies of our carb is not prone to warp if the flange bolts are over tightened.

Material - JRC Superior carbs are made of aluminium with a chrome plated brass slide. We do not employ pot metal in our carburetor. This makes the unit lighter and longer lasting.

JRC POWER JET - OUR LATEST VERSION OF THE SUPERIOR CARBURETOR

THE ADDITION OF THE POWER JET IMPROVES TOP END PERFORMANCE.

https://jrcengineering.com/product/jrc-power-jet/
 

OFFERED IN THE FOLLOWING BORES - 30mm, 28mm, 26mm, 24mm, 21mm
Also in 32 and 34mm

SEE OUR CARB MOUNTED TO VARIOUS APPLICATIONS AT THE END OF OUR TECH PAGE:
https://jrcengineering.com/technical-support/jrc-pwk-carb-instructions/

JRC-30PJ
30MM POWERJET - STANDARD 2 INCH MOUNTING FLANGE - FITS MOST BRITISH BIKES - TRIUMPH, BSA, NORTON, VELOCETTE, ETC

just a few application pictures:

TRIUMPH TR6 https://jrcengineering.com/wp-content/uploads/2017/09/tr6pwk.jpg

BSA A65 https://jrcengineering.com/wp-content/uploads/2018/04/A65.jpg

JRC-26PJ
26MM POWERJET - STANDARD 2 INCH MOUNTING FLANGE - FITS MOST BRITISH BIKES - TRIUMPH, BSA, NORTON, VELOCETTE, ETC

ALSO CAN SUPPLY IN 28, 24, 21MM BORES
 

 

JRC-30PJ/E
30MM POWERJET - 38MM SPIGOT - REPLACED AMAL MK2 - NEW URAL 750
JRC-30PJ/B
30MM POWERJET - 35MM SPIGOT

JRC-26PJ/E
26MM POWERJET - 38MM SPIGOT -
JRC-26PJ/B
26MM POWERJET - 35MM SPIGOT

ALSO CAN SUPPLY IN 28, 24, 21MM BORES WITH 2 INCH FLANGE

JRC-32PJ
32MM POWERJET - 38MM SPIGOT - NOT AVAILABLE IN 2 INCH FLANGED

JRC-34PJ
34MM POWERJET - 38MM SPIGOT - NOT AVAILABLE IN 2 INCH FLANGED

JRC-30PJ/A
30MM POWERJET - 58MM FLANGE - 2005-NEWER 500 ENFIELD BULLET

JRC-26PJ/A
26MM POWERJET - 58MM FLANGE - 2005-NEWER 350 ENFIELD

JRC-32PJ/A
32MM POWERJET - 58MM FLANGE - 2005-NEWER 500 ENFIELD AVL MOTOR

 
CUSTOM FITMENT REQUESTS ARE WELCOME.

THE FOLLOWING MOUNTING OPTIONS ARE AVAILABLE UPON REQUEST:
BORE SIZES JRC-30PJ, 28, 26, 24, 21mm:

(NO LETTER SUFFIX) STANDARD 2IN FLANGE
(B) 35mm spigot
(E) 38mm spigot - MK2 carb replacement/ New Ural 750
(A) 58mm horizontal flange - New Enfield
(C) 53mm vertical flange - Ural Dneper/ BMW

BORE SIZES: 32, 34mm
(NO LETTER SUFFIX) 38mm spigot - Norton 2-1 manifold kit
(A) 58mm horizontal flange - New Enfield AVL motor
 

CUSTOM FITMENT REQUESTS ARE WELCOME

THE FOLLOWING MOUNTING OPTIONS ARE AVAILABLE UPON REQUEST:
BORE SIZES JRC-30PJ, 28, 26, 24, 21mm:

(NO LETTER SUFFIX) STANDARD 2IN FLANGE
(B) 35mm spigot
(E) 38mm spigot - MK2 carb replacement/ New Ural 750
(A) 58mm horizontal flange - New Enfield
(C) 53mm vertical flange - Ural Dneper/ BMW

BORE SIZES: 32, 34mm
(NO LETTER SUFFIX) 38mm spigot - Norton 2-1 manifold kit
(A) 58mm horizontal flange - New Enfield AVL motor
 

[muskrat]

G'day Sluggo.
Thanks for posting that.
I'm a very happy customer.
Having two 30's on an A10 meant I had To "tune" them, and that took a bit of work, but great once sorted.
My only errr is the pilot screw on the right carb is hidden by the left carb. Not really a problem now their sorted.
Cheers

[Billybream]

First outing today with the SRM supplied PWK (JRC) 30mm carb, started first kick with use of the enricher, pulled well but popped on overrun, quick stop after 10 miles for adjustments to air screw and plug chop. Very pleased, liked the choice of idle adjustment  screw position and no more tickling. Just need more practice of use of enricher.
Pilot jet 35
Main jet 134
Needle position middle
Air screw 1 1/2 turns

[Billybream]

A couple of pics of PWK carb on my Super Rocket

[Billybream]

Missed a pic

[Sluggo]

I passed on your comments and a copy of your pix to the staff at JRC.  Got this in return.

Hey Doug,

Tuning has been an issue when we introduce a carb to a new market. We always are seeking jetting data. That why the next customer in that region will benefit. Fuel formulations vary considerably since most vehicles are fuel injected these days. Any difference is compensated for by the computer. Not really to good for us. The addition of ethanol to fuel has also played a big part in tuning troubles.

We actually offer an extended pilot screw.
https://jrcengineering.com/product/p17a/

Regards,
Nick Willcutt

[muskrat]

G'day Sluggo.
I just downloaded their parts dogalog. Wow they have some stuff!
I looked at the link for the P17A and this is where the terminology of different countries become a problem. In the parts list it's called a idle screw, I know them as pilot screw (air in this case or fuel). What I call an idle screw they call throttle stop screw! So I took one out of a carb to compare to the pic on the web page. Yep their the tomartoes/tomaatoes.
Cheers

[Peter in Aus]

Hi all, I have obtained a PWK carby from a friend that didn't use it, it was supposed to be jetted to suet the A7, it has main jet 115 idle jet 68 and JJH needle 26mm bore. Dose this sand right for the A7 iron head?
Any info would be appreciated.
Peter
 

[Billybream]

You may well have to try and see how she runs, saving grace the jets are plentiful and inexpensive, best of luck

[muskrat]

G'day Peter.
Idle jet way too big. Have a look here https://www.jrcengineering.com/technical-support/jrc-pwk-carb-instructions/
Cheers

[Peter in Aus]

Thanks BB and Musky, Musky, I have had a look at that, but was hoping for some one that had fitted a PWK to come back with what jet size they ended up with for the 54 A7 iron head, could save a bit of work for me and others.
Peter

I E-Mailed JRC and got this reply, I might ad very promptly.

Hello Peter,

We have found the following specs work well for A7:
110 main jet, #35 slow jet. Is the richness you are encountering at idle or at a specific throttle position?

Regards,
Nick
JRC