Honda Urban Express Revolution Carburetor


Installation video

A revolution is here! Introducing the Honda NU50 Urban Express Revolution Carburetor! Finally, a carburetor solution for the Honda Urban Express and Honda Express SR NX50 that is revolutionary in so many ways.

1. Better performance than stock carb. You should see an immediate difference in how your bike runs after installation and dialing it in. I’ve reworked the internals and made other modifications so your Urban will hum right along with this carb. I’ve set up the carb according to testing on several different Urban Expresses but every bike is different. You’ll need to dial in the idle/air screw and the throttle stop screw for maximum performance on your particular bike. This carb is set up for stock bike with stock exhaust and stock cylinder. If you have a performance exhaust or larger top end or both, let me know and I will provide you with an approximate jetting.

2. A carburetor solution that lets you keep your rear fender without any modification! This is huge! And I mean huge! I’ve sat on the fence so many times about getting a new carburetor or air filter or carb/filter combo because I didn’t want to lose the rear fender. The bracket that connects the rear fender to the bike hogs an enormous amount of space right below the carb. Yeah, I know, find a radiator hose elbow and hook it up. Oh screw that! Just give me something that works out of the box. This one does when combined with the K&N RC-2540 air filter, you can keep your rear fender with all the related bracketry, etc.

3. No throttle cable modification! Yes, that’s right! You don’t have to mess with adjusting the throttle cable. Hallelujah!

4. Manual choke! Honda’s auto-choke crap got you down! No more. Get rid of that tangle of hoses, cap off all four auto-choke passages and say goodbye to that mess forever.

5. Tell all those eBay sellers to go to hell! I’ve seen USED NU50 carbs sell for $175 on eBay. Are you kidding me? $175 for some 30+ year old carb! Screw that! Get this for almost $100 less then sell your old carb on eBay and pocket the profit! Oh hell yeah!

6. Bolts right up to the stock intake no problem!

7. I’m running this on premix as there is no inlet for the oil injector on the carb although you MAY/MIGHT be able to route the oil injector hose to the bottom of the intake where the auto-choke hose attached. I have not tried this so no guarantees.

Ok, it’s not all sugar plums and faeries. You will need to dremel off or hacksaw off a portion of the choke lever because the Urban Express rear brake cable interferes with operation of the complete choke lever. Took me 2 minutes! See picture. I just took a dremel to it and then wrapped the sharp edges with duct tape. Now the choke lever is fully operational and the rear brake cable won’t interfere with it. I was able to install the carburetor with the full choke lever by just moving the rear brake cable slightly. See installation video above. You will also need to get two metric bolts to attach the carb to your intake. Or remove the studs from your stock carb and put them in the new carb.

As always, it is a great idea to replace your fuel filter or add one if you don’t have one already. While you’re at it, replace your old fuel line as well.

That’s it! Let ‘er rip, dude!

If you are ordering for the Honda Express SR, please so indicate as jetting will be different.

Revolution Carb on the Express SR
Revolution Carburetor on the Honda Express SR, nx50.  To install it, you have to substitute a tube of some sort for the long brass tube that Honda used on the stock carb above the slide chamber cap.  I just used a piece of old, hard fuel line that was of similar length.  The Express SR also used a smaller main jet than the Urban Express.  So if you order this for the Express SR, let me know and I can include a proper main jet.