Honda NU50/ Runaway/ Urban Express - Carb hoses???

Hi,

I recently cleaned my carb - going to give it a test ride now to see if everything is sound. Seems to be moving at the same time I move the throttle. I don't have to feather it to get it going. And I can now put the petcock on 'ON' instead of 'REV'. Will get back to the forums on some road tests soon.

Anyway before I removed the carb there were two hoses that were not connected. Anyone know what these are and should they be connected to anything. I looked at the manual but its hard to see from the images.

Going from left to right - its the first and the third hose.

Thanks in advance.

Re: Honda NU50/ Runaway/ Urban Express - Carb hoses???

Captain Janeway /

The one to the left hangs free as a vent, the one to the right hooks to your bystarter chamber (the little black thing hanging with two hose hookups.

Yeah, online manual pictures aren't great, but have this become your new best friend

NU50 manual

Re: Honda NU50/ Runaway/ Urban Express - Carb hoses???

just tested on the road... also bought a new spark plug.

seems to idle just fine (air screw - 2 turns in and idle - 1/2+1/4 turns). If I do unscrew the idle more the throttle response/ acceleration is better but will bog out more quickly and won't idle. With the adjustments above I would need to feather the throttle for quite a bit to get it going. I've played with different screw combinations but can't seem to get it to idle nicely and have good throttle/ acceleration.

I am missing the bystarter unit - do I really need this? - used the bike before cleaning the carb and it was working fine - except for the acceleration (which I needed to feather to get up to speed) .

Re: Honda NU50/ Runaway/ Urban Express - Carb hoses???

Without the bystarter you will have no choke function at all.

Re: Honda NU50/ Runaway/ Urban Express - Carb hoses???

Inspired by a Rube Goldberg schematic, Honda developed one of the most hose-heavy choke systems I can think of, and tested it on one of their smallest bikes. And, you need ALL of it to work; no half-way shit here (although it is pretty clever).

Without delving into detail, you need to have the carb connected to the bystarter, which in turn must be connected to the choke control box (on the bikes I have, at least the choke control box has numbers printed on the hoses that correspond to the correct locations). The mess of return hoses must also be fully connected. Otherwise, like Ryan said, no choke. I suppose you could run rich & wait until it's warm, then dial it back, but that doesn't seem fun; I wouldn't do it.

Janeway's had good results with stock, but I don't hesitate to swap in a Mikuni at the first sign of failure (although you will need to premix if you do this).

Re: Honda NU50/ Runaway/ Urban Express - Carb hoses???

Yamaha beats Honda in spades on any of it's older scooters, especially the CV180... there's yards of hose in that thing.

Re: Honda NU50/ Runaway/ Urban Express - Carb hoses???

Captain Janeway /

Photograph everything so I can see what you're missing or sort it out from the manual and tell me. Are you missing just the little bystarter chamber or the whole setup with hoses. I may have some of the parts around.

Re: Honda NU50/ Runaway/ Urban Express - Carb hoses???

Hey, I have the hoses, intake and dealio on the head that are going to the trash. If you want them, p.m. wher to send em.

« Go to Topic — end of thread

Want to reply to this thread?

We'd love to have you join the discussion, but first you'll need to login (or create an account).