to those with Urban NU50 + pipe

are you running stock carb and airbox, or do you have to use hiflow filter for expansion chamber to work right? it seems like i have been advised both "get a unipod" and "dont mess with stock airbox". does elevation play a big part in advice from people around the country? i'm about 50 feet above sea level, fyi. can i get away with only upjetting? finally got my carb gasket set so i cleaned my carb for the first time tonight and saw i have an 85 jet. i also ordered whatever jets they could find that fit, i got an 80. are there bigger jets made for this carb, or do you always end up drilling yours? i tried my new pipe (pocketbike chamber/nu50 header) on my otherwise stock urban but it barely ran, giving slow, heavy puffs of smoke and the sound like someone slowly tapping a cowbell coming from the silencer, and would barely move at WOT, so i replaced (clogged) stock one until i get all the parts i need. i think running slow and smoky means running lean, since it would only run if i held the throttle open a bit. or do i have it backwards, was it bogged down coughing oily smoke and gasping for air? i looked at performance spreadsheet, but the only NU50 had a 70cc kit.

yeah, my first ped, if its not obvious.


Re: to those with Urban NU50 + pipe

Sounds like you need more air to me if you have to keep the throtle open some just so it runs.And the smoking mesns rich but that may be a matter of poor oil/fuel mix. Do you have an oil pump? Do you premix? Dont do both How did it run before you did anything to it?


Re: to those with Urban NU50 + pipe

right now im using oil pump, not premix. it runs well stock, but wont go over 27 on flats because exhaust is really clogged, even after the BBQ treatment. and its not the iowa model. stock air filter element was new in july, put about 300 miles on it since i've had it. would like to keep carb i have for now, maybe i could higher flow foam for inside the airbox? i think i saw uni makes that. or maybe i could trim foam i have now, i ordered 2 since bike bandit had them for $3.33 each. hoping to get close to 40 with new pipe so im not stuck on the side streets.

Re: to those with Urban NU50 + pipe

i put on cleaned carb with new gaskets, still 4 strokes/bogs at 25. at least my first carb rebuild was a success.

fact or rumor, the express always runs rich from the factory? 80 jet and stock airbox, or 85 jet and a unipod, hmmm? i need to find a good road to do plugchops. how do those unis hold up in the rain? i know im gonna get stuck riding or parked outside in the rain someday soon.

Re: to those with Urban NU50 + pipe

well today i tried putting new pipe on again, dont have a unipod yet, so i experimented with running with cover off of airbox, then with cover off and filter removed, it still runs really slow, lots of smoke, wheel barely turns at WOT. is the 85 jet way too big? seems to work fine with all stock setup, starts every time, good pickup, no smoke, just 4 strokes at/wont go over 26mph. i thought you always should upjet when increasing airflow and adding expansion chamber, right?

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