Urban Express won't start

Glenn Krueger /

I have an Urban Express NU50M with 2150 miles on it. It was stored for years and needed a complete re-do. I have done most everything. I am getting fuel to the carb. The carb has been off and cleaned twice. Reeds and seal seem fine.

All electrics are working - lights, new battery. No wiring harness issues.

Compression is 155 psi with just the starter motor and the pressure is held. No bypass evident.

Good spark and the timing is good.

The gas tank and petcock was inspected and cleaned. Good fuel flow. Carb bowl has fuel.

Motor will fire on one stroke, then nothing. Obviously not getting the right fuel mixture. Ether does not help.

Mixture is 1.5 to 2 truns out and the throttle is at specs. All needle valves and seats are fine - No wear or indication of problems. The idle screw is working correctly.

Oil pump is OK.

Muffler is OK.

I have reviewed the posts and I am thinking the cankcase seals may be bad. How does one check that with a leak down test?

The control box was loaded with gunk. Cleaned and re-installed. Does the bimetal strip move in or out when heated? I suspect the control box is the problem as the gunk found may have blocked the valve operation - carbon deposits. An answer on the operation of the control box may be the cure.

I will install new rubber tubing from the control box to the carb. That may be the problem

The bystarter has not been cleaned. I am not able to get it appart. I am afraid to break it as it is plastic and brittle.

Any suggestions from the experts?

Glenn

Re: Urban Express won't start

Gruff "(OFMC)" - /

you have good compression, good spark, and fuel so you say! so hows it acting? take the f'n auto choke off, plug the inlets to the carb(Oriellys plug pack). you didnt say anything about the air filter take that off too. after that shoot starter fluid in the carb opening while starting. see if that works ifn that dont work take the pipe off and then try. if none of this works let us know and we'll go from there.

If it does work put back 1 thing at a time, and try and start it, to see where the issue is. and clean the carb again. look for fatrat440 video on youtube on cleaning the idle jet circuit and blow out all holes with air compressor. probably not airleak with the crank seals or it would have started with the starter spray well maybe post: put inline fuel filter on A MUST!! (edited)

Re: Urban Express won't start

Gruff "(OFMC)" - /

if none of the above gets it started, take the intake off and do a visual on the reeds. If one is stuck open just a little, it will act as your saying. You are using the correct plug right?

Re: Urban Express won't start

Glenn Krueger /

I have removed the carburator, intake manafold and the reed assembley.

The carburator idler tube was found to be open. I put a silcone tube on the idle tube and applied carb clearner under pressure using the red tube. The cleaner squited right through the tube and outside the opposite side (top) of the carb.

The reeds look good-except that one reed is open a fraction of an inch about 1/64th or less of an inch. Could that be the problem? I assume if it is open even just a little may cause the reed not to seat tight.

What is your opinion?

I have re-cleaned and taken off the control box. Tested it and it functions correctly. Put it in the freezer and heated it to test the action.

If I get a new reeds set, I will plug off the control box lines to start the moped. The bystarter will also be plugged.

Since it is Memorial Day, the reed assembly will have to be bought tomorrow or ordered off the Internet.

The above is the progress to date. Thanks for the help.

Glenn

Re: Urban Express won't start

The NU50m Reeds I'm currently running in my hobbit didn't seat all the way, it would start, but had no low end power at all. They were metal, I just removed them and gave them a little bend with my fingers and have been running them ever since.

Re: Urban Express won't start

Gruff "(OFMC)" - /

you can try and bend the reed so it seals, it may not be the main issue but its still an issue that isnt helping you any. I would still take auto choke off completely until you can get it to start, its not that much trouble to put it back on once youve isolated the starting problem.

So are you saying you took the autochoke assembly off and capped the inlets to the carb AND take air filter off AND took the exhaust pipe off all at the same time and you tried to start it and it still didnt start? IF not you need to follow those steps then repost, worry about the reeds after you tried this

Re: Urban Express won't start

Downhill Harvey (OFMC) /

Did you ever try squirting a little bit of premix in through the spark plug hole, and see if it'll fire?

Re: Urban Express won't start

Glenn Krueger /

Thanks to all who helped. It is running very well. I cleamed the muffler this spring and placed it outside because of the cleaning fluid. Insects placed mud in the muffler with the warm weather. I did not recheck the muffler. Cleaned the mud out and she started right up. Hopefully others will learn from this rather odd experience.

Glenn

Re: Urban Express won't start

Downhill Harvey (OFMC) /

Pic of the bike?

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