82 honda nc50 issues

Ok, so I've been working on an 82 2 speed honda express nc50 I picked up at a yard sale a few weeks ago.

It had a carb on it, but the auto choke stuff was broken and missing, so I swapped it to a weak ends intake with a mikuni vm 20mm round slide carb in preparation of kitting it at some point soon. Also put the stockish boysen reeds in. Also has new battery.

Stock cdi ignition.

I'm using the 22 idle jet, and I currently have a 150 main in it now.

The issues I am having are:

No low end

Sputters and stumbles past 1/2 throttle

Top speed is only 20

Seems to run slightly better with even bigger main jet, or with the choke on, making me think it's lean

I have a clean tank, new fuel filter, new trans oil, new plug, air filter, etc...

Compression is 120psi cold

No air leaks - checked with starting fluid and found nothing

Plug shows black build up, showing me it's running rich, despite previous info on how pulling choke helps

Good spark at idle

Exhaust is still stock for now, but not restricted, does not run any better with pipe disconnected

I'm at a total loss on this. Any ideas?

Re: 82 honda nc50 issues

So, I guess not...

Did some checking today, found my spark is breaking up as the rpm's increase... Bad thing is, this is a cdi setup and from what I've read they either work or don't...

Removed and cleaned the stator wheel, cdi, etc with no change...

So I've ordered a replacement setup from fleabay and a new cdi box and coil as well. I'll swap them piece by piece starting with the cdi box and update as I can.

Re: 82 honda nc50 issues

>>>>>>start here with Fred's Guide>>>> http://www.mopedarmy.com/wiki/Category:For_Newbies

Re: 82 honda nc50 issues

That was my first stop with no luck.

Re: 82 honda nc50 issues

What air box do you have?You may have a bad ground or intermittent short check volts at the stator un hooked black/white wire (if you have stator with black/white ,yellow and white wires) This may be the diagram you need . http://www.hondaexpressmoped.com/2010/02/honda-express-electrical-wiring-diagram.html (edited)

Re: 82 honda nc50 issues

No air box as it's a k&n filter.

I've checked all the connections off the stator, and they looked ok...

Re: 82 honda nc50 issues

CDI either works or it don't but a bad connection from the stator to the coil will cause bad sparking. You have a ground at the stator coil, then hot to the coil another ground. Is your coil loose? What about the hi volt wire/boot to the plug? Was that the right wiring diagram? Don't give up on wiki .

Re: 82 honda nc50 issues

That wiring diagram is not for an 81 or 82 with the cdi, it is for one with points.

I'll have a peek at the wiring again today to double check...

Re: 82 honda nc50 issues

Cleaned everything again, sanded down grounds and the mounts for the coil. Even added a new ground from the green and the black wires to the crankcase.

No luck. same result.

Idles fine with great spark, but the spark cuts out and flickers at higher rpm and more throttle.

Re: 82 honda nc50 issues


Re: 82 honda nc50 issues

Did some more digging, and found several of the wires coming from the stator had been worn through from the rear wheel rubbing them and covered with tape. Fixed them, and now it runs great.

Re: 82 honda nc50 issues


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