Honda Express NC50 Won't Start

Just traded for 3 Expresses. 78,79, & 80. None of the 3 run, but are 90+% complete units.

I am working on 80 Express II first, got spark, 125 PSI compression after 5 crank/brake cycles, Good spark, new float needle, will sometime sputter but never really starts. I have cleaned the carb.

Looking for ideas, could bad carburetor gaskets cause this problem? I have ordered a carb gasket set from treats. I thought about checking timing.

Re: Honda Express NC50 Won't Start


carb gaskets aren't usually the problem, unless it's the intake gaskets, but even those will just lean it out unless they're real bad

could be bad crankcase pressure, you're only measuing topend cylinder pressure. Could be timing but that doesn't usually go out on it's own. still worth a check

have you tried running it straight off starter fluid? don't do it for any prolonged times, but it's great for diagnosis.

read thru this:'s_Guide

Re: Honda Express NC50 Won't Start

Manual, Freds Guide, make sure idle circuits and carb are


Re: Honda Express NC50 Won't Start

Is the bottom end flooded with gas or oil?

Re: Honda Express NC50 Won't Start

My next step was to try and figure out how to check for leaks in lower end/crankcase. Not sure how to inspect other than removing tranny cover, flywheel side is clean and dry.

How do you check for leaks in lower end?

Re: Honda Express NC50 Won't Start

Got one of the mopeds running last night.

1. Installed new Petcock - don't believe this had anything to do with it, as the old one leaked around the valve but let fuel into carburetor.

2. Attempted to start, sprayed some gas in carb, and it popped a couple revolutions.

3. Checked point gap per manual, but this was pain

4. Would not start

5. Checked spark and had intermittent spark, adusted point gap, had good spark

6. Attempted to start, engine ran about 5 seconds then stopped, would not restart

7. Checked spark, intermittent again

8. Consulted Moped Army Guide on NC50 repair. Per this oiled felt cam follower on points, adjusted carburetor settings per NC50 wiki on this site, set points per fatrat video on youtube.

9. Started on first attempt.

Re: Honda Express NC50 Won't Start

I just a 1979 Honda express2 na50, the issue is that I have a crank and no start condition. I checked for gas, spark and compression and it has all three. Could it be possible that the timing could out? The next thing I’ll check for is to make sure that the woodruff key in the magneto side broke off or non existent it’s a crazy thought but enough to check for. Any thoughts out there? Any guidance would be helpful, I got the with the condition already existing. Thanks in advance and ride safe.

Re: Honda Express NC50 Won't Start

Christian Kyrmse /

My Honda express wouldn’t run because the exhaust was clogged. It would sputter and stall, but as soon as I cleaned the inside of the exhaust, it started right up.

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