honda nc50 express

Need help..I purchase a one owner NC50 Express...starts and runs fine. I installed a new plug, removed and cleaned the carb...reset as instructed on the WEB. I am 230 lbs....scooter will only run around 13-15 mph. Once the motor reaches top rpm it will sort of sputter and if I back off of the throttle a bit it smooths out a little. Any suggestions as how to get it running smoother at top end and also how I can get a bit more MPH. Thanks to all...from a 58 year old kid !!!

Also looking to purchase a nice, clean, low mileage ExpressII or Urban Express....or Honda Passport....Ohio,Michigan, Indiana Area...Scalenut@hotmail.com.

Re: honda nc50 express

Andrew Squiggman /

are you missing your air cleaner box assembly? it may be running lean, and backing off the throttle is letting it run right. many of these are missing the air boxes.

Re: honda nc50 express

Air box is complete with new filter??? Steve

Re: honda nc50 express

Andrew Squiggman /

also, is yours an Iowa model? if it is, its a slow model to begin with. but not that slow. has the carb been thoroughly cleaned out? how about the choke. is it functioning correctly? is the cable adjusted so the choke is not always on? some of these things could be culprits. also, check the wiki, lots of info there, and the guide for yard sale expresses.

Re: honda nc50 express

Andrew Squiggman /

check this article.. i think you will find your answers.

"click here":https://www.mopedarmy.com/forums/discuss/6/130021/130021/

Re: honda nc50 express

Not an Iowa model...I took the carb apart and cleaned it thoroughly...choke works fine...Starts everytime on first pop....what would be the best way to check if the choke was on all the time??? Steve

Re: honda nc50 express

Thanks...I followed this exact some printing...I forgot to mention that we BBQ'd the muffler in our weber grill for an hour or so...boy did it flame out the intake hole for a while !!! Steve

Re: honda nc50 express

Steve, need to know what year your express is? this will help in diagnosing your problem. Your weight should have nothing to do with your top speed. It will however slow down your take off speed. Less weight=faster acceleration. If your express is only running 15mph tops, something is definitely wrong. Even if is an Iowa version, those run 25mph tops. A regular express should run about 26 to 29mph.

The next thing to check is your exhaust. Muffler and exhaust port for clogging. Also do a compression check. I forget what it's supposed to be but should be at least 100psi or more. That's great that your 58 and into expresses. 38 here and have 4 of them.

Re: honda nc50 express

We cooked the muffler in the grill...I looked in to the exhaust port and it was spotless....my bike is a 1980 nc50 express 1600 miles...2 adult owners...any suggestions???

Re: honda nc50 express

Andrew Squiggman /

i am not sure. is 1980 automatic choke, with lots of hoses? or is it still the cable choke?

Re: honda nc50 express

cable with lever on right handle..

Re: honda nc50 express

Check your transmission case oil. Sometimes if they are filled with either too much or too thick of oil, they will run really slow. From the sounds of what you are saying though, it sounds more like carburetor issues.

Also, have you played with the mixture screw and or the needle setting? As an experiment, take a pair of panty hose and put them over your airbox intake. Make sure it covers the hole where the air comes in. Take it for a spin, if it is better, you are running too lean, if its worse, you are running too rich.

Lastly it could be poorly sealing reeds. This would be the least likely culprit, but honda reeds are the worst, so its possible they have some serious fatigue going on.

Re: honda nc50 express

Thanks for the tips...I'll check them out...Steve Bowling Green Ohio

honda nc50 express

Could the clutch be slipping? Check tire pressure, gearcase oil weight and make sure you have good fuel flow. Does it have CDI or points? If so, points worn and closing up or retarded timing?

Re: honda nc50 express

80 is points. 81 is CDI.

are you able to blow any air through your exhaust? use a compressor or try and not lick the pipe at least.

Re: honda nc50 express

Sounds like you've been through the things you need to for it to run right. I would disagree with the guy saying the reed valves, especially on your bike if it's got less than two thousand miles. But......I may be wrong, still a good idea to check them to make sure their not stuck closed. If you cooked your muffler, did you check after it cooled to make sure you can blow through it like AJ said? Blowing through it should give you almost no resistance at all.

Lot's of good advice in this post, make sure to check everything that has been said. One thing no one has said yet is to make sure your throttle is opening completely, sounds stupid I know, but it's happened to me.

Re: honda nc50 express

We put it in the charcoal fire and burned it out for 2 hours it ia clear.

Re: honda nc50 express

Being new to this hobby....how would I check the reed valves and where are they located??? Thanks

Re: honda nc50 express

reed valves are in between the intake manifold and the engine case. There will be four Phillips head screws holding the intake manifold to the case. Your gonna need an impact screwdriver to get the screws holding the intake manifold out. Trust me, if you go at it with a normal Phillips head screwdriver, you'll never get them out. Once you get them out check to make sure the are opening and not broken. Pretty easy to figure out once you've got them out. It's just two little openings covered by very thin metal flaps, "reed valves" that are riveted to a plate. When reinstalling make sure they go in the right way. They open downwards. as in if you were trying to push your finger down into the engine case. If they are upside down they would not work right and would never open like they should.

Good to hear that your exhaust is clear. Did you by chance do a compression check yet?

Re: honda nc50 express

no compression check yet...drained the trans oil and replaced it with 30w...made sure choke was not stuck...made sure throttle was openiing all the way...I adjusted the bottom screw with the throttle wide open on the stand...and it now will go 15mph with my 235# on it.

I'll check the reeds this weekend??? and see what that does.

Keep those thoughts coming...Thanks Steve Bowling Green Ohio

Re: honda nc50 express

here is another question to ya'll...do I need to lubricate the front and rear wheel axles and if so...how do you do it and what do you use??? Steve

Re: honda nc50 express

Good point Steve, Guess I never really thought of that. I'll see if I can look it up in the manual. But that makes me think... by chance are your brakes dragging? Lube up those cables with some wd-40 or whatever you use. Make sure they are good and free. Then check both front and rear brakes to make sure their not dragging and slowing you down, but adjusted so they work right.

The rear axle should be lubed by the fluid in the transmission buy the front you will need to do yourself.

Re: honda nc50 express

The manual doesn't really say what to use for grease. I would just use a good wheel bearing grease, should be fine with that.

Re: honda nc50 express

Thanks for being kind enough to help...I sure would like to see 25-30 mph some day !!! Steve

Re: honda nc50 express

Michael Thomas /

I would also check two more things. First, check the plug and make sure it is gapped correctly. Second, and this just happened to mine, make sure the plug boot is screwed all the way into the wire. The end of the plug boot has a screw in the end that screws into the wire. Mine came loose and it would not run properly. I snipped about a 1/2 inch from the wire and re-attached making sure it was tight and now she runss like a rabbit. My 1980 Express with 1749 miles will get my 250lb. up to 33 mph no problem and 35 down a hill. Hope this helps.

Re: honda nc50 express

Thanks for the tip...great speeds for we hefty ones !!! Steve

Re: honda nc50 express

you guys are lightweights compared to me. 6'5'' 320. my stock expresses hate me, but my kitted express rox the sox off.

Re: honda nc50 express

TONIGHT I TORE IT DOWN...WENT THRU THE CARB AGAIN....REMOVED MANIFOLD...CLEANED THE REEDS...DECARBONED THE HEAD AND PISTON...TRIMED PLUG WIRE...RESCREWED PLUG CAP IN TO GOOD WIRE...DRAINED GAS ONCE AGAIN...GOOD FLOW...THIS BIKE HAS BEEN RUNNING ON 40 TO 1 MIXED GAS...IT RUNS GREAT AND STARTS JUST FINE...STILL WILL NOT GO OVER 15 MPH.

TOMORROW i WILL INVEST IN A COMPRESSION TESTER AND SEE WHERE IT STANDS ON THAT ISSUE.

LAST WEEKEND WE COOKED THE MUFFLER...CHANGED THE TRANS OIL...NEW PLUG..WENT THRU CARB AT THAT TIME///

WHAT THE HECK IS WRONG??????????????????????/

Re: honda nc50 express

i know you cooked the muffler, did you actually try blowing air thru it?

it might be compression.

why are you premixing?

Re: honda nc50 express

Leon Swarmer /

If by chance you are premixing and using the oil tank/pump you are ending up with a 20:1 mix. way tooo rich and you would get poor performance.

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