Monday, November 16, 2009

Honda Express Top Speed - NC50 Max MPH Speed Limit

So, what is a Honda Express moped's top speed? Well, they don't have a governor built-in like you can have on cars or other motorized vehicles. The stock engine on an Express nc50 moped is 49cc. Here are some common factors that will determine the TOP SPEED of your express scooter:

  • Grade of gasoline/petrol fuel - If you use the cheap stuff... you will get lower performance. We all know Honda mopeds are not built as a stock performance bike, but the fuel grade really does make a difference. As with many types of engines, the better the fuel... the better the speed, acceleration, performance. The premium grades of gasoline have additional additives an higher octane (which burns faster). So, try using a high grade gasoline (octane greater than 90) to increase your Honda Express moped top speed.
  • Type of oil your moped uses - Again, the lower quality oil... the decreased chance of performance. You want to use a honda moped oil that will increase the moped's performance like Lucas semi-synthetic 2-cycle engine oil. Don't just use any type of oil (like regular car motor oil), because it could literally cause your engine to "melt-down."
  • Gear oil in the crank case - Is the gear-oil in the nc50's transmission case is low or old this could slow the chain and gears down from turning at their maximum rate of speed. The older the oil gets and the more it is used, the lower the oil's viscosity potential becomes.
  • Air in your tires - This is a simple one, but easily missed. Inflate your 1978 Honda Express nc 50 tires to the correct PSI labeled on the moped's rear fender. Or, consult your Honda express moped manual. Cold tire pressure: psi(kg/cm2) : FRONT 21(1.5) REAR 28(2.0)
  • Wheel ball bearings - If you moped scooter has been neglected or someone has reassembled the wheels incorrectly you could be loosing precious moped top speed due to this. You can repack your wheel bearings using wheel bearing grease at any performance bike shop.

    New spark plug - Make sure your spark plug is clean. If there is oil or corrosion then this will hinder your honda scooter's top speed.

  • Clean air cleaner - Your honda moped's carburetor needs to receive the proper amount of air/oil mix to operate properly. If the honda air filter/cleaner does not get enough air you can find you honda express motor lacks power.
  • Too much weight - No offense... but do you weight too much? The lighter load on the moped... the faster it goes. The 1978 Honda NC 50 scooter has a "vehicle capacity load" of 180lbs OPERATOR ONLY. Front 7lbs (with optional carrier fitted) Rear 11lbs.
  • Muffler no holes - Check to make sure your muffler is free from major holes or rust spots. If exhaust comes out any other part of the muffler than the tail-pipe, you could be loosing engine compress and top speed too.

So, if you have inspected the things listed above you should find that your 1978 Honda Express nc 50 moped's top speed is 25-30 MPH. Under optimal conditions you should be crusing at 30 mph with good fuel and oil. Although, the 1978 nc50 was designed for a normal max speed of 25 mph (according to manual documentation).

You can always INCREASE your Honda Express moped's top speed by "Performance Tuning" it. I will go into further detail in the weeks to come about how to and where to buy parts for performance turning your Honda Express II, Honda Express SR and Honda Urban Express moped.

12 noped comments:

Jason Evans Groth said...

JFK -- What kind of oil should I use in the transmission? I've seen everything from SAE 30, to 5-30, to 5W-30, to 10W-40... what's the real answer?

jfk said...

Jason, sorry for the extremely long delay on response. I have used "Coastal SAE 80W-90 Gear Oil" for my transmission before. Remember, when assembling the Engine L. Cover/Starter Pour 0.75 liters (0.79 qt.) of oil in case before installing L-cover.

Unknown said...

The coming weeks have come. How do we increase performance???

Eli Taliafero said...

I second Andrew's post. I've searched online for information on how to performance tune my '80 Honda Express, but I can't find much. I've read about people doing stuff to their exhaust and other such things, but I can't seem to find any exact details or a guide. What do you have for us JFK?

jfk said...


Please see new post:


Nick and Sarah said...

Hi, I'm new to the noped community, I bought a 1982 Honda Urban Express to ride back and forth to work and turns out I really like this little bike. It's in fairly good condition, but needs a good cleaning. I'm not very mechanically inclined but am learning all the parts, etc. I was reading your comment on a governer or rev limiter and how there is none, but I could swear that my express has one on it. I get up tp about 32 or 33 mph (it happens at the same speed every time) and you feel the engine stop accelerating, it just kinda cuts off, and you hear the rpms wind down and once it drops to a slower speed, like 30 or 31 mph it comes back on and accelerates just to cut out again at the same speed. Is this a govener/rev limiter?? (is there even a difference?) If so, how do I disable it? and if not, then what is it? Thanks so much for the help, I really like this website, there are a lot of interesting things on here and it will be a big help as I start to work on my express.

jfk said...

@Nick & Sarah,

Funny you say that... I just read this recently on mopedarmy wiki:

"My 1982 bike stops accelerating at 25 MPH. I already did everything in your guide though!
There was a version of the later Express released only in Iowa. This bike had a restrictor that prevented it from going faster. The model number is NC50I instead of NC50."

Is your model number NC50I?

Nick and Sarah said...

No, I have a 1982 Honda urban express deluxe nu50m. I read the post you mentioned. I've done a couple of modifications since. Cleaned the carb, done the muffler mod listed on this web site. Its 4 stroking at about 30 now. Performance actually decreased a lil :/ Dont really know what im doin wrong. Someone suggested downjetting but i dont really know what that is. Any Thoughts? what about adjusting the air/fuel screws on the carb first?

Unknown said...

I got a big bore kit on mine, on flat ground it runs 45mph easy, maybe close to 50 but I cant tell cuz the speedo doesnt go high enough.

Up the biggest hill I can find here in WA its a steady 30-35.

captain-janeway said...

I'm using 91 octane gas, carb cleaned, stock air filter, tranny oil changed. only running 22mph. with exhaust off it runs at closer to 30. I tried burning carbon off in coals, but it didn't seem to work (bike only has 2300 miles on it). It's an '83 NU50M urban express. Any ideas before I try your mod? I'd like to keep the noise down.

Unknown said...

mine is a all stock 1981 na50 honda express ii. i get er up to about 31. i wanted to know how fast i get get it up to using the exhaust mod on this site. thanks.

Unknown said...

i have a na50 honda express ii. i can get it up to 31 stock. how much faster do you think that exhaust mod will make it?

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