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.