1978 Honda Express Moped, Scooter, NC50, NC-50, April 8, 2018

* Order more throttle cable ends
* Order more mini bike throttle cables
* Correct length head bolts

Treatland Order List
* Cylinder
* Head
* Gasket set for 1982 NA50
* Cylinder spacers
* Reed spacers
* Cir clips
* Upper connecting rod bearing
* Reeds

Saved Treatland Order List
* Reed Spacers
* HPI Hobbit CDI
* HPI CDI Lighting Coil
* Universal Forks
* Sheet of 0.25mm reed material
* 14x2.5 inch rear tire speed rated
* Gaskets for NU50 engine
* Look at Honda Wallaroo DR 70cc cylinder and piston
* Look at available shocks with preload

* Frame
* Rear Rim
* Look at Urban Express, NU50, parts
* Look at Hobbit Parts
* Look at Wallaroo Parts, PK50, This ran until at least 2000 and looks like the cylinder head is compatible
* Look at Honda DIO parts
* Look at Honda City, SH50 parts
* 320 mm shock
* Front green headlight rim

Major Battles
* Head coming lose on the Green NC50
* Spokes on the Green NC50
* Fuel Starvation

Next Steps
* Fuel Starvation
* New spark plug wire for the Green NC50
* Measure Shock
* Search for another motor NA50 or NU50 motor
* Machine Seal drivers for the crankshaft and rear seal, the manual gives a spec for driving them in correctly.
* Machine another plug for the spare gas tank
* Machine a plug for the oil filler cap
* More holes in the spare gas tank
* Order new tires and tubes
* New 70cc cylinder kit
* Order Cylinder Head
* Once we have the cylinder head, we need to start determining a non-protruded spark plug
* Red Line Oil
* Oil Block off from Scooter Assasins
* See if we can find what washer should go in between the rear axle and hub
* Torque wrench
* Need to put a better fuel filter in.
* Grease the throttle cap, dirt is getting in.
* NGK Spark plug decoder
* Open up the timing plate holes
* Test Red Line Kart Oil
* Work on my squish program
* Work on getting Moto up and going
* Compression check on 60cc motor
* Leak down test on 60cc motor
* Measure new tire diameter
* 1980 NC50 CDI Ignition or NA50 CDI Ignition
* Need to solve the oil tank leak
* Need to measure the oil cap
* Need to decide whether I can machine an oil cap with a vent tube
* Find O-Rings for the carb that will resist Ethanol
* Add the heat equations to hp.py
* Add Heat of Combustion data from Wikipedia page
* Get an Ethanol tester
* Get 5 gallons of E85 to test with
* Build aluminum oil vent for the motor
* Build aluminum plug for the gas tank eye sight
* Build aluminum plug for the oil cap
* Build aluminum plug for the oil tank line out
* Order a 12 volt headlight
* Dimensions for oil cap
* Grease the carb throttle cable boot
* Find out what the minimum points gap is
* Set the points at the minimum gap

12 Volt Conversion
* Will this battery work? - http://shop.antigravitybatteries.com/antigravity-batteries-ag401/
* Need to measure the space for the battery
* Taillight bulb
* Headlight
* Speedometer bulb
* High beam indicator bulb
* Measure headlight and see if I can find an LED headlight for it
* Horn
* Ignition Coil

Parts List
* Degree wheel

* Measure Dellortro Air Filter outside diameter
* Measure Mikuni Air Filter outside diameter


Stock spark plug
* Denso W16FPR-U (U-groove), Denso Stock Number 4192

Alternate spark plugs
* NGK BP2HS (hot)
* NGK BPR2HS (hot resistor)
* Nippon Denso W9FP-L
* Nippon Denso W9FPR-L
* NGK BP4HS (1 hotter than stock)
* ND W14FP-L
* NGK BP5HS (stock)
* NGK BPR5HS (resistor stock)
* ND W16FP

Outerwears Prefilters that I am using are
* Red 20-1542-03, WR125-3DTRD Denier top 4” diameter, 3” tall, no log

Fuel Line is 4.5mm, 3/16 is close being 4.8mm


Dellorto SHA 15.15 carb
Started with 78 Main (Black plug)
Tried 76 (Plug is more brown, still 4 strokes pretty easily at the top end)
Ran 74 for a long time
Now 72
Filed the slide a little on one side

Mikuni VM20
* 180 Main 22 Pilot (very rich), 60cc cylinder
* 185 Main, 22 Pilot (looks rich, but hot), 70cc DR cylinder

A 49 cc scooter which was manufactured from 1977 until 1983, it featured an air-cooled 2-stroke engine. The versions from 1977 until 1980 had a manual choke, points ignition, and a spring starter. Versions from 1980 onwards included a kick start, capacitor discharge ignition, and automatic choke as well as an improved compression ratio. Most versions include an automatic one speed transmission with a centrifugal clutch, double suspension, and oil injection. Two speed automatic transmissions were introduced towards the end of their production run.
* Engine: 49cc 2-stroke single cylinder
* Bore 40mm
* Stroke 39.6mm
* Compression Ratio 6.5:1
* The engine was lubricated by oil injection.
* Spark plug: BP4HS
* Plug gap: .028
* The ignition was controlled by breaker points.
* It also had a manual choke.
* The starting system used a wind-up spring.
* Battery: 6N4-2A-6 (see also 6N4-2A-8)
* Transmission: only one speed
* N/A
* N/A
* Colors:
* Parakeet Yellow
* Pal Green
* Mars Orange
* It had a two-tone black and white solo seat.
* The downtube featured a logo change with the name "EXPRESS"
* Serial number began NC50-2000013.

Rear Wheel Diameter, approximate 18.5”
Rear Wheel Circumference 58.2” (pi * diameter = pi * 18.5)

Engine uses a 14 tooth primary sprocket on the crankshaft

First counter shaft uses a 30 tooth sprocket

Gear Ratio 14.220/1

(from http://endless-sphere.com/forums/viewtopic.php?f=10&t=59952 )

Service manual also gives the Gear Ratio as 14.220 : 1

MPH = (RPM * WheelCirc/GearRatio * ft / 12inches * mile / 5280 ft * 60 mins/hour)

38.7 MPH = 10000rpm * 18.5 * pi ÷ 14.220 ÷ 12 ÷ 5280 * 60

Gear Ratio that SIP wants is the Gear Ratio (14.220) divided by the tire circumference in meters (18.5” is 0.4699) which is 30.2617

Old engine 100psi of compression
Seals leak down within a minute

Retarding the Ignition

* 18 degrees BTDC is the stock points timing
* The Timing plate bolt centers are about 3.8" apart
* Circumference would be diameter * pi() = 3.8 * 3.14159 = 11.938"
* 1 degree out of 360 would be (1 / 360) * 11.938 = 0.033" or about 30 thousandths
* Need to measure the peak RPM before and after slotting the timing plate
* 4 degrees may net as much as 1000 RPM

Second Engine
* Trouble starting it
* Felt like it was down on compression
* Torn O-Ring on carb
* Water and dirt in carb gas
* Magneto side seal was blown and there was oil in the flywheel cover

NGK Spark Plug Decoder