Engine Technical Spec's
Parts Pricing {general}
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Timing and Points
NC/NA Express maintenance schedule

Honda Express Misc Data
Gas .53 US Gal.
Oil tank .84 US qt
NC 50 dry weight 104 lbs
NA 50 dry wt 112 lbs
Tranny case holds .79 qt
Battery 1977-79 #6N3-4A...1980-81 #6N3-4A

#1..ALWAYS be sure you have a working ( rechargeable even if weak ) battery installed and hooked up..running the engine without the battery WILL burn out your headlight .!! and it costs $32 to buy a new one..Express Charging Curcuit

#2..You can rebuild the headlight using a ceramic socket and 20 watt tungsten 12v lamp.. available at your local lighing have to unsolder the base of the burned out lamp..then break the lamp.. NOT THE HEADLIGHT GLASS.install new lamp in socket, epoxy socket into base of headlight ( lamp # JC 12v 20watt by O'Claria or equivelent) get the matching CERAMIC socket with metal mounting brackets ( make's it easier to hold in place while the epoxy set's up [ you can also use a hacksaw blade to carefully cut off the base of the old bulb, remove the rubber boot, cut off the wires at the terminal YOU WILL NEED THEM , use the blade to cut just below the crimp line , then using a long nail or skinny punch, break the lamp/bulb and shake out the glass] then continue with the epoxy job.after everything has harden you can solder on the wires,,you will have only 1 filament so only 1 selection ..I usually hook it to the blue wire for high beam..this gives you off & on..

#3..Crank the spring of the tap starter ..SLOWLY and easily..this is not a kick starter !! hard force is not needed!!.ALWAYS keep your foot off the pedal while starting...resting your foot on the pedal will cause it to snap back against the stop inside the transmission case/cover and it's possible to break the main starting spring..I recently had to replace the starter spring on somebody else's bike

#4..Carburators can be swapped between the NC50 and the NA50 also between different years..just be sure that you swap the intake manifold with the carb (keep the two of them together) the oil injection port/nipple was on either the carb or the manifold..and you must have one someplace.. Express Carburator {most common} the Honda manual has inital air screw setting at 2& 1/8 turn out from being seated..I have found this untrue on most of these cycles and a setting of 1 turns to be a better starting point

#5...TIMING & POINTS because the points ARE NOT mounted on a movable plate.! you have to set the timing first, Then check to see if the point gap is within spec.. one way to set the timing is to use the cellophane from a cigrette pack .. as a gap gauge..with the timing marks [ "F" for fire ] lined up it should just slip between the points.. after you set the timing rotate the fly wheel untill the points are at full open..then use a feeler gauge to measure the gap..thay must be within spec 12 thous to 16 thous.14 is perfect

Sparkplug info Click here


Service Manuals ...Clymer Publications ISBN: 0-89287-194-6....printed USA 1979 & 1980


cylinder head bolts torque 9 ftlbs tighten in criss cross pattern
piston rings
Nippon are marked 1N top ring ...2N 2nd ring
Tteikoku marked 1T top ring ...2T 2nd ring
always there is an expander ring behind the 2nd ring (oil ring)
s1 = 0.00984 nomialy 10 thousants
s2 = 0.01969 " 20 "
s3 = 0.02953 " 30 "
s4 = 0.03937 " 40 "
To use oversize you must hone/bore the cylinder to right size
It best to buy oversize piston and rings together
use the mfg that matches the orginal ones N or T

The rings are marked you may have to clean the old ones to see the mark before you buy the new ones hope this helps




Especialy peformance mods on Express , any thing you discovered on your own.. heavier clutch springs...carb mod' on

From Tim H
My favorite mod is..cut the exhaust in half, rip out the guts, reweld together.
instant 33mph cruising the clock downhill, wahooo.
removing air filter can help with a needle raise.