I'm going to try my hardest to keep her going For as long as possible. How often should the oil be changed? What kind of maintenance should be done on it and how often?
here a few things to do right away:
Change oil & filter. Use nothing but an oil designed for Harley Davidsons. Both are Oil cooled engines.
Change the spark plug. Gap to .020-.022"
Adjust valves. This is very important. Most likely if it is all stock, it probably has NEVER been done. This is something that needs to be done every 2 years or more often if you ride the motor against the rev limiter all the time.
drain and remove fuel tank. remove petcock and clean screen and replace. there is a rubber oring under it, so NO gasket is needed.
lube all zert fittings. dont over do it. just grease em some. do it again after a couple of rides, then do it again. let the grease work its way around, dont just try and pack it in there.
lube and adjust chain. replace sprockets now if needed. the longer you keep it from EVER break, the more fun it will give you.
inflate front tires to 10lbs and rears to 8lbs
if you are under 150 lbs rider weight, adjust shocks to the softest position
throttle and clutch cables should be very easy to move. it not, just replace em. the throttle spring on the stock carb is very soft and if you have a hung cable it could stick open on ya. the clutch setup on a stock 400ex has soft springs and a long leverage actuator, so it too should be very easy to engage.
lastly, the battery. they are weak. they are undersized and vibration kills em quickly. get your self a trickle charger and keep it topped off at all times that you arent riding it. bring a rope/tow strap just in case you need a bump start to get home.
good luck and show us some pics
