Motorcycle Repair: 1979 honda XL75, valve stem seals, bikebandit com

Question
my 1979 XL75 keeps throwing to much smoke and its like a blueish kind of smoke wat should i do or cahnge

Answer
Angel, if the engine is throwing up blue smoke all the time, the piston and rings are probably worn out or it has been seized before, causing grooves in the cylinder walls, so the rings can't control the oil anymore. Blue smoke is burning oil, black smoke is excess fuel. White smoke, first thing in the morning is just moisture evaporating from inside the exhaust pipe.

If the engine only smokes when it sits idling for a minute or two, then clear out when riding under power, then the valve stem seals are bad (probable after 28 years), or the valve guides are worn, which happens when the air filters are not hooked up or maintained properly.

In either case, you need to disassemble the top end for inspection and repair/replacement of worn parts.

http://houseofmotorcycles.bikebandit.com/honda-motorcycle-xl75-1979/o/m3002

for illustrations of the parts involved.

Buy a shop manual from Ebay or www.helminc.com or local m/c shops, get a good set of metric tools and have fun.

Bill Silver