How do you check the timing and adjust the carb. My problem is every time I try to start my 75 yamaha 400 endro it will kick over but won't run I have spark and it wants to go and sounds like it will...
Hi, is this still on points ignition?
The spark should occure between .5 and 1 mm before top dead centre, on some of the older machines the ignition timeing is not addjustable as the backing plate is fixed, however the ignition timeing can be determined by the correct points gap, the points should open at the correct time as the piston reaches the top of the stroke, if you dont have a top dead centre gauge, you could improvise by making some markings on a thin rod which you will insert into the spark plug hole, rotate the engine in the correct direction by hand until the piston is at top dead centre, that is the piston has reached its upermost stroke before it starts to decend, at tdc turn the engine back the required amount untill your markings point out the required amount, it is at this point the points should just sepparate creating a spark, a test light with a small 9volt battery in line will indicate the separation of the points, i would however like to stress the third most important item to make a two stroke run is compression, spark and fuel alone is insufficiant without it, on machines that have been standing for long periods of time the piston rings can become stuck in the piston, not allowing the rings to seal the bore, remove the exhaust and look up the Port the piston should look as new with no scoring to it, any damage will prevent the engine from running, as will worn crankshaft oil seals which can become soft from old fuel contamination
Oct 29, 2011 |
2001 Yamaha SR 400