Why wont my 2stroke motorcycle start?Dirt bike will only start when pushed. Wont kick start. 1987 honda CR500?

weak spark, possibly just the spark plug .. alot of times people end up putting the wrong plug .. or you just might need a hotter plug then stock or just a new clean plug being twostrokes burn oil ..

weak compression, two strokes need to be rebuilt alot sooner then 4 strokes .. being its an 87 it might be time for an overhaul two stroke motors are pretty simple to rebuild
if compression is the case
you need to mic the cylinder to see if it needs overbored or if you can hone it
piston rings/head gasket base gasket and piston rings.. pretty cheap and somthing like 6 bolts and normal hand tools to get the head off you have no timing to mess with

and then it could be carburation .. if its running too rich it could be fouling the spark plug
if its too lean it might not be getting enough gas to start

being its a big cube two stroke it might be just how your starting it they can be tempermental

try not touching the throttle and slowly pushing the kick start down "not trying to start it" let it come back up and slowly push it down again thus priming it without flooding it

and then give it a good solid kick and barely just barely twist the throttle try that a few times .... it just might start ... if it fails
try holding the throttle wide open n kicking the crap out of it ... without the priming it stage before it
then you have a problem other then it just being tempermental


when it starts up .. does it run fine? if it wont idle after it gets running and cuts up at anything below 1/4th throttle it might be a cloged idle jet .. might just be a dirty carb

the list goes on and on, i would personaly start with the cheaper things, spark plug .. adjusting/cleaning the carb,

if you have a buddy with a compression gage i would test it ..........a simple way to test compression without a gage would be taking the spark plug off and holding your thumb over the plug hole pressing down .. and push the kickstart with ur hand if air blows past your thumb as u try to hold the hole closed..... you have enough compression for it to run right

Weak magneto. Can check the spark while kick starting, it will be very weak. Push starting is higher rpm, and stronger spark.

It could be over 100 different reasons why.

Cant tell, without seeing the bike.

try a compression check my guess is that you need a topend rebuild...