Motor Won't start, electric works, fuel also works

[flyingafro]

Ok so a few days ago i was riding my bike coming back from school in the rain then down the street the motor suddenly seized and would not start again. So first thing i figured would be that i shorted the cdi or magneto because i did't weather proof anything. I have 3 other kits so i took a working cdi and magneto from one of those and put it onto the broken motor.
Still nothing, i have fuel flow and recently went out and got new gas thinking it was that....still nothing. So i decided to tighten all the bolts thinking some were loose...head bolts...muffler...carb...
This is a motor that ive put around 1000 miles or so on already and never had a problem like this...i hear the piston move so i figure i have compression....any help would be greatly appreciated, i ride 18 miles to school and i hate sitting through rush hour, id much rather just blow down the side streets haha.

 

[Stan4d]

http://www.motoredbikes.com/showthread.php?t=9619
http://www.motoredbikes.com/showthread.php?t=29554
http://www.motoredbikes.com/showthread.php?t=28151

 

[motorpsycho]

well is it seized or not?
if an engine is seized, that means that the piston will NOT go up & down.
you say that you hear the piston going up & down.
just because the piston is going up & down DOES NOT mean that it is making compression. you could have a blown head gasket and all of the compression will be forced out of the blown head gasket.
you say the electrics work...so did you check for spark?
is there fuel in the carb bowl? just because you have fuel flow from the gas tank, do not assume that the bowl is filling up with gas, you need to pull the drain screw out of the float bowl and verify that gas is getting into the float bowl AND that it is flowing into the float bowl with the fuel valve open.

 

[flyingafro]

ok so i went through and had my friend who works on cars check it out and we took apart the engine to check the piston to make sure it was moving up and down and if it had both oil rings, checks out good. So we then put the engine head back on and check to see if the piston is pushing air upward, checks out good with lots of air being forced upward, so we then put the spark plug back in and connect a working cdi and magneto to my ngk spark plug and check to see if it causes a spark by placing it on the head, blue sparks show up on the head of the engine.
This is where i could be wrong? i know that since it sparks doesn't mean that it will work under compression but i used both working. on previous motor bikes so not sure...anyone have a idea?
Also i took off the muffler and started to start the engine and i could see the gas spray where the muffler was and get my bike frame wet with gas....

 

[motorpsycho]

Ifyou are getting wet gas sparying out of the exhaust port while trying to start the engine (with the spark plug in), you are not getting any spark or not getting a hot enough spark to ignite tha gas.
it is possible that you have the magneto on backwards, which would cause the spark plug to spark 180 degrees out of time (spark when the piston is down instead of up)

 

[Stan4d]

http://www.motoredbikes.com/showthread.php?t=29554

 

[HeadSmess]

if its spraying fuel from the exhaust its waaaaaaaaaaaaay too rich.

vapour is flammable, liquid is not.

 

[flyingafro]

ahahaha thank you so very much....the magneto was in backwards lol i feel so smart. well that solves that, thank you very mucho

 

[Al.Fisherman]

Get a new mechanic, at least one that can tell if a engine is in time.

 

[HeadSmess]

well you do have to admit this engine has a few unique features.... i cant think of any engine where you can put the magneto/rotor/flywheel in the wrong way round and it doesnt exactly come with timing marks...

but i agree. get a new mechanic... one that can think, not just change oil filters...