First try starting my yfz it fires i get it warmed up and it stalled and now i can't get it going again, i charged the battery, Filled it with new gas, and i took out my spark plug which was black at the end and looked very corroded, i replaced the NGK plug with a NGK Iridium IX plug which the dealer told me it was "better" but now my bike still won't start, I'm wondering if its cause my gas lines are cloged with old gas or their Frozen but I haven't changed the oil yet and my air filter seems to be clean, does anyone know what the problem is...

 

First, you need to describe what is happening in better detail. If it is turning over, but not firing, do this: Check for fuel flow to the carb. Check your airbox/filter/intake(sometimes critters will leave you a nice "present.") Check for adequate spark.

 

how do i check for adequate spark? like i've removed it before cause i replaced my old one but how exactly do i check to see if it does spark? and im going to check to see if my gas lines are clogged, and my air filter is good to go... and my bike will turnover just won't fire up..

 

Put in some gas line anti-freeze, then drain the carb bowl.
Condensation builds up when bikes sit too long.
Common problem, easy fix.

 

The quick and dirty way is to pull the plug and hold it to a ground as you turn over the machine. careful, they can have a little bite! You can also put a little gas down the plug hole while it is out. If you have good fire/spark it should start/run for a little bit on that. Did you check the gap on the new plug? Bad gas still in the float or a partially glogged jet could also be causing your issue.

 

I Took the Bowl of the carburetor it was getting fuel inside their, i checked if i had spark and it does, i put some gas in the plug hole it seemed to start but wouldn't stay longer than 2seconds but it wouldn't start every time i put gas in the plug hole, i just don't get why it would start the first time i tried after the winter and then stall and now nothing, would it be the Oil? or other parts to the carb, i'm not a mechanic so i couldn't take apart my carburetor but i don't want to waste $85 per hour at a yamaha dealer just to fix some stupid problem, does anyone have any easy steps or any other ideas why this would happen?

 

Do a compression test to see if rings or valves are not gummed up from old gas from sitting over the Winter.
I have encountered engines that had sat for a period of time that allowed the fuel to sour or go bad. Customer didnt smell the fuel before starting the engine .
They added fresh fuel to the old fuel and started the engine.
After a minute or so engine stalled and would not start.
Did a bunch of checks to find the cause (not knowing about the bad fuel)
I finally did a compression test and found very poor compression
caused by lazy valves.
When the engine was ran with the old gas, it quickly built up as a varnish on the valve stems making the valves stick in the guides.
Brake cleaner wouldnt remove the sludge enough for the valves to opperate freely allowing the engine to start,
so i had to remove the valves and clean by hand.
Just trying to cover all the bases why your engine wont start.

 

It Just doesn't make sense because if "After a minute or so engine stalled and would not start." why would it start up when i poured gas into the plug hole? i wouldn't think that's the problem...

 

If it fires up by putting gas in spark plug hole,
then your carb is not working like it is suposed to.
Fuel might be able to get into the bowl, but clogged jets or passage ways
are not allowing fuel to be drawn up through it into engine.
You will have to pull and dunk the carb for a day or two,
then clean out with compressed air.
Dirt must have been sucked up into carb.
No rubber in the dunk tank ie: fuel inlet needle with rubber tip.
A good small engine shop should be able to do this if you
dont want to pay a dealer big bucks for.
You can buy a gallon of carb dunk from most auto parts stores.
Use a large coffee type can with a lid for a dunk tank.
Fluid after being strained can be used several times.
Wash carb with water hose, then with compressed air.
You might have to check small holes in jets and carb body with a very fine tag wire.

 

Well thanks for helping out 450kodiak, I'll be bringing my bike in to the dealer on Monday to hopefully get the problem fixed without having to spend too much money$ but I just want to get my biked fixed, not being able to ride in this nice weather in Ontario,Canada right now is really getting on my nerves , but i will reply to this thread after my bike gets back to say if it works or not maybe on thursday or friday next week.