I can't start my YAMAHA YZ426FP Dirt Bike, What Am I Doing Wrong?

Question

My Dirt Bike's engine is so big that you have to use a decompressor, and it just wont start, I have tried so hard that it put a hole in my shoe. What I do is, turn the gas on, pull out the "Cold Starter" k**b, decompress about, 6-10 times, and it never seems to start, it sounds like it wants to start if you know what I mean, but it just doesn't. Could it be the Spark Plug? I could really use some help on this, Thanks Guys.

Answer 1

DONT GIVE THE BIKE ANY GAS WHATSOEVER... and mak,e sure the cylinder is at top dead center, by lightly pushing down on the kickstarter until it builds up resistance.  choke it and kick it over, it should fire up easily....and once it souinds like it wants to start, turn off the choke. and you dont use the compression release to start the bike, only use it if its flooded.  andif its flooded kick they bike over 6 times or so and then release it.   and if you do pull the spark plug and its black, the best way to clean it is with a torch.  or just replace it.  and to find out if its getting spark, pull the sparkplug and put it back in the spark plug wire, then place th eend of the plug against the cylinder head and kick it over and you should be able to see the spark.  you will probably need 2 people for this.

Answer 2

Try replacing the spark plug and also if the fuel is stale that could cause problems so drain the fuel and replace with fresh.  

Answer 3

First of all have you tried "bump" starting it? Its a little trick, but put it into neutral and roll down a small hill and shift it into first. Another thing is check your fuel mixture valve. You mentioned the spark plug, that could be it, but thats unlikely. If you want to be sure take it out and if the cap is black then clean it out as best you can WITHOUT WATER. Just use a dry rag, and if you cant get that oil out of the spark area, then get a new one. Try putting a little high octane gas in it, it might rev it up a little.