The easiest way to check your float level is like this using a 1/8" piece of clear tubing from the hardware store.

The quick & easy way to check float levels is to use a clear tube that fits the dump hole on the bottom of the carbs. You'll need at least one foot of tubing. Don't worry about an exact fit, the tubing can be a little bigger which will cause some of the gas to leak out but gravity is forgiving and is constant! You can get the tubing from your Yamaha dealer for a few bucks. Remove the stock dump hole tubing, put the new tubing on there & then bend up the other end so its touching the carb housing where the float bottom half meets the top half. Then turn on the gas pitcock & the level of gas in the tube should fill up & be level with or slightly above the bottom/top half of the carb's mating surface. If not, you'll need to adjust the float levels. A sign that the float levels are too high is if the stock drain tubes leak gas while your riding, you'll smell it for sure.

Which timing marks on the flywheel did you use the (l or the ll) could have used the wrong one.

Your main jets would not be the problem, they have little or no effect with starting.

 

I used the I mark on the the flywheel

 

Sounds like your timing is correct.I would check the float level next.If that is good I would pull the carbs and clean them out.

 

BTW make sure parking break is off [img]i/expressions/face-icon-small-wink.gif[/img]

 

Another thing I have heard of happening that would cause the same problem. When adjusting the idle mixture screws some have turned them in to far and break the tip off of them, plugging off the idle circiut.

 

well guys u aint going to beleive this but it was the plug i pulled it and grounded it to the case and it had a good blue spark so figured it for good so i went on ahead an ran and got a new one put it in and fired right off,took it it down the street ran good till wide open throttle cutn out and has no pull like its lean mains so im running 165/170 now 3clip on the needle and iair fuel 3 1/2 out thinking of bumping up to 170/175 what do u guys think.

 

Duece25.
Maybe its because its a Jap(aneese) bike. I am sorry I couldn't resist. You know I am kidding. I am working on my sense of humor.
Thats funny that it was your plug, I had almost the exact thing happen with a 400ex once. Weird.

 

Damn spark plug!!!![img]i/expressions/face-icon-small-happy.gif[/img]