Originally Posted by
Clawhammer
My old spark plugs looked good, a little out gap spec, but fine. Yamaha tech pulled them when he had the bike the other day and said they were still fine. I almost want to say it's fuel. I know it's getting spark, and I know I'm firing and in order and such. Sprayed the headers down with water and watched em. Nice and even evaporation. The only thing is sometime when it's idling it almost sounds like it's missing.
I can't prove it yet, but the other day I rode 24 miles with my gas light on. The whole time it was running pretty good. Under 4k it was great, and at 8 it was a little shitty, would hesitate for a second and then go like normal.
So I realized that it seems like it always runs well right before I get gas...so I only put a couple gallons in to see, and it's running kinda shitty again. Will see what happens when it gets low. What sense does that make?
Mine does the opposite and gets shitty, I'm guessing due to sediment in the tank and the ratio it's getting into the carbs. Have you looked into the tank? How about the fuel filter ? My mower had an intermittent problem like that and when I took off the old fuel filter I had to cut the line and found a piece of some plant in there that had I'm guessing been moving around at the filter entrance.