Valve adjustment

[Brian Moffet]

BTW, V plugs are supposed to fire together.  It's called a "wasted spark" system.

Actually, they're not suppose to fire together.  They are supposed to fire at TDC for each cylinder, even on the exhaust stroke.  That's the waster spark.  If you have both front and rear cylinder fire together, one of those would be firing way early and cause pre-detonation.

[Re-Vision]

At the time I wasn't interested in the mechanical end of things and I wasn't happy with the work I was getting from the dealer where I bought the bike. I took it to a dealer in Ft. Worth thinking the big city boys would know what they were doing. Ha. When I got my bike back and went home it would barely do 55mph. They refused to be responsible for my poorly running machine so I took it back to my dealer in Mineral Wells,TX. The dealers son finally got it to running right again and told me it was firing one cylinder at the wrong time. That was a long time ago, took it back to Yamaha West in Ft. Worth and told them what had been found,  they kindly offered me a free tune-up the next time in lieu of a refund. I politely asked them why I should give such incompetent bastards an opportunity to screw-up my bike again. I sincerely hope I had a hand in putting them out of business.     BDC

[Rikugun]

I wonder if it was simply running on only one cylinder. That would certainly explain the power loss and would be easy to accomplish with just a bad plug wire or the like.

[QBS]

Correct Brian.  Should have thought it out more fully.  I know better.