The last time I enquired about this with a local dealer's mechanic he said
the EFI needed to be remapped. This would correspond with RSRBOB's theory.
Too bad Yamaha won't do the remapping for us. If thats what it is there will
be very few economical ways around it. In my case I have noticed adjusting
the tps seems to vary the rpm range where the flatspot occurs so I tried to
adjust it to a higher rpm where its not as noticeable (at very low rpm the
bike was almost impossible to ride stalling off idle just trying to roll
from a stop right now it seems to be around 2500rpm still annoying but
driveable). About the same time I was having problems I was corresponding
with someone else off list that had a bike with much fewer miles (mine had
over 40,000 when I bought it last year)who had seemed to run into the same
or very similar situation. I believe he replaced his tps and that solved his
problem. Conclusion? Well there are probably a number of reasons why any
particular sample of this bike can exhibit the symptoms making this a
difficult problem to trouble shoot. I think I know of only one person who no
longer has too worry about this at all but of course switching to
carburetors well it kinda seems like cheating no tps no mapping of course
jetting to "me" would be a nightmare as well. I know I'm not being much help
but I don't think anyone has found exactly "the cure" and even if it was a
cure for one bikes probs it might not be for another. I tried using the
recommendations on the website hoping for a cure but found it to be a work
around in "my case".YMMV definitely!Good luck.
Darren
