Mark maybe confusing the F11 w the F8
No confusion here John, I've spent a lot of time with all 3 bikes and the F11 wasn't any slower than a DT1 or Sav...don't believe the magazine articles of the time, the results bike "tests" were all based on the amount of advertising in that particular issue, no matter what mag we're talking about. If the Yamaha topped the Suzuki or Kawasaki in a test you can bet your goolies that Yamaha had more ad space that issue.
The Kawasaki responded very well to porting, a bigger carby and a pipe. When I was building my 'DT1 from Hell' back in the 90s I spoke to ace porter Gary Treadwell and he asked me why I was using a DT1 instead of an F11. When I explained the pre 70 class aims of the bike he responded that of all of the 250 trail bikes of the period, the Kawasaki showed the best flow characteristics and had the most potential for horsepower. That theory translates over to the Kawasaki F11M being a far better bike than the MX250 Yamaha and TM250 Suzuki, even though it's pretty hard (
near impossible) to find one.