Originally Posted by dmcc67
I've tried searching this without success....
Anyone want to report their average MPG after going to the 351cc?
I'm considering the big bore sometime this year.
I commute on my 250, and I am probably wringing it out, but I only get 50mpg average. This is my second KLX250s, my first one got 58mpg average, day in and day out. Both 06's. Go figure.
When new my 07 would get in the mid to upper 50s for MPG (high was 58). I was very disappointed with that. I put the 351 on with only ~750 miles. With the number of mods I have done, it's pretty much impossible to say what has impacted mileage and what hasn't. Now I typically get around 65+ MPG (high was 74). I can say for sure that the 351 itself isn't a complete MPG killer - getting jetted with intake and exhaust properly sorted probably has a far bigger impact. The one mod I have done where I did notice an immediate and sustained increase in MPG was the 15 tooth countershaft sprocket. The 351 has no issues pulling 6th gear with the 15 tooth. Others on this thread and elsewhere have said it a thousand times and I couldn't agree more, the 351 makes it a completely different bike. The increase in raw power numbers doesn't really tell the story, because there is such a large increase in where the usable power is available in the RPM range.