That doesn't surprise me.

The stock cams are very mild, and far too mild for a 351. With the extra cubes, you could use more lift, and duration, and easily have the torque to pull the extra duration on the bottom.
I was thinking 300 piston/barrell, and cams.

 

Finger Mullet - can you let me know exactly what cams you ended up with? And I'm guessing you had to have the head worked for the larger valves?

I was thinking of new cams this winter, wasn't sure what to get though.
Thanks

 

So you guys with the 300 mod. do you just buy a 300 jug and piston? will any year 300 work? I have an 09 SF????

Thanks for the info.

I'm not looking for a KTM killer I just want to bump up my speed and torque curve a little.

 

Yep, makes a big difference. Four of us in the shop I worked at had the origninal '79/'80 KLX250 that was based on the old KL250 DS bike...nothing resembling the current KLX250/300 design. Kawasaki stuffed that old DS motor in a '78 KX125 frame. One of the guys sent his engine to Powroll, and they made a 318 out of this antiquated, 2-valve, air-cooled motor...stroked, bored, headwork, cam. That guy went on to win the '80 or '81 Open B class in the Texas state enduro circuit for the year. It was never dyno'd, but the power increase was big, it was still reliable, and the power was very tractable. Done right, these kinds of mods can make an amazing motor.

 

Just finished modding my 09 250s.

330 KK big bore
101 Web Cams
light port work on the head
Big Gun Evo R exhaust
TM36-68 pumper carb

It's sporting a new set of 17" wheels too. I'll be putting it on a dyno when I get more spare cash. I'm betting 30+ hp. wheelies on demand and it will pull to redline in 5th gear. Don't know the top speed because the speedo isn't hooked up yet. I've gotta get a speedo healer.

 

Or a Vapor

 

I picked the 101 grind from Web Cam.....I figured if it was "Larry Roesler's favorite".....lol....marketing...lol.....It was good enough for me.

Yes the guy that ported the head put in larger stainless valves for me.