With stock or near stock power levels, a 13 tooth primary is a fantastic - almost "must do" - mod. Top speed is same or better as well as all accel scenarios.

However, once engine power reaches into the mid 20's - thru the various mod recipes we have developed - the stock 14 tooth primary is perfectly useable - and top speeds can see 100 mph ( indicated).

Note: There are no reports of the differences realized, between 13 and 14 primaries, on a 24 hp (or +) KLX.

 

IMO, one has to consider the 13 as more of a riding issue. With the 14 I was always at that 1-2 speed, with the move your just in a higher gear when the trails open up.

 

For riding dirt, I still prefer the old KLX300R gearing of 14/50. It's easier on the chain too.

 

You are using the bike primarily as an off roader, as opposed to supermoto/street. Makes a difference for sure. I ran I think a 13/45 or 47 when riding in the deep sand in Michigan. No problem getting rolling, problem was steering in the deep stuff when the front wheel dug in and the bike got on the harder ground underneath. Kept crabbing up the side opposite what I wanted.

Now it's a 13/42 but when I get new chain and sprockets I will do a 14/45, which is virtually equal to the 13/42, so I can go up a bit with a 15 or down a bit with a 13 when needed. I mainly do dirt/gravel and tight back roads with the occasional more dirt oriented stuff. That is I do if I ever get all my joints working together again. Shoulder is doing great, but the knee is still crap. Double cracks every time I stand up and sometimes doesn't want to work too well.

 

But Mark...what about the brain surgery? Were they able to improve anything in that area?

 

Lost cause... But they said I could leave my brain to Ohio State med school in my will, they'd really like to check it out.

Oh, and today I stood up and the knee cracked four times.

 

Snap, crackle, pop...ouch! Knees are scary. I've had a completely snapped ACL since 1981 from the Permian Basin 100 Enduro out near Odessa, TX. Oddly I've still been able to continue riding with a brace and mountainbiking without much issue. Tennis, b-ball, volleyball, and any other aggressive cut and turn sports have been out for decades. I've had a little more issue with it in the last year, and I'm sure I'll be needing to have some work done. Hoping you get full recovery and use.

 

I kept the stock SF (SuperMoto) setup on my 2009, which I believe is 13/39, and have no issues off road, on road, or Supermoto. Still goes 87 MPH on GPS.

 

13 front really helped me trail riding on steep mountain downhills. Will buzz along at 70 mph, approx 7000rpm

 

Why would anybody even want to do this on a KLX? Our bikes feel terrible at high speeds, so why even think about raising the top speed ceiling at all? Take the acceleration where the gain will actually be utilized.