Apologies for the necro, but now that it's been 12 years I'm wondering how the longevity of the 351 kits is?

I have a 2012 KLX250S and was thinking about upgrading to the 300 or the CRF300L, but it seems like just moving to the 351 would accomplish my goal of "being more comfortable on those rare occasions when I need to do 55-60mph."

I was also looking at maybe a DRZ, but if I could get even remotely similar HP with the KLX handling I am 100% in favor of that...

 

15k trouble free miles here of hard abuse oil changed every 1000miles with a magnetic oil drain plug

 

Well, if you'd like to mod for a top speed of over 100 mph, all you need is a barker exhaust system a DJ2206 carb kit, and a DJ144 main jet.
Set up your carb using the lidless recipe for full exhaust system.
Done.

 

Awesome, thank you! I've found a couple of other threads here and in advriders that say the same.

Now I'm thinking of this more as a platform than a motorcycle. So many things you can do with it...

 

Same as Tacoma on my '12.
Tons of solo adventuring through the back-country of NE GA, SE TN and SW NC on the KLX.
I've had the kit on it since '13 with zero issues.