Decision time! I live in Vietnam where dirtbikes are very limited. The KLX250S was imported around 2018 in small numbers and I bought one new. But as I age, I'm wanting more from the bike.

Suspension definately needs to be upgraded... No questions there. However I'm thinking a big bore kit will help move my 120-130kg self along better with it especially when tackling the more mountainous scenic roads.

So looking at the Keng Engine page in Thailand, I can see he has a number of kits available with the main contenders being 300, 330 & 351 cc.

Which one do you think will be the best suited to the 2018 KLX250S EFI model keeping longevity in mind?

As I know sweet **** all about engines, I hope to be having all the work done by a pro mechanic.

This so far is my best street legal option for a less fatigued body at the end of a solid day riding on and off road.

The only other option is to pay about double for what a used KTM would cost me back home. There wouldn't be many here that's for sure, so these are my two options... Could always do both I guess 😂

 

I put a 331 big bore on my 2010 in 2011. I thought about the 351 kit, but didn't want to hassle with a different carb or clutch springs, which (at that time) most were swapping out with the 351 kit. Most of all I wanted a reliable bike that I could trust when I was out in the middle of nowhere by myself. Fast forward to 2022 and now at 67, I still think it was the right move by putting in the 331 big bore kit. The bike is very responsive, a lot of fun to ride and still reliable.

With your bike being EFI, I'd imagine with the 351 it wouldn't be need to adjusted. The clutch springs would be up to you. IMO - being in Viet Nam, I'd go with the 300. At least you could get OEM parts if and when needed. No matter how you look at it the KTM is $$$ with thte initial cost and then maintenace. As for fatigue at the end of the day, the fun factor should help a little with that.

 

No upgrades will shave 50lbs off the KLX... So there's that.

 

Except for maybe a diet and exercise regimen for the fat slob (in my case) riding said KLX!

 

I didn't want to say that, but I rarely see a human anywhere near their ideal/healthy weight anymore. It is a long standing joke about gaining HP at track days...then they serve BBQ. lol

 

There’s a well known saying that the very best “mod” anyone can make to a bike is improving the rider upon it.

Now, I’m totally NOT the poster child for this cliché. But I do agree with it.

Should anyone disagree, go watch “The Seeker” videos on YouTube. That dude’s skills are amazing and he makes riding a T7 look like it’s a trials bike.

Yeah, I need to get out and practice more….

 

The whole thing depends on how you want to ride. If you want to lug it around a bit and just go a bit faster then the KLX with a big bore should do well. If you want to bust *** through the woods - KTM450/500 or CRF450L. But you're going to increase your maintenance needs over time. The KLX can be "neglected" a bit longer than the plated racers can.

 

I'd do the 300 kit as it puts the least stress on the bottom end.

I shaved 12 pounds off my KLX. It weighs only 292 pounds even with a 2.7 gallon tank full of fuel and a 3 pound rear carrier.
I keep my weight under 140 which makes for lively riding.

 

Bought the ktm back in Feb. Been having a blast on it. Kept my klx for multi day DS rides and when I'm leading beginner rides because nobody can keep up otherwise.

Dare say I'll be upgrading the klx suspension and a few power mods later this year though.

Happy braapppin all!