Have you tried with different gearing? 13-50 maybe?

 

Biggest thing I'd be concerned with if riding the bike in a hare scramble or enduro would be breaking stuff. Sure it is not a light bike and no, it does not have a lot of power, but it certainly can do the job. I doubt many riders would take an over all, but a good rider can trophy with one. I saw a rider riding in a wet muddy harescramble in 1973 riding a Suzuki TS125 dual sport running not just for the class lead, but for the over all win. My friend on a Penton 125 actually won the over all. Two very good riders on 125s one being a dual sport model fighting for the lead in a muddy race. Yes, it can be done. So go play hard if you want. Gear as needed - that's even true on competition bikes.

 

I had an opportunity once to try out a KTM SX125 on MX track. It has almost 3 times more power than the KLX, and I was kinda afraid of riding that bike. To be honest, my skill level is so low that I can't even so all the power the KLX has. There's an MX track nearby, I am planning on taking the KLX out on a ride as soon as I get appropriate tires. I agree with klx678, the thing I'm most afraid of is dropping the bike and breaking something. I'm pretty sure that the coolant tank on the back left of the bike would be the first thing to break off.

This guy on this video modified the bike in a way that kinda looks like an actual dirtbike.

 

Making a KLX look like a dirt bike and a Penton 125, are whole different worlds!

 

That Penton is probably 100lbs lighter. I'm sure a good rider can win a muddy XC race on an old bike in C class. It's substantially harder to do that on a 300lb bike. And it won't happen, if it's a hard enduro race.

 

Didja miss the part about the guy chasing the Penton around on a Suzuki TS125 on a muddy (and rainy) day in an Ohio hare scrambles? It was also noted the race was in 1973 so it wasn't an old bike at that time. By the way, that rider on the Penton was pretty good, placing 9th in the first Blackwater 100 on a stock KX420 in 1975. Neither one were slouches, just pointing out that a small engine can run hard. And I guarantee you any good hare scrambles will be as hard as any hard enduro. The Penton family used to travel south in Ohio to the area in training for the six days, so those hare scrambles must have been pretty good.

It is not that the KLX is a racer or anything, but can be raced if one wants to do so. Having been a member of a motorcycle club that ran hare scrambles I can tell you seeing someone racing a bike that isn't a pure racer and having fun doing okay was not unusual. An acquaintance raced a 255 lb supposedly 11.8 hp XR200R in harescrambles for at least a year and did pretty well with it winning the class a couple times over lighter faster bikes and ahead of a lot of far better lighter faster racers. So why would a thirty pound heavier (if parts aren't removed) motorcycle with superior suspension and another 8 hp not be able to run hard off road? What keeps it from taking the conditions as well as a 1983 Honda XR200R?

Really, it is far more off road capable than you are giving it credit for. Again, sure it isn't a KTM or a motocrosser, even an enduro like a CRF250X, but it can make it around the track no problem. I'm betting a rider could lap a hare scrambles track faster and easier on a KLX250 than they could on a 1972 Penton 125. Point being if you can make an 18 hp 6" travel two stroke go around the track an 18 hp 11" travel four stroke should be able to do the same. Just because it isn't 250 lb and not having 25 hp doesn't make it inept at going across rough ground. Just not true. I'm betting a lot here can tell you they do pretty darn good, riders that have raced and ridden faster lighter bikes will tell you it can make it through an enduro or hard enduro or hare scrambles.

By the way on a wet muddy day how much weight do you think is added to that 250 lb bike in accumulated mud? So suddenly on a good day a 300 lb bike is pretty much the same weight as some racer on a bad day.

 

that was my thought when i quit racing, but showed up to pit for my buddies at the gncc track outside athens ohio with my 86 xr200. what the hell, i signed up, too.
worst day ever. the track was so beat up after several years of use, that those spindly forks threw me all over the place, just not where i wanted to go. gave it up after one lap. lesson learned.
but what was fun was running another gncc on a 10 year old cr125. i felt like tommy norton at blackwater.