KLX300 question

What kind of a bike is a KLX300? Is it comparable to a XR250/400? I ride a XR400 now but wanna try something different?

Stock, it's comparable to an XR 250. With some simple mods and suspension work it'll shame an XR 400.

What are the "simple mods"? Also, how is it for durability & maintenance? Do they need to be rebuilt often like the MX 4 strokers?

What are the "simple mods"? Also, how is it for durability & maintenance? Do they need to be rebuilt often like the MX 4 strokers?

No, the valve train on the KLX is not near the sevice level of the later generation competition 4-strokes. It's a very understressed engine. I had 4 XR250's from '84-'90...even raced them in enduro competition. I have an '06 KLX250S...basically a factory street legaled KLX300 with an electric starter.

Right out of the box with no mods whatsoever, I think the bikes are fairly close in power with a slight nod to the 300. However, I think the water cooling on the 300 starts to shine over time and with more mods. I found my XR's to be decently tough on piston and bore wear. This was one of the first short-skirted pistons for a production engine back in the day, and they went through pistons quicker than some older tech designs. This is understandable and was never a problem for seizing or breaking a piston in my case...just quicker wear. It's an air cooled engine with a short piston skirt. It's logical.

When you start modding with big bore kits, cams, and/or other performance mods, the KLX takes it in stride with almost no increased wear or service interval. The cooling system of the KLX is somewhat overdone too. I have an inline sensor and guage on my KLX, and it is a very cool running engine. All of this combines to make a very durable, long lasting, reliable engine.

I loved my XR's, but I wouldn't go back compared to the KLX series. I installed a 300 jug on my S model and have been totally pleased with it. There are many KLX's out there with Bill Blue's 351 kit that have been running for many miles with no issue.

I'm happy with my KLX300. A bit less "umph" overall than I remember from the last XR400 I rode, which was a while ago....but MUCH easier to get started (I can start mind with my hand, hot or cold). I feel like I sit a bit lower on my KLX than on virtually any other full sized dirtbike - the seat isn't flat on top like most, but rather cuves down. Mine was a lightly used 06 when I bought it in 07. I don't get to ride as much as I'd like and have put about 120 hours on it. It hasn't needed a thing maintenance/repair wise other than oil changes and the air filter cleaned. I've checked the valves twice, with no sign of any movement at all.

The bike comes very softly sprung, so I did change out the fork springs for heavier springs to suit my fat @ss. Would like to put in Gold Valves or something similar as well, as the fork doesn't seem to respond well to sharp edged hits.

All in all, I'm very happy with my 300 for the way I ride, which is fairly mellow trail riding.

I love the torque of my XR400 but could do without the weight & sometimes hard starting. How much lighter would a KLX300 be? Also, what mods can be done to get a bit more grunt out of the engine? And what years are the best ones?

The KLX is more nimble than the XR, and a few lbs lighter. After '03, the factory finally got the timing right on the ACR, which takes the load off the idler gear. With "free mods"(see PlanetKLX), and the addition of an aftermarket head pipe and Dyno-jet kit, these bikes really run the way they should. Heavier fork springs are a must.

I love the torque of my XR400 but could do without the weight & sometimes hard starting. How much lighter would a KLX300 be? Also, what mods can be done to get a bit more grunt out of the engine? And what years are the best ones?

Bill Blue's 351 kit is probably the single best mod for more power, and the good thing is that the power is very down low useable and the kit doesn't do much to affect the reliability of the engine from all accounts seen at this point. The big bore kit with an aftermarket exhaust and a bigger opening on top of the airbox do wonders for this bike. Some even go to a pumper carb and that helps too, but even the OEM CV carb works well with the big bore kit.

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