Easy, Affordable, Capable

The XR150L Performance Blueprint from TTM

There's no question, the XR150L is an excellent gateway into the world of dual-sport motorcycling and straight-up dirt-biking! But, can it ever be more than an entry-level machine?

I spent years exploring that question since I took delivery of a unit from the first shipment of North American XR150Ls. I've tried more setups than I care to admit! Ultimately, after developing a setup that is entirely my own, I found the answer to the above question to be a HUGE YES. I've been taking this bike out and smashing many trail times that I set on bikes such as my XR277R build, CRF250X build, and the legendary KDX200. Even better, I found that the perfect setup is very reasonably priced, which is perfectly in alignment with this bike's original allure! Win-win!

So what does it take to make this bike capable of thriving under my rigorous demands? Let's get into it.

Front Suspension

Surprisingly, my setup retains the original front fork stanchions and slider bodies. With completely re-worked internals, I've developed a setup that functions beautifully. While the external shell of the fork is original, the internals and damping functions share nothing in common with the unmodified fork.

The unmodified fork is simple, and terrible. All it really does is shove oil through two fixed holes in the damper rod in a sad attempt to smooth the action of the travel. It just doesn't work. In order to make the 6.6" of travel in this fork feel great, the fork needs a complete internal makeover. 

The solution that I fell in love with converts the two fork legs to handle different tasks, turning it into a separate function fork.

In my setup, the left fork leg handles speed-sensitive compression damping, meaning the damping valve blows-off in a controlled fashion to absorb sharp hits comfortably while providing resistance and feel over smoother stuff so that the fork doesn't feel "mushy" like the original setup.

There is almost no rebound damping in the left fork leg. Instead, rebound damping is handled in the right fork leg using a position-sensitive method. Meaning, when the fork is way down in the stroke and the spring pressure wants to explode back, the fork provides more damping from that deeply-collapsed position to create a perfectly controlled re-extension. The right fork leg also provides compression damping in a position-sensitive manner once it reaches a certain point in the travel, which catches big landings and G-outs very gracefully.

The best part? The conversion is easy to do, completely inexpensive, and I'll teach you how to do it, so you can just copy me. Check out my guide here.

Rear Suspension

My setup does not retain the God-awful original rear shock. Instead, it uses a fully-adjustable 40mm Showa shock body with piggyback reservoir and an application-correct spring rate.

This shock completely blows the original shock out of the water and makes it look like a joke in comparison. I mean seriously, Honda, the original rear shock was a joke that we were meant to laugh at, right? Intended or not, it is a joke. That original shock has a hilariously-inappropriate spring, has dangerous and uncomfortable damping, fades after a split second of hard riding, and doesn't even survive a single rip through a good whoop section before it is physically destroyed. Pathetic.

The perfect setup that I've created is superior in comfort, light years ahead in performance, and is much more easily tailored to the conditions because it has externally adjustable compression damping, externally adjustable high-speed compression damping (separate from overall/low-speed), externally adjustable rebound damping, and of course adjustable spring preload. The original shock has none of that, not even spring preload!

Again, the best part? My shock setup is built using a shock body that is extremely widely available at throw-away prices. Junkyards are littered with them. Ebay is overflowing with them. I purchased five of them for testing and media kits, and they were all acquired between $46-70 each.

There's some building required to make it work perfectly for the XR150L, but again the process is easy, inexpensive, and I'll teach you how to do it, so you can just copy me. I don't have my guide published for this yet, but I'm working on it. I expect to publish on 31 March 2026.

Engine

The original 149cc motor struggles so badly, I have actually found roads at elevation where it would simply run out of power in 1st gear and not continue to move uphill. So, it's so underpowered it won't even make it up all of the paved roads in my state. Pretty sad!

Fortunately, the solution is simple and affordable. It just needs... more. More engine! I was very pleased with the results of testing out big bore kits on the XR150L, and find that a simple big bore kit is all I need to make this bike haul ass and do anything I want.

The following kits can all be had at very reasonable prices, and I'm happy to recommend any one of them, just see my notes;

• SXParts 208cc big bore kit - Very high quality kit. I would recommend lowering the compression ratio. In my case it did not work well on pump premium without octane booster until I lowered the compression ratio. The head gasket included is quite thin, lots of room to go thicker.
• BBR 195cc big bore kit - Good quality kit. I would recommend WPC treatment of the cylinder for longevity.
• ScooterSwapShop 222cc big bore kit - The piston is a little rough (casting is iffy, piston pin bore on mine is clocked a little off and tilted slightly, valve cuts are clocked pretty far off) but it definitely works and the torque is lovely. Just inspect it to make sure nothing is too far off, especially the piston pin bore as you don't want a piston sitting too cock-eyed in the bore, and I would recommend WPC treatment of the piston to help fortify the casting for long term use.

Alternatively... You can be like me and just throw a whole different engine in the bike. I used a CRF230F engine, which can be found whole from an otherwise withering bike. It fits the frame and bolts in using the CRF230F top mount.

 If not a genuine CRF230F engine, there are many, many (too many to list) other engines that will bolt into the XR150L frame. The Zongshen ZS172FMM and related engines will mostly just bolt right in. Non-counterbalanced varieties are the ones to go for to ensure fitment without interference.

Geometry

I'm listing the geometry fix-up last, because it's the least glamorous, but I would easily rate it as the most important thing you can do to the bike for off-road applications. And, again, the solution to make this bike just right in the geometry department is easy as 1-2-3.

1. Get a handlebar with less sweep. The original bar is swept so far back, it leaves no leverage to row the front end up and down, which is terribly uncontrollable while riding off-road.
2. Get rid of the rubber pads on the pegs. They eliminate almost all ability to apply input at the pegs, and they raise the pegs so much that standing is difficult. They simply unbolt from the peg. You won't miss them.
3. Get a larger front tire. The original 19" front, 17" rear configuration with the tiny front tire makes the bike extremely squirrely off-road. A higher profile tire greatly stabilizes the handling. It's a must-do. I run the 3.50-17 Shinko 241 tire on the front, and I'm in love with the handling on the trails. The tire lasts a very long time and offers way better rim protection, too!

 

That's all.

A cheap mod to the front suspension. A cheap mod to the rear suspension. A cheap mod to the engine. A few tiny mods to the geometry.... And bam, you've got yourself a bike that's fully capable. With 20 years of racing experience, I'm still pushing the limits and I'm doing it on this bike, with nothing but the above blueprint.