The grace period is officially over. If you still don’t know what a Rieju is, you might want to start paying attention. The Spanish company has become a legitimate player in the off-road world in just three quick years. Alfredo Gomez, two-time winner of the Erzbergrodeo, switched to a Rieju 300 two-stroke this year and has been a serious contender in the World Hard Enduro Series. Stateside, we were just learning to pronounce Rieju when Dominik Olszowy showed up on one and started torturing the announcers in the EnduroCross series even more. Rieju two-strokes are popping up everywhere. Now there are dealers in about 25 states. That’s fast progress, and the 300MR Racing is the bike that’s creating all the buzz. It’s the mainstay of the company—a competitive 300cc two-stroke worth a serious look for serious off-road riding.

THE GASGAS CONNECTION
Rieju didn’t really spring out of nowhere. The 300MR has been evolving for almost 30 years with the name “GasGas” written on the shrouds. Back in 1999, GasGas expanded from trials into the off-road world with an amazing machine that influenced KTM and all the 300cc two-strokes that followed. By 2015, however, the company was in trouble. The motor was still good, but the chassis was hopelessly dated. That’s when a Barcelona electric scooter company called Torrot invested in GasGas, and the result was a completely redesigned and surprisingly competent chassis.
How did they get up to speed so quickly? They were accused of making a near-exact copy of the KTM chassis of the time. It would have been a hit if not for one thing: Torrot didn’t manufacture very many of them. There were major supply problems until 2019 when Pierer Mobility stepped in. The KTM parent company wanted ready-made membership in the trials community, and GasGas was a perfect fit. They didn’t, however, want what they considered a copy of their own off-road bike. The intellectual property, tooling and rights to build the off-road GasGas bikes were sold to nearby Rieju, a company that specialized in small-displacement two-strokes and scooters. Under the new stewardship, the bikes formerly known as GasGas have finally reached their real potential.
THE PARTS
There are a number of good things that happened when Rieju took over. First, quality control made dramatic improvements. There was a crossover period when KTM, GasGas and Rieju were all working together, and the result was an improvement in manufacturing technique. The 300MR also uses excellent parts. The brakes are Nissin, the exhaust is FMF, the suspension components are KYB, and the hydraulic clutch is a Magura. In some circles there’s a fundamental misunderstanding of where the bike is supposed to be situated in the market.
Some riders assume it’s meant to be a budget two-stroke. Not so. Rieju is aiming at the top of the market with premium components and high-quality materials. The motor is not especially high-tech, though. It isn’t fuel-injected, there’s no electronic power valve and even the electric starter looks like it was graphed in place after the fact. Experimenting with new designs isn’t within the company’s capability or part of its business plan. The bike is built with completely established designs. That has proven to be its biggest strength.
You can see a lot of KTM influence in the Rieju’s steel frame.
OLD-SCHOOL
If it’s been a while since you dealt with a carbureted motorcycle, you’ll have to access some old muscle memory when you first ride the Rieju. Turn on the gas petcock and pull the choke—all familiar routines. The first thing you notice is how fast the starter spins the motor. It fires up instantly. Then the easy pull of the clutch, the tight gearbox and the light throttle return spring all add to the impression of quality. The motor revs cleanly right off the bat with virtually no warmup, at least it does at our altitude and temperature (1500 feet MSL, 75 degrees). The carb is a 38mm Keihin PWK. It’s pretty much the high-water mark for two-stroke carburetors.
The one personality trait that elevated this motor to such an iconic status 30 years ago is how it runs so perfectly at low rpm. It has smooth, even torque with virtually no lower rpm limit. It doesn’t stall, cough or flame You can see a lot of KTM influence in the Rieju’s steel frame. out. Today’s riders have grown up believing that 300 two-strokes have always been like that. The original GasGas set that standard. You can still feel that original trials bike influence in the Rieju.

After such amazing low-rpm performance, the 300MR’s mid-range and top-end are fairly typical of a modern two-stroke. If you’re transitioning from a four-stroke, it will feel flat on top. The Rieju’s happy zone is down low, so to get the most of it, you shift early and avoid over-revving the motor. Throughout the powerband, though, the motor is always clean and crisp. It’s worth pointing out that in the two-stroke heyday, they never carbureted this well. Back then there was always some detonation, missing or even plug fouling. Arriving at the proper jetting was a dark art. The Rieju has none of that, and we know from experience that it will continue to run well at higher altitude and different temperatures. You can give part of the credit to advancements across the board, including ignition systems.

Another well-established design that’s just gotten better and better is the mechanical power valve. The Rieju’s exhaust valve is driven by a centrifugal ball-ramp device, just like the first Yamaha YPVS system in 1982. The Rieju allows a slight amount of adjustment via spring preload against the ramp, similar to the Beta and early KTM systems. Internet forums are full of bad advice on adjusting power valves. Contrary to what you might read in the blogosphere, no setting will give the bike more low-end power. Anything other than the right setting will only delay power in the midrange, usually to a small extent. For the Rieju, that setting is two turns out. Set it and leave it alone.

THE STEEL FACTOR
So is the Rieju’s frame really a copy of a 2015 KTM steel frame? Not exactly, but you can certainly see the influence. If there’s any frame you want to copy, that’s the one. The current KTM frame is much more rigid and places more emphasis on perfect suspension setup. The overall handling of the 300MR has a good balance between agility and forgiveness. It turns easily with very little input, but on the other hand it’s not twitchy or nervous. The bike isn’t as light as those early KTMs, though. On our scale, it weighs 245 pounds without fuel. That’s forgivable but certainly not optimal.
If there’s any real flaw in the overall handling package, it’s the confusing suspension setup. Your initial impression is that the settings are very race-oriented. The suspension feels firm at both ends, which is somewhat compromising in the slow- speed arena where the bike should feel most at home. When you reduce compression damping, that harshness doesn’t go away, but the overall balance suffers. The real problem is the age-old issue with all off-road bikes. The guys at the factory can’t know where you ride or how fast you want to go. There is a zone where the Rieju is perfect, somewhere between tight trails and high-speed GPs. The good news is that it uses a KYB shock and closed-cartridge fork. There are suspension shops in every town that will know exactly how to tailor both ends to your needs.
THE BIG PICTURE
The real story here is that the Rieju is the right bike for this particular place in history. While KTM, Husqvarna and GasGas are going deeper and deeper into uncharted technological territory, Rieju is sticking with what has always worked. If there’s any market that places its faith in tradition, this is it. As long as two-stroke off-road riders continue to be so fiercely devoted, the Rieju will have a place.
The Rieju 300MR has a legacy that started in the trials bike world 30 years ago. You can still feel that influence today.
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