Enduro21 avoids the Spanish power meltdown to visit in Catalonia and test ride Rieju’s all-new MR300i fuel injected two-stroke enduro models. 

Sitting in the lush, late spring sunshine, Rieju’s all-new MR300i fuel-injected two-strokes are ripe enough for the Spanish manufacturer to pick and send to the market.

These two new models mark a milestone for Rieju, a significant one in their more than 80-year history. The family business is based in Figueres, northern Spain, and specialises in smaller capacity bikes, mainly street bikes.

But they have a decent racing history and, when they took over the former GasGas platform in 2020, it was a step literally into a global world market they’ve made gains in. By now they’re on the map and we are seeing Riejus in the EnduroGP and Hard Enduro World Championships, as well as high-profile national series like US Hard Enduro.

2025 marks a whole new milestone for Rieju however, and we think it’s a big one. Proudly announcing their two new enduro MR300i Pro and MR300i Racing models, they have taken a bold step forward with a fuel-injected two-stroke all of their own making.

In a nutshell it’s been a while coming but they’ve moved on from the former GasGas bikes to what they can legitimately call something of their own creation.

What you need to know about the new Rieju MR300i models

• Home-grown engine designed, developed and manufactured in Spain
• It features two injectors operating in different parts of the power curve to replicate carburettor feeling
• New engine positioned for more front-end bias and feel from the chassis
• Diaphragm clutch (adjustable) on both bikes
• Three power modes
• Runs premix fuel
• Two models with high-spec standard parts plus upgrades on the Pro model for enduro and hard enduro
• Oh yes, and still with competitive price tags

Dual-injectors working at low and high rpm – “like a carburettor”

Getting straight into the details from this media launch at the Nasser Camp, North and West of Barcelona, Rieju explained their engine stands apart from competitors in the enduro market with a dual-injector throttle body. That’s not unique, but each injector operates separately, one in lower and one for higher parts of the rev-range, which, they say, gives the MR300i a more carburettor-like throttle response.

This came as a refreshing nugget of knowledge to be perfectly honest. Enduro21 perhaps held a cynical point of view that the new engine might just be a copy of, or a combination of, other manufacturers’ design solutions.

Instead, it’s clear a lot of development necessarily went into the new motor, with R&D happening at the races as much as in the Spanish hills and forests to arrive at their own motor.

The other good news is the new engine also features a counterbalance shaft to get rid of the ever-present vibes in the previous models from Rieju. It’s not just about no longer having tingly hands and feet but also about having a tighter-feeling bike under you, a sharper and more precise tool to play with.

While we’re talking new stuff, the Fi engine also features a diaphragm clutch for improved feel and consistency. It’s adjustable too, with three options for different feel depending if you want it sharper and stiffer or softer and more forgiving (for moto tracks through enduro to trail riding).

How does it feel to ride?

We’re going to have to say pretty flawless, with a precise throttle connection to the engine, clean fuelling through the revs and as you blast through the six-ratio gearbox. The pick-up and response is still not 100% like a carburettor feeling, but it’s not far away and is different to the very linear power from the Austrian fuel-injected rivals.

A brand-new engine could easily have arrived at the end product — these bikes on the media test were the first pre-production models to roll out of the Figueres factory — and could potentially have had some issues, but in all fairness, we found none.

Carb-like FI feeling

We tried the bike in a mix of conditions, from lugging low-revs, first and second-gear hard enduro steep and rocky climbs, to fifth-gear blasts and everything in between. On different laps of the long test track, we also attacked it in different ways and used different gears, sometimes slugging it out in a high gear to really challenge the fuelling and pick-up. Other times over-revving and using the gears much higher in the rpm range.

Whatever the approach, the fuel injection was glitch-free and the 300i motor proved to be a powerful big two-stroke, just as we’d hoped it would and should be.

It is tempered right off the bottom of the revs, at the first throttle pick-up, which helps for enduro to feel the rear wheel grip and stands this engine apart from, say, a two-stroke MX bike. But the power still comes in strong and, in the baking hard-pack conditions of this test, it was clear the new Rieju has the punch and strong power of a two-stroke 300.

Three usable modes

We don’t know if it is just us but there are times when you don’t want to ride like an E3 world champion. Rieju’s three modes help here with options for more rear wheel control. 

Race mode, Forest mode and Wet mode are relatively easy to select with a button on the left side of the bars – it flashes the number of times corresponding with the mode; you press and hold for a second to change between them.

A recommendation from one of the factory riders on this test, Toby Martyn, to use map two for the hard enduro section rang true.

Where traction was hard to find (two bikes failing the rock and root climb in front of us was a pretty good clue!), map two gave low-end feel and drive but didn’t take away the burst of midrange power needed to get up the steep, rock and roots step-up. The poke was still there but it gave good feel for grip initially to launch the bike up the rocks.

The third map, the wet one, in a way turns it into a more linear motor so suitable for wet conditions, yes, but also simply a nice bike to trail ride on to be honest. The power is less likely to catch the back wheel out as you come on the throttle but there’s still plenty of acceleration and poke and it still sailed up that same steep uphill rock and root step.

In the end, the full power mode was the one we used most, but Forest mode actually made life easier in some riding situations.

Rieju dealers will also have plug-in software which will allow them (and you) to adjust a number of parameters including fuelling, advance timing, and tailor one of the maps how you want it – i.e. for hard enduro or more aggressive if you’re planning on racing EnduroGP.

Running premix fuel

“There’s a debate” with enduro, even within the Rieju team they say, about whether to run a separate oil tank or premix. As many people know, that debate spreads out to the wider enduro world where you’re either for or against it. 

In the end, Rieju settled on premix still, firstly because they say it feels more normal for a race bike. Secondly, because it means less weight and “less things to go wrong,” Dominik Olszowy said in the presentation.

Without the separate oil tank and pump you have a small amount less weight, not a lot, but they are right about it being mechanically less complicated and oil pump failures and oil line blockages causing seized engines are a reality.

One note to make here is the bikes appeared to us to be thirsty. Less than two hours’ riding guzzled a lot of a tank on our test bike, certainly it was more than we’d expect on an Austrian TPI or TBI bike, for example.

Chassis handling

For all the newness of the engine and fuel injection, much of the rest of the new MR300i remains the same – although there’s definitely a different feel and character about the chassis and handling compared to the previous generation.

That means the same steel backbone-type main frame, aluminium chassis and swingarm. The KYB suspension is Rieju’s specification and one of the many things the test riders have been clocking the hours in the Spanish hills to arrive at a setting.

One significant change, however, is how the motor is positioned in the frame. Pivoted a little further forward, it means the new models put more weight on the front end, giving more feel for the front tyre and helping accuracy in turns.

This is one of those things which you wonder what actual difference it makes but we tested the Gomez Edition MR300 last year and, by contrast, notes from our test record a lack of feel in the front grip.

In truth it is probably better than it felt on this test too because Rieju chose to run the standard tube set-up and, in these hard-pack conditions, also high tyre pressures, which meant a lack of feel from either tyre.

(Note the MR300i Pro comes with new Michelin Enduro tyres while the MR300i Racing will have Mitas tyres as original equipment.)

DLC-coated forks on the Pro model

KYB suspension as original equipment, particularly the AOS system and black anodised DLC-coated forks on the Pro model, are sweet. Both bikes have a meaningful range of adjustment which takes the standard setting from soft trail bike to motocross track in a few turns of a screwdriver. It’s another thing which marks the Rieju out from at least some of its 300 two-stroke rivals, certainly when you look at the price tag.

2x Models?

Yep, there are two, with the base bike not what you should be calling a basic bike by any means as it comes with all the same standard parts. You tell them apart by the colours: red for Racing, black for Pro.

What’s the difference in the Racing and Pro? 

Just over 100kg dry weight, 9.8 litre fuel tank, the original equipment on the Racing includes black anodised Excel aluminium rims, Mitas Terra Force tyres, Neken handlebars and grips, Funnelweb airfilter a crankcase protector, OXA exhaust system, X-Ring chain retainer, Nissin brakes and Galfer discs. 

The Pro model adds black anodised DLC Antifriction Treatment on the forks, Renthal Fatbar handlebars and grips, Polisport Bullit handguards, X-Trig Rocs aluminium triple clamps, Excel rims with red machined wheel hubs and fitted with Michelin Enduro Medium tyres, and a two-tone non-slip seat.

The Pro model is upgraded with what they told us is nearly €2K of extras for a €1K extra price tag: €9099 / £8195 for the Racing model while the Pro is €9999 / £9195 (apologies, USD not yet known).

Any other business?

Jumping from different bikes and testing them in different conditions all within the space of a few days means anything not quite right can stand out. You have to be adaptable in this job; as a rule of thumb it is best to just get on with it and ride the bike as standard because that tells you more.

When Enduro21 jumped on these bikes something felt like they still needed tailoring to suit the rider; it wasn’t a bike you just jump on and feel totally comfortable with straight away.

We look forward to testing the bike more with time to adjust suspension and maybe handlebars or footpeg height to get comfier. We didn’t spend a lot of time riding the Racing model but it was certainly softer and more pliable whereas the Pro was more ready to attack the terrain and felt better set-up for enduro (and hard enduro).

That said, this might be down to the hard tyre/tube decision, mind you, which sapped confidence in the dry terrain and in the end you can point to personal preference.

Other facts worth noting are the new switchgear compared to previous Rieju enduro models has been upgraded — thankfully now more intuitive and easier to use.

The starter motor is still not connecting 100% of the time and once or twice we had it do that whizzing up thing and not connecting, which we think has been common on every Rieju enduro bike we’ve ever tested.

Rieju tell us there’s a new online “One to One” system which lets you customise spec and order your bike, which will then be delivered within 15 days. Bikes are due out in Europe in early May and into North America by June/July is the plan.

It’s hard for us to comment on parts supply – Enduro21 stands in the stratosphere with readers all over the globe – so this will vary depending on your national dealer network.

But they tell us parts supply, as much as the new models, were the priority all along in taking this next step as a brand in the enduro market.

Enduro21 Verdict

Apart from all that, we left the Rieju media launch with a lot of positive vibes about the new MR300i and a desire to ride it more. 

The positive vibes are genuine and it was refreshing to find they had created something which didn’t just meet the expected standards – great throttle connection and, on our test bike, flawless fuelling – but also exceeded them with a powerful 300cc motor capable of satisfying the anti-fuel injection two-stroke brigade.

For all those people who say, “I’m sticking with my 2017 [insert bike here],” this is like your bike, only better because it is new.

And for all those people looking for a new 300cc two-stroke under €10K with a damn good standard specification, you have to take these bikes seriously.

We’re not looking here at self-inflated price tags from a manufacturer struggling to connect with its customers. Neither are we looking at a cheap, Asia-built knock-off machine but a tried and very tested base bike and a long list of quality parts for your money.

The Rieju MR300i might have elements from older models lurking in here but the new engine certainly doesn’t lack power and packs a punch which marks it out from the Fi 2T rivals it stands shoulder to shoulder with in the showrooms. 

Things have certainly moved forward for Rieju.

Photo Credit: Future7Media | Nicki Martinez + Rieju