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Euro 5+ Emission Regulations – A Complete Guide

Starting in 2025, Yamaha will no longer offer the YZF-R1 as a road bike in Europe. It is reportedly due to a requirement known as Euro 5+ Emission Regulations. But what does this strange combination of letters, numbers, and symbols mean, and how is it “killing” one of our most beloved motorcycles?

Euro 5+ Emission Regulations

Euro 5+ Emission Regulations – A Complete Guide

The most recent in a long series of European emissions regulations for motorcycles is the Euro 5+ Emission Regulations, sometimes referred to as Euro 5b. It covers all new bike models released in 2024 and will apply to all new bikes sold from January 1, 2025 onwards. Predictably, the first of these standards was Euro 1; the most recent was Euro 5, established in 2020.

The general idea hasn’t stayed the same over time: limits are set for specific pollutants, and a test cycle is used to validate the bike’s emissions. The big three are hydrocarbons (burnt fuel), oxides of nitrogen (respiratory problems and acid rain), and carbon monoxide (toxic). These limits are reduced with each new regulation. To put things into perspective, the hydrocarbon limit for Euro 1 was 3g/km. The R1 meets current Euro 5 requirements, which limit it to 0.1g/km, just a third of the previous limit.

Considering the current situation, one might reasonably assume that Euro 5+ Emission Regulations would result in another sharp drop in these figures, but this is not the case. Tested emissions meet Euro 5. There is only one test cycle. So what stops the R1 from passing Euro 5+, given that it already meets Euro 5? We interviewed Paul Etheridge, Director of Business Development for Ricardo Motorcycles, and Walther Liardini, Development Engineering Manager at renowned automotive engineering consultants Ricardo.

The main drawback of the Euro 5+ Emission Regulations is a phenomenon known as catalyst degradation. It would help if you woke up from behind. A catalytic converter, which helps eliminate exhaust pollutants from motorbikes, is part of every modern exhaust system. However, all catalysts need more efficiency over mileage and time. While it may sound exciting, Euro 5+ sheds light on the long-term viability of catalysts, one of the main hurdles in building contemporary motorcycles.

“In the early days, catalytic converters just had to work from new,” says Paul. Now, they have stability and catalyst monitoring requirements, and the whole system needs to be heavily engineered.”

One of the main changes the Euro 5+ Emission Regulations brought about is the testing and harmonization process for catalytic sustainability. To calculate emissions under Euro 5, you have to measure emissions using a brand new catalyst and multiply the number by 1.3 to account for the Cat’s potential future performance. It was cheap, simple, and quick to do. But now, thousands of miles of real-world testing — 35,000 km, or 21,700 miles — for bikes over 130 km/h (about 80 mph) should demonstrate the catalysts’ effectiveness.

According to Walther, “Manufacturers can test durability in several ways.” “They can test on a track, in an automobile, or on a dyno roller bench. However, testing in a natural environment is becoming more critical.

Another modification to Euro 5+ Emission Regulations is the need for a bike’s ECU brain to monitor the state of the catalyst constantly. Two lambda (oxygen) sensors are used for this: one before the catalyst and one after. The Cat’s entire life can be ascertained by comparing the two readings. Walther says a specific OBD [on-board diagnostic] technique will be used to measure catalyst performance. “This will turn on the malfunction indicator lamp on the dash and limit the bike’s power if emissions are not kept within 20% of the homologation level for the OBD. To determine the problem for the user, the service will be forced to view.

It can have a significant practical effect. Motorcycle manufacturers cannot build a bike that passes a single, predetermined test cycle and is ridden at a reasonably constant speed on the first try. To avoid disappointing their owners, Catalysts must be designed to easily withstand the rigors of everyday use and last the bike’s life.

With a high-powered, high-tech bike like the R1, the challenge is doubly difficult. Walther states, “Full load conditions on sporty bikes with mighty engines are far from normal driving conditions.” Even if you are putting out ten times the power under “standard” use, you still need to protect the catalyst’s life.

It gets more complicated the more electronics you have on your bike. Techniques like quick shifters and traction control can also affect the temperature of the catalyst,” Walther adds. You must be very careful when adjusting spark timing; you can’t delay ignition too long without overheating the catalyst.”

“Calibrating all these systems is another level of work,” says Paul. The technique becomes considerably more complex. It all depends on how much time and effort you put in. You can be successful. To proceed with further model development, a business case must be presented. Manufacturers make decisions about their products for a variety of reasons.

Here is the real test of Euro 5+ Emission Regulations. Introducing a fresh set of ridiculously low emissions restrictions hasn’t “killed” the R1. R1 isn’t killed at all. Yamaha will continue to sell it in regions where Euro 5+ Emission Regulations are irrelevant. Yet in Europe, where sales of superbikes have fallen significantly, many less popular bikes can no longer afford development costs. Superbikes, in general, are not going extinct thanks to Euro 5+ Emission Regulations—only those whose business dealings were already somewhat dubious.

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