[General_Apathy]

Now that the euro 5 bikes have been around for a few years what are the real world downsides to having a euro 5 instead of a 4?
Initially there was panic over the restrictions but I still see mods on euro 5 bikes with no consequence.
Was it not as bad as everyone thought it was going to be?

[SteveThackery]

Now that the euro 5 bikes have been around for a few years what are the real world downsides to having a euro 5 instead of a 4?
Initially there was panic over the restrictions but I still see mods on euro 5 bikes with no consequence.
Was it not as bad as everyone thought it was going to be?

Your last sentence seems to sum it up perfectly. There appear to be no downsides, at least when you leave the bike stock. In fact quite a few manufacturers seem to find an extra couple of horsepower when they go up to Euro 5, presumably due to small but continuous improvements in the state of the art.

I don't know if Euro 5 makes any difference when modding a bike. The regulations require that the ECU is locked against tampering (eg to modify the internal maps), but that applied to Euro 4 as well and eventually people found ways to break in. They are also finding ways into Euro 5 ECUs as well. Maybe it's harder? I don't know.

[General_Apathy]

Thanks for the reply 👍 I am pretty sure there are maps now for Euro 5 and I see RE still offer S&S kits for the E5 bikes so it must be possible you would think. I guess it depends how far you want to go with mods but mods always have a knock on effect with other areas of the bike whether it’s fuelling, air, exhaust or even brakes and suspension.

[mowerman2005]

I have tried 2 different after market exhaust cans on my euro5 GT650 and the open mouth for the air box, both mods resulted in engine management lights and poor running so I now use the factory exhaust and air intake/filter. That said plenty of people with euro5 have added after market cans and other mods with no problems! I did finally get the ECU changed under warranty last summer due to poor running issues and engine management faults, so maybe I should try again

[whippers]

Your last sentence seems to sum it up perfectly. There appear to be no downsides, at least when you leave the bike stock. In fact quite a few manufacturers seem to find an extra couple of horsepower when they go up to Euro 5, presumably due to small but continuous improvements in the state of the art.

I don't know if Euro 5 makes any difference when modding a bike. The regulations require that the ECU is locked against tampering (eg to modify the internal maps), but that applied to Euro 4 as well and eventually people found ways to break in. They are also finding ways into Euro 5 ECUs as well. Maybe it's harder? I don't know.

That’s not correct. Most bikes with a reasonable level of performance are significantly worse under Euro5. Go and look at the requirements to see how much of a change it is and 5+ is even worse.  Most manufacturers coped by building a bigger engine hence the MT09 Yamahas went up in capacity etc..

Specifically in the USA many modern bikes are significantly weaker than other markets due to CARB. For example the Honda Transalp 750 parallel twin will be 83 vs 90hp in world markets.  The Kawasaki ZX4RR is an extreme case where the 75hp in-line 4 screamer 400 only makes around 55hp in US spec.

The low stress Enfield is only a fraction of a hp weaker in EU5 vs 4 trim but will be a lot leaner at idle and part throttle. That explains the bunch of stalling at lights etc that many reported. In terms of mods there are more requirements mandated into the ECU to try and detect changes and throw warning lights etc..

[SteveThackery]

That’s not correct. Most bikes with a reasonable level of performance are significantly worse under Euro5. Go and look at the requirements to see how much of a change it is and 5+ is even worse.  Most manufacturers coped by building a bigger engine hence the MT09 Yamahas went up in capacity etc..

Specifically in the USA many modern bikes are significantly weaker than other markets due to CARB. For example the Honda Transalp 750 parallel twin will be 83 vs 90hp in world markets.  The Kawasaki ZX4RR is an extreme case where the 75hp in-line 4 screamer 400 only makes around 55hp in US spec.

The low stress Enfield is only a fraction of a hp weaker in EU5 vs 4 trim but will be a lot leaner at idle and part throttle. That explains the bunch of stalling at lights etc that many reported. In terms of mods there are more requirements mandated into the ECU to try and detect changes and throw warning lights etc..

You are right to call me out because I made an assertion without backing it up with hard data, something I criticise others for!

Having said that, I can't find a good source that compares E4 with E5 bikes, so I can't support your assertions either. Obviously we could each find specific examples to support our claims, but really we need a dataset with a number of bikes comparing their E4 and E5 characteristics.

I must admit that I know nothing about the US situation, so I should have made that clear.

One thing I do want to ask you about: why would an E5 bike be leaner at idle and part throttle? My understanding is that bikes normally run closed loop under those conditions, which means running at the stoichiometric ratio of 14.7:1. I don't think that could change between E4 and E5. Are you saying that E4 bikes don't run closed loop at idle and part throttle? When I did my degree we were taught that these are the very conditions that produce the most pollution, hence the need for closed loop.

[Quest]

You are right to call me out because I made an assertion without backing it up with hard data, something I criticise others for!

Having said that, I can't find a good source that compares E4 with E5 bikes, so I can't support your assertions either. Obviously we could each find specific examples to support our claims, but really we need a dataset with a number of bikes comparing their E4 and E5 characteristics.

I must admit that I know nothing about the US situation, so I should have made that clear.

One thing I do want to ask you about: why would an E5 bike be leaner at idle and part throttle? My understanding is that bikes normally run closed loop under those conditions, which means running at the stoichiometric ratio of 14.7:1. I don't think that could change between E4 and E5. Are you saying that E4 bikes don't run closed loop at idle and part throttle? When I did my degree we were taught that these are the very conditions that produce the most pollution, hence the need for closed loop.

It is my understanding that there is a loss of power with the E5 models. RE lists it as about a 2% loss. How accurate that is ... ?
A big change is that the EU has mandated a way for the onboard system can compare temperatures at two points to determine if the exhaust and / or AF ratio has been changed by modifications. It shows up as a check engine light AND on the dealer diagnostic tool.
The EU also established "significant" fines and penalties for any manufacturer who knowingly allows any work-arounds.

For what its worth, I have a EU4 bike and I bought a spare ECU for the shelf. I also learned that this ECU is used in a lot of 4 cylinder cars and the hotrod tuner crowd has tons of cracking programs to remap. I don't know anything about the EU5 CPU, but I would suspect the same environment of hackers exists.

[SteveThackery]

A big change is that the EU has mandated a way for the onboard system can compare temperatures at two points to determine if the exhaust and / or AF ratio has been changed by modifications. It shows up as a check engine light AND on the dealer diagnostic tool.
The EU also established "significant" fines and penalties for any manufacturer who knowingly allows any work-arounds.

Yes, the emissions are tightened up, and so are the anti-tamper features. From what I can tell, people still find ways of breaking in, but I don't know how widespread that is. I would imagine there's quite a lot of effort required to crack the protection on the E5 and E6 ECUs, so perhaps it's mostly done for enthusiasts vehicles?

To be honest, I think I would probably try to "roll my own" using a generic box such as the Microsquirt if I was in a bind. Trouble is, you really need a dynamometer to create a good quality map, so you need to hope that someone has already done it for your vehicle.

[whippers]

You are right to call me out because I made an assertion without backing it up with hard data, something I criticise others for!

Having said that, I can't find a good source that compares E4 with E5 bikes, so I can't support your assertions either. Obviously we could each find specific examples to support our claims, but really we need a dataset with a number of bikes comparing their E4 and E5 characteristics.

I must admit that I know nothing about the US situation, so I should have made that clear.

One thing I do want to ask you about: why would an E5 bike be leaner at idle and part throttle? My understanding is that bikes normally run closed loop under those conditions, which means running at the stoichiometric ratio of 14.7:1. I don't think that could change between E4 and E5. Are you saying that E4 bikes don't run closed loop at idle and part throttle? When I did my degree we were taught that these are the very conditions that produce the most pollution, hence the need for closed loop.

I am by no means an expert but my understanding (and there are plenty of sources you can find online to support this) is that other than for NOx leaner is how you reduce the other CO and hydrocarbon emissions. Obviously the balance is in what you can do with the catalyst, how quickly you can heat it up etc..

Nevertheless that means the ECU is programmed to run the bike leaner at idle and low load and this is what leads to the occasional issues seen with the EU5 bikes of just stalling at idle or very low throttle.

[andif62]

Due to some German motorbike websites there are 2 main differences in Euro 5 and Euro 4:
1. emissions are reduced by a third
2. a standardized OBD2 interface is mandatory, so you can check with every standard OBD reader

[JohnLA]

I have tried 2 different after market exhaust cans on my euro5 GT650 and the open mouth for the air box, both mods resulted in engine management lights and poor running so I now use the factory exhaust and air intake/filter. That said plenty of people with euro5 have added after market cans and other mods with no problems! I did finally get the ECU changed under warranty last summer due to poor running issues and engine management faults, so maybe I should try again

Hi. Hoping I don't have this issue. I just put Enfield Precision headers and silencers, from Hitchcocks, on my Euro 5 GT 650...curious if anybody besides you mowerman2005 have had this issue with a Euro 5 bike? I'm going to pick-up my bike today from my mechanic. I'll report back. Fingers-crossed.

[General_Apathy]

Hi. Hoping I don't have this issue. I just put Enfield Precision headers and silencers, from Hitchcocks, on my Euro 5 GT 650...curious if anybody besides you mowerman2005 have had this issue with a Euro 5 bike? I'm going to pick-up my bike today from my mechanic. I'll report back. Fingers-crossed.

There should be no issues at all with silencers and a performance filter on a euro 5 👍 This was my point - there was a big panic over Euro 5 and apart from the annoyance of the ‘man’ interfering in our passion there seems to be little or no impact.

[SteveThackery]

..... other than for NOx leaner is how you reduce the other CO and hydrocarbon emissions. Obviously the balance is in what you can do with the catalyst, how quickly you can heat it up etc..

Nevertheless that means the ECU is programmed to run the bike leaner at idle and low load and this is what leads to the occasional issues seen with the EU5 bikes of just stalling at idle or very low throttle.

The thing is, a three-way cat requires a stoichiometric fuel-air mix if it is to reduce all three of the major pollutants. Also, the narrow-band lambda sensors used on most bikes (I believe) only detect mixture changes around stoichiometric, so if you want to run closed-loop it has to be around 14.7:1 unless wide-band lambda sensors are used.

So my understanding is that the idle mixture won't be weaker than stoichiometric (14.7:1) for two reasons:

1/ A narrow-band lambda sensor only responds to mixtures very close to stoichiometric, so a closed-loop idle would need to be around stoichiometric.

2/ A cat cannot reduce NOx when there is free oxygen in the exhaust gas (ie when running weak).

That is my understanding. Having said that, I might well be wrong for a number of reasons. Perhaps the combustion at idle is so good that the NOx content is low enough not to need reducing further, so the engine can idle open loop, weaker than stoichiometric. Perhaps most or all bikes now use wide-band lambda sensors, so closed-loop operation can take place when weaker than stoichiometric.

I would love to update my knowledge in this area. If you come across an authoritative and trustworthy source I'd be delighted to hear about it. 

[El Saif]

I bought a Royal Enfield Continental GT650 in Rocker Red last week.

To achieve Euro 5 emissions compliance, Royal Enfield did not change the 650 twins engine capacity.

Royal Enfield engineers instead removed the secondary air injection (SAI) system and updated the On
Board Diagnostics (OBD). The camshaft design was changed, as was the catalytic convertor.

A high power ignition coil was added and a second MAP sensor was fitted to the right hand cylinder. This in turn required changes to that cylinders throttle body and a redesign of the wiring harness to suit.

There were also changes to the ECU (now a Continental type, instead of Bosch), O2 sensor, purge valve, magneto rotor design and left hand crank mounting boss.

As a result of the above changes the engine produces 34.9 kW at 7,150 RPM compared to 35 kW at 7,100 RPM from the Euro 4 engine. Maximum torque of 52.3 Nm is produced at 5,150 RPM compared to 52 Nm at 4,000 RPM from the Euro 4 engine.

[JohnLA]

There should be no issues at all with silencers and a performance filter on a euro 5 👍 This was my point - there was a big panic over Euro 5 and apart from the annoyance of the ‘man’ interfering in our passion there seems to be little or no impact.

Thanks General Apathy. Just back from getting my bike with the new exhaust, and no issues...told my mechanic, and he told me he took it for two long rides the last few days, after putting the new exhaust on, and also had no issues.

Maybe mowerman has something else going on.

Cheers!

[SteveThackery]

As a result of the above changes the engine produces 34.9 kW at 7,150 RPM compared to 35 kW at 7,100 RPM from the Euro 4 engine. Maximum torque of 52.3 Nm is produced at 5,150 RPM compared to 52 Nm at 4,000 RPM from the Euro 4 engine.

That's very interesting. The differences are so small we would be justified in saying they are insignificant. Perhaps it's because the engine is in a relatively low state of tune? Perhaps it's much harder to maintain the power output with an engine that is already highly tuned?

Mr El Said: I was impressed by your detailed list of changes. Could you say how you found out all that?

[General_Apathy]

I bought a Royal Enfield Continental GT650 in Rocker Red last week.

To achieve Euro 5 emissions compliance, Royal Enfield did not change the 650 twins engine capacity.

Royal Enfield engineers instead removed the secondary air injection (SAI) system and updated the On
Board Diagnostics (OBD). The camshaft design was changed, as was the catalytic convertor.

A high power ignition coil was added and a second MAP sensor was fitted to the right hand cylinder. This in turn required changes to that cylinders throttle body and a redesign of the wiring harness to suit.

There were also changes to the ECU (now a Continental type, instead of Bosch), O2 sensor, purge valve, magneto rotor design and left hand crank mounting boss.

As a result of the above changes the engine produces 34.9 kW at 7,150 RPM compared to 35 kW at 7,100 RPM from the Euro 4 engine. Maximum torque of 52.3 Nm is produced at 5,150 RPM compared to 52 Nm at 4,000 RPM from the Euro 4 engine.

That’s some proper data there 👍 Thank you for sharing. So power down ever so slightly and torque increased by a bit but higher up the rev range. I wonder if that’s enough to be felt at a ‘seat of the pants level? Probably not.

[whippers]

That's very interesting. The differences are so small we would be justified in saying they are insignificant. Perhaps it's because the engine is in a relatively low state of tune? Perhaps it's much harder to maintain the power output with an engine that is already highly tuned?

Mr El Said: I was impressed by your detailed list of changes. Could you say how you found out all that?

Here are the 4 to 5 changes

Royal Enfield 650 Twin changes from Euro4 to Euro5

Camshaft changes
Catalytic convertor changes
Higher powered ignition coil
Introduction of second MAP sensor for RH cylinder and throttle body modified to accommodate
ECU change from Bosch to Continental
New purge valve and O2 sensor
Magneto rotor changes
Change in the crankcase LH mounting boss
OBD-2 and wiring harness changes
Elimination of the secondary air injection system

The claim about peak torque going up a 1,000rpm is not correct.  This does appear on a few websites but peak torque was alway ~5,200rpm.

I’m sure that it’s much easier to make a lower tuned engine like the Enfield twin comply as one of the things the designers do is to reduce valve overlap.  That is going to make a much bigger difference to a high power rev box than the Enfield.

https://www.mcnews.com.au/2022-royal-enfield-650-twins/

This is a good article about the challenges in general of meeting euro5 featuring commentary from a Riccardo engineer.

https://www.bennetts.co.uk/bikesocial/news-and-views/features/bikes/euro-5-emissions-what-they-mean-to-motorcycles

[SteveThackery]

Excellent - thanks, @whippers.

[whippers]

Excellent - thanks, @whippers.

By the way it has bothered me for ages that I didn't know who your avatar was so I just reverse image searched it.

[El Saif]

SteveThackery,

My source for the differences between Euro 4 and Euro 5 models is a hard copy magazine from Australia - Just Bikes 4 November 2021. The article was written using a Royal Enfield Press Release Kit. The same kit was used for the article in the online MCNews.

My sources for the differences between Euro 4 and Euro 5 power and torque outputs are the Royal Enfield cardboard brochures. The Euro 4 brochure uses a figure of peak power of 47 bhp which I converted to kW for the sake of comparison.

The Euro 4 brochure lists peak torque as "52 Nm @ 4000 rpm". This figure has been widely quoted as it comes from Royal Enfield itself.

[SteveThackery]

SteveThackery,

My source for the differences between Euro 4 and Euro 5 models is a hard copy magazine from Australia - Just Bikes 4 November 2021. The article was written using a Royal Enfield Press Release Kit. The same kit was used for the article in the online MCNews.

My sources for the differences between Euro 4 and Euro 5 power and torque outputs are the Royal Enfield cardboard brochures. The Euro 4 brochure uses a figure of peak power of 47 bhp which I converted to kW for the sake of comparison.

The Euro 4 brochure lists peak torque as "52 Nm @ 4000 rpm". This figure has been widely quoted as it comes from Royal Enfield itself.

Thank you, El Saif. One of the things we struggle with in this forum (and every other like it) is people making unsubstantiated claims, presenting opinions as facts, presenting subjective data as factual, and generally misrepresenting the truth. So it's wonderful to be given data with actual sources so we can investigate further, either to substantiate (hopefully) or debunk. That's why dyno charts are so much more valuable than "much faster" claims.

[General_Apathy]

Thank you, El Saif. One of the things we struggle with in this forum (and every other like it) is people making unsubstantiated claims, presenting opinions as facts, presenting subjective data as factual, and generally misrepresenting the truth. So it's wonderful to be given data with actual sources so we can investigate further, either to substantiate (hopefully) or debunk. That's why dyno charts are so much more valuable than "much faster" claims.

What he said 👆

I love it when forums actually bring reasonable discourse.

[whippers]

For the record see the link of an early 2018 review when only euro4 (BS6) bikes were in existence with the correct max torque figure of 52Nm at 5,250rpm.

You can find a few websites who erroneously report 4,000.  Not sure where that first came from. One ride of the bike will show it isn’t correct.

https://bikeindia.in/royal-enfield-interceptor-650-and-continental-gt-650-first-ride-review-re-defined/#more-32959

[General_Apathy]

I have found another small difference on later euro 5 models related to the crankcase breather. It is now cast into the cover and therefore can’t be removed as it could on earlier models. Not a huge problem if a bit untidy. Another step towards anti-tampering I would assume.

[DreadPirateRoberts]

That’s not correct. Most bikes with a reasonable level of performance are significantly worse under Euro5. Go and look at the requirements to see how much of a change it is and 5+ is even worse.  Most manufacturers coped by building a bigger engine hence the MT09 Yamahas went up in capacity etc..

Specifically in the USA many modern bikes are significantly weaker than other markets due to CARB. For example the Honda Transalp 750 parallel twin will be 83 vs 90hp in world markets.  The Kawasaki ZX4RR is an extreme case where the 75hp in-line 4 screamer 400 only makes around 55hp in US spec.

The low stress Enfield is only a fraction of a hp weaker in EU5 vs 4 trim but will be a lot leaner at idle and part throttle. That explains the bunch of stalling at lights etc that many reported. In terms of mods there are more requirements mandated into the ECU to try and detect changes and throw warning lights etc..

That's interesting about the ZX4RR, so I lookup up a tuner on Youtube. Reflashing and exhaust got it up to 71 hp at the rear wheel. The ECU was restricting throttle to something like 50-60% throttle up at 13K.

[Deathwish]

That's interesting about the ZX4RR, so I lookup up a tuner on Youtube. Reflashing and exhaust got it up to 71 hp at the rear wheel. The ECU was restricting throttle to something like 50-60% throttle up at 13K.

My 2024 Ninja 1000SX had those restrictions in the lower gears. Once you got up close to 9.5k, the throttle was cut back to 50% or less, depending on the gear. Once I put a full exhaust on the bike, I had the ECU flashed and all restrictions removed, as well as the quick-shifter tweaked. It's a different bike now.

[El Saif]

Other than changes to satisfy Euro 5 emission standards, there are other differences between the early RE 650 twins and the later bikes.

The early bikes had simple wire knee protectors, that could be easily pulled out of the cooling fins. The later bikes used rubber pads between the fins to secure the wire knee protectors.

The early bikes had combined km/h and mph speedos for all markets. The later bikes had km/h only speedos for the Australian market and possibly other markets.

[whippers]

Other than changes to satisfy Euro 5 emission standards, there are other differences between the early RE 650 twins and the later bikes.

The early bikes had simple wire knee protectors, that could be easily pulled out of the cooling fins. The later bikes used rubber pads between the fins to secure the wire knee protectors.

The early bikes had combined km/h and mph speedos for all markets. The later bikes had km/h only speedos for the Australian market and possibly other markets.

Not sure about the Speedo thing.  Here in NZ I’ve seen early bikes with a km/h Speedo.

[John Flatt]

Now that the euro 5 bikes have been around for a few years what are the real world downsides to having a euro 5 instead of a 4?
Initially there was panic over the restrictions but I still see mods on euro 5 bikes with no consequence.
Was it not as bad as everyone thought it was going to be?

I have a GT E5 and have fitted aftermarket exhausts, headers and cans (VEREX Tasmania Aust). A straight swap out, no problems at all runs sweet, actually an improvement.

[Kranis]

Royal Enfield engineers instead removed the secondary air injection (SAI)

SAI systems are usually only working up to about 90 sec after cold cranking so the benefits may not have been that significant even with the Euro 4. But I am not privy to any information on the specifics. If your exhaust contains excess hydrocarbons, SAI will reduce emissions but also heat up your catalytic converter since the heat is a direct consequence of how much it can oxidise. Engines with bad plugs get hot cats too. While it may be correct that removing SAI lowers cat temperature, it is only because you prevent it from working efficiently, thereby increasing emissions. If the cat gets unusually hot, it is because it has an unusually amount of work to do.

There were also changes to the ECU (now a Continental type, instead of Bosch)

In Euroland, my 2022 Euro 5 has a Bosch unit so I think this may be more due to different markets.

Contrary to many contributors here, I genuinely sympathise with stricter emission standards as a general direction. However, since motorcycles are usually not object to emission tests during inspection, you can do whatever you want to your engine after you bring it out of the dealer's, as long as it does not produce excess power. And even then, that is mostly a problem you will have with your insurance company. But should you, God forbid, use a non-ECE tail light, you may fail inspection. So, even with my, well, loathsome metrosexual environmentalism, I am still miffed: either authorities should apply the emission rules as if they mean it and include them in inspections or else they should leave bikers TF alone. Current situation is just BS and a waste of noble metals.

/Kranis

[whippers]

Pretty sure the switch from Bosch ECU to Continental for Euro5 was universal. What makes you think yours is Bosch?