BMW R1200RT/R1250RT Forum

David. wrote: The exhaust flap is purely mechanical and has no impact on the products of combustion (emissions) formed by burning fuel in an internal combustion engine, end of story.

Agree looking at the video I posted of how it works then I think its down to noise not emissions. Removing the CAT that could be the real issue.

David. wrote: The exhaust flap is purely mechanical and has no impact on the products of combustion (emissions) formed by burning fuel in an internal combustion engine, end of story.

Exactly, that's the job of the cat which is further down the line.

Currently, within the UK, motorcycles used in ULEZ's need to comply with Euro 3, otherwise they will be charged to enter.

In London, there is only one government approved emissions test centre for TfL.

David. wrote: The exhaust flap is purely mechanical and has no impact on the products of combustion (emissions) formed by burning fuel in an internal combustion engine, end of story.

There have been extensive discussions and tests on what the flap does (do a search on UKGSER, there was a very long post on there and a few very knowledgable posters did some tests), yes it seems it is for noise, but amazingly Noise is also part of emissions as per the vehicle emissions guidelines. But through the iterations of the flap over the years, on EU 4 and 5 it seems it is now linked into the ECU in that it is providing some back pressure and feeding back on startup, which will also impact emissions. Now I have been an advocate of it is noise only (Noise emission) but after reading various articles, I am now moving to believe it does also have an impact on other aspects of the engine and back pressure. But do your own research, but it is still illegal to tamper with any part of the system that is different from the original implementation, which if the MOT starts to measure this on motorcycles, will mean you will have to turn up at an MOT with all the original exhaust in place and functioning as intended. 

David. wrote: https://www.sciencedirect.com/science/article/pii/S2590123019300805

Interesting, but not sure how EU3 from 2000 has any relevance on EU5, think things have moved on and noise is part of the equation now. Some forces are now also doing road side noise tests, so again this very shortly will be part of all MOTs. Emissions, including Noise Emissions are going to be front and centre very shortly.

Casbar is correct,  noise abatement has been introduced more and more over the years. Smart motorways will reduce speeds at times of the day and night just to reduce noise and emissions.


The M1 has had me twice in the early hours going through the average camera's to quick. The course instead of points was quick interesting......


[size=2px]CANS for example is the [/size]latest[size=2px] thing councils and police are acting on. [/size]

Maybe I’m just lucky, but after five years and 25,000 miles I’ve had no problems with the exhaust valve on my 2016RT. I put this down to only ever using Shell V Power fuel which has additives and detergent in it which I believe keeps the valve shaft bearing from seizing. My local BMW independent mechanic agrees with me. I also don’t ride it in the winter and it’s kept clean and in a dry garage.
Obviously, for the valve to show a fault after 1000 miles sounds more like a manufacturing fault from new.
If however my bike’s valve does become faulty I’ll remove the valve and fit a Healtech servo eliminator.


Sent from my iPad using Tapatalk

Cambridgeshire Police has noise testing equipment but are not targeting motorcycles,
https://www.bennetts.co.uk/bikesocial/n ... -equipment

David. wrote: Cambridgeshire Police has noise testing equipment but are not targeting motorcycles,
https://www.bennetts.co.uk/bikesocial/news-and-views/news/2020/august/cambs-police-noise-testing-equipment

Yet... Its only a matter of time.

They need to make their money now before we all go electric. Then it will small number plates only. Speeding will be out of the question because we will all suffer from range anxiety or be stuck on the side of the road with no power. Looking forward to candles as the lights go out. The future looks dull but silent. 

B787MECH wrote: Maybe I’m just lucky, but after five years and 25,000 miles I’ve had no problems with the exhaust valve on my 2016RT. I put this down to only ever using Shell V Power fuel which has additives and detergent in it which I believe keeps the valve shaft bearing from seizing. My local BMW independent mechanic agrees with me. I also don’t ride it in the winter and it’s kept clean and in a dry garage.
Obviously, for the valve to show a fault after 1000 miles sounds more like a manufacturing fault from new.
If however my bike’s valve does become faulty I’ll remove the valve and fit a Healtech servo eliminator.


Sent from my iPad using Tapatalk

Yes you have been lucky, nothing to do with fuel. My first 2014 RT, I used 98 or plus fuel, but still had two failures, and two new headers. So nice theory but rubbish. Sorry

Casbar wrote:
Yes you have been lucky, nothing to do with fuel. My first 2014 RT, I used 98 or plus fuel, but still had two failures, and two new headers. So nice theory but rubbish. Sorry

Well, like I say, my independent BMW mechanic agrees with me so I’d rather believe him,sorry!
Has a lot of sense to it, too many people use rubbish supermarket fuel. German petrol is made to a higher standard so it would be interesting to find out if German bikes are effected to to same extent.


Sent from my iPhone using Tapatalk

B787MECH wrote: Well, like I say, my independent BMW mechanic agrees with me so I’d rather believe him,sorry!
Has a lot of sense to it, too many people use rubbish supermarket fuel. German petrol is made to a higher standard so it would be interesting to find out if German bikes are effected to to same extent.


Sent from my iPhone using Tapatalk

What your mechanic believes using super 98 stops the flap seizing, hmmm. Like I said, I always use 98 or higher and never use supermarket fuel, normal try BP or Shell. Had two failures and two new sets of headers on my 2014. My mate has just had a failure on his 1250, he only uses high octane fuel and only from non supermarket garages. We are having a flap replaced on one of our 1250 blood bikes after 3k miles again we have a BP fuel card, so non supermarket fuel. But maybe you are onto something My 1250 flap on my own bike hasn't seized yet aft 6k, so it will be a good thing for me to look out for, although I do grease mine occasionally.

Sorry guys cannot see how a premium fuel is going to lube something on the other side of the CAT. I use the cheapest fuel going and have just had my first seize after 46k miles on a 2014 bike. Now what's interesting is I moved house last December and with that and lockdowns the bike has not been used much. So for the first 5+ years it gets regular use, kept clean including the external components of the valve and no issues. Due to move and lockdown in the past year I have done only 1500 miles and get my first seize. Makes me think that lack of use and possible sitting in a cold garage has caused the problem. Well I'm now in a position to ride more this summer so we will see what happens.


Casbar have ordered a small tube of the grease you recommended so when it arrives will see if I can get some into the spindle bearings.