[canyondancer]

I'm still waiting for one single bit of information that specifically pertains to TRIUMPH Daytona 675 motorcycle engines, and NOT Yamaha designed engines.

Any time you're ready mate.

The rest of us are talking about Daytona 675's, y'know, this being a Daytona 675 forum and all, and you're here telling us all that we've got it all wrong despite entertaining your insistance that an outdated device on a completely different motorcycle engine has actual relevance to why Triumph chose to build a device that bears an implementational resemblance, but has been proven numerous times to have absolutely no functional resemblance to why Yamaha chose to implement it on some motor they built donkey's ages ago.

Triumph don't call it an EXUP valve either, so I don't know why you insist on calling it that. Triumph call it an EXBV, (EXhaust Butterfly Valve), so why do YOU insist on calling it an EXUP valve, and mistakenly ascribe the reasoning for Triumph's use of it as being the same as Yamaha's? To retain your argument perhaps?

Whenever you're ready to stop clutching at those straws and join the rest of us on the same page you're most welcome to do so. Hey, I've been wrong in the past too, hate admitting it, but I reckon I look less like a tool if I just come clean and say that what I once believed to be true across the board is now no longer relevant in a new and different modern application, rather than stubbornly hold onto outdated beliefs.

People used to believe the world was flat at one point too. No offence mate, but right now you're starting to act and behave with much the same fervour as the original round world denialists. I, for one, won't think less of you for discarding outdated beliefs.

Oh my. Seriously....you're looking rather pathetic now FLUX. No matter what you call it..and EXUP valve or an EXBV...it's exactly the same thing on any brand of motorcycle with a collector. All it is is a butterfly vlave located in the header actuated by an electric motor. It looks the same....and works the same on a all bikes that have one. How can you possibly believe that on a Yamaha it works different than on a Triumph?
The problem here is that you don't understand exhaust design and wave resonance. Long header length creates torque. Short header length creates high rpm hp. Exhaust waves reverse within the header and that affects how well the cylinder fills with a/f ratio.
The EXUP or EXVP fools the engine into thinking that the header length is longer by reversing the exhaust waves and thus filling the cylinder with a richer mixture that creates more torque. A fuel map can't do the same thing because a map can't measure back pressure or wave resonance within the exhaust system.
EXUP or EXVP or whatever you want to call it are used on three into ones and four into one headers because these header/collectors only work right at high RPM. At low rpms they are not efficiant.....so the manufacturers install a power valve into the header to fool the engine and make it efficiant at low rpms too. That's what's it for. They all work the same.
For a racer or a guy that wants the most HP....an EXUP is useless. Racers don't ride under 7k rpm so it wouldn't do them a bit of good. However on a street bike where you want low end torque...then an EXUP is usefull.

No matter what...you were wrong. An EXUP valve is not for noise control. It does quiet the bike...but that is NOT what it is for. Any bike maker can control noise with muffler design that is free flowing enough to reach hp requirements. The only way to control back pressure and make exhaust waves do what you want is with an EXUP valve.

 

[[FLUX]]

Whatever CD. People here have supplied evidence, spent their time, provided actual dyno runs, provided hard facts, and proved their point.

You've done nothing but wail and moan, and no matter how much people prove to you above and beyond all reasonable doubt, you then start insulting people and calling people liars simply because their facts don't fit your now proven-to-be-false beliefs.

You're acting like a little brat who sticks his fingers in his ears and says "I'm not listening, I'm not listening, You're all liars and you're all pathetic".

This now well beyond a joke and I think the only reason why anyone ever bothered entertaining your insanity up to this point was because they had some grudging respect for you, which has now evaporated.

I'm out.

 

[carpel21]

Why is the EXUP on the daytona then if the same torque figures can be achieved with optimised mapping? Please just answer this question specifically without quoting Yamaha's design brief.

 

[pointagrouse]

So, in fear of getting caught up in this battle, I'd like some advice. I've been having some issues with the exup valve, and want to either remove or disable it. I don't feel like spending the money on a fabricator to remove it for me (if I did, approximately what would it cost?) so I'm leaning toward leaving it open. If I disconnect the wire, how would I go about leaving the valve open 100% of the time?

Thanks,

Oh, and if I don't get a custom dyno tune done, would the dealer supplied Arrow tune do for the bike without the exup?

 

[Neo187h]

No matter what...you were wrong. An EXUP valve is not for noise control. It does quiet the bike...but that is NOT what it is for. Any bike maker can control noise with muffler design that is free flowing enough to reach hp requirements. The only way to control back pressure and make exhaust waves do what you want is with an EXUP valve.

So if the only thing the EXUP valve is for is power gains on Yamaha engines and is NEVER used to noise control than why on Euro spec Yamaha 636s does the bike make an extra 5-10HP in the upper RPM ranges? And why does the US spec bike gain an extra 5-10HP in the upper RPM ranges once the exhaust valve is opened by jumpering the connector?

...Not that it has anything to do with Triumph bikes but if your going to use Yamaha as an example here why not prove you wrong using your own examples.

 

[carpel21]

If you have a Tuneboy you can just turn it off. If not you can just cut the wires and the spring will hold it open. Either way the fueling will be a little off below about 6k. A fabricator can cut it out and replace with a bit of straight through for about £30-£60 UK but make sure they use stainless steel (sometimes called dairy tubing) and TIG weld it not MIG. Which ever way you go the torque loss isn't drastic and from 4k you would need a dyno to tell. Read through this entire thread for an informed desicion and you will see that with correct mapping nothing is lost (thanks Hordboy for putting in the work to prove this).

 

[carpel21]

So if the only thing the EXUP valve is for is power gains on Yamaha engines and is NEVER used to noise control than why on Euro spec Yamaha 636s does the bike make an extra 5-10HP in the upper RPM ranges? And why does the US spec bike gain an extra 5-10HP in the upper RPM ranges once the exhaust valve is opened by jumpering the connector?

...Not that it has anything to do with Triumph bikes but if your going to use Yamaha as an example here why not prove you wrong using your own examples.

It's the lower rpm that's affected on the Daytona. I'll stick my neck out here (for you to chop at CD) and sum it up.

• If you remove/switch off the EXBV on your Daytona without changing your mapping to suit, you will lose some torque below 6k.

• If you remove/switch off your EXBV and get your Daytona suitably remapped, your torque curve will be near identical to before and you will no longer run the risk of a CEL from the valve siezing or the cables going out of adjustment.

 

[[FLUX]]

Okay, wanted to address this one point.

The EXUP or EXVP fools the engine into thinking that the header length is longer by reversing the exhaust waves and thus filling the cylinder with a richer mixture that creates more torque. A fuel map can't do the same thing because a map can't measure back pressure or wave resonance within the exhaust system.

Who's fooling who here? You're trying to tell us that the fuel map can't be modified to provide a richer mixture at a particular RPM point as suits what the exhaust system is doing? Come again?

Yamaha developed EXUP valves in a time when engines were carbueretted and largely non-adjustable. At that point in engine development history Yamaha's EXUP valve was put there to compensate for the lack of rpm-specific adjustibility, and it did its job.

Moving forwards to the 21st century with detailed fuelling maps that can be adjusted with specific fuellings as per the dictates of what the exhaust system design/layout requires, and the original reason for an EXUP valve is no longer valid. With a fuelling map change, it makes no difference whether it's there or not.

THERE ARE HARD PROVEN FACTS PRESENTED WITHIN THIS THREAD TO BACK THAT STATEMENT UP.

What have you provided here, other than endlessly spouting outdated and proven-to-be-wrong reasons for Triumph's inclusion of an exhaust butterfly valve that are no longer applicable to modern engine design? Any time someone points out the facts with evidence, you call them a liar, and proceed to spout the same old outdated garbage as if it were fact, but you yourself provide absolutely zero evidence as performed on a modern Daytona 675 to actually back up your statement, which others have done.

 

[badmonkey]

Oh my. Seriously....you're looking rather pathetic now FLUX. No matter what you call it..and EXUP valve or an EXBV...it's exactly the same thing on any brand of motorcycle with a collector. All it is is a butterfly vlave located in the header actuated by an electric motor. It looks the same....and works the same on a all bikes that have one. How can you possibly believe that on a Yamaha it works different than on a Triumph?
The problem here is that you don't understand exhaust design and wave resonance. Long header length creates torque. Short header length creates high rpm hp. Exhaust waves reverse within the header and that affects how well the cylinder fills with a/f ratio.
The EXUP or EXVP fools the engine into thinking that the header length is longer by reversing the exhaust waves and thus filling the cylinder with a richer mixture that creates more torque. A fuel map can't do the same thing because a map can't measure back pressure or wave resonance within the exhaust system.
EXUP or EXVP or whatever you want to call it are used on three into ones and four into one headers because these header/collectors only work right at high RPM. At low rpms they are not efficiant.....so the manufacturers install a power valve into the header to fool the engine and make it efficiant at low rpms too. That's what's it for. They all work the same.
For a racer or a guy that wants the most HP....an EXUP is useless. Racers don't ride under 7k rpm so it wouldn't do them a bit of good. However on a street bike where you want low end torque...then an EXUP is usefull.

No matter what...you were wrong. An EXUP valve is not for noise control. It does quiet the bike...but that is NOT what it is for. Any bike maker can control noise with muffler design that is free flowing enough to reach hp requirements. The only way to control back pressure and make exhaust waves do what you want is with an EXUP valve.

I can't believe you're still holding on to this ridiculous idea. You're also wrong about "Richer Fuel mixture" or "fooling the engine"--exhaust scavenging occurs when the negative pressure from exhaust pulses sucks out any remaining exhaust gas from the combustion chamber when the piston is TDC, thereby increasing the efficiency or the effective displacement of the engine.

YES, scavenging occurs at various point in the rev range depending on the exhaust pulses and the header design and all that--and yes, restricting flow at low rpms could help EG scavenging and improving power in that rev-range--however, without modeling the flow and testing prototypes you cannot say that this 100% absolutely happening with the 675 and its EXBV.
ESPECIALLY when third party empirical data and testing prove otherwise.

 

[Neo187h]

It's the lower rpm that's affected on the Daytona. I'll stick my neck out here (for you to chop at CD) and sum it up.

• If you remove/switch off the EXBV on your Daytona without changing your mapping to suit, you will lose some torque below 6k.

• If you remove/switch off your EXBV and get your Daytona suitably remapped, your torque curve will be near identical to before and you will no longer run the risk of a CEL from the valve siezing or the cables going out of adjustment.

Didn't mean to disagree on those points at all, just saying the valve is also obviously used for noise even on the Yamahas so why is it so hard to grasp that just maybe the Daytona uses it for noise suppression rather than power gains.

 

[canyondancer]

Okay, wanted to address this one point.

Who's fooling who here? You're trying to tell us that the fuel map can't be modified to provide a richer mixture at a particular RPM point as suits what the exhaust system is doing? Come again?

Yes the fuel map could be modified to adjust for a richer mixture. But if Triumph did that....they couldn't use the catylitic converter. A richer than normal mixture produces unburned gas and that destroys the cat convertor in shot time. A richer mixture than normal to compensate for loss of torque also fouls spark plugs....and the a/f ratio wouldn't pass emissions tests.

Nice try at changing the subject though. You said the EXVP valve is only there for noise and nothing else. You can apologize any time you're ready too.

 

[carpel21]

You sound as if you are clinging to any possibilities now CD. The adjsutment to the fuel map is not enough to foul the plugs (i have a 2t that runs much richer and still doesn't foul plugs). As for the cat, how much unburnt fuel is bunged down the exhaust at higher rpm (A lot more)? That is partly the job of the SAI to protect the cat i guess? If you remember, turning the valve of is a test for me before having the whole lot cut out anyway.

 

[[FLUX]]

You sound as if you are clinging to any possibilities now CD.

He's certainly starting to sound desperate now. Following the usual pattern of concocting up whatever story, without actual emperical evidence, to justify his position. If I have anything to apologise for, it's for being so stupid as to waste my time even entertaining this madness.

 

[carpel21]

I asked a wrench at work (C of G so knows his stuff), and he said it would take neat fuel on a hot cat to really damage it. Also, perhaps if I had opened the EXBV from day 1 I would not have suffered the progressive power loss, likely due to the EXBV's proximity to the cat, focusing a hot spot on the lower part. I commuted a lot last year so was in that rpm range most of the time.

 

[hordboy]

I'm not holding my breath, but I'm still kinda waiting on an explanation on why it is he seems to be able to interpret the data I presented, while at the same time he can't interpret his own. Oh wait, I just answered the question... he's misinterpreted both! :duh: Nevermind.

 

[pointagrouse]

So, in order to get the fuel mapping correct without the valve, I would need to buy a tune boy? Is there a less expensive way to remap it? A mapping from the dealer perhaps?

 

[carpel21]

The dealer can only flash a map that has already been designed, such as the arrow or TOR. While the arrow has been designed without the EXBV, it was designed for the arrow full system so wont run right for anything else. You could get a Powercommander and a remap at any dynotuner but this obviously means buying the PC3 and getting it set up ($$$) and you will have a CEL which I think a dealer could get rid of for you. If you can find a dynotuner near you that has the Tuneboy software, then you only need to purchase the ECU unlock code for your bike to get it remapped but tuners using the TB software are still rare unfortunately. This would be the cheapest way I think if your lucky enough to find one though. Last option is buying the complete Tuneboy, (software, connection cable & unlock code) and trying to remap it yourself with the butt dyno (not easy as I'm finding out) and is a bit pricey, but you also have all of the fault diagnostics like the dealer tool, and can balance the throttle bodies etc.

If all you want is to get the bike remapped for the missing valve, then look for a tuner using TB. That's the cheapest option.
If you can't find a TB tuner then the PC tuner is the next cheapest.
If you do all your own maintenance then buying the TB might be appealing as you can save money not paying for services but then you must attempt to map the bike yourself, or take it to a dynotuner and convince them to map it with your TB which many won't want to do as it requires learning some new software, and they don't get to sell you a PC.

Hope this helps, and hope I got it all correct. Someone will surely correct me if I'm wrong about something! (and I will graciously conceed)

 

[canyondancer]

You sound as if you are clinging to any possibilities now CD. The adjsutment to the fuel map is not enough to foul the plugs (i have a 2t that runs much richer and still doesn't foul plugs). As for the cat, how much unburnt fuel is bunged down the exhaust at higher rpm (A lot more)? That is partly the job of the SAI to protect the cat i guess? If you remember, turning the valve of is a test for me before having the whole lot cut out anyway.

Does your two stroke have a catalytic converter? NO. Do you remember the thread about the guy who had the 675 only run on two cylinders? Well the unburned gas from the dead cylinder made the cat glow bright orange and ruined it. We all know the cats on our 675 clog up even if the bike is running properly.
I'm not "clinging". I said from the beginning that the EXVP valve is for improving low end torque at lower RPMS. If folks like Hordboy and FLUX want to believe that the EXVP is for noise control only.....they need to back that up with something besides theory.
If Hordboy and FLUX were right....then there is no reason to put an EXVP or Exup valve on any motorcycle.
If you could make up the loss of torque with a fuel map...the manufacturers would have done that long ago. If noise is the main concern....mufflers can handle that.

If you remove the EXVP from your Triumph....you will lose low end torque at low RPMS. That's all i'm saying...and all i've been saying from the beginning. Anybody that says different doesn't know how an EXUP valve works...or why....and doesn't understand how exhaust waves work. It's a lot cheaper for Triumph to build a muffler than it is to build a EXVP valve....cables to operate the valve...and actuator motor....electrical connections...and the software to make it operate. If noise was the only concern ....all manufactureres would do this.

Let me say this too. Hordboy is a lot more qualified than i am...but i believe he has the same agenda as FLUX does. He's out to prove the EXVP is for nothing but noise control. Yamaha invented the power valve. If they invented it for noise control....they would say so. It's not on there for noise. It's on there for low end torque.

 

[Tripped1]

He's out to prove the EXVP is for nothing but noise control. Yamaha invented the power valve. If they invented it for noise control....they would say so. It's not on there for noise. It's on there for low end torque.

Yeah because Yamaha super sports are KNOWN for low end punch right? right?

....anyway

The stupid exhaust valve is there mainly for emissions.

Since these motors are designed to operate at higher RPM so the engines are going to throw a lot of emissions below the power band. The valves allow you to run a leaner mixture through the low RPM sections and pass emissions standards (and Euro III is more strict then ours).

Come on? Noise? When the valve is closed you aren't making a racket yet anyway, you are still at low RPM, by the time noise come into play the valve is open any damned way.

 

[whiskey]

If folks like Hordboy and FLUX want to believe that the EXVP is for noise control only.....they need to back that up with something besides theory.

uhh, what do you think the dyno charts were for? maybe you should be posting up something besides theory