Removal of exhaust valve....

[954spider]

I know I will probable get a bunch of nasty responses back from this but I'm going to ask the question anyway. I have the Devil 1/2 system that I would like to keep and was wondering have anyone ever just removed the exhaust valve from the exhaust valve body to get a constant free flowing exhaust similar to a full exhaust system but with a bolt or slip on can?

Or

Do anyone make a section of exhaust pipe that will just eliminate the exhaust valve body all together?

[rockets25]

I pulled out the valve in the exhaust assembly and fabricated a plate to cover the hole. I've been running my bike like this for several thousand miles and had the custom map done to match it. Everthing works fine, and it gets rid of that nasty exhaust rattle. Can't say it gave me much more power if any because I never had it dyno'd with the valve installed.

[Chain]

There's a great tech article in the last pages of this month's print copy issue of Motorcyclist on this very subject - if you're like me and concede that they know more than you about they way these bikes are engineered, you'll probably come away with the feeling that leaving the HTEV in working order is best UNLESS you opt for a full replacement exhaust system, PC and custom mapping. My .02 worth only, YMMV.

[Oz]

I concede that the Honda engineers know more than I do about the way these bikes are engineered.

I also concede that in order to be sold and registered, bikes must meet certain standards (EPA regulations, for example), which requires engineering that is quite often not in line with maximum performance.

[954spider]

These are the type of answers I notice that guys would get when someone don't no the answer to a question.

So just say it... I don't know!!

[Chain]

Oz : I concede that the Honda engineers know more than I do about the way these bikes are engineered. I also concede that in order to be sold and registered, bikes must meet certain standards (EPA regulations, for example), which requires engineering that is quite often not in line with maximum performance.

After reading the article in question from Motorcyclist, I conclude the HTEV has as much to do with performance as it does emissions or the EPA.

[smilertiv]

The Akrapovic Slip on evolution can comes with a titanium link pipe that eliminates the exhaust valve. If the valve is about performance how come the racers always junk it in favour of a full straight through system with corresponding power commander ecu map??? The valve has more to do with noise regs than performance. Fact!! Visit www. hardracing .com and check out myths versus facts.

[CBRBob]

Ahh a place that sells pipes telling you that the stock pipe is no good. Yep, must take as gospel!

As far as gutting the valve body, ???????? Never even considered it!!!!!

[CBR929RE]

Originally Posted by smilertiv The Akrapovic Slip on evolution can comes with a titanium link pipe that eliminates the exhaust valve. If the valve is about performance how come the racers always junk it in favour of a full straight through system with corresponding power commander ecu map??? The valve has more to do with noise regs than performance. Fact!! Visit www. hardracing .com and check out myths versus facts.

forget what they say and think about it yourself. Some people say anything to try to seel a product. The manufacturers say the exahust valves are meant to stimulate low end power. Do racers use the low end? no. so the exhaust valve is meant for low end performance and full race exhaust systems are used for high end.

I didn't even bother to go to that site because I figured they thought too hard about it.

[DavidW]

Wow. Impressive resurrection of an 18mth old thread, lol!

Exhaust valve works well with all the other emissions limited stuff (airbox flapper, PAIR valve and stock fuel maps). All these components work pretty well together, but you have to remember they are a compromise. Honda designed a powerful, high performance engine but then have to strangle it to keep the emissions people happy.

If exhaust valves do such a great job of boosting low and midrange power, why do they not appear on all the 600s and 750s? Surely those bikes need the low rpm power improving more than a 1000cc bike would?

If you want to improve the power throughout the rev range, fit a full system, dump the flapper, PAIR and fit a properly set-up PCIII.

I don't work for anyone that sells exhausts, but I know a guy that worked for Honda Racing on their 2004 HRC supplied race Fireblades in the British Superbike Championship. I pretty much thought his opinion on this should be valid!

[smilertiv]

my point exactly, its no coincidence that the exhaust valve and the flapper are engineered to be closed at exactly the speed and rpm required for the drive by noise decibel test. I have nothing to do with selling exhausts either. One thing is clear without the two restrictive valves the engine breathes and flows out the gasses resulting in an increase in power that is proven by back to back dyno tests between stock bikes and bikes with the valves removed. Slingshot racing supplied a blade with standard engine but with the mods we are discussing here for the Macau grand prix. It wouldnt have been competitive in standard trim. I rest my case!!!

[.gulliver.]

Originally Posted by rockets25 I pulled out the valve in the exhaust assembly and fabricated a plate to cover the hole. I've been running my bike like this for several thousand miles and had the custom map done to match it. Everthing works fine, and it gets rid of that nasty exhaust rattle. Can't say it gave me much more power if any because I never had it dyno'd with the valve installed.

I did the same thing with mi '00 929. where did you get the custom map for your modification

ever since a did that I'm having the 34 - error code in my dash . should that solve the err problem?
otherwise the bike is running ok !

[strumfuadi]

the error appears because you removed the wires from the motor that drives the HTEV. If you woul just set the cables from the motor "in air" you'll not have that error anymore.

[.gulliver.]

Originally Posted by strumfuadi the error appears because you removed the wires from the motor that drives the HTEV. If you woul just set the cables from the motor "in air" you'll not have that error anymore.

yes that's true. I've removed all the wiring - cables ....

[strumfuadi]

see that? (pai vezi? )