EXUP delete question

[theCATman]

Well...... a little update. For my own piece of mind, I took both apart to check alignment and function. 1st one went smooth, was barely off center. Slight adjustment, and it was spot on. 2nd one, not, so, much. It was off a bit too, but I cycled through the diagnostic process to make sure, and BING!!! snapo-cable. PHUUUUCCCKKKKK!!!!!

Needless to say, it is currently wired open and two delete plates are on their way from BOP.

I of course rode it to see if there was any noticeable power difference. My findings are this...

At idle and with a "cold" engine and pipe(s) it is a bit louder and choppier. However, this quickly went away as everything got hot/hotter. Idle smoothed out, and the tone mellowed out as well.

It feels ever so slightly "flat" in the 5000ISH-6000ISH RPM range, but I had to intentionally feather it in that range to notice it. If I revved thru there quicker, there was zero difference in powerband feel.

It also seemed to have "hit" or surge in power once it went thru its "flat" spot under gentle throttle pull.

This hillbilly concludes, that the EXUP is there to smooth out power delivery in the midrange and take away that surge in power that's felt as RPMS increase at a more gentle throttle pull, making it much more linear for your average rider.

I believe the intake, cam, and timing changes that were made to the 11-up all added up to a much more aggressive feel, and the EXUP is only there to tame it for the average person. Is it actually helping increase power within a certain RPM range??? No, I personally don't think so. It's only smoothing it out and hiding a "flat" spot in the power curve.

Just my opinion anyhow.

 

[Stubbs]

If you look at a dyno graph from a 06-10 Apex there is a noticeable dip in the power curve in the midrange. The addition of the exup, along with revised intake runner length and cam timing on the ‘11 + sleds was designed to tune out this dip and make the power delivery more linear while not losing any power up top. Sounds like that’s exactly what you’re feeling with the valve locked.

 

[03RX1-ER-LE]

Well...... a little update. For my own piece of mind, I took both apart to check alignment and function. 1st one went smooth, was barely off center. Slight adjustment, and it was spot on. 2nd one, not, so, much. It was off a bit too, but I cycled through the diagnostic process to make sure, and BING!!! snapo-cable. PHUUUUCCCKKKKK!!!!!

Needless to say, it is currently wired open and two delete plates are on their way from BOP.

I of course rode it to see if there was any noticeable power difference. My findings are this...

At idle and with a "cold" engine and pipe(s) it is a bit louder and choppier. However, this quickly went away as everything got hot/hotter. Idle smoothed out, and the tone mellowed out as well.

It feels ever so slightly "flat" in the 5000ISH-6000ISH RPM range, but I had to intentionally feather it in that range to notice it. If I revved thru there quicker, there was zero difference in powerband feel.

It also seemed to have "hit" or surge in power once it went thru its "flat" spot under gentle throttle pull.

This hillbilly concludes, that the EXUP is there to smooth out power delivery in the midrange and take away that surge in power that's felt as RPMS increase at a more gentle throttle pull, making it much more linear for your average rider.

I believe the intake, cam, and timing changes that were made to the 11-up all added up to a much more aggressive feel, and the EXUP is only there to tame it for the average person. Is it actually helping increase power within a certain RPM range??? No, I personally don't think so. It's only smoothing it out and hiding a "flat" spot in the power curve.

Just my opinion anyhow.

What position did you place the ExUp gear notch too when wired up? Going through threads someone posted it goes to the 3 o'clock position when commanded by the servo at 9k rpms. When placed there my exhaust rattled and the engine ran rough at idle, using a stethoscope on the pipes it was effecting the far right cylinder. Rotating it to any position other then 12 o'clock it rattled and ran rough. I locked mine at 12 o'clock to smooth idle and get rid of the awful noises. Have ridden it around my house and seems to run fine, will find out this weekend in UP how it does on hard long pulls.

 

[theCATman]

What position did you place the ExUp gear notch too when wired up? Going through threads someone posted it goes to the 3 o'clock position when commanded by the servo at 9k rpms. When placed there my exhaust rattled and the engine ran rough at idle, using a stethoscope on the pipes it was effecting the far right cylinder. Rotating it to any position other then 12 o'clock it rattled and ran rough. I locked mine at 12 o'clock to smooth idle and get rid of the awful noises. Have ridden it around my house and seems to run fine, will find out this weekend in UP how it does on hard long pulls.

I took the muffler off so I could see what was going on, but yes it's basically at 3 o'clock, actually past 90° by a bit, between 3 & 4.

I didn't notice any rattling, just the choppy idle til everything got good and warmed up/hot.

I also think the funky idle and sound could possibly be caused from the area that houses the valve essentially becomes a hollow box with the valve locked open, giving the gases a place to bounce around and not flow freely out.

 

[03RX1-ER-LE]

I took the muffler off so I could see what was going on, but yes it's basically at 3 o'clock, actually past 90° by a bit, between 3 & 4.

I didn't notice any rattling, just the choppy idle til everything got good and warmed up/hot.

I also think the funky idle and sound could possibly be caused from the area that houses the valve essentially becomes a hollow box with the valve locked open, giving the gases a place to bounce around and not flow freely out.

Cold start mine sounded fine, when warm is when I noticed it. When on the TY ride I could here the noise at idle/stops, however not at all stops as since both cables were broke the valve was flopping/moving round. I was in a hurry to get the sled back together as have several more rides planned and wished I would have thought to pull muffler and take a look in there with my borescope
Have a 4 day trip planned starting Sunday, when I get back may have to tear back into it to decide what to do. This trip is with my Wife, Daughter and her BF so will be a lot of easy riding so valve blocked closed may not be to bad of an issue, we will see.

 

[theCATman]

Cold start mine sounded fine, when warm is when I noticed it. When on the TY ride I could here the noise at idle/stops, however not at all stops as since both cables were broke the valve was flopping/moving round. I was in a hurry to get the sled back together as have several more rides planned and wished I would have thought to pull muffler and take a look in there with my borescope
Have a 4 day trip planned starting Sunday, when I get back may have to tear back into it to decide what to do. This trip is with my Wife, Daughter and her BF so will be a lot of easy riding so valve blocked closed may not be to bad of an issue, we will see.

You don't need a bore scope. With the muffler off, a bright flashlight is all that's needed. You can lean your head over and look right in. It's only 8-10"?? or so beyond where the muffler clamps on.

I personally don't think the valve in the "closed" position hurts an darn thing, unless you're running WFO most of the time. Then I can see it posing a problem for flow characteristics.

 

[03RX1-ER-LE]

I will be curious how it performs this weekend in the closed position. This thing since the Star upgrade is a skilee monster.