The interactive exhaust system utilizes an actuator valve in the muffler which is connected to a servo motor via a cable. The valve position automatically adjusts to enhance engine performance. How do I know if my servo and valve are working? Thanks Bill
Ignition switch on cycle the engine "run" stop switch and you can hear it under the airbox cover. To be certain pull the cover and watch it move. It's tough to see the cable move unless you mark it.
I took the cover off and let the bike warm up. Drove up and down the road and the servo never moved! I could pull on the cable and open and close the Valve. If I unplug. The check light comes on.
It's funny, but my servo "fails" and causes the check engine light to come on almost every time I get ready to leave my buddy's house after working on a project for about 4 hours. Scenario: Startup after work and ride 15 miles to his house. Work 4 hours or so, startup to go home, CEL comes on (8 times out of 10). Stop engine, restart, CEL goes out. Once rode it all the way home to see if it would self-correct: it didn't. Normal 4 days a week use: Startup cold in the a.m. and again after work, ride 35 miles, NEVER a CEL on. Including stopping for gas and restarting hot every other day. Weird.
Per the manual (on my '07) there is a cycling procedure that, with the air cover off, lets you see it operate, and of course, see if it operates properly.
I replaced mine (on an 06) - when you run through the procedure to get it to cycle it should operate in a nice smooth, fluid motion. The one I replaced stuttered like there was a stripped spot on the gears. I heard the gears in the 06 were plastic and changed later on. What a difference.
When I was playing with my valve. The bike sounded great with the cable pulled and the valve open. So do people wire there valve open and cheat the sevro for that True ThunderStorm Wide Open Sound? Just asking?
Yamafreak, many have done just that. You can do a search and find some threads telling you how. Most said they lost a little low end grunt but loved the sound too much to care. My actuator's plastic gears broke in the open valve position and I agree the sound is much better.
Ourdee - Man that is classic/cool!!! Since I'm lazy by nature, I just disconnected my cable at the actuator and pulled it out all the way then securing it with a fishing lead-weight. Like the sound and really haven't notice any difference in the bike.
I have found that I get slightly better fuel mileage with the actuator operating as it should. However it does sound better with the actuator fixed at the open position.
When mine failed I was in Nashville and heading home. I was a little leary riding with the light on but I had oil pressure and it was running well so screw it. I was doing 75 mph most of the way and when I got to Mt. Vernon Ill. I filled up and had gotten 52 mpg. That's an improvement. I later hooked up ecm spy and found the actuator had broke in the open position. No wonder it sounded so good!
I have a 2009 Uly XT that only had 250 miles on it when the servo motor for the muffler went south. The check engine light came on and it ran rough at the low end! The dealer replaced it and said that mine was not the first that he had seen go bad in a new bike.
In the past, I held the valve in the open position with a fabricated aluminum bracket. I had it that way for a while and it did seem to loose some low to midrange power. I ended up putting it back to stock. I only had a few thousand miles on it at the time. Since then, I have a new ECM and a couple re-flashes. Now the bike runs very smooth.
I may just try it again to see how it feels. The sound was much better but not to loud.
I just went back to stock on my '06 - removed the Drummer and the race ECM and put all the OEM bits back.
To make sure my servo still worked (it's been unhooked for about 10k miles), I rode around the block with NO outer airbox lid and kept an eye on the servo.
I was AMAZED at how rarely the valve actually gets opened. WOT only, top 10% of throttle position, and that was about it. Rest of the time, it stayed shut.
I was TWICE as amazed at how much better the bike ran, compared to my initial "back to stock" setup of the muffler only (for quiet) with the valve wired open, and still running the race ECM. Running it that way...it was a pig. Flat spot, no power, running hot, pinging (I'm guessing the advance curve is more aggressive on the race ECM).
If I'd known about the power difference...I'd have left the valve shut when I still had the race ECM in the bike. But now, all stock with a working valve and factory ECM? It's a freakin' ROCKET.
As I mentioned, I had mine locked open. I did not have any pinging or operating issues at that time. However, at that time the bike only had a few thousand miles and it did have the standard dead spots above 2000 rpm with the stock setup. I think locking the valve open would just exasperate the dead spot. With the current ECM setup the bike no longer has the flat spot and has very smooth power delivery.
I may try it just to see how it feels now compared to then.