Check engine light

[FJR1300David]

My check engine light came on today on my '07 XB12Ss. Hooked up my ECMDroid and got a code 21-AMC Stuck/AMC shorted. What is this?

[lowkey]

http://www.buellxb.com/forum/showthr...103#post588103

[njloco]

Also,

http://www.buellxb.com/forum/showthr...market-exhaust

Notice in the post how they're asking for specifics.

[FJR1300David]

OK, I see a code 21 relates to the exhaust/muffler valve. My bike is stock all the way down to the muffler. I will check the servo drive unit on the air filter cover and also check to see if the cables move freely. I'm guessing a defective servo drive unit?

Thanks!

[njloco]

Also, you should make sure the muffler valve is also moving, I've heard they sometimes bind up. So just make everything in line is moving.
Let know how you make out.

[FJR1300David]

OK, pulled air box cover off to take a look at exhaust servo unit. Cable moves freely. Tried to rotate pulley and it felt very stiff. It had a very noticeable sticking right at the beginning of movement. Also it remains in whatever position I leave it in.

I assume it should move freely and return to "parked" position?

Also tried to do the exhaust valve test through ECMDroid...no response from servo.

So I guess I look for a replacement servo unit. Is P/N S0138.2AA the item I need or is P/N S1138.1AA the latest?

Well...I think I answered my own question. P/N S1138.1AA is the one I need. Surdyke HD has one, $161.00!

[vicenzajay]

That kind of money is well on the way to just getting a better/replacement exhaust (and not ever worrying about the exhaust servo/IAV thing again).

Just my .02...the stock system is great - not knocking it. I'm just not sure I would throw close to a couple of hundred bucks at the servo unit.

[FJR1300David]

Sure I understand your point. However I really like and enjoy the stock sound level. At 62 years I'm kind of done with the loud bike thing. Not sure if there is even any aftermarket exhaust that would meet my needs.

[njloco]

Well, don't run out and buy that servo just yet, there was just a post on this recently and apparently Ford makes a servo that is identical to ours only with all metal gearing, you only have to change out the attachment mechanisms, or what the cable connects to thingamajig.

Here you go

http://www.buellxb.com/forum/showthr...valve-actuator

Also, you must check the spring on the valve as sometimes they let go. I spray mine down with the liquid graphite, while I don't have much milage on my buells I don't see why it won't keep them from binding.


IMG_20170604_130941.jpg

IMG_20170604_131024.jpg

IMG_20170604_131348.jpg

Hopefully this helps.

Oh yeah, 62 huh, your still wet behind the ears sonny, I have a special ops muffler, I haven't installed it yet, I'll let you know how much louder over stock it is when I put it on. I believe it's the only muffler mod that retains and uses the valve.

Later!

[user_deleted]

david: it's pretty simple. if the cable bound up it needs replaced or lubed. if the actual muffler valve bound up it needs serviced. get yourself kano kroil or something similar though i find that product to be the best....and lube up the valve pivot point. takes a bit but that should free it up. if cable bound up do the same. both must function smoothly or a new servo box will quickly strip its gears like apparently your old one did. you can remove and disassemble the servo to confirm but you probably have stripped internal gears. here's the link on a common ford motor co. replacement. takes a bit of easy fiddling to do the replacement cable bell crank but is a very nice reasonably priced alternative that contains internal components far superior to the oem servo unit.

http://www.buellxb.com/forum/showthr...valve-actuator