Exhaust servo

[wull]

Am I right in thinking that when the ignition is switched on the servo will turn to fully closed, fully open then settle at around 60% open ish then stop and stay in that position?

I was doing some work to the bike yesterday and had the fairings off and had to put the ignition on and noticed it was making a weird noise, what mine is doing is doing the initial check, fully closed, fully open then when it gets to the position it usually would settle in it doesn’t, it keeps moving back and forward quickly but with very minimal movement, like a quick shake. I’m fairly certain I’d have heard it before so I don’t think it’s just because the fairing is off.

Does this seem like the servo motor is on its way out? I’m not overly convinced it’s opening up fully either, i think I’m going to have to look more into this.

[weeksy]

I'm sure i had the same on the P7F ZX6R after removing the exhaust and disconnecting the servo at the can end. I then removed completely and it was OK... I thought we'd need a servo buddy, but in the end we never. Doesn't help you much, but we've deffo seen the exact same thing. I'm sure there's a reset procedure it needs to go through that it mustn't be able to complete. Our Leo Vince came with a blanking plate for the exhaust servo

2018-05-11_02-33-52 by Steve Weeks, on Flickr


But again, it wasn't needed. I suspect i may still have it in the box of track spares if it'd be any use.

[Le_Fromage_Grande]

Depends on the bike, early Yam EXUPs are either open or closed.

[wull]

I’ll strip it down after work to see if there’s anything I can see that’s clearly amiss with it.

[dern]

I'd disconnect the motor and make sure the cables and flap are free first of all.

[wull]

Cables are good and the flap is moving freely as it should and with the cables removed it snaps to the fully open position with the spring load on it.

So it must be an issue with the servo motor itself, it probably would work with regards to having the flap 60% open and then fully open etc etc but that noise was too much for me to deal with so I’ve removed the system.

It’s thrown the FI on so I’ll get the ESL and that’ll do it.

[Skub]

It'll throw on the management light if it can't do what it wants,so if you've no light it's probably ok.

Sticking cables are the most likely source of grief.

[wull]

It'll throw on the management light if it can't do what it wants,so if you've no light it's probably ok.

Sticking cables are the most likely source of grief.

That’s on the basis that it can’t go from fully closed to fully open which it can do, the problem is when it comes back to the 60% open position, instead of it just sitting there which it’s meant to it just rattles back and forth, making the most annoying noise ever. This I imagine isn’t enough to throw the FI on as it’s within its parameters.

A sticky cable would cause the light to come on if it couldn’t reach fully open or closed and a seized flap would also cause the light to come on for the same reason, both are good, it’s the servo motor.

I’ve just ordered the Eliminator which will solve the light problem. Bike is a little louder at idle now with the flap being 100% open now. Should keep the neighbours happy

[Count Steer]

Doesn't matter now you've taken it off but servo jitter could have been be electrical. Supply to the servo or eg a dodgy capacitor in the servo (if it's got anything like that built in).