I may be crazy but this has been confirmed by two other people.
so today a buddy and I were out riding. I noticed after about 20 minutes that at stop lights my 99 883 seemd to be idiling kinda hard. did not think too much about it. then while we were parking I noticed it was not idling as hard. until,, I pressed the rear brake. yea.. at a stop in N at ldle when you press the rear brake is starts to shake. not super violent or anything but it is noticeable. my buddy sat on my bike and confirmed it. my girl also did it and she said she could feel a difference.
I unplugged the rear brake light and it still did it. I have been having an issue with the rear brake light. maybe this could be the problem.
all the LED stuff is coming off this coming week. we are stumped... any thoughts or suggestions would be greatly appreciated.
trust me I know it sounds weird.....
Willy

Only the rear brake and not the front??

What kind of gas are you using? My sporty used to idle kind of high, too. But when I switched from 87 octane to 89, it idled noticably lower. Slower burning fuel seemed to help. (I'm too cheap to use 91) Although, I never noticed applying the rear brake to cause vibrations. You should get that looked at.

yup only the rear causes it. when it starts to shake the idle doesnt change. I run premium. dont mind spending the extra on good gas since I am used to filling the Lightning on a regular basis.

I aint no mechanic but if it is just the rear brake doing it then it wouldn't be the lights. It would have to be in the rear pedal, rear brake line or the rear caliper. If it had something to do with the light it would do it when the front brake was squeezed as well.

It's a frame mount so maybe the spocket cover is loose or something and when you press on the rear pedal you are moving something there. Maybe a loose motor mount and the pressure on the pedal is tightening it up enough to make it shake more? Just a thought.

Yep this sounds weird. Just another thought to throw into the mix. When you clamp the disc in the caliper it creates a more rigid bond with the frame. It could have something to do with that???

Gazza

i'm with you gazza physics is a biatch!. it could also be the angle of your foot when you push on the brake changes the dynamic stability of the flux capacitor to emulate the ergyroptic nerves in you glutious maximus ;)

This was posted before except with the front brake, On a frame mount when at idle the bike shakes and moves, When you press the brake you stop it from moving the bike, Thereby "Loading" the engine somewhat.


Hope this makes since...

Check your ground wire on the tail light.

Check your ground wire on the tail light.


He stated that he disconnected the brake light and it still did it.

This was posted before except with the front brake, On a frame mount when at idle the bike shakes and moves, When you press the brake you stop it from moving the bike, Thereby "Loading" the engine somewhat.


Hope this makes since...

It makes perfect sense, if it's only increasing vibration. It would make a frame mount, "more" rigid. If it's actually changing the idle speed, that would be strange.

Must be the flux capacitor too loaded by all the current draw.
Buy some new chrome parts for her and the problem will soon fade away.

thanks for the replys guys! I am going to to with the "makes it more rigid" theory.
that and taking some of the chrome off it...
:tour
I have all new rear end lights coming soon. if it changes anything I will let you guys know.

i'm with you gazza physics is a biatch!. it could also be the angle of your foot when you push on the brake changes the dynamic stability of the flux capacitor to emulate the ergyroptic nerves in you glutious maximus ;)

Ahmm What???

sorry bikenut .. i was just saying in a tounge in cheek way that holding the rear brake would stiffen the bike up as per wot gaz siad and make it feel like it was shaking more than usuall....has to do with harmonics and vibrations finding there pitch etc ...like wot they did on myth busters with the bridge that collapsed becuase of a battlion of soldiers marching in step cause a resonant frequeincy that was in pitch with the size and wieght etc of the bridge :)

I think Milmat1 nailed this one.... as the engine idles it shakes the whole bike..... some of thet movement is absorbed by the rear wheel moving slightly..... when you apply the rear brake you are clamping the wheel to the frame, stopping all relative movement between the two..... the vibes still happen, but now they all go to the seat

Ww