|Posted on Monday, July 14, 2008 - 08:51 pm: ||
Hey guys. I've developed a NEW vibration in my Ss that's kinda' freakin' me out, to the point I'm worried about riding it. I was hoping someone might have a clue where to start looking.
The best way I can think of describing it is this: you know the high speed vibration you get cruising at, say 70 mph @ 3500 rpms? Well, this is almost a counter-vibration. The little gaps in the original vibration now have their very own thump, so in essence it feels like the engine is suddenly vibrating twice as much. This effect comes on without warning, like I've flipped a switch. There's really not any more noise, just extra sensation throughout the footpegs, bars, etc. It seems to kick in right around 70-75 mph, and on occasion I can detect it when I'm revving up through the gears, so I think it's RPM related, but it's hard to tell.
I have NO idea where to start looking, since there's got to be 400 spinning parts that could be involved. What scares the bejeezus outta' me is the possibility it's something that's working itself loose, and that could seize my engine while I'm doing 70 mph down the road. If anyone has any clue what it could be and how to check, PLEASE chime in!
|Posted on Monday, July 14, 2008 - 09:58 pm: ||
Check the easy stuff first, then check the known stuff. I'm not on an XB so I don't know all the XB stuff. Does your bike have the retorque value on the crankshaft nut? Check the primary chain slack (easy stuff), check the tires carefully for cuts/bulges/slices (easy stuff), check your front isolator visually (easy stuff to check), check your suspension (easy stuff), check your front engine mount bolts (easy visual stuff). Rule out the easy stuff, then start looking into the more involved stuff that others have had symptoms with on their XB's.
|Posted on Monday, July 14, 2008 - 10:14 pm: ||
It's probably best to look at what was last done to the bike. Was it in for some kind of service at the dealer or did you change anything before the symptoms started to appear?
The normal things that can cause un-normal vibrations related to engine rpms are:
1) excessive primary chain slack (chain whips up and down increasing vibrations with rpms),
2) broken muffler mount (mass of muffler vibrates out of phase with engine rpms),
3) damaged front motor mount (engine drops relative to frame and causes metal to metal contact with frame).
4) possibly crank or tranny shaft bearings going away (unlikely but this is probably the area you're most concerned about); the other stuff is easily fixed.
|Posted on Monday, July 14, 2008 - 11:14 pm: ||
Try replacing your engine temp sensor.
3500 cruising is about where it changes from closed to open loop.
Mine has shifted AGAIN! and that is where the vibrations tend to smooth out.
Have done some research about temp sensors and it would seem that Volkswagen also had issues with their temp sensors in their air-cooled motors.
Their fix was to provide an optional spacer about one inch long that allowed the sensor to sense the temp but not have the wiring/body be affected.
Looking for one now and will let you all know how it pans out.
|Posted on Monday, July 14, 2008 - 11:40 pm: ||
Check for tire or bearing issues as well. Will it do it in neutral?
|Posted on Friday, August 01, 2008 - 07:28 pm: ||
Swordsman - Did you ever get this resolved? I'm getting the exact same symptoms you experienced... the only recent change on my XB was I had the TPS reset about a week ago. vibration Happens between 3600-4000 rpm cruising at highway speeds is when it is most noticeable.
|Posted on Sunday, August 03, 2008 - 01:24 am: ||
Have found a local temp sensor manufacturer.
They have aeronautical spec temp sensors that basically just glue on to the place you want to take the temp from.
The factory temp sensor is listed as a 20% variation to be withing spec.
The local ones are listed at 3-5% at the same temp range and have a longer life.
The voltage output per temp is a little different so the setting will have to be changed in the ecm.
Will have a go with ECMSpy.
The salesman is letting me have one to try so I will see how it goes.
|Posted on Thursday, August 28, 2008 - 10:39 pm: ||
+1 on the primary chain torque specs. I have an 06 ss also and mine was acting very similiar to yours, took it into the dealership and they fixed it free of charge. Try it out and see what happens,