Hey guys,
Here's one for ya. I have an 08 Street Bob with 14K miles on it. I recently started feeling an odd oscillating vibration in 4th gear between roughly 52mph and 58mph. I checked all other gears at topped out speeds for each gear and everything felt smooth. As soon as I shift into 5th gear, maintaining the same speed, the vibration goes away.

Here's what I mean by oscillating vibration... It's not a continuous vibration, it sort of cycles about twice per second (was counting in my head while riding). Kind of a "zzz - zzz" thing. I brought it to the dealer and they couldn't get the symptom. It seemed like it went away for a ride or two, but now it's back.

My inclination is that it's not an RPM thing, or it would likely do it at that RPM in every gear. Harley counter guy half assed something about maybe a bent shaft or something, while telling me they could tear down and inspect for a minimum of $400 if I wanted. Not the most compelling sale...you don't have a clue, but you'll investigate randomly on my dime? Anyhow, seemed like if the drive shaft was bent, it would pose a vibration problem in every gear. I read several posts about vibrations possibly being linked to a tuning issue...I had the bike Dyno'd with a SERT and Thunderheader, seems to run fine...can a Dyno map get off? Does it ever need to be checked or redone? I'd be surprised if it's a tuning thing given that it only happens in 4th gear, but who knows? Just throwing out things I've heard...

So, any input, is my reasoning correct? My gut tells me something is maybe funky with whatever parts are unique to 4th gear...

Any input, advice, help would be awesome and very appreciated. I'm going to bring it to a different dealer (the place where I've been going, where I bought the bike, has a track record of not fixing things to my satisfaction, so I'm done with them) to have one of their mechanics test ride it, but figured I'd check with you all here as well...maybe someone's had a similar problem? I did a search on the forum and didn't find anything like my problem...just more consistent, vibrating all the time issues...

This has, of course, cropped up just as my factory warranty is about to expire. I have no intention of buying Harley's extended "fear" warranty that they want a small fortune for, only to have the dealer or Harley deny that something is warranty-able (it's already happened to me within my 2 year warranty). So yeah, I 'd love to figure this out before my warranty expires in just over 2 weeks, ha!

Thanks,
Rob

 

No replies? Is there a better section of the forum to post this in?

 

Not a single reply? Bummer. I guess the "which gloves do you like" questions get all the answers

 

I like the summertime Gloves with the little air holes in them...

 

If you still have the warranty go to the other dealer and let them figure it out !

 

Few warranties cover NVH (noise vibration harshness) so the dealer's not out of line there.

But I would most assuredly get the problem reported to the dealer, recorded, on paper, and keep a copy in case you find out it's something serious.

If they ride it and can't hear, feel or notice the problem, then how can you blame them for not wanting to tear the bike apart and look for a possibly phantom problem?

I understand your dilemma, been there (with cars). So do what you gotta do to protect yourself. Get it reported to the shop accurately, keep a copy of the record and drive it.

Hopefully, if the tranny grenades down the road at some point in time, they'll cover it because you reported it while under warranty. If not?

Dunno.

 

Saw some cool looking gloves at eagle leather last week, they were made out of HOG hide!

Sorry, I feel your pain. My warranty just expired too, and I'm not about to pay for the privilege of being told that since I do my own maintenance the extended warranty won't cover that manufacturer's defect.

If the vibration is more repeatable, take it back and have them check it again. If you have more dealers close enough, take it to them too. Every dealer has to honor your warranty, and some service managers are better than others.

Good Luck!

 

Intermitant vibrations on a Harley are about the hardest thing to figure out, these things vibrate a lot at the best of times. Tuning, or low rpm's with a high torque load can both feel like vibration. primary chain and clutch can also give off intermitant vibs. I agree that if you are still on warranty the stealer should take care of it for you.

 

Saw some cool looking gloves at eagle leather last week, they were made out of HOG hide!


Deer Hide makes the best gloves. I think I bought mine online from a place in WA. Chilhowee sound right?

No "fuquoiee' jokes please.

 

This happens only in 4th gear at that MPH, can you get it to do in any other gear at the relative same RPM
Have you checked all of your engine mounting fasteners? Also check the front mount and see if the case is resting on the rubber (@14K you might need to replace the mount) and you might also check for a gap on the front mount.
I found the bolts came loose on the top center link mount that is bolted to the engine and I had a weird vibration on deceleration. I also found my rear mount loose when I installed my TT.
Check your belt tension and rotate the rear wheel and checking the tightest section to see if it is in spec.
Of course the dealership should have done this as a routine check for your complaint, whether they did???
CB

What I do to check the gap on the front mount is to jack the bike up so it is vertical or get someone to sit on it to hold it straight and then place a scissors jack under the engine case as close to the front engine mount as possible. Lift the engine just enough to take the weight off of the mount. Loosen the 2 bolts at the frame and see if the mount pulls away from the frame. If so, loosen the 2 mount bolts at the engine letting the mount settle towards the frame and if there is still a gap, tighten the mount to engine bolts and then shim the remaining gap with washers. If the gap is still quite large you may need to use longer bolts to make up for the washers so you have the proper thread engagement.