FLHX Vibration Problem - Harley Forum

Robb · #1 03-12-2009, 09:08 PM

I'm the proud owner of an '06 FLHX 'Streetglide'- 88 CI w/ Rush Exhaust & new module. I've put 15K miles since purchase. At about 10K miles I started to notice an increase in the bike's vibration. This vibration has caused the Fairing mounts to break twice...both Upper & Lower mounts. It has also caused the front motor mount to break at about 13K Mi. I have the "Service Plus" Package & extended warranty, so my ride is dealer maintained. The dealer has done extensive diagnostics on the motor, tranny & wheels & has not come up with the 'Culprit'. The vibration is so pronounced & my handlebars shake so much, even at cruising speeds ( not to mention at Idle), that my mirrors do not reflect a clear focus view, of rear traffic. It has also caused the windshield screw lugs on the inside of the fairing, to work themselves out. I've also experienced extensive hand fatigue, cramps & even had my hands "fall asleep" from the vibration, (even though I use a Throttle Rocker). Any thoughts on this problem would be most welcomed. Last things Techs checked, were motor/tranny align-tranny/final drive align-final drive/rear wheel align & new rear wheel @ 11K Mi, was balanced(of course). I run Redline in entire Powerplant/Tranny.
Thanks,
Robb
P.S. Bike, when vibration is most pronounced, when at a red light, it seems the idle drops way down to the point of stalling, then gradually works it way back up to what seems as 'Normal'.

frisco-rigid · #2 03-13-2009, 03:35 AM

Holy Cow

Very good descriptions.. Rubber mounted,, is it carb or EFI..?
They have apparently checked & eliminated almost everything that I & most others would advise to check..
Did they check inside the Primary cover.? I cannot imagine such a bad vibe coming from the primary components (motor sprocket, chain, clutch hub & shell) without making a Monstrous clanging and grinding But it is something to check and eliminate..
Us older guys with the old style sickles would mostly look "around/outside" the motor for a new vibration first like motor-mounts, alignments, broken brackets etc etc & once all "outside" stuff is eliminated it pretty much lands on the motor being the culprit..

Until you said the Vibes are most pronounced at Idle and Twitchy at that I was blank, but, that idle prob makes me think it's in the motor,, prob not a mechanical problem but some sort of intake and electronic prob especially if it's EFI..
In an old style sickle a Twitchy up/down idle would lead a guy to check for intake leaks & weak/broken timing springs..
Wish I had more but I bet Wrightturn & other smart cookies have something..

evoKENevo · #3 03-13-2009, 08:30 AM

Hey Robb
Last spring a friend brought his FLHX over because someone had told him his primary chain needed to be adjusted (not shifting real smooth) and he was due for primary fluid change anyhow. He also mentioned that he'd made an appointment at a dealership to have his EFI remapped (over my head) because his bike was doing pretty much what you've described here.

When I checked the primary chain, it was right on the money. So, I left it as-was...changed the fluid...and figured I adjust his clutch & cable while I was at it. After loosening up the cable and clutch adjuster lock nut, I found that I had to turn his adjusting screw in quite a bit more than the correct 1/2 turn or so.

Readjusted everything and that not only had the bike shifting much smoother...but, to our surprise, all the vibration mentioned was history too. Could it be that your tech over looked this one little thing ???

Robb · #4 03-13-2009, 09:58 AM

Thanks Frisco' & Evo for the quick response, yes it is EFI. I don't know for sure how far into the EFI, other electronics or fuel supply/injectors the techs have gone, but I will bring that to their attention. Beleive me it has everybody stumped. Let me add one thing in regards to 'Remapping' the EFI... the injectors were increased in size, due to a 'stalling' issue...you know this was about or around the same time this vibe thing started, I will bring that to the table also. Now in regards to the clutch cable, I'll risk presuming that this was checked at 15K Mi service, yet I will also bring this to their attention.
Thanks again Gents for your response, I promise not to tell anybody about the 'Gents' thing(LOL). If you have any more thoughts please let me know.
Ride Free, Ride Safe but most important, Ride Often.
Robb

GrayRider · #5 03-13-2009, 11:27 AM

Check your front motor mount.

Also, have your dealer set your idle up to around 1000 RPMs. That will smooth the idle out and stop the shake.

frisco-rigid · #6 03-13-2009, 02:49 PM

Bingo......

One of the first things folk should look at is any Mods, changes and work performed at about the same time a problem arises..

OK, there was a stalling issue and work done and a prob starts,,,,,,, 1 & 1 equals 2..

From what I've learned about EFI, the size of the injector is not as important as the time it is injecting.. In-other-words,, the "squirt" length of time is expanded in order to inject more fuel.. To do that it must be programed into the computer..
However, just changing the size of the injectors will, I guess, attempt to inject more fuel BUT then the 02 sensor picks up on the increased fuel and tattles to the computer and Momma computer puts the Kabosh on the extra fun.. Bad injector..!!
Go to your room..

Sooo, if this change was Not re-mapped/programed and OK'd with the computer it could confuse the EFI Brain and rough running might result.. Just something to consider..

I went through this with my car EFI,, there was no rough running or probs cuz I was simply looking for more power,,,,, but, being that the 02 sensor is kinda the Queen Bitch of the system anything you do that is Not OK'd by the computer will be voided by it and possibly create confusion for the motor..

Anything else you did not tell us..?? Hmmmmm?

Robb · #7 03-13-2009, 04:02 PM

Thanks Frisco-Rigid, I can't say for sure if that procedure was done when they changed the injectors, it does not show up on my service print outs.
I will contact my dealer to confirm. I'll let you know the results.
Thanks,
Robb

aceharleywrench · #8 03-13-2009, 05:44 PM

While they have your bike,have them check that the injectors are plugged into the correct connectors,it's a long shot,but I discovered this on a FLHR that had been wrecked & had the frame replaced.You would think the bike wouldn't run at all,but it will.Also look for any wire rubbed through anywhere near the induction module.

unclepsycho · #9 03-13-2009, 10:29 PM

Every time I gass up at a Shell station, my bike runs ruff and has a very low idle, so low I tend to rev it by instinct at a red light. I ride an 06 Ultra with 35k on it and no mods, all stock. After I run the Shell gas out, it runs fine.I noticed it last weekend. it was a different Station each time too.

I use shell in my work truck for years with no problems, so I dont know why it would make the bike run bad,

Good luck !