Front end vibration, especially on decelleration

[Klubis]

My apologies to the admins if I should have found a reference to this in NEPRT.

This is a new one to me. My '07 had been producing some vibration that feels like it is coming from the front. It was there just cruising at a steady speed, but it really woke up when I would decelerate. Once, going down a slight slope at about 60 mph, I let off on the throttle and there was visible back and forth wobbling of the handlebars, much like head shake. Braking doesn't seem to affect it positively or negatively. I suspected the front tire because it was near EOL and cupped/worn/feathered, so I replaced both tires up at Lejuene Motorsports. Nice Michelin PR2s, btw. After I paid the bill but before I rode off, the service manager asked me if I had noticed any vibration. I said yes, but I thought the new front tire would fix it. He said the mechanic noticed a vibe when testing the bike after tire installation. The mechanic suspected, and this is the new part, that the center stand springs may be the culprit. He said they were weak and they were piggybacking off the front tire imperfections. I said to my self but not out loud, "Self, whiskey tango fox trot?"

On the way back to beautiful downtown Hampstead, I noticed the vibe was mostly gone, albeit still there when I imagined for it. I went ahead and ordered new center stand springs, and I'll let you know if they cure the problem when I receive and install them. Later today I'll check the steering head bearings for looseness. Also, I think maybe a throttle body sync is in order, but I really don't feel like buying or making the tool today. Maybe later.

My question is, does it seem reasonable that fatigued center stand springs could cause a vibration like I'm experiencing? Have you ever heard of such a thing?

 

[Klubis]

My apologies to the admins if I should have found a reference to this in NEPRT.

This is a new one to me. My '07 had been producing some vibration that feels like it is coming from the front. It was there just cruising at a steady speed, but it really woke up when I would decelerate. Once, going down a slight slope at about 60 mph, I let off on the throttle and there was visible back and forth wobbling of the handlebars, much like head shake. Braking doesn't seem to affect it positively or negatively. I suspected the front tire because it was near EOL and cupped/worn/feathered, so I replaced both tires up at Lejuene Motorsports. Nice Michelin PR2s, btw. After I paid the bill but before I rode off, the service manager asked me if I had noticed any vibration. I said yes, but I thought the new front tire would fix it. He said the mechanic noticed a vibe when testing the bike after tire installation. The mechanic suspected, and this is the new part, that the center stand springs may be the culprit. He said they were weak and they were piggybacking off the front tire imperfections. I said to my self but not out loud, "Self, whiskey tango fox trot?"

On the way back to beautiful downtown Hampstead, I noticed the vibe was mostly gone, albeit still there when I imagined for it. I went ahead and ordered new center stand springs, and I'll let you know if they cure the problem when I receive and install them. Later today I'll check the steering head bearings for looseness. Also, I think maybe a throttle body sync is in order, but I really don't feel like buying or making the tool today. Maybe later.

My question is, does it seem reasonable that fatigued center stand springs could cause a vibration like I'm experiencing? Have you ever heard of such a thing?

 

[Fred W]

Worn tires. New tire misbalanced?

 

[15wannabe]

That's an entirely new one on me (center stand spring?)...never heard of that supposed phenom b4 !

My first FJR had the front end shake, only on deceleration regardless of type of tires and condition, and only when I let go of the bars. In some cases, a loose steering head bearing is responsible.

 

[Klubis]

Worn tires. New tire misbalanced?

It's possible, but I don't know how to check accurately. They're Michelin PR2s. But the vibration sensation is much diminished with the new tires.

 

[Klubis]

Sorry for the double post. Don't know how to delete it.

 

[rushes]

Be sure to replace the sidestand spring too.

If it's weak, it might make it pull to the right.

 

[graler]

If the center stand spring is weak and the stand is vibrating it is easy enough to rule out. Take a cable tie and cinch the center stand up in place and go for a ride. If the vibration is gone you figured it out. By the way I do not believe that this would manifest itself in the handle bars. I would expect bar vibration to be tires (cupping), Tires (out of balance), if during breaking only then pads then rotors. If all the time and the tires are not an issue (you addressed this already), then the bearings and their related torque and seating.

Just my 2 cents

 

[russperry]

This is definitely a NEPRT - lots of threads on the subject and lots of opinions about how to mitigate. My FJR has the same - new tires didn't fix it, tightening head bearing no help, but after a fork service including new fluid it got a lot better. I've got a worn out front tire now and the wobble is back really bad, but I'm hoping on a tire change I'll get some relief.

Good luck, but I'm guessing you'll have this off and on for the life of the bike.

 

[audiowize]

You should be able to zip tie the center stand spring up tightly to test that idea.

 

[Ignacio]

My apologies to the admins if I should have found a reference to this in NEPRT.

Don't apologize. What did you search on to try and find the often-discussed subject?

 

[Road_Runner]

I had the same issue, and mine was loose steering head bearings.

 

[Uncle Hud]

^^^^ That's my guess, too; steering head bearings. (And trust me -- it's a guess.) I would think that if they were even the slightest bit loose, you'd have a wobble/shimmy that would cut your front tire mileage in half.

 

[NTXFJR]

Might want to double check air pressure on that front tire.

 

[Oakdave]

Try adjusting the front fork rebound and compression settings (and, replace the fork fluid if it's been awhile).

 

[Bill Lumberg]

Mine had no wobble on decel, until about 16K. Started near a new set of tires. Pressures, suspension adjustment, and rechecking torque didn't help. Haven't bothered getting a rebalance. Will wait and see if it goes away with the next set of tires. It's already less pronounced than it was when it began.

 

[garyahouse]

I posted this before. But I'll chime in here. Bike was running fine. Bought a new front PR3. Handlebars started shaking on decel. Got it re-balanced. Helped a little. However, kept getting worse as the tire wore. Had it re-balanced again. Helped a little, maybe, but not much. Tire just continued to get worse. Near the end of its life, if I let loose (very carefully) of the handlbars on decel from 45-30, the bike would do a genuine tank slapper. Finally changed it out for a new PR2. Problem solved, smooth as glass.

My take on this? Some tires are gonna do this even when they ARE balanced. Out of round? Out of whack? Out to lunch? Who knows. But I do know - that tire had a demon, and balancing it couldn't fix it. Michelin wanted me to send the tire back to them for evaluation. Hmmm... wonder why? What do you suppose they wanted to see? It was indeed balanced, but it made the handlebars shake like a hammer. Oddly enough, it didn't seem out of balance. At higher speeds, it was smooth as glass. But the handlebar shake was intense (on decel) and undeniable. So - Why were they so eager to evaluate this... when this particular tire could not be fixed by balancing, and a new tire completely fixed the problem?

I'm guessing that tire companies don't talk about this much, but there is such a thing as a "bad" tire.

It's not that it couldn't be balanced. Actually, it didn't require a lot of weight to balance it. However, I decided just to "use it up." I never sent it back to them. And I don't think it was the "kind" of tire, because collectively, we've used and enjoyed gazillions of those PR3's. I'd be willing to bet that every manufacturer turns out one of these odd duck tires every once in a while.

 

[user 8909]

Center stand springs?

I don't think I would let that dealer see my bike again.

Good observation on the head bearings, tire and head bearings would be where I'd start. Also look at the rear wheel for front end wobble.

Check all wheel bearings too.

Make sure your handle bars are tight too.

Suspension might be next.

Good luck.

 

[RaYzerman19]

There is the odd bad tire. I had brand new one on my GL with a squiggle in the center tread, approx. 1/8" lateral runout in inches. They gave me a new one and wanted the original back. I had a second bad tire a couple of years later, and they wanted that one back too..... they will give you pro-rated price depending on amount of tread remaining. I haven't had any bad tires on the FJR though.