Handlebar vibration inconsistent?

[oldryder]

I know this topic has been beat to death here but I couldn't find any threads that dealt with this specific wrinkle:

'05 with helibar risers sometimes has a bar vibration bad enough to put my right hand (no effect on left) to sleep in about 20 minutes.

I understand a bit about harmonics and why some of the various strategies for dealing with this can help.

My question is why this problem would be intermittent. I commute to work at 80mph indicated and some days my right hand is numb when I get to work and other days not at all. same route, same rider, same gloves ... ?????

I have noticed recently that the problem seems to be absent when I have a passenger but I need more rides to confirm that observation.

I'm open to suggestions for why the problem would be intermittent. I intend to fix the problem but I want to understand it better before I start spending money.

ps. has anyone ever tried putting rubber washers under the handlebar mounting location? Lots of 2 strokes back in the day had rubber mounted handlebars to alleviate buzzy bars.

 

[Fred W]

Have you tried an unauthorized TBS yet?

 

[oldryder]

had tbs done by the best mechanic I know. no difference.

 

[SkooterG]

My 04 does the same thing. It didn't early in it's life. But for the last 50k or so of it's 178k the vibration has gotten a bit worse - but only sometimes.

It's got me stumped. Sometimes, I wonder if it's just a rider (me) perception issue, but I am pretty sure it's not.

Instead of letting it drive me nuts, I just go to my 'happy place' and try and forget about it as much as I can.

 

[FJRBluesman]

I have similar issues, nothing bad just kind of puzzling.

 

[JamesH]

I know this topic has been beat to death here but I couldn't find any threads that dealt with this specific wrinkle:
'05 with helibar risers sometimes has a bar vibration bad enough to put my right hand (no effect on left) to sleep in about 20 minutes.

I understand a bit about harmonics and why some of the various strategies for dealing with this can help.

My question is why this problem would be intermittent. I commute to work at 80mph indicated and some days my right hand is numb when I get to work and other days not at all. same route, same rider, same gloves ... ?????

I have noticed recently that the problem seems to be absent when I have a passenger but I need more rides to confirm that observation.

I'm open to suggestions for why the problem would be intermittent. I intend to fix the problem but I want to understand it better before I start spending money.

ps. has anyone ever tried putting rubber washers under the handlebar mounting location? Lots of 2 strokes back in the day had rubber mounted handlebars to alleviate buzzy bars.

I am with you as well. I get vibration 4k RPM and above but only sometimes. It's like it depends on how the bike feels that day. I heard from somewhere that it happens when the throttle bodies are slightly out of sync, but I just had the bike serviced less than 500 miles ago and whenever I get it back from service the vibration is gone. I wonder if they neglected to sync the throttle bodies this time or it's just a coincidence.

Oh well. I will have to keep an eye on this thread.

 

[radman]

The bike's vibration will change depending on temperature. It's a mixture thing. You may also have an intermittent connectivity problem, such as the large white connector just below the tank at the headstock-a known issue on Gen I's. A TBS, unauthorized or regular, may help-or it may just move it up or down the rpm scale. Throttle body synchs on this bike can and will drive you nuts if you let it-perfect when fresh then crap the next morning. Smooth going to work-vibey going home. Or vice versa. Temp, humidity, altitude-all will affect how this bike runs, and with it's predilection towards a vibe issue anyway, it's a brain ****. The ambient sensors (air temp, map) are pretty low tech, limited in their range, sensitivity and effect on the overall fuel mapping-some input data only at startup, and aren't "live" while in motion (remember the altitude sickness early Gen II's displayed anyone?). The ECM isn't star wars sophistication either.

 

[reddog]

I have a 07 that does the same, but I seem to think it has more to do with how tight you hold on to the bars. When I first start to notice my hand tingling I relax my grip a bit and it seems to go away FWIW. Reddog.

 

[johnny80s]

My 04 does the same thing. It didn't early in it's life. But for the last 50k or so of it's 178k the vibration has gotten a bit worse - but only sometimes.
It's got me stumped. Sometimes, I wonder if it's just a rider (me) perception issue, but I am pretty sure it's not.

Instead of letting it drive me nuts, I just go to my 'happy place' and try and forget about it as much as I can.

The happy place between your pockets?

 

[Fred W]

had tbs done by the best mechanic I know. no difference.

That wasn't what I asked. I asked if you've done an unauthorized TBS. When a mechanic follows the TBS procedure they are only adjusting the air bypass screws, which have their main effect at idle. The unauthorized version adjusts the throttle plates. There is no official procedure for doing this, but some folks have said it makes all the difference in the vibration / buzz at 4k rpm.

 

[Constant Mesh]

Even the amount of gas in the tank affects the vibration profile.

6.6 gallons = 41 lbs.

The 37 lbs. change in weight as a full tank empties seems to noticeably affect the vibration on my '04 FJR.

The vibration profile also seems to be affected by the aluminum alloy frame as it heats up from a cold start.

 

[PA1195]

Some thoughts on vibration. I'd try the following just to eliminate potential sources. Torque the engine mounts, steering bearings, and any major frame bolts. Do the throttle plate synch mentioned, and confirm the balance by driving the bike with the manometer still attached at the speeds you normally travel (and readjust if required). Install fresh plugs, make sure the plug wires are good, and while doing that check the compression for balance within about 10%. Look for any intake leaks. Install Helibar risers and grip ends - In my case installing the risers and Throttlemeister bar ends squelched the bar vibes. You could also fill the bars with lead shot. I've done that to successfully dampen vibes on other bikes. Install sponge Grip Puppies over the existing grips (they're available here). The frame/engine will slightly change dimensions with temperature swings, and a passenger may alter the vibes due to changes in frame geometry and mass loading. Try scooting back and forth on the seat to see if that makes any difference. Probably not much. If the vibes are speed, and not RPM related, it may be from an imbalance in wheels or tires.

It's really like trying to put a handle on a snake, as some of the causes are controllable, but the rest just move around when they want. The FJR really is smooth compared to some, like the original Concours that I had, but the bar buzz can be reduced if you're motivated to spend the time. Numb hands are no stranger to those of us familiar with chainsaws, and buzzy bikes can be as bad.

Gary in Fairbanks

 

[caryt]

My 06 has had it since new and I have repeatedly done everything mods, syncs, authorized and unauthorized it ..makes no difference. I have come to the realization the some will buzz and some won't. I have seen 2 other FJR's that basically don't buzz. Only remedy for me is a McCruise

 

[jjsC6]

My 06 has had it since new and I have repeatedly done everything mods, syncs, authorized and unauthorized it ..makes no difference. I have come to the realization the some will buzz and some won't. I have seen 2 other FJR's that basically don't buzz. Only remedy for me is a McCruise

I agree. The vibration is obviously due to the inherent design of the engine. The only thing that makes any difference on mine is the gloves I'm wearing. My winter (winter for Houston, that is) gloves have pretty heavy gel in the palms and that makes a big difference. But with summer gloves there is no avoiding the problem. I simply have to engage my throttle lock every 20 minutes or so to give my hand a break.

 

[Constant Mesh]

They all buzz a bit above 4K rpm. It's just a characteristic of in-line 4's. The dual counterbalancers do a fair job of minimizing the vibration but they can't cancel out all of it. The FJR's longer piston stroke increases the vibration but it does offer good low RPM torque.

FJR's Bore & Stroke = 79 mm x 66.2 mm = Ratio 1.193

Concour's Bore & Stroke = 84 mm x 61 mm = Ratio 1.377

I suspect this is one of the reasons why the Concour's engine is a bit smoother. One might assume that Yamaha and Kawa both implemented the counterbalancers as well as possible.

Honda in-line 4 car engines are counterbalanced and have vibration absorbing engine mounts. Yet one can feel engine vibration particularly at low RPM's.