Vibration (again)

[woodwizzard]

Got a vibration through the right hand bar at 80ish mph. It starts at around 4k and is worse at around 5k rpm. It makes my fingers go completely numb after awhile. Can get it to do it on the centre stand, so engine related as far as I am concerned. Will check the carb balance when I get a chance. Have checked the TPS, loosened engine mounts and retorqued them all to no avail. Any other things to check? Surely this can't be normal!! Bike will have to be sold if it is, I do most of my miles sitting at those speeds so need it to be smoother. Any ideas chaps.

[b1k3rdude]

Any ideas chaps.

Not knowing what other posts you have made about this, I might be repeating some old questions -

1. Can I assume the oem bar end is present and tight..?
2. have you check the rubber under the handlebar risers, are they perished or in good condition are the rise nuts tight..?
3. are all the top yoke bolts tight (while your there check the lower yoke bolts)
4. are the handlebars in good condition..?

If none of the above applies I think I remember someone saying they filling up the inside of their handlebars with lead shot.

[woodwizzard]

I haven't posted on this myself, but have noticed others have had similar vibe problems at these revs.


Bar ends are not original, but they are fitted well and nice and tight. Loads of lead shot came out when I took the bar ends off. I rolled up some sheet lead and put that in instead, 83 grams each side, made no difference. Tried removing the risers the other day, but couldn't budge them, will look into this further.


Yokes are torqued up as I put the forks back to standard when I got the bike.


Bars are renthal 758, should they have a brace on or not?


Bike is smooth other than between 4 and 5500rpm.

[b1k3rdude]

• Bar ends are not original,
• Bars are renthal 758, should they have a brace on or not?

• The oem bar weights are quite heavy, so the 3rd party ones you have atm might not be heavy enough to dampen the vibes..
• They are thicker and more sturdy than stock, but beyond that I dont know.

[PieEater]

I have the 758's tapped out to take the OEM bar ends, certainly I noticed more vibes in the short while I used lightweight aftermarket ends, but if you've weighted the bars anyway you may have that base covered. I don't have a brace, I can understand wanting one on a bike that has a propensity to hit the dirt a lot, and need to be picked up and ridden again but for road bikes I think they are more for cosmetics really. However every time I've balanced my carbs I've noticed a reduction in vibes so hopefully that will be the answer for you, or at least go part way to resolving the issue.

[Fazafou]

If you've only got the vibration recently then something has happened to cause it (rather than being a character of the bike if you see what I mean).

Check nothings loose, this can even be caused from loose silencer fittings or the exup valve buzzing at certain frequencies.
Definitely check and balance carbs/TBs and not just at idle, check at a few thousand revs just to be sure.

Check all fairing fixings and nothing is buzzing - I recently put foam padding behind certain parts of the fairing and all vibration disappeared.

[b1k3rdude]

Check all fairing fixings and nothing is buzzing - I recently put foam padding behind certain parts of the fairing and all vibration disappeared.

The infill's and the screen are demons for that, I got some foam tape from the local car spares shop. Leaving the cover on one side I applied the tape to the underside of the screen and cut small strips for the edges of the infill's.

[woodwizzard]

Thanks for the suggestions guys


Not had the bike long and this was the first long trip I have done on it, hence noticing the hand deadening vibe. Was there before, but thought nothing of it as not used at such a constant speed before. Have just fitted a fabbri DB, but as said, I can't help thinking that because it vibes stationary, it probably stems from the engine. Is it possible to get new engine mounts, these must harden and go off with age.



Balanced the carbs tonight, they were all out, but not massively. Not ridden it yet, but on the stand vibes still there, maybe not so much though.


Will fit new spark plugs, there are iridium ones in, but I don't know how old they are. I took one out and it looked quite manky.


As its only 2 bolts, I could drop the whole fairing off to eliminate it as the cause.

[shrekster]

I sold my last fazer mainly due to the vibes, I tried everything, TPS adjustment, loosening the engine mounts, balancing carbs etc. I even bought a new front engine cradle to replace the rubber mounts, nothing worked. I sold it and bought a Pan Euro, sold that and I bought another fazer last year and it's the best of the 3 I've had, almost completely smooth at all revs. It seems you can get a good or bad one when it comes to vibration levels.
One thing I did notice was that sometimes the vibes were really bad, I could stop for fuel and when I set off again it was much smoother, this could also work in reverse I.e. It'd be smoothish, then I'd stop then the vibes would appear when I set off again. Just couldn't figure it out. It was definitely engine related because if I rode at any speed and pull the clutch in the vibes disappeared completely, let the clutch out and bring the revs up again the vibes were back.
Hope you sort something out.
Jim.

[Falcon 269]

It's an inline 4-cyl motor with no balancer shaft so some vibes are inevitable.

The engine mounts go some way to isolating them from the chassis but won't completely eradicate them.

I've found that a full tank of fuel acts as damper, too. 

Altering the TPS setting can move the most noticeable vibes up/down the rpm range by 500 - 1000 rpm.

Having worked on over 500 Gen 1s, I've found some that are definitely rougher-running than others.  Some sound & feel the same even after the most careful carb synch. 

Others - a small percentage overall - are what I call 'accidentally blue-printed' from the factory - all the rotating/moving mass components (pistons, rods, crank etc) are perfectly matched.  These motors run like silk compared with the usual run-of-the-mill donks.

One of the FZ1OA guys, Ravenrider, blueprinted a Gen 1 motor during a rebuild and found that the difference in weight between lightest and heaviest piston was the equivalent of an old penny.  That's quite a lot of imbalanced weight thrashing around at 5k rpm.

Some days mine runs smoother than others ... weather plays a part, I'm sure. 

You could drive yourself nuts trying to eliminate vibes.  Good luck with your efforts but don't be too disappointed if you don't achieve your holy grail.

[woodwizzard]

I don't mind a few vibes, all part of the riding experience for me, but when your right hand goes completely dead on a 6 hour ride it's no longer enjoyable. Love the bike to bits and runs sweet, but if I can't dial the vibes out abit it will have to go.

[Falcon 269]

Sure, I do understand what you mean and those kind of hand-deadening vibes are - literally - a pain.

Are you disposed to suffer from 'white finger' syndrome or whatever it's called medically?

Have you experimented with the angle of the bars?

[woodwizzard]

Strange thing is, that it is only through the throttle grip. I suppose its' because the tube is free floating.

[Fazafou]

Strange thing is, that it is only through the throttle grip. I suppose its' because the tube is free floating.

Yeah that's normally the reason for only noticing on the throttle sometimes. Also it can be the frequency that is an issue. I had a Tiger 800 I had to get rid of as the high frequency vibes at 6k were making the bike unpleasant to ride. They weren't that strong, just an irritating frequency that left your hand buzzing for hours after getting off.

Quite often the heavy bar ends aren't actually 'absorbing' the vibration, but adjusting the frequency at which they vibrate, hopefully to a pitch you don't notice or can live with.

[Falcon 269]

You could try different grip material.

Also, try Ivan's method for adjusting the TPS. 

Warm the motor to operating temp and pre-loosen the Torx screws on the TPS.

Next, set the rpm to 3,800 by winding up the idle adjuster.  Slacken the TPS screws and rotate the unit in either direction looking for the highest achievable rpm.  You should be able to get an increase of 200 rpm or more.  A final reading of 4,200rpm is not unusual. 

What you're doing is finding the ignition timing sweet spot for part-throttle cruise.  Once you've found it, tighten the TPS screws, reduce the idle back to 1,250 - 1,300rpm and then go round to apologise to the neighbours.

[NorthWestern]

It does seem to be a case of some are worse than others as Falcon says. 


I have 758's with no bar ends or weights in them with no vibe issues at all.  I later fit R1 forks and the top yoke has no rubber mounts for the risers like the standard one, even then it didn't produce any vibes (although the rubber mounts are rock hard so prob wouldn't do much to dampen anything).  I do have a cross brace but fitted that a week after putting the bars on, it made no difference to the vibes.

[Jinx46]

I find using branded fuel reduces vibration through the bars.

[woodwizzard]

Only managed a quick ride yesterday and didn't get a chance to sit at those revs, but went upto and through them when I could and they do seem to be less after the carb balance.


Setting the TPS up Ivans way, does that alter the timing, or can I still try an advancer?


Will fit new plugs this weekend and try the branded fuel also.

[Falcon 269]

Setting the TPS up Ivans way, does that alter the timing, or can I still try an advancer?

Yes, it advances the ECU-controlled ignition curve below 6k rpm.  If memory serves me right, max advance is 55 deg BTDC and that comes at 6k rpm.

[woodwizzard]

Sorry for being dumb, but is it best to only set the tps up Ivans way OR fit an advancer? Is it ok to do both or just one or the other?

[Falcon 269]

You can fit an advancer and use the same technique to find the sweet spot but start with Ivan's way and see how you get on first.

[PaulSmith]

You could try different grip material.

I tried these with resonable success. http://www.grip-puppy.co.uk/

Once you've found it, tighten the TPS screws, reduce the idle back to 1,250 - 1,300rpm and then go round to apologise to the neighbours.

Are you sure about that idle figure for the Gen1? I thought it was supposed to be about 950rpm?

[Falcon 269]

Stock is 1050 - 1150 rpm according to workshop manual. 

The higher figures help maintain oil pressure at idle and the transition from idle to part-throttle.

950rpm is way too low.

[woodwizzard]

May give those grips a try, thanks for that.


Received my advancer today, so that may shed a few more vibes. It is better after the carb balance and it does vibe less with a full/half full tank.

[PaulSmith]

May give those grips a try, thanks for that.


Received my advancer today, so that may shed a few more vibes. It is better after the carb balance and it does vibe less with a full/half full tank.

As a matter of interest, how long is it since you last changed your plugs? (miles/years)