Bad vibrations (Full Version)

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Bad vibrations

  

Noe -> Bad vibrations (6/25/2008 12:11:10 PM)

Hi all
 
Lately the vibrations from my engine is getting worse than ever before. Earlier the vibrations in the handlebars never caused any problems for me, but now 1½ hour of driving leaves my fingers buzzy and slightly numb, like when you have been using a chainsaw for an hour or so. Not as bad, but the same kind of feeling.
 
What can have caused this increase of vibrations in the entire bike, but especially the handlebars?
Are there rubber mounts between the engine and the engine mounts on the frame that can have grown old, and needs a replacement? Or what about tightening the bolts in the engine mounts, could that help?
 
The carburettors have been synchronised lately, The valves have been checked about 3 months ago, and I adjusted the balancer a week ago. None of it really helped.
 
I really hope you guys can help, because my otherwise great bike have gone bad, and my 4000 km trip to the Austrian alps is at stake here.

  
BayAreaRider -> RE: Bad vibrations (6/25/2008 1:09:48 PM)

you may be able to pick something up from this thread.
http://www.cbrforum.com/m_16260/mpage_2/key_/tm.htm

GILL -> RE: Bad vibrations (6/26/2008 4:58:18 AM)

Check all your rubbers (and not the one in your wallet[:D])  Over time they wear out.  Especially check the engine mount rubbers, the ones the engine sits in when mounted to the frame.  If you get them worn out bad enough, they will cause nasty vibrations.  Also check for any broken welds on the frame of your bike.  I had three, probably from some wheelies in the past which are hard on your frames, but after they were welded back up, the bike was vibration free and tight again!   Hope this helps
Oh one other thing, check for loose bolts on the frame and engine, anywhere there might be looseness.  How are your steering head bearings?

Noe -> RE: Bad vibrations (6/30/2008 7:20:40 AM)

The steering head bearing was replaced 3 months ago, so the problem shouldn''t be there. Today I tightened the engine mount bolts with the correct torque numbers with a torque wrench. Some of the bolts could be tightened a little bit, so they had come a little loose over time. I didn’t look for rubbers though. I didn’t thing that the CBR had those things…

I will report later if the tightening helped

GILL -> RE: Bad vibrations (6/30/2008 10:03:56 AM)

yes, there are engine mounts that separates the engine from the frame, otherwise it would be metal to metal and you would get all the engine vibrations transmitting right through the frame.  Tighting the bolts wont do much if anything, you should have a good look at the mounts, the actual rubber part.  Something else to try Noe is put the bike up against a wall with the front tire.  Put it in 1st gear and let the clutch out a bit and watch the engine.  You might have to remove a faring or two. Dont go crazy hard on your clutch, just enough to "rock" it with a engine load.  If you see excessive movement in the engine on the mounts I would look ito replacing the mounts.  there should be a few of them.  I''m not saying this is your problem, but from what you are discribing, it could be.  Does the vibration happen if you put in the clutch and coast?  Trying to rule out engine from drive train...

Hopefully its not something internal.......

I''m pretty sure there are no rubbers in the steering, unlike BMW''s who use them on their setup.

Aracanth -> RE: Bad vibrations (6/30/2008 11:19:33 AM)

Errr.
OK, I replaced my engine last year, and there definitely arent any rubber mountings between frame and engine. I have checked the Honda manual, and they arent listed either. The engine I bought had the mountings attached, and they werent rubber. Are these things an aftermarket kit, or maybe from a later/earlier year than mine? Vibes are something I have kind of learnt to live with a bit, but if rubber is available, well might try it...

Ara

ps Mine is an FL - ''90

Cheers

GeorgePBurdell -> RE: Bad vibrations (6/30/2008 3:22:11 PM)

A lurker unmasks.

I have two ''87 ''Canes - one I keep in New Mexico at a friend''s house, and a second I picked up locally (Atlanta, GA) as the first was so much fun.  The second bike - about 18,000 miles on it - is essentially original - no obvious signs of much of anything having been done to it other than routine maintenance.  It definitely vibrates more than the one in NM.  Following this discussion, I''ve learned about the balancer adjustment - didn''t know these bikes had this feature.  I knew they had balance shafts, but not that they were adjustable.

Following the procedure in the manual, I statically adjusted the balancer - turned it counter-clockwise until it "stopped" - then backed off a smidge.  The result was about 1/8 - 3/16 of a turn counter-clockwise.  To me, it feels somewhat smoother, but I didn''t have time to get it out on the road to truly try it.  I''ve seen discussion of making the adjustment on a running engine - any advice on the "correct" procedure for doing this?

DRam -> RE: Bad vibrations (6/30/2008 3:50:03 PM)

quote:

ORIGINAL: GeorgePBurdell



Following the procedure in the manual, I statically adjusted the balancer - turned it counter-clockwise until it "stopped" - then backed off a smidge.  The result was about 1/8 - 3/16 of a turn counter-clockwise.  To me, it feels somewhat smoother, but I didn''''t have time to get it out on the road to truly try it.  I''''ve seen discussion of making the adjustment on a running engine - any advice on the "correct" procedure for doing this?


Speaking strictly from memory without checking my manuals here, but if memory serves correctly the adjustment is to be made with the engine off.  I certainly could be wrong though.

GeorgePBurdell -> RE: Bad vibrations (6/30/2008 4:23:09 PM)

I may well be the one confused here - the manual does describe an adjustment procedure with the engine off.  From the conversation of this thread, I had gotten the impression that there was also an engine running procedure.  Not being anything approaching an expert, this seems a little suspect to me because of what the balance shaft is trying to do - but I am ALWAYS willing to learn from those who know - hence the question.

Shadow -> RE: Bad vibrations (6/30/2008 11:16:29 PM)

Welcome to the Forum ! Opinions differ on this - manual says do the adjustment with engine off, but the resistance is so slight that many members can''t feel when the shaft is correct. If you do it with engine running, you''ll know - if it whines, back it off until the whining stops.

boink1079 -> RE: Bad vibrations (7/1/2008 5:19:00 AM)

Hey Shadow.  I have been reading the threads on this and as I have never adjusted the balancer - I am a little cautious.  Any cons for adjusting while engine is on?  Any pitfalls to look out for? Manual states to add thread lock to bolt - is this necessary - does it work loose?

Noe -> RE: Bad vibrations (7/2/2008 8:19:34 AM)

Problem with vibrations solved. the fault was running on two different tires. The front tire was a michelin pilot road, while the rear being a Michelin pilot road 2. I know it shouldn''t be a problem with same make and type, but it was. The minute i went for a pilot road 2 in the front, the vibes dissapered. Very odd, but there it is.

Shadow -> RE: Bad vibrations (7/2/2008 12:35:43 PM)

Well, that''s one to put in the memory banks, guys - Noe, could it not have been wheel balance ?
Certainly, one should check the simpler things first, sometimes.[X(]

Noe -> RE: Bad vibrations (7/2/2008 1:35:05 PM)

The guy replacing the tire said that the wheel balance was spot on, so he didn''t change a thing there. just replaced the tire, and it was fine.
I still can''t belive it could be something so simple as mismatched tires even within the same make and type...

GILL -> RE: Bad vibrations (7/2/2008 7:28:58 PM)

I''m with Shadow on this one.  The mechanic acually checked your balance before removing your old tire? I hope he re-checked it after you had the new one installed.  It sounds like you perhaps had a bad front tire.  I''ve never heard of a mis-matched tire causing a vibration.  Wheel balance would be a 99% chance of being the culpurt, I would think, but I''m only human. 
End of the day, your vibration is gone, thats the main thing......... [:)]

  

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