Vibration on 2,5k r.p.m.

[MOTOMYSZOR]

In general my FJ running very well. Carbs  synchronized, valve done.......

But when I have to ride slower, especially in city, engine starts vibrating from 2,2k rpm. 2,5 k rpm is the peak and some plastic parts in fairing and something around cluster starts being noisy. Over 3000 rpm engine running very smooth.


Should I look inside engine or that is just normal and I need get used to?

[FJmonkey]

Make sure your chain is properly adjusted, not too worn/stretched and aligned. It has been known to be a source of vibration.

[simi_ed]

I had a huge amount of noise inside the 'bubble' after my FJ hada few years.  Most of it was from the screens in the inner panels of the fairing.  I RTV'd the screens so they could not vibrate.  This made a world of difference.
I would try running the engine to the rpm that induces the vibe-mode, then start searching for the offending pieces.  Find & fix; next!

Ed

[The General]

Greasing the front engine mounts makes a huge difference on your model. (and it always sows up in the 2500 - 3300 rpm range)   

[Bozo]

My bike is the 1989 model which is different to the later models (as yours is), not bad around the city but I do have minor engine mods which would make the engine characteristics different. Previously mentioned chain sounds like the culprit (if the mounts are greased as The General mentioned).

[Arnie]

They are all more "viby" under 3K rpm.
For the rubber mounted late model bikes like yours, you can minimize the vibes by:
Making sure the valves are in adjustment
Sync'ing the carbs
Making sure the chain and sprockets are not worn or too tight.  Check the C/S sprocket under the cover, it can wear or be loose and cause bad vibes (just before it comes off! )
Make sure you're using HEAVY bar end weights (OEM or RPM vibranators)
Also, check the bolts on the lower frame links.  These can loosen or shear and not be obvious. 
You have to remove the footrest plate to properly inspect and/or repair

[Bozo]

They are all more "viby" under 3K rpm.
For the rubber mounted late model bikes like yours, you can minimize the vibes by:
Making sure the valves are in adjustment
Sync'ing the carbs
Making sure the chain and sprockets are not worn or too tight.  Check the C/S sprocket under the cover, it can wear or be loose and cause bad vibes (just before it comes off! )
Make sure you're using HEAVY bar end weights (OEM or RPM vibranators)
Also, check the bolts on the lower frame links.  These can loosen or shear and not be obvious. 
You have to remove the footrest plate to properly inspect and/or repair

Arnie, how are you? glad you mentioned the vibranators, I keep on forgetting I have these and they do make a difference, especially on the older models.

[Burns]

does the rubber in the motor mounts harden with age?  seems like they would.

[Arnie]

does the rubber in the motor mounts harden with age?  seems like they would.

Don't know if the rubber hardens, but the grease is lost between the shaft and the sleeve. When this happens, they corrode and lock together. This allows the vibes supposed to be absorbed by the rubber to get through to the frame AND you.  Freeing this joint and re-greasing is a worthwhile maintainance procedure, probably every 5 yrs or so.
 

[FJ_Hooligan]

As The General said, this is the RPM range where frozen front motor mounts transmit huge vibration.

[Bob]

As The General said, this is the RPM range where frozen front motor mounts transmit huge vibration.

Yup... made a huge difference when I cleaned mine.

Removing them was lots of fun...

[ribbert]

As most folks who have done these know, they can be unbelievably tight. Many of us, having underestimated just how tight, have broken our first efforts at making pullers.

What would be better suited to the task, a fine threaded puller or course threaded puller?

Noel

[Pat Conlon]

Fine threads = Closer threads = more threads per inch = more load can transferred to the threaded shaft, and it's easier to turn the nut.

After stripping out the threads on the hardware store "all thread" rod,  I had my machinist buddy Paul make a fine thread puller with 1" long nuts.

When my job was done, I sent this tool to Randy @ RPM for his use and other FJ folks to use. Give him a call.

[wainot]

Ok  .I had the same problem with my 94 FJ1200 . Very bad Vibs  going right through the Bike and Me from about 2500 to 4000 rpm .
I also noticed that the right mirror was more blurred than the left at all times .
I made myself up  3 puller,s  from threaded rod  (THEY ALL BROKE) while trying to pull the inner bush out of the engine mount.
I ended up getting a bolt exactly the same as the engine mount bolt ,but just an inch or 2  longer .that worked fine,
The Left Bush was lightly rusted in and stuck in pretty good ,but it came out under medium pressure ,
But the right side Bush was Rusted in real real  good and I had to put 3 times more pressure on it to get it out .
I think that's why the Right Mirror was Vibrating more that the left at all times. 
I then cleaned the 2 Bush's up .Greased them and re-installed them.
,,NO MORE BAD VIBS .. 
This is a must do job ,,  The only real problem I had was
when I reinstalled the engine mounts .I then had a real problem getting the  spacing pipe between the mounts.
The spacer pipe that's about a foot long, that the main long  Bolt goes through .
(It seamed that the spacer was about 3mm to long).
I loosened the mounts back off but that made no diff .
!!!!!After about 1/2 an hour or so !!!!!.
I worked out that when I removed the engine mounts and spacer ,the Bike's lower Frame must have sprung closer together bye about  3mm .
So I cut a small piece of 1' x1' Wood and a small wedge ,put them between the lower frame
and wedged the lower frame apart by 3mm .
"""BINGO"""  it all then fell into place real easy.
So its smooooooth  as silk again
I have hopefully attached a photo of the right hand side Bush and my 1st attempt of a puller .
I found its best to use a Bolt the same a the Bolt that can out of the engine mount . but an 1" or 2" longer.
Its well worth the effort ..
Hope you have all had a good  Xmas .
regards  "wainot"   Phil from Aussie

[ribbert]

As most folks who have done these know, they can be unbelievably tight. Many of us, having underestimated just how tight, have broken our first efforts at making pullers.

What would be better suited to the task, a fine threaded puller or course threaded puller?

Noel

I have should have made it clearer, which one has the greater torsional strength?

Noel