Engine vibration on acceleration

[1340evo]

Hi.. was out on the bike over the weekend and after I got tired, was getting a bit fed-up of the vibration on acceleration...
bars and front end are okay, but I feal it more through the seat and bit in the solid mounted peg's... was thinking I may try line it up better?.. removed the top engine mount and the bolt is free in the hole... Is there a good procedure for doing / checking this at all?... Think its sitting right ... bike drives fine, straight, does no feel out in corners etc .. Cheers

[tmwmoose]

What model ,makes a difference

[1340evo]

1989 FXR.. so rubber mount...
from what I remember, it vibrates more than my old FX Shovel on acceleration... at speed and part throttle its okay.. just when you turn on the gas...

[Hossamania]

Check for loose exhaust or broken mounts on the exhaust. Give the bike a general inspection looking for loose or broken fasteners.
How old are the motor mounts?
There is a procedure in the service manual to check for alignment.

[tmwmoose]

Well the easiest thing to check as I'm sure you know is the front rubber mount especially look at bottom see if it has ripped ,you may also get a thud/klunk going over a good sized bump. Is there anything you've done lately to the bike?

[Deye76]

I've been chasing a vibration in my FXR, also. Spoke with several shops that do alignment, they said alignment won't cause vibration. How does the bike track?

[1340evo]

Hi All.. basicaly, everything is new 2000 miles ago... nothing broken, no thuds, exhaust new etc... it tracks fine and turns fine... when I had the clutch in bits last week, I checked the final drive was in line with the clutch and engine and found it to be spot on but this is obviously determined by the rear mount... it may be my rubbers are hard.. I actualy drilled a couple of holes in the front rubber to make it more compliant as it didn't move when the engine was placed on it..... just wondering how the procedure went to see if I could find anything?... May be just in the fly wheels??... I could always try dirrect bolting the front and see which way that goes

[Pete_Vit]

Tires ? Tire Pressure ? 

[Hossamania]

You could try loosening the front mount and starting the motor, letting the mount "shake" into place.

[1340evo]

not sure how tire pressure would make the engine vibrate?? and I've run it up with the front mount(s) lose.. sits where it is...

[Pete_Vit]

hum, didn't see that in the original post Engine vibrating, just vibration vibration on acceleration.....

[thumper 823]

Kiss-
Do a leak dwn or comp test.
Next, I would reexamine everything in the primary case .
Worn sprockets, chain, busted compensator.

[1340evo]

Compression test they are both spot on to each other.. and no oil burning.... and I was hoping doing the clutch (used 1990 unit) and fitting a new primary chain, comp sprockett and Rotor would make a change... but I think its as bad after the strip down and replacement of parts as it was before?....
But it's not in the bars or front end.... my bars are dirrect mount so no rubbers... and they are fine... its your seat that gets it??..

[thumper 823]

There are way too many models for me to know the differences -
SO-
If you have a swing arm check the rubber bushings.

Jack rear wheel off ground.
Unhook bottom shocks.
Grab rear tire and move laterally  (lef/ right)
Any perceived looseness is a big problem.
Most rubber swing arms are shot and most people dont know it.

[Hossamania]

You mention everything new 2000 miles ago. When did the vibration start?

[Rugby_fxdwg]

Drilled holes in the front motor mount?!? Did I read that right?

[1340evo]

I'm not sure.. I bought it with 1500 miles on the clock and have put 500 on myself... I'd guess it was there from re-build... could have been there before... the guy who did it was quite good and had the bottom end checked in the cases and it passed... but what they can't check is balance I guess...
Yes.. are bushes new and re-checked... but again, how does this make the engine vibrate?...
and yes... i drilled the front mount... it was solid.. putting 4 holes at 15 min spaces made it a lot better.. LOL... I have the original also and swapping back makes no differance... but thats why I'm thinking are the rears the problem?... although they are new could they be harder rubber also??... judging by what he paid for them (I hame all the reciepts), they must be gold plated... swo could assume they are quality units?

[Hossamania]

New mounts will sometimes transmit more vibrations when new until they "loosen" up a bit. My front motor mount was a bit stiff for a few thousand miles.
Have you yourself double-checked your exhaust mounts, and other fasteners, or just assuming they are right because everything was done new before you got it?

[1340evo]

No.. I've just had the exhausts off as I upgraded to a 1990 output shaft in the gearbox to go with a 1990 splined clutch hub I bought... so I know they are fine.... It was me fitted the exhausts in the first place as it had SS straight through pipes on when I got it... put some V&H Straightshots on from a Dyna... had to modify the headers a bit and make all new backetts... so I know they are okay...
wondering if its worth checking the cam timing and measuring runout on the crank end... can't take long to do?... I don't suppose the cam timing could be out?.... would have to be a full tooth... would it run?... can't see it being this but other than the crank itself, I've checked the rest?

[thumper 823]

check your wires as secondary leakage could have a miss fire going on on the wrong cylinder.

[Burnout]

No one has mentioned the rear motor mounts or the swing arm bushings which deserve equal attention.

Inner primary to motor connection, the trans to motor adapter if equipped and all other hardware.

Exhaust is also a source of problems if the early mounting system is used.

Some exhaust will hit the mid mount controls under power.

[1340evo]

Wires okay, but rear plug does run with a bit of black on it for some reason....

Only thing with rear bush is its its too stiff being new maybe....

[hbkeith]

are you using the rubber mount on that exhaust ?

[1340evo]

No... but all the bracketts bolt to the engine / box....

[hbkeith]

you say it has new bushings , CCE or Sta Bo kits will make em vibrate