Vibration all over bike at different RPMs

[chrisfed]

Hi Everyone,

Done a fair bit of reading. Vibration at 4k at the gas tank, 5k at the pegs, 6k badly in the bars, some RPM vibrates my chode ...etc. RPM dictates frequency in engine/exhaust, causing vibration in different areas of the bike. Vibes stop around 8K>. Unrelated to speed, just RPM, so not a tire/wheel issue.

Anyone ever had vibrations on the stock exhaust setup then replaced it with a full exhaust (not slip on) and the vibrations went away? My hope is that the vibes are in the exhaust, not the engine.

I've reseated the engine (loosened all mounting bolts/nuts and retightened to spec), retorqued the handlebar 4 bolts, reseated the airbox / gas tank, tightened all exhaust mounting bolts, tightened down the windscreen...etc. I need a fix, not a band aid so please no recommendations for grip puppies or lead shot (both of which i have b/c the vibes drive me nuts).

I need a solution or the bike has to go! I'm open to all suggestions for finding the source of the vibe.

2008
1500 miles (2nd owner)
Stock exhaust

I have not done a throttle body sync.

Whomever gets me the right answer wins a prize. Anything from a giant ASCII smiley face to something tangible, like a stack of scratch and sniff stickers

Looking to take the bike on a cross country tour NY->Cali then south to the bottom of South Am starting in the spring so I need this vibe gone.

Cheers
Chris

 

[DownrangeFuture]

Synch your throttle bodies and adjust your idle to closer to 1500 RPM. Some people suggest synching at 4,000 RPMs to smooth it out a little more.

Unfortunately, this is a buzzy bike. So I doubt the problem will ever truly go away.

 

[FinalImpact]

OP - you did what I would have done had the bike been mine so the next step is to confirm the sync is good.

Lets say we weed out ignition as the source and look at the next most vulnerable aspect being the throttle body sync. If you do this and they sync up nicely at idle and up too 4000 RPM I would bet it helps. If however you have issues getting them sync'd as in "GOOD AT IDLE" but off at higher RPMs I might consider looking at the throttle shaft adjustment between the two throttle bodies. You noticed the throttle bodies are two sets of barrels with the throttle shafts bound by an adjustable spring loaded mechanism yes?

If the two bodies are not adjusted to flow the same amount of air at idle and above it could easily cause the vibrations you have. Not that i'm saying this is your problem but if the balance issue is hard to obtain (between idle and higher RPMs) I'd be looking closer at the two different bodies and confirming both are opening the same amount at the same time. I have no idea if the factory setting was based upon flow rates or a simple mechanical measurement. But it might be worth checking.

 

[chrisfed]

Will take me some time to do a throttle body sync but i'll raise the idle in the meantime. Cheers

 

[TownsendsFJR1300]

As posted above, the throttle sync WILL make a big difference. I did sync at 1350 RPMs and 4K.

My irritating vibs were at about 4k RPM. Checked / re-adjusted at 4K(besides at idle) got rid of 90% of them. I have my idle set at 1000 RPM's once to temp, well below the recommended, my mirrors have NO vibration.....

Grip puppies on the grips, a Spencers modded seat and leather vented gloves with gel (on the inside of the hand) make it a completely different bike...

Also, as noted above, most inline 4's will have some vibration inherent with the bike.

BTW, the factory usually puts a small spot of paint on the center throttle body shaft adjuster screw (it is not meant to be adjusted once done from the factory). If that paint "seal" is moved/broke, when doing the sync, you may have to set that back to factory settings if you can't get the sync within spec's using the air screws...

 

[FIZZER6]

After performing my first ever Throttle Body Synchronization on my bike this week (14,000 miles), I can tell you without a doubt that this is 90% the cause of the typical 5-7K rpms high frequency vibrations (buzz).

On a scale of 1-10 of annoying vibrations, my bike was an 8 before...after the sync it's probably a 2 or 3. :thumbup:

 

[chrisfed]

wow that's quite inspiring. guess i have a tbs in-store. which tool did you use? did you sync at idle then at 4,000? Which idle did you sync at...1,000, 1250, or 1500?

 

[FIZZER6]

wow that's quite inspiring. guess i have a tbs in-store. which tool did you use? did you sync at idle then at 4,000? Which idle did you sync at...1,000, 1250, or 1500?

Check out the "How To" section...I just posted my Manometer build and throttle sync How To yesterday.

I synched at 1,350 rpms (idle) and at 4,000 rpms and ended up with a balance between the two.