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View Full Version : Bike on the road!!! vibration heavy :/



JBW5
07-11-2014, 9:02 AM
So I took my little cafe build for her first night ride and lingest ride yet. All seems to be running well but the thing just about vibrated my arms off at speed. Any suggestions on fixing that? Could it be chain tension, motor issue or that just how this thi gs gonna ride? Thanks!

Ato
07-11-2014, 9:06 AM
My first thought is maybe the carbs are out of sync but it's hard to say w/o more details and/or seeing it in action.

JBW5
07-11-2014, 9:24 AM
That probably has something to do with it. All I have done is bench synced them at this point. I plan on doing a manometer this weekend but was surprised at how well it ran as is. Wasn't sure if that would cause vibration or not.

Ato
07-11-2014, 9:31 AM
Actually the more I think about it that probably isn't going to cause the really violent vibrations you describe especially at higher speeds.

farmall
07-11-2014, 11:03 AM
Describe symptoms in DETAIL. I assume the 750 in your profile pic? Happy CBs are smooth so something isn't right.

What sort of vibration? "Vibrating your arms off" can be an uncomfortable buzz or a violent shake.

"At speed" isn't specific enough. At what precise mph range does it vibrate unduly? Have your wheels been spin-balanced? Checked tire pressure with a guage? Checked tires visually if old for lumps or other signs of belt/cord failure?

I'm not thinking carbs if properly bench-synced.

JBW5
07-12-2014, 8:24 AM
It's not a violent vibration, more a heavy buzz. I feel it in my hands and arms most but can also feel it in my seat. Not sure of the exact speed but it more just seems when rpm's get in the higher ranges. No tach or speedo at the moment. Tires are fairly new don't think they have been spin balanced though.. This is all on a 1978 cb750k.

JBW5
07-12-2014, 8:32 AM
Here is a quick pic I grabbed of it.

JBW5
07-12-2014, 8:34 AM
Could it be a timing issue? I've adjusted the valves and points but not sure if my points are right where they need to be...

TwoLaneFever
07-12-2014, 9:00 AM
solid mount h/bars/ thin grips,, going to viberate,goes with your set up ,,,use super bike grips soft rubber somewhat insulates from the tingles

Dinlow
07-12-2014, 9:42 AM
Have you checked the top motor mount?