Vibration like mad

[Rockjaw]

i like the bike ..its cool for the beach but it vibrates the pedals ..my feet cant take the vibration when i throttle...its like the feeling of someone tickling under my arms when i was a kid..
just cant take it
.i used rubber handle bar grips cut up on the mounts and it still vibrates the pedals . Any ideas ? maybe rubber on the pedal bars?

 

[butre]

ditch the rubber

 

[Rockjaw]

you think the rubber is making vibration worse? i havent tried without,..but i thought rubber helps stop vibration

 

[keatonx]

The rubber allows the engine to wiggle more from each vibration, which sometimes makes the vibration worse.

 

[keatonx]

Basically the consensus on here is don't use rubber and let the heavy bike frame dampen the vibes

 

[Rockjaw]

yeah i have the bolts very tight but when im riding i can see the motor moving a lil bit..i guess ill ditch the rubber

 

[butre]

soft mounts are fine if you have something like polyurethane and no fewer than 3 mounting points, but hard mounts are a necessity for an engine with only 2 mounting points.

 

[Deleted member 12676]

click on my signature link and read about how to cure the vibration

 

[Fabian]

you think the rubber is making vibration worse? i havent tried without,..but i thought rubber helps stop vibration

Wrong!

Rubberised mounts only work if the frame/chassis weighs significantly more than the engine, because you need the frame to have excess mass over the engine to dampen the full amount of cyclic movement being transferred back to the chassis.

In the case of a motorised bicycle, the engine needs to be solid mounted to the frame, as rubberised mounts will amplify vibration, not reduce it.

 

[KCvale]

yeah i have the bolts very tight but when im riding i can see the motor moving a lil bit..i guess ill ditch the rubber

There is one simple test you should do at least every time you add fuel:

Grab the top bar with one hand and the top of the head with the other.
Now try as hard as you can to shove the engine back and forth.
No kidding here, give it all your arms can do.
If it moves AT ALL that is a fail.

A big common mistake is not getting the back motor mount to a nice 90 degree angle from the seat post, all of your engines pulling force is here and it has to have full contact, not just an edge of the mount.

All your lateral torque has to be handled by the front mount.
I don't dink with the stock front mounts, I use a muffler clamp that fits the downtube, a steel plate (via the SickBikes front mount kit or shop fabbed), pull the studs out and bolt the plate to the engine with good bolts.

The difference with a muffler clamp opposed to just a U-bolt and flat plate against the downtube is the all important grab to resist lateral twist.

A bonus with the SBP front mount kits is an assortment of spacers for those really wide bike cavities and you can put them on the nice fat U-bolt.

This won't help vibrations from a poorly balanced or timed engine but it will make it more bearable and your engine won't fall out ;-}