Engine vibration

yalipito

yalipito

Member
#1
#1
Hi guys, looking for suggestions/thoughts on causes of extreme vibrations. I have a briggs animal engine that is smooth up to 5k, then from about 5.3k to 6k is horrible, and smooth as silk above that. I swapped the flywheel, no difference, removed clutch and fired the engine with the new flywheel only and it still vibrates like crazy. The engine has very little time on it.:cursing: Thanks
 
minibikekid

minibikekid

New Member
#2
#2
My intek is the same way. I've read that the OHV's are suppose to have less vibration than flatheads but i think that isn't so true. Time for someone to invent rubber motor mounts for mini bikers haha
 
9

956yerfdog

New Member
#4
#4
Im about the add a rubber slab from a semis mud flap thats about a quarter inch thick between my predator 212 and yerf dog frame. Will post with results of before after. And wait for arrival of swing arm.
 
125ccCrazy

125ccCrazy

Well-Known Member
#6
#6
if you try anything under the engine I'd use polyurethane sway bar end link bushings but put a plate under the engine with the bushings between the plate and the frame.. you don't want to snap the mounting flange off the block when the engine torques up...
 
MoTo-BunnY

MoTo-BunnY

Member
#7
#7
I used a piece of neoprene scrap I got from our local hardware store. They have a display in the store where they sell metal scrap of different kinds as well as different thicknesses of neoprene, sourced from a local manufacturer or something. You could probably find similar material as part of a mat or mud flaps or something.

These mounts aren't truly vibration isolated though, since there are bolts that go all the way through, but it is pretty vibration free and with the whole area supported with the neoprene (as opposed to just a small round area) it's not going to break any of the mounts. :thumbsup:

 
B

Bill Ellerby

New Member
#8
#8
May not be the motor, rather the unbalanced clutch or Torque Converter added to the motor. But since you already tried it without the clutch I think you just hit on the motors harmonic sweet spot where the vibrations are resonating just right. All rotating masses have them. I worked on helos with the Navy for 26 years and them babies have some outragous vibration rates,lol.
 
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yalipito

yalipito

Member
#9
#9
Bill Ellerby said:
May not be the motor, rather the unbalanced clutch or Torque Converter added to the motor. But since you already tried it without the clutch I think you just hit on the motors harmonic sweet spot where the vibrations are resonating just right. All rotating masses have them. I worked on helos with the Navy for 26 years and them babies have some outragous vibration rates,lol.
Click to expand...
I'm going to swap the crank to see if that is the problem. Will post results when done.
 
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