Vibration rpm limit

velardejose

New Member
Sep 9, 2008
120
0
0
Lima, Peru
Hi
Is there anything we can do to reduce engine vibration above certain rpm?
Why are other engines smoother than our china girls at high revs?
I am new to two stroke engines, sorry if this is a dumb question
Thanks in advance
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,843
236
63
up north now
Not very easily. If you have knowledge of and ability to perform a balance job, it would help.
These engines are crude and pretty much unbalanced.
They are 40's technology.
They are made in China with little quality control.
They are under 200 bucks.
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,843
236
63
up north now
I have had a couple that were ALMOST as smooth as a Japanese dirt bike engine....others that would go 40 mph, but vibrated so bad, you could hardly hang on.

Going to a 40T sprocket will help, so will balancing your wheels.

I have gone to mounting all engines with small 1/16" thick sheets of lead between the mounts and the frame (4 pcs. total)...works like magic!
 

OSCAR383

New Member
Jul 22, 2008
243
0
0
36
WEST FRANKFORT, IL
two things i have done and i love it is one cut up an old tube and wrap around the frame where you mount the engine to and the other is get a lower tooth count sprocket. lower rpm = less vibration
 

crassius

Well-Known Member
Sep 30, 2012
4,032
156
63
USA
yeah, in this decade, try a piece of PVC plumbing pipe between mount and frame for best results
 

wildwood

Member
Jul 25, 2017
43
4
8
35
I used the rag joint in between the motor and the rear mount with out a problem. The smaller sprocket is a wise choice 36 teeth and I still don't need to pedal up the hills of Pittsburgh..all that and some port cleaning plus a tight nkg plug boot 40mph on a 107 dollar motor kit off amazon. Damn thing runs better then the flying horse