Engine Vibration Iinsulators

danford1

danford1

#1
#1
I have an old Cat with a 3hp Tecumseh.
I want to isolate the engine vibrations from getting to the frame.
The engine is just hard mounted to the steel plate with bolts like most minbikes.

I tried adding some vibration pucks used for air compressors under the engine. They work great at eliminating the vibrations but the engine moves around to easy and the movement loosens the chain and it pops off. I added one to stop the side the side movement from engine to frame and another one to stop the fore and aft movement.
The engine still twists and the chain falls off. If I ride it slow and easy, it is fine but any fast acceleration pops the chain off. Oh, this is a new chain by the way. I rode it with the new chain prior to this and it didn't pop off.

How do you guys eliminate engine vibrations?
I wasted a lot of time and money on this idea :-(
These are about 1" in diameter and 1 1/4" tall. They DO wok but you can't hammer on it. What fun is that?

Danford1

PS I tried to edit this post to correct my typo in the title, but the "system" won't let you edit the title...

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creia

creia

#2
#2
Nobody uses them do to the problems you have already mentioned. There have been many previous discussions on this topic. use The Google Custom Search bar at the top of this page and you can read about them.
Michael
 
Aircooled

Aircooled

Member
#3
#3
Maybe using something that isn't as soft and spongy as rubber...a firmer urethane type bushing, perhaps?
I'm also experiencing a vibration problem, but still not 100% sure if the vibration is telescoping thru the frame from the engine.
I'd be interested in what you come across to remedy the problem.
 
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minikenny

minikenny

Member
#4
#4
Like you found out, you can't have the engine able to move independently of the rear axle with a chain drive. Actually bolted tight and solid to the engine plate is the best for less vibration.

If you are feeling excessive vibration, look for something loose or cracked. Maybe the fork to neck connection is loose? Also check where your handlebars are bolted to the forks.
 
Roadmaster75

Roadmaster75

Member
#5
#5
I used an isolator kit that I got from MFG Supply I believe.
Used it on the Gilson swing arm chopper I built a couple years ago. It does a great job of dampening the Hemi
Predator. Has not shifted around at all.
 
CarPlayLB

CarPlayLB

Well-Known Member
#6
#6
Kenny gives great advice! Is your engine plate cracked cracked under the layer of gunk? I have bought frames that looked to be in great condition and when they come home from a sandblast, nearly every weld has a crack! These old minibikes were hopefully ridden hard...that is part of the fun! Vibration, fumes, noisy clutches, sketchy brakes, loose tolerances....it's all part of the minibike dynamic!

Just tell yourself you are Indian Larry riding a rigid chopper at 60 MPH for on a 300 mile road trip!
 
danford1

danford1

#8
#8
I'll inspect the plate and all the welds on the frame. The steering joint is tight as I just put that back on and made sure it was as tight as it could be without binding.

In another thread I was reading about vibration, someone said to put a Predator 212 on it.
Why would that make it vibrate less? Wouldn't that be worse?

Danford1
 
Raskin

Raskin

#9
#9
Bent crankshaft? slop in crankshaft flywheel broken fin..clutch issue? got another clutch to try on it?
 
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buddy44

buddy44

Member
#10
#10
Those rubber isolators are way too long. Something much shorter might help, 1/4" would be better. The old horn insulator bolt off of an old Harley FL Shovelhead might work. It's probably about 1/2" thick with a 5/16 threaded stud on each side.
 
danford1

danford1

#12
#12
The vibration isn't anything unusual. It is the normal type of minbike engine vibration I felt on other bikes. I was just trying to eliminate it.
I have a 1/2" thick hard rubber pad. I'll try that.
A friend was saying they make "Lord Mounts" for airplanes that stop vibrations but don't allow a lot of movement like my vibration mounts.
He said the web site is lordmounts.com but I haven't studied the site yet. My guess if it for airplanes, it is expensive...

My clutch is a Max Torque. It has some slop but nothing excessive (I don't think). Crank isn't bent and it tight in case. No, I don't have another clutch to try... If someone has one they want to send to me, that would be fine...

I should be trying the 1/2" thick hard rubber pad this week. I'll post back to let you know how it works.

Danford1
 
creia

creia

#13
#13
With the rubber sandwiched between the engine and the mounting plate you will have real difficulty keeping the engine from moving (back) and loosening the chain.
Michael
 
Raskin

Raskin

#15
#15
...I was just going to say,bolt a L bracket behind the engine to the plate to stop walking back...looks like that pad would be good on my pressure washer/ generator too ..stay tuned ..more at 11
 
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creia

creia

#16
#16
Aircooled

Aircooled

Member
#18
#18
It looks like good stuff. I wonder if you can get a larger piece to fit under the base of the engine.

Btw, thanks for posting the link to Amazon.
 
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