Bad vibrations

rubber isolaters

Check the rubber under your motor mounts. Mine require replacing every 6 months and you might want to consider upgrading your spokes to 12 gauge instead of the usual 14g. It will help keep your wheel true and round.
 
Currently im thinking of taking the following steps:

1. Add on some very thick foam handlebar grips, with some weatherproof but removable glue.

That won't fix the cause of the vibration..just a band aid.

2. Add thin rubber under the flat handlebar mount bracket and the seat post mount all the way along the inner tube (if it will fit!).

Same as above.

3. True up the motor alignment, add another set of rubbers (2x) to the engine mounts and tighten all mounting bolts

If you feel the motor has shifted you can make a "L" bracket to stop this from hapening..look at my photos. http://www.motoredbikes.com/album.php?albumid=892&pictureid=5578

4. Give the clutch and chain a really good greasing/oiling.

Doubt that is the cause but won't hurt.

5. Mix some fresh fuel with a racing 2 stroke oil (currently inadvertently using a lawn mower 2stroke). (Will this/Could this have an effect on vibrations?)

I really don't think so. I have never experienced it in any 2 cycle.

6. Grease and repack wheel bearings, retighten, check tyre rim for buckles and attempt to fix as possible, check tyre is not out of round.

Possibility.

Any other happy time generating vibe tips appreciated!

Check out the rear sprocker for trueness.
 
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Ofcourse it wont fix the cause, the cause is its an oversized bicycle frame with a motor attached running at max speed (wide open throttle, not gaining speed). The ride upto this degree of speed is very smooth

How smooth is your ride in this condition, maybe i'm wrong in my assertion.
 
Ofcourse it wont fix the cause, the cause is its an oversized bicycle frame with a motor attached running at max speed (wide open throttle, not gaining speed). The ride upto this degree of speed is very smooth

How smooth is your ride in this condition, maybe i'm wrong in my assertion.

Both my ride (cruiser) and my sons ride (mountain bike) have no vibration issues at any speed (other then the standard that most engines have). I do not have rubber between the engine and tubes. I did have a problem on my first bike (frame split in 2 due to drilling a hole in frame)...my fingers felt they were still vibrating long after I got off the bike (in this case it was the bike as same motor installed on my current bike). The cause of vibration needs to be found not masked up. Now you can find out if it is the bike itself or the motor causing the problem. Have someone tow you on your bike with the engine off and clutch disengaged.
 
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Haha, well, it seems as though over the course of a weeks daily commute to work, the reason I kept noticing increasing vibrations was because it has literally been vibrating itself apart!

On my way to work the other morning, I had to stop 4 separate times from things literally just rattling off... Shocking mechanic work on my behalf I can only surmise.

Spent nearly an entire day cleaning every part of the bike and engine, re-oiling/greasing, tightning the chain, adjusted the clutch, tuned the gears and brakes etc.. Now it's quite literally the best ride. I couldn't be more happy with it, besides possibly a few tweaks for winter (see my other thread).

At this point id just really like to thank all of you on here for your continued patience and support, I literally could not have done it without you guys.

I'll post some pictures when I get a chance!

Cheers!
Hajuu
 
chain alignment

Chain alignment is also very important for the chain must run true to achieve max results. With my Felt Hot Wheels cruiser, the chain is not aligned properly so I went out and picked up a billet aluminum set of motor mounts to offset the "Felt" factor,lol.
 

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Hi Ron, Hajuu, Everyone -

Attached should be a photo (I am an amatuer at attaching photos) of a small turnbuckle that I used and found it to greatly decreased the vibrations of my engine.

I am of the opinion that vibrations are a default function of these simple engines rocking forward and backward while running; they are not balanced and we all accept that more or less.

Rubber insulations help isolate the engine vibration from the bicycle frame, so we think that the engine no longer vibrates. I maintain the engine still shakes as much as ever.

My thought is that if I can stop the engine from rocking, there will be no vibrations being transmitted to the bicycle frame, and to our hands, senses, etc.

I attached the turnbuckle to a fixed point on the bike frame that will not move. Centers of downtubes and seattubes move back and forth in unison with the engine vibration. My thought is the three fixed points of the engine mount triangle don't move.

I took some 14 gauge steel wire and a small turnbuckle. I threaded the wire through some point on the engine (I chose a jackshaft frame) and pulled that point toward the bottom bracket. I really had other reasons for the turnbuckle, but greatly diminished vibrations was a side effect outcome.

So now I am thinking: If I anchored the engine to "hard points" like the bottom bracket or to just under the seat at the tube weld, the engine can't rock forward and backward while running. In the future, I am going to extend my turnbuckle finding to pull various parts of the engine toward "hard points".

One thought is to loop a wire around the cylinder and draw the cylinder a tenth of an inch or so up toward the point under the seat. Frame tubes will resist the drawing tension. If the cylinder can not move forward or backward, there will be no vibration to transmit to the frame tubes. Tension of the pulling effort cannot be too much; I don't want to pull the cylinder off the crankcase block.

If my thoughts work, pulling the engine in various directions with baling wire will look like it should be banned. But why not? My bike has been one experimental fix after another, and most have worked so far.

Comments?

MikeJ
 

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I agree with Ron. Vibration shouldn't be a serious concern, if everything is set up right. I barely notice engine vibration. The only vibration that bugs me is caused by rough roads, high tyre pressures, poor front suspension and no rear suspension.
I check all nuts and bolts regularly and have never had any loosen from vibration, despite using very little Loctite.
If vibration is an issue, fix the cause, not the symptoms.
 
Ahhhhhh yes vibration....I remember that. My first and only build that I had issues with, the mountain bike that the frame broke due most likely (see I don't want to take 100% of the blame which I'm due, I'm sure the hole didn't help tho) to me drilling a hole in the frame, had vibration so bad that my hands remained numb for a 1/2 hour after I got off the bike riding a 10 mile trip. I to thought it was the engine. I soon realized that when I changed frames (to a cruiser) and mounted the engine correctly (according to my thoughts in the link above) 90% of the vibration was gone. So in the next 4 builds I made the engine fit the frame and not the frame to the engine. Have not had a abnormal vibration since, and they are now a pleasure to ride.
 
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