Help, vibration issues!

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Mattjb

New Member
Mar 21, 2013
25
0
0
San dimas
Hears the deal. I have a vibration problem that's focused in the front fork/steerer/handlebar. At first I thought is was handlebar related due to a long wide cafe cruiser bar (electra cruiser stock bar) so I went to a shorter 5-1/2 rise typical bike bar for stiffness and the vibration was so bad I couldn't hold the bar. 5 miles and my hands were in serious pain. So I started doing more testing to try and pinpoint the source/cause of the vibration. I was thinking motor mount related but I can hold onto the top tube at 40mph and its totally fine. Every part of the bike is good. If I place my hand on the fork, stem, or handlebar that seems to be where the energy is being dispersed at. So, how the bloody **** do I fix it?!?! Lol I'm thinking a fork with shocks but I'm also wondering if a triple tree would work. I don't know. All I know is the rest of the bike is cool vibration wise. Oh, and the threaded nut on the steerer is NOT loose. Any ideas as to why the vibrations are focused there and solution to fix it is greatly appreciated.

Bike specs.
Electra cruiser
Hf79cc
Decked head 9.5 compression
19mm carb
12.1 gear ratio

Thanks, Matt
 
bluegoatwoods

bluegoatwoods

Active Member
Jul 29, 2012
1,581
6
38
Central Illinois
Man, this sounds awful...

Okay, now, you mentioned that the threaded nut on that headset is not loose. That's good. But it sounded like you were talking only of the hold-down nut. You'd better check that the actual bearing races (maybe these are called 'cones') are tight and adjusted properly. Maybe you'd better have a look at the actual bearings in that headset. Maybe a missing ball or crushed cage could account for this.

If that checks out, then check that the wheel is sitting straight, and tight, in those front drop-outs. Though I suppose you'd have noticed that if that weren't right. Still, double check.

If these things don't locate the trouble, then I'd be suspicious of some kind of manufacturing flaw in that front end or wheel


In any case, THIS SOUNDS VERY DANGEROUS. I mean it. I don't think you should ride until you've figured this out. I can easily picture your bike breaking in two while you're riding. Did you say 40 mph and more? That could easily mean death.

So best of luck to you and keep us posted, okay?
 
M

Mattjb

New Member
Mar 21, 2013
25
0
0
San dimas
The bike is perfectly safe. Nothing is loose, broken, misadjusted. No faulty bearings. Like I said, the bike is solid.
Ill clarify the question. What shock/fork/stem assembly is best for removing road vibrations and engine vibrations?
 
professor

professor

New Member
Oct 14, 2009
500
1
0
Buffalo ny area
Very strange, the 79 I have is pretty smooth.
The 212 needed to have the engine isolated in rubber (it was so bad).
How about filling the handlebar with sand or something, to change the natural frequency?
 
maniac57

maniac57

Old, Fat, and still faster than you
Oct 8, 2011
4,484
22
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memphis Tn
Changing the frequency is about all you can do without redesigning your mount or possibly adding a head stay.
I've had good luck using shot or sand in the bars to dampen vibes. There are also handlebar weights designed for this purpose.
Experiment is all I can say.
 
M

Mattjb

New Member
Mar 21, 2013
25
0
0
San dimas
Head stay? As in 3rd motor mount in a triangular fashion?
I'm currently experimenting with bar weights. If I can find a front shock fork like a mtn bike style with a 1 in steerer ill do that as well. Don't trust the springer front forks. All else fails and ill order up some vibration dampening pads from McMaster and fabricate away.
 
maniac57

maniac57

Old, Fat, and still faster than you
Oct 8, 2011
4,484
22
0
memphis Tn
A crossbar might help the bar vibes, but a headstay is another mount connecting the head to the frame. Controlling the rocking motion with a headstay makes a big difference in most single cylinder applications, a chinadoll should be no different.
 
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