Ok, I've finally bought the speakers from uniqcycle.com and installed them. They sound great. I do have a small problem. Every time I hit 3000 rpm, the stereo turns off!!! and it comes back on at about 3100 rpm. Is there anyone who knows anything about this? The stereo takes power from the rear brake light.

http://www.bikepics.com/members/feelinjunky/01savage/

Sorry, I've removed the pictures that were here because they were just too big and you could just click above to see them anyway, a little redundant too keep them...

3K RPM....  hmmmm

First thing I would do is take power off the battery (with fuse...).  Taking power off the tail-light means you are taking power from a circuit that goes all over the bike.  Lots of possibilities to get interference.

If that doesn't work,  you may need to go to your local Radio Shack  and rummage thru their catalog.  They make a filter for two-way radios to eliminate ignition interference.  Pretty sure they no longer have it in the store (cell phones shot most of the customer demand for two-way radios).
Heck....   http://www.radioshack.com

OK, so I reread your post, and figured out where ya got 'em...


Do you wear a helmet?  If so can you still hear the tunes?

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You can use a relay for this, but that might not solve your problem.

If your comfortable with a soldering iron then try this:

Use shielded wire as short as possible.  I use 18 guage mic wire a lot for power wire, but usually never fuse it above 5 amps.  Only connect the shield at one end.

You can also solder a cap across the power wires close to the amp/stereo.  Even better are 2 caps.  A large electrolytic say 1000uF or larger in parallel with a small ceramic .1uF or larger. (The small ceramic responds to high frequencies better).  Even better is a coil in series before the caps.  Something in the mH range or larger.  They work together to make a great low pass filter.

Very simple but not as effective are the clamp on ferrite shields.  You see these all the time on modern electronics close to the connector.  You can buy them at radio shack.

It may be as simple as rerouting your power wire where it does not pick up noise as easy.  Also keep it as short as possible.  

Try a different ground point and make sure you have a good connection.  You could be picking up noise through the frame.

It could be a mechanical vibration problem with your electronics, Amp, mp3 player, whatever your using.  Try isolating them with some foam.

Also make sure all your connections are good and protected from vibration.

Rather than deal with external speakers, I went to Helmet Audio.com and bought speakers for inside the helmet.  Works excellent w/ MP3 player.  Mini amps also available for about $50.

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Regardless of speed, the stereo turns off at 3k rpm when riding. No other noise is heard, except just before it turns off...a little rattle, like the sound of an unclear radio station...

I also forgot to mention that when the bike is in neutral and the engine is revved to ANY rpm (including 3k rpm), the stereo DOES NOT turn off, so it can't be resonance, therfore the mp3 player isn't the problem. I've also tried other mp3 players (friend's ipod) with same result.

While rummaging through my old electronics, I found a nice 3300 uF 25 Volt capacitor. I'll put it in parallel this weekend and see if it solves the problem.