here's more info-- Thanks for the help!
Just to make sure I mentioned this; The stereo amp and air horn are powered by a seperate battery in the pannier bag, not hooked to the moped electrical system at all-- I did try grounding the amp to the moped but the interference got worse.
I haven't tried to build an aluminum box yet, tried foil, some success (at least a signal...) but not quality sound at all.
The moped needs to be about 4 feet away and the stereo will play fine, come in close and it crackles out.
What pisses me off is that the other amp (road gear brand name) was a 35$ Wal-Mart special, and it had no trouble, the new amp, same company same price range, new model is totally affected. I wish I'd saved the old one to look inside and see what was different.....Maybe I could have swapped parts.
I'm going out soon to get a new amp, but I don't know what to look for as far as shielding or features to prevent this. I tried an RCA ground-loop isolater, knew it wasn't going to help, and it didn't. I had to try, though.
Ree: I've got a Tomos Targa, 2000 model, with Bi-Turbo, no piston kit.
Jon: For real? 1000 watt amp on a moped? wow I am humbled-- would love to get some info on your setup, please! for example, where do you get the extra power?? I gotta know more!!
Richard: Will I need to build a box, or can I screen the EM/RF with a partial shield facing the engine?
How thick would the screen need to be? I was also told to use copper-- Tin foil was a big pain in the ass. I've got a bunch of photos of my moped here on the army site, so I'll clip one to one of the next posts.
Thanks again for all your help--!!!