I just installed a new setup on my 2004 Electra glide. Overall it sounds solid. I do however have some engine noise and a thumping sound. First, the engine noise. It is engine noise...changes pitch with engine revs. So my plan is to go through and tape up RCA connectors, and run an independent ground from the HU to the ground on the amp. Amp is grounded to the battery. I have the antenna plugged into the back of the head unit as well but no antennae on the actual bike. The end of the antennae is coiled under my seat and I do still get some FM reception. But wondering if the antenna might be causing an issue. Any suggestions on other things to check out?

My other issue is there is a thump or a boom when I start the bike and the radio is on. If I turn the radio off and start the bike, no thump or boom. I don't think this is a critical issue, but it is annoying and I am unsure if there will be any damage to the speakers. I never used the factory radio but a handful of times and it made some similar noises when turning the bike to the on position and also when turning the bike to the off position no matter if the radio was on or not. I went to a quick detach tour pack which is why the antennae was relocated. Any thoughts on what to look for in this situation would be appreciated.

As for equipment...
Sony MEX m70 BT
Infinity kappas 6.5"
CV B52 Grounded to battery.
Scoshe handlebar interface.

 

Are your RCA cables the shielded type?

 

The RCA's are shielded. Mono price from amazon. 1.5 ft

 

Try moving the antenna to a different location, temporarily. Or, try starting the bike and move the cables around, to eliminate the possibilities.

 

Is your power wire away from the RCA's? Is it fused within 18" from the battery? But, I'm betting it's because you've run the antenna too close to the power wire.

 

The antenna is close to the power wire. I will take a look at that when I get the chance. thanks for the input so far.

 

Checked everything out yesterday and made a couple of minor changes. Added a ground from the HU to the negative terminal on the amplifier block. wrapped up RCA connections, and also moved some wires around. Mainly away from my amp power and ground wire. Seemed to eliminate the engine noise. I messed with the antenna wire as well, but that didn't seem to be an issues from what I could tell. That being said, yesterday was a great day here in south-eastern VA. The wife wanted to go for a ride, so this was a good test run. At speed the new setup sounded incredible (for my budget). Everything was clear and loud up to 75 MPH. No doubt it would still be clear and loud beyond that speed. I have to tip my hat to everybody on here that goes through all this trial and error and actually shares results. Without all the equipment suggestions, I would have been down a deep rabbit hole and blowing all kinds of cash on this for sure. If there is anybody new on this audio forum...take these guys serious. They know what they are talking about.