I just installed the 4180 while retaining the stock HU. Lost two of the six stations I listen to, and another is staticy now.
I used the same ground as my last amp, which was attatched to the bolt where engine guard attaches to the frame.
Still using the stock full size antenna.

 

Can anyone explain to me why there not grounding there amps to the battery? I'm not going to argue that the kenwood doesn't have a better fm reception than the factory hk head unit because I think it does.

 

Grounds should always go to the same point. If you ground your amp to the battery and the rest of the bike's electronics are taken from a lug on the frame then you are going to create 'ground loops.' Because of the difference of voltage and current potentials between various grounding points it is always best to feed all your grounds to the same point or location. If your amp's ground is run straight to the battery's negative terminal and your radio is grounded at the grounding lug on the frame, yet is also connected to your amp through the audio or speaker wiring, then you are going to have various voltage potentials between your amp and radio. This will induce noise as the return voltage (ground) seeks to find the shortest way back to its source. It might seek it through the audio wires which are definitely not rated to carry the current an amp can draw.
Also, any conducted or radiated emissions (class D amp fm interference) needs to be taken to ground via the shortest possible route. A ground wire stretching all the way back to the battery then becomes an unintentional radiating antenna for this interference. Ironically, the battery's negative terminal is the best place for the most stable voltage, but unfortunately each electrical device that required a ground would have to be to this terminal, this would become a rats nest of wires in short order. Because of this, vehicle manufacturers will run a heavy gauge wire from the battery to the frame and pick up the ground from lugs placed on the frame. This can also create problems as various parts of the vehicle's frame are not necessarily connected together very well electrically. A case in point would be the steering neck/forks and swing arm. These areas can also induce noise or voltage differences. A proper fix would be to install heavy gauge copper braided straps between them and the central frame. On cars these straps would be added between the doors, trunk and hood to the car's frame. This way the whole vehicle is at one ground potential and not relying on the frame's metal to metal contact, especially where moving or rubbing parts are concerned.

 

Wow, awesome write up see-saw.

What he said...

plus both amp manufacturers instructions were specific to attach close to the HU. I may try to shorten mine and see if that helps.

 

I personally think this is a bigger issue then what is known. I think there are plenty of people that A. Don't Care, B. Don't belong to this forum so you would never know, C. Install the system and don't even listen to FM, so they have no idea they have FM signal loss.

I took the 4180 and 7P1's out and sent them back for a refund. It's just my opinion, but I won't pay that kind of money for a system that does not allow me to listen to my audio the way I did before I installed it. I am sure there are all kinds of people very happy with this setup and that's awesome. It just doesn't work for "me". Streaming Pandora or listening to a CD sounded very good, but that is not the main part of the way I listen to audio when riding. At this point not sure if I will try another system or not.

Excellent write-up on the ground. I tired both where the radio is grounded and the grounding stud to where the battery grounds.

 

Another great explaination Seesaw,
I looked for antenna cable at a couple auto part stores and a custom car stereo shop but they didn't have one with a connector that would screw on to the mount at the rear fender, So I figured might as well try my local HDealer, Expecting to pay double. Well they had one and it was only $13.00 lol.
Now all stations come in loud n clear, Bike hasn't moved yet.
After reading your latest post I'm going to add a strap or 12 guage wire from triple tree ground nut to the mainframe just to be safe. The Sony HU uses the stock HK's ground there.( It's a wimpy spade type connector ) The install instructions also said you can use the screw hole in the back of unit body to run an additional ground to the triple tree if you had any grounding issues. So I did just to not have to do it later. Thanks again Seesaw.

 

I installed the 4180 last year and 7.1s on the stock HU and Antenna and They work just fine no lost FM signal, so I fine the setup to be excellent.
Hidden Antenna Form or Function? I will always pick Function.
Oilsmoke

 

Let us know if this helps. I'm having similar interference issues with my install of the Rockford Fosgate T400x2ad amp.

 

Hope it's alright for me to put my 2 cents in here. Have a after market Fairing on a 05 roadking Standard bought the biketronics 2180 amp, sony mex 810, and a set of 6x9 speakers. Sounds real good everything fit also got the Hogtenna antenna could get 1 station in but not good enough to lisiten too. Ordered the J&M flex antenna installed it today still no reception. Went to auto zone got a $8.00 antenna stretched and held it on the seat bolt lo and behold i could get 3 stations in real good. I like my setup but want radio also just doin't no if i return the amp only what other amp i should get to replace it that will still sound this good. I can live with a antenna on the back do any of u no if harley sells one that would fit on my bike. I also tried grounding @ the battery and the triple tree neither one changed anything thank's

 

I tried HogTunes, but didn't care for the sound. It was early in the riding season and I had not left town, so I am not sure if it messed with my FM Signal. The BT4180 made my radio pretty much useless. I returned the BT equipment the other day. I am debating on buying a used Harley Boom Audio for the sole purpose of seeing if it messes with my reception also. J&M Audio also seems to be an option. When I get my refund from Biketronices I'll decide what I plan to do next. Some suggested Rockford Fosgate, but then on another post I have, there were a couple people that also chimed in and said they had the same issues with those amps. I don't know if there is any sure bet/winner....