Hi Everyone,

I recently purchased an '05 Road King Classic, with 23,000 miles on it. At idle (and only at idle) there's a frightening-sounding knock, which isn't very consistent (not rhythmic, kind of random....). It sounds like it's coming from the the bottom end of the engine....not sure. Once I get it in gear and roll, it runs strong and the knocking isn't audible....only at idle. My first thought was rods or crank bearings, but that seems like it would continue at higher RPM, and especially under load.

The mileage on the bike is pretty low, and I believe it was well taken care of....yet this sound is disturbing. I'm wondering if I have an expensive rebuild in my future, or a common minor repair, and would really appreciate any wisdom you have for me.

My email is gregernsthomes@yahoo.com. Any help would be great! Thanks in advance!

Greg Ernst,
Long Beach, CA

 

Maybe your front motor mount (rubber) doesn't do it's job anymore. If this rubber mount wears out the engine can "drop down" and come in contact with the chassi. Check if there's any space betwen the front exhaust pipe and the downtube of the frame. Check the space the entire lenght of the headpipe. This is the first thing I would do.

 

its your compensator, just talked to tech today and he said this would be the noise you would hear if it was bad not at a pull only at idle or coast

 

Thanks to both of you....IDI, I checked the engine mount, and it's solid as a rock....er, solid as a rubber mount. Good thought, but that is not the problem. Fred, looks like it might be the compensator...seems to be a popular answer, and I'm just very glad it's not a rod or bearing! Taking it into HD today, as it is still under an extended warranty that came with it when I bought it.

Thanks for the help!!!!

Greg

 

You may also want to check the Cam Chain Tensioner, my 05 started knocking at about 25k miles, replaced the tensioner, no more knocks. Note; If this is the problem, you may want to look into Andrews gears.

 

I had an 05 RKC with the same noise and was the compensator nut loose, pulled the cover and torqued it back down no more peoblem.

 

Yeah, the compensator nut...now torqued and Loc-Tited, was the problem. No unwelcome noises since!

Thanks a million to everyone who posted a reply! Looking forward to swapping more info with you all.

Greg Ernst
Long Beach, CA

 

This post saved my brother in law a trip to the dealer. He has a 2001 road king police package that only has 3000 miles on it. He started hearing the knocking noise only at idle and he couldn't figure out what the sound was. He thought it could have been something in the motor. Sure enough we took the outer primary off and the compensator nut was loose (very loose). It even scuffed up part of the primary cover it was so loose.
My question is how can this happen with only 3000 miles. The initial poster has more than 7 times the miles.
My brother in law did buy the bike used but it was from a close friend of mine that never used it. Very strange.

HD Forums to the rescue again.

 

Check primary-chain tension. If loose it will hit the top of the primary cover with a knocking sound, usually random in my experience. Remove the inspection cover (front of primary cover) and you should have 5/8" of slack when the engine is warm, assuming you have a stock tensioner.