Hey guys, just got back from a long trip up to the Smoky Mountains and all went well but today we decided to go for a short trip around town. When we got back we noticed my brother's fatboy is making a strange noise. He has a 2003 FB with a Twin88 that's been bored out to 95. The noise is heard when the engine has warmed up and idling. It can be in neutral or in gear with the clutch pulled in. It appears to disappear when moving but then again it might just not be noticeable then either. It sounds like a light grinding noise or rubbing noise coming from the engine that comes and goes and only lasts for a second. You can feel the vibration of it in the handle bars when sitting on it. Changed the oil as it smelt like it had some gas in it and no difference was made. The performance of the bike is the same, no loss in power or sputtering etc..and there is no pinging tinking noises, just the rubbing noise. Any ideas before we have it hauled in to an indy?

 

Ok guys. Changed the oil twice and the oil filter. Went back in with 20W50 in engine and Primary and 85w140 in the trans. Warmed her up and took her around the block and the noise still persists, tried to get it on video. The sound we are listening for is the scrapping/scuffing noise. Any ideas?

 

03 id pull the cam cover.

 

Looking for what exactly? The cams were upgraded to SE cams and the tensioners were changed out to the hydraulic ones...or so I was told lol.

I keep googling the noise and finding a lot of people talking about the compensator nut being loose. Any thoughts to this possibly being the noise?

 

Have you tried a mechanic's stethoscope to try and isolate the area the noise is coming from?

 

Comp nuts that are loose tend to sound like a rod knock at idle.

You could check the primary chain tension though.

 

I have not, don't have one. Right now I'm just guessing, hoping someone has heard this issue before and is an easy resolution before I have to haul it to the mechanic and pray it's not something severe.

 

comp nut and also remember the lolder SE upgrade doesn't change the inner chain (still the silent chain,, not the newer roller chain that last longer). so If U've got enough miles on her, the inner Tennsioner pad can be bad again.



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Looks like I need to open her up soon and check that nut, the bike only has around 25,000 miles on it. He does tend to use engine braking a lot, especially on our visit to the mountains. I heard that can cause the compensator nut to loosen, true?

 

Just a follow up for future google searches lol. Opened up the primary today and the compensator nut was loose enough to twist with my fingers with no pressure applied! Pulled it all apart to inspect everything and no damage was done to anything. Put it back together with some red loctite and tested the bike out and no more noise. Looks like we got lucky and checked it out as soon as the first sign of noise was heard.