First let me say that I have noticed there are a couple of "regulars" to this site and I really hope they are able to chime in.

I recently installed a SE 204 cam, Johnson Lifters, and 0.030 Cometic HG - thanks to any and everyone that helped with advise on the install. Anyway, the bike (09 St.Bob) seems to be running strong and I am in the process on running V tune with my TTS (time and weather permitting).

Although the bike is running pretty strong both in town and on the hwy - there seems to be a very faint occasional noise that sounds like it is coming from the throttle body or air cleaner area. The noise does not sound like the usual valve train or lifter noise. This sound is at idle (this is my best attempt to describe it). A slight popping or light tapping on hollow plastic - it does not sound metallic. It seems to be at idle and goes away as I accelerate. Just can't seem to pin point it.

The good thing is - the bike runs good and I'm not done with the V tune process so it should only get stronger. I realize that I will probably have to take it to a tuner eventually but my seat of the pants results are pretty good. It's just that little noise ???

Very interested to hear some input.

Jimmie

 

aint your injectors, is it???

 

Maybe a little lifter noise. I know you said it wasn't lifters.

 

I will make a bet that you changed AC when you did this to a free flowing AC? In either event... you are most likely hearing the intake valve closing. The cams close the valves faster and you are hearing this thru the intake track now. It's kinda faint noise right? Not like lifters, right? Some guys really DO hear better than others. I can stand beside a bike and go WTF and the dude beside me doesn't hear a thing, even when pointed out.

I remember certain carbed bikes could make the throttle slide make that kinda noise.

For peace of mind... get it to the tuner sooner than later is all.

 

Double check the exhause gasket tightness. Maybe a tiny leak there.

 

You might try listening with a stethiscope ... might make it easier to rule in or out any of the above ....

 

wurk_truk may be right, but there is another possibility. As he indicated, you most likely have changed the air filter assembly and you could be hearing the slight movement of the thrttle plate under the high vacum conditions present as idle. Once off idle, the plate no longer contacts the sides of the throttle body. Just a thought. And I bet with my hearing, I wouldn't even notice what you are hearing.

 

Thanks everybody for the reply's

Even though I have not pin pointed the noise - I'm thinking along the lines of "wurk truk". Possibly a little valve noise reverberating through the trottle body. The fact that the stock cam has no overlap and this cam does (30 degrees) is bound to put out some different tones. My senses are on high alert when I ride to and from work but its running strong. I'll continue to keep checking on it until I can get it to a tuner.

Jimmie

BTW - still taking input and / or suggestions.

 

Dalton and Work Truk may be closer than me.
thinking back I had a IAC stick once and got into that more that I wanted.

When running that thing doesn't just open, so far, up or down. It cycles open and closed, up and down, many times a second, depending on the ECM signal.

When I opened all up and got things loose again and had my ears and eyes close to it you could see and hear it, just a going, as the engine idled. Little bitty "tapping" sound

 

I changed ac & had that same issue, swapped back & it went away so sounds like your hearing the same noise as I have.