Hello Thumpers, spring is here and my bobber came out of hibernation running great thanks to this community.

But for one little thing that’s starting to drive me a bit crazy.

https://youtu.be/O3va5xjUT4c

I get this buzzing sound at higher rpms and I haven’t been able to figure it out. Thought maybe one of the silverbacks here might be able to offer some advice before I dig deeper.

First I figured my horn must be loose, but holding/playing with it didn’t help. Read that the headlight can be a problem. Had it apart but couldn’t find anything amiss. I verslavy’d the cam chain tensioner last spring (just in time) so I’m decently sure it’s not loose.. Read the spacing on the valve rocker arms can make noise so I got in there yesterday to re-gap them (they might have been a bit tight, but it didn’t have an effect). Saw sometimes the decomp cam can get hitting the rocker arm so I popped that out for a look. It doesn’t appear to be hitting though it doesn’t sit in there all that tight. Holding onto it doesn’t seem to affect the buzzing sound.

Next thing I see is to take the... top thingy off (valve cover?) and see if the cam chain wheel-thingy is doing something bad(?). Just playing with the rocker arms was deeper into any engine work than I’ve ever gone. I’m game to keep going, but would feel much better about it if someone was able to recognize the sound.

While spring is nicely rounding out we’re just getting into our seasonal infestation of shad flies here in eastern Ontario. Wouldn’t be a bad couple of weeks to miss picking bugs out of my teeth. Assuming I’m able to stay up after getting these 3 little demons kids to bed.

Thanks!

Hand on the gas cap key way to eliminate rattling key tumblers?

Well, the speedometer is bobbed. The cable is only about 10” now and a little mini gauge sits just inside my right knee. Is custom sporty tank with no keyed cap, which fits very snuggly.

The bike being bobbed like this is part of the mystery. There is almost nothing there to buzz like that!

Still scratching head.  

The headlight ring on my bike rattled so loud - I thought the cam/rockers were self destructing.
(A full face helmet collects all this sound and makes it seem louder than it really is).

No kidding!  I am experiencing the same thing, it just popped up.  This year I put in raptor, installed LED headlight, normal other maint., And put  the seat lift mod in.  I really tried to secure the headlight internally.  

The sound I have does not correlate with rpm, but does seem to stop when I pull in the clutch.  I am going to look at the speedo more closely, and remove the seat again and to check for loose stuff.  It's annoying, perhaps I will posts video.

Well, just to let the forum know in my case it is completely the speedo that was rattling.  Push down on it while the rattle is going on and it goes away.  Gonna search and see what was said about securing it.

I had the buzzing recently too and thought it was time to fix the springs in my speedometer.  But it ended up being the chrome ring on my headlight.  Found out by just tapping on it with my fingers while the bike was parked.  

Mine's an aftermarket 7" housing with an LED bulb.  I pulled off the ring to see what could be done.  Ended up just needed a little reinstallation and a tighter turn on the screw.

While I had it apart, I wrapped the big LED electrical box and a couple bundles of the other plastic connectors with the plastic mesh stuff that comes on wine bottles or beer bombers and secured them with Velcro.  I wanted to make sure nothing else was rattling too.  I'll open it back up soon to be sure the heat sinks on the back of the LED bulb aren't melting that stuff.  But they guy from ADVMonster says the braided mesh heatsinks on the H4 R3 "can get up to 160f in a sealed environment ie no airflow after a month of running continuously".  So I think I'm safe  .

I checked out the video.  Two possibilities come to mind.  It could be the bell on the outside of your horn.  Try tightening the acorn nut in the center, or removing the outer bell and see if it goes away.  Another thought is maybe the metal on the outside of the front brake line.  Maybe where it passes under the top clamp or down around the front of the frame.  Could be buzzing against one of those, or where it looks split right near the horn.