4-5k buzz

Have had my '93 for about 6 weeks now. I notice a marked BUZZ sound from the engine that kicks in almost precisely at 4,000rpm and continues to whir until 5,000rpm. The bike performs very smoothly through it, and seems to pick up power at this point, so I imagine the sound is supposed to be there.

Anyone know the technical explanation for what is going on in there when this happens?

 

What you are experiencing is natural. It is the harmonics of the bike and engine and they 'merge' at about that rpm. I am sure someone has a better description than me, tho.

 

I had something very similar on my 93 happen. Whenever I would downshift I would hear something vibrating. I figured it was either the seat or the tank. When I took the tank off I noticed at the very front it seemed to be in contact with the frame. Took a piece of double sided foam tape and put it on the frame. Also there are two other contact points on the side of the tank on the frame rails that I put some foam tape on as well. No more noise, all I hear is cam whine and that's not noise that's music.

 

I took the gas tank off... put rubber tape in every possible place that the tank might be making contact... still getting buzzing between 4000-5000rpm. The buzz doesn't happen when I have a full tank of gas, and gets louder as the tank gets emptier. I can dampen the sound by pushing the middle of the gas tank with the palm of my hand (only in the middle).

This is getting a bit irritating... any suggestions??? Thanks!

 

Terry, I put some double sided foam tape on the frame right behind the headset. I think the foam tape will do a better job than rubber tape. Maybe try both. If you put the rubber tape on the tank try putting foam tape on the frame in the three spots (front of tank behind the headset, two spots on the frame rails sides). Also It may be where the bolt goes through the tank in the back. Check it out. I know how frustrating it can be. It was driving me crazy once I started noticing it on my bike. Good luck.

 

Do the 3gen tanks have large rubber dampers on the front contact points like the 4gen?

 

Thanks for all your help guys, but nothing seems to be working. I got the thickest rubber foam tape... taped the front and side contact points, the part at the back where the bolt goes in, even put a couple strips between the airbox and tank... the buzz is completely unaffected.

I can only conlcude that it is the actual tank (or something in the tank) resonating. The only thing that dampens the sound is a full tank of gas.

Guess I'll just have to scratch my noodle on this one, and see if any genius solutions come to mind.

:frusty:

 

I think I have been experiencing the same sound. It sounds almost like a reed vibrating very loudly coming from somewhere in the middle of the bike. It comes on slightly above 4,000 RPM the loudest is about 4,500 and is completely gone by 5,000 RPM. If I hold the RPM right where it makes the most noise, I can make it completely dispappear by giving just a bit more throttle. I don't seem to see it disappear, though, with a full tank of gas. I think it is there all the time. I figured it was a fairing vibrating or something. I do have to admit it is reallllllly annoying. If you do manage to find a solution, please post it as I would love to get rid of it. Likewise I will do the same.

 

Try dynamat

http://store.summitracing.com/partd...&part=DYC-20425&N=700+400319+115&autoview=sku

the bottom is heat radiant too. I would cover up the bottom of the tank with it, should solve all your problems.

 

First of all - Terry, your '93 is gorgeous. Absolutely a stunning example.

I do not have a buzz like you do, but have an idea... Could it possibly be the fuel level sender inside the tank that is doing the buzzing? Could explain why it happens less with a full tank of gas...

 

Well I seem to have pinpointed the noise on mine. Not sure if it is the same as yours, but it appears to be the lower left fairing. I recently put a new chain with new front and rear sprockets. After removing all the fairings on the left side to gain access to the front sprocket, I tightened the bolts that attach the lower fairing to the frame and for a period of about two days the noise was completely gone! It was so nice to be able to cruise around town in 4th at 4,500 RPM with no annoying buzz. It has since come back. Sometime soon I will remove the bolts, apply threadlocker and re-tighten all the bolts in the lower fairings. Hope this was some help.....

 

cure for buzzzzzzzz?

EARPLUGS!!

(the carb slides are known to emit a ratteling sound at various RPMs)

 

I'm telling ya: Dynamat

The stuff kills all kinds of harmonics. A little pricey but well worth it. I used a little bit on the bottom of my old GS500 and it worked like a charm. That stupid little twin had the most irritating rattle too, like 2 big pieces of steel just barely touching. Really loud at anything above 4k rpm. I tried weather stripping all along the bottom edge, no luck. I used about a 1' x 1' panel of dynamat, cut it into strips and decorated the bottom of the tank. No more vibration noise.

 

I have found only one solution, and I hope it is temporary. If I place my suction cup GPS mount on top of my tank, it dampens the noise to almost nil. Not pretty, but it works. I'll try the rest of your suggestions one by one.

Thanks for all the help on this guys!!!

 

UPDATE: Ordered that dynamat stuff... covered the bottom of my tank with it. Still getting the buzz. Checked all fairings, buzz is not coming from them. Guess I'm stuck with riding around with the GPS mount suctioned to the top of my tank.

 

Sent you a PM. Sorry it didn't work.

I did forget to mention what a great looking bike you have. Looks killer in white.