Raddling/Vibration at 2500rpm

[Siebold]

Hi, my name is Herbert and I am new to the forum. I have a 1993, CBR900RR that I purchased in 1994. It only has around 9,000 miles. A month ago I noticed a raddling noise when the bike is between 2,500 - 3,000 rpm (riding or standing still). I replaced the cam-tensioner but the noise remains. Any ideas

Please advise, thanks.

[Blademan]

Are you sure it is from the motor? I hear something rattle everytime I go over large bumps or cracks in the road and I cannot figure out what it is. I have thought it might be my headlight bracket making the noise.

I recomend giving everything a once over. Set your idle to 2500 and walk around the bike to hear.

[NIHILator]

If it does it sitting still, It might be something mechanical, or a harmonic vibration. But those usually occur at a higher, tighter RPM. If you can, I suggest getting one of those mechanics stethoscopes with the probe on it. You just find where you think the noise is, then keep touching it to parts until you find where the noise is loudest.... Very effective.

[Siebold]

Thanks for the quick response;

Blademan, I am sure the noise comes from somewhere underneath the tank and it is annoying as hell. Specially when I am splitting lanes through traffic and the noise bouncing of the cars makes the vibration noise even louder. I'll do the once over this weekend and see if I find anything loose.

NIHILator, It does sound like at 2500 - 3000 rpm I hit a harmonic. I took it to the dealer and they said that is common with the CBR's ..... what is, the noise? They have no fix for it just an off the shelf answer. I will use a stethoscope to listen and will poke around the bike to see if I can narrow down the location of the noise.

Thanks for the advise, I'll keep you posted.

[Blademan]

Can you get ahold of a rear stand and maybe let the rear tire spin while you

[Siebold]

I guess I could get one but since the bike makes the noise while standint still in neutral, I doubt that would help pin point the problem.

[NIHILator]

Who knows..... To tell the truth I've heard that all the Big CBR's are a bit rattly.... Mine's a 2004 CBR1000RR and I've noticed a rattle at low rpm. I don't even run my bike that low. I launch at 3000rpm (mag guy said same thing) and keep it upward of that always. If I launch it lower than 3k rpm the bike rattles like hell. And its brand new :)

[wingnut1]

Check your motor mounts I had to tighten mine back down after 15k miles last year

[Siebold]

Thanks for all the tips. I did use a stethoscope, checked the motor mounts, etc to no avail. Finally took it to the shop. They replaced the cam-tensioner and the problem is gone. $250 but the noise is gone.

[NIHILator]

Nice....Glad to hear it!

[66droptop]

After I got my tank back from the painter, I threw it on and the bike would have the most annoying rattle. I don't think it was even touching the frame. But apparently without those little black things that are glued to the tank on either side, the bike will make a hideous racket. I glued them back on, and no problems.