Need some help with noise problem

Recently I've noticed a noise on my 82 650. I'm still trying to pin it down but haven't been able to yet. Maybe someone has some thoughts or ideas.

The other day I was riding pretty slow, 20-25 mph or so when suddenly somewhere in the front of the bike comes a noise. I can't tell whether it's from the wheel or the front of the engine. The noise lasted only about 100 feet and was gone as I was pulling up to the stop sign.

My first thoughts were that it was either the brakes sticking or the front wheel bearings. The rotor was not hot or even warm and the front wheel spins freely. I can get it do make the noise if I get the bike warmed up (doesn't seem to do it the first mile or so) then speed up to 40-50 and then start slowing down I can begin to hear it. I can't tell if it's happening at speed because of engine noise and wind. It always stops before I get the bike to a stop.

It sounds like (sorry, but it's the best I can do) ruh-ruh-ruh-ruh but it doesn't seem to vary much with the speed difference. Like I said, it's aways gone before I get the bike stopped.

The only other thing I haven't tried yet (but will tomorrow) is get it to happen and kill the engine and pull the clutch. That would eliminate an engine problem, right?

Thanks! I'm open for ideas or thoughts.

 

Run some high test gas.
Tape some tissue to the tip of a Looong screwdriver and probe around the exhaust collars looking for evidence of a leak.

Pull the front pads and Chamfer all the leading edges.
Cool weather will cause the speedo cable to make noise; occasionally.

Something stuck in a tire?
Leak in the collector box?
Stuck caliper?
Warped rotor?

Also ... make sure the upper forks are secure in the pinchers.

I'm betting on pre-ignition caused by ethanol in the gas ... or, some exhaust leak.

Relax.

 

Thank you Rick! As long as the weather holds out I'll work my way through your list. Thanks!

 

I had a noise like that in my front wheel. It was the wheel bearings - the wheel rolled fine, but the bearing had been crushed on one side, so the the tire was sort of wobbeling back and forth. To check for play in the bearing - if you already haven't- put the bike on the centerstand and weight down the back of the bike( a second set of hands is a big help here) to lift the front tire. grab the top and bottom of the tire and rock it back and forth see if there is any play in it.

I know thats long winded, but it can be a big mess if you drive hard on ruined bearings

 

I'd go along with the warped rotor theory or something rubbing on the tire tread. Pop it on the center stand and spin the front wheel. Just barely apply finger pressure to the front brake and see what happens; if the rotor is warped, you should hear it. Look under the fender for something caught that could be rubbing on the tire as well.

 

I'm hearing a warped rotor as well. Any chance your getting a fluttering sensation in the brake lever feedback?

 

I get a ruh-ruh-ruh coasting at about 25-30 that is due to a slight warp of my rotor. No evidence of it when stopped but the sound is the give-a-way.

 

This to me suggests it is not a warped rotor, as the noise would slow as the bike slows down. Shutting the engine down like you suggested should narrow down the area significantly.

Ryan

 

Well thanks for all the suggestions. I really appreciate it. It turned out to be the speedometer cable. I hadn't even thought of that until Rick mentioned it. It looks like it has been a problem before because it is jammed with this black grease.

Again, thanks for all the help!

 

Go to the pharmacy and get one of these things:

http://www.narang.com/rubber_goods_surg ... yringe.php

Remove cable sheath from bike.
Remove cable from sheath.
Hang cable.
Use bulb to flush-out the sheath. Use gas ... NO Smoking.
Flush-out that baby ... good.

Clean cable.
Use old white sock soaked with the above mentioned solvent.
Grab cable and pull through "clean" sections of sock until cleaned.

Evacuate bulb.
Spray WD-40 into some clean container until you have enough to suck-up with the bulb.
Lube the flushed-out sheath with the WD-40 sucked-up in the bulb.
Lube the cable by dragging it through a clean part of the sock soaked with the WD.
Smear the cable with a very, very thin film of Synthetic waterproof grease.

Put it all together and shoot a tiny bit of WD into the bottom connection of the speedo before buttoning it up.

(That part about the noise stopping before the bike actually stopped rolling was a good clue. I wish everybody would give accurate info and sound effects -- like you.)