New noise

[jermaineman]

I have a 98 r1100rt that I bought 6weeks ago. Now suddenly there is a rattling noise coming from the front of the bike that sounds like a loose screw rattling around, that gets louder and faster as I give it throttle. Any idea what that could be?It came outta nowhere , just started doing this suddenly with no warning. 

[King Herald]

Could be alternator bearing, or belt.

Or could simply be loose bodywork vibrating in sympathy with engine speed.

[dirtrider]

5 hours ago, jermaineman said:

I have a 98 r1100rt that I bought 6weeks ago. Now suddenly there is a rattling noise coming from the front of the bike that sounds like a loose screw rattling around, that gets louder and faster as I give it throttle. Any idea what that could be?It came outta nowhere , just started doing this suddenly with no warning. 

Morning jermaineman 

 

You didn't give us quite enough information to help you. 

 

It could be a LOT of things from a speedometer  noise, to loose front brake rotors on their bobbins, to a chunk missing from your alternator belt, to a rattling engine cam chain, to ??????

 

When the noise first appears try pulling the clutch lever in, then letting the engine drop to idle as you just coast along, see if the noise decreases with the engine RPM drop, or if it decreases as the motorcycle slows down. 

 

Then pull to stop in a safe area & revv the engine slowly to see if the noise comes back & increases with engine RPM increase. 

 

This will hopefully tell us if your problem is engine related or chassis related. 

 

Then, when riding again with the noise present, very lightly pull on the font brake lever (do not back the throttle position off or back the vehicle speed off). See if  lightly pulling the front brake lever changes the noise intensity or frequency?

 

If nothing found or discovered in the above then with the motorcycle parked use the palm of your hand & go over the front of the motorcycle lightly tapping on everything, like windshield, front fender, mirrors, body panels, headlight, etc.

 

If it seems to be related to throttle position & engine load (louder noise under light to heavy acceleration)  but no noise at same speed at very light throttle then possibly even a spark knock problem. So pay attention to this as it can be harmful to your engine if persistent & constant.    

 

 

 

 

[jermaineman]

Sorry for the vague info. I noticed the noise got louder as I went faster, quieter but not completely silent when clutch was pulled in. So I parked put it on center stand and started it. Sounds like a penny rolling around in an empty dryer . But today I was forced to ride it and the noise has completely gone away. Bike rides the same aside from maybe a little hesitation when starting....took longer to crank up, I almost thought it wouldn't.  Wasn't the usual start time. If that helps at all.

[dirtrider]

4 hours ago, jermaineman said:

Sorry for the vague info. I noticed the noise got louder as I went faster, quieter but not completely silent when clutch was pulled in. So I parked put it on center stand and started it. Sounds like a penny rolling around in an empty dryer . But today I was forced to ride it and the noise has completely gone away. Bike rides the same aside from maybe a little hesitation when starting....took longer to crank up, I almost thought it wouldn't.  Wasn't the usual start time. If that helps at all.

Morning jermaineman 

 

I'm still not sure what you are working with. 

 

If the noise is there while free-running the engine with motorcycle on the center stand then your noise is probably in the engine, engine accessories,  or transmission. 

 

If the noise intensity is less with the clutch lever pulled in then that more points to a transmission or clutch issue but neither of those are in the front of the motorcycle.  

 

You are still a little cryptic on your information, keep in mind that YOU are eyes & ears on this as we can't see or ride that motorcycle over the internet.   

 

You are probably going to need to pin down the exact area on the motorcycle & EXACTLY what it takes to get the noise to come & go before we can give much more than a wild guess.  

 

As of now my best suggestion is, if that noise comes back to have a local motorcycle technician listen to it. It might be serious (like a cam chain, or not so serious like chain tensioner, or alternator belt, or something starting to fail in your clutch or transmission). 

 

The starting issue might be connected if there is a fueling issue involved but things like pre-ignition or a spark knock seldom happen free-revving the engine sitting still.  

 

When diagnosing keep in mind that a lot of the old BMW 1100 5 speeds do what is known as neutral gear rattle (warm engine idling, clutch engaged), this is normal & should become much quieter with clutch lever pulled in, & completely go away with engine idling, clutch lever pulled in, & transmission in gear.

 

If your alternator belt replacement history is not known then it might be a good idea to replace that as a precaution. When you have the old belt in hand turn it inside out, then pinch it to have a tight radius, then move it as it would while rotating looking for missing areas or bad spots.