Join Date: Apr 2005
Location: Guilford, CT, USA
I suggest you try to identify the system from which the noise comes before trying to diagnose it. This is pretty difficult to do when riding the bike - wind noise, tire noise, traffic noise, even the characteristics of the helmet and the height of the windshield can affect what you are able to hear. Don't assume yet that it only occurs within a certain rpm range or that it only occurs under certain conditions (e.g. clutch engaged). This might be accurate in the final analysis, but all you know right now is that you only hear it on the road within a certain rpm range and with the clutch engaged.
You might try this: put the bike up on the center stand, making sure that it is stable and that the rear wheel is not touching the floor. Remove the left lower fairing. Wait until the engine is dead cold, like you were going to check valves. Get a mechanics stethescope or roll up a piece of cardboard. Have a helper start the bike in neutral, and let it idle at 1000. (Danger: make sure the space is very well ventilated.) Listen all around the valve cover with your "stethescope." See if you can localize and identify the noise. Have your helper rev up to 2000 (still in neutral). Note changes, localization, etc. Have your helper rev up to 3000, still in neutral. And again to 4000. With each trial pay particular attention to the front of the valve cover (not left side forward; front front - closer to the wheel) vs. the left rear of the valve cover. The former is where the timing chain, tensioner, and cam sprockets are located, the latter will resound more to the sound of the valves.
Next, make double sure that the rear tire is off the ground, and do the same set trials with the bike in first. Then do it in second. Then do it in third. By this time you may have gathered useful data, e.g., noise does not appear in neutral at any rpm, occurs when bike is in first, second, and third gear and clutch engaged rpm > 1000. If by this time the noise has not appeared, get a light weight to hold down the rear brake lever, very lightly, so you put a higher degree of load on the drive train. (CAution: the brake pads and rotors will get hot. Do not prolong these trials. If necessary, let the bike and the brakes cool off before continuing.) Run through the trials. If the weight causes too much braking action, replace it with a lighter weight.
If you have not heard the noise by this point, try other hypotheses. Noise at the oil pump? Noise from the exhaust headers? Vibration from fairings, front fender, exhaust sheild? Injector noise? Noise from the gear box? If by this time you have not heard the noise or have not been able to isolate the noise, button up the bike, put in earplugs, and go for a long ride. The noise may not be normal, but it's not going to reveal itself to you today. Good luck.
'99 Canyon Red K1200 LT - Buddah Bike