droning harmonic at 60+ mph

[1948man]

I have a droning, kind of harmonic noise starting at about 60 mph. A wallowing wahhahhahhahh sound. I know my carbs need to be synced but the rpms are not fluctuating. The carbs couldn't cause this could they? I was thinking maybe something in the final drive. When you are pulling up to a stop, if you hit the kill switch and coast to a stop, things seem nice and quiet. Have checked final gear level and it is fine and fluid looks okay although I haven't changed and inspected it. PO said fluid changes were recent before I got it about 1000 miles ago. Gs 1100GL shaftie.

[Nessism]

Did you check the secondary gear chamber oil level? These gears lead a hard life on the 1100's so that's one thing to check.

[trippivot]

what condition are the tires in? bias ply tires do weird things

carb sync does not seriously effect anything over 1/8 throttle opening. that is for smooth idle and cold start assistance.

rear gears and clutch hub gears are helical to deaden noise. when they begin to sing you have a real problem.

man if i had a dollar every time I had to address a complaint of strange noise for KZ 's and their straight cut gears. concours ZG 1000 zx 1100 xs 1100 so many loud engines to a nonmechanical ears.

[1948man]

Thanks for the replies. I haven't had as much time to devote to the bike lately what with work and family situations. Also, it's been mid 90's temps and stinking humidity here. I'll definitely check the secondary gear situation and break out my new "just arrived" Clymer manual.

[rphillips]

This may seem silly, but do you hear it when riding alone? This is a normal happening for 2 or more 4 cyl. bikes riding together, near enough to be able to hear the other bike or bikes. Louder the exaust, the more prominant the droning harmonic sound. You should hear it with 2 big 4 cyl bikes, with 4 into 1 pipes, with the baffels out, at night, cruising about 4000rpm. It gives me a really creepy eery feeling, I love it.

[mostholycerebus]

I had a similar sound coming from my tachometer before the cable snapped. Then it stopped. Replaced the cable, and I still get it now, must be something wrong with my tach.

Eventually im just gonna replace the whole thing with a digital dash, so it doesnt really bother me much.

[1948man]

I've heard that on another bike when riding with a buddy but on this Gs it is when riding alone. Thanks.

[1948man]

When I checked my secondary gear level screw, the gear oil came out and continued to flow out enough to make me think it was overfull. I have heard this is not good for the final gear. Is it a problem for the secondary? I guess I should just drain and refill

[Steve]

There are several potential sources of noise. Some of these include engine, transmission, secondary drive, final drive, brakes, tires. You say that if you kill the engine, the noise stops. This would tend to rule out tires. You can further isolate it by shifting gears. Get to your noisy speed in fifth gear. Hold the same speed, shift to fourth. Do you still have the noise? Did it change with the engine speed? Do you have to actually kill the engine to eliminate the noise or can you do the same thing by just pulling the clutch and letting the engine idle? When it's noisy, it is only with steady throttle? Does it happen when gently acellerating or decellerating? You need to check loading forces in multiple directions on multiple items.

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