knocking sound on hard braking

[knary]

I've noticed that my GS has an interesting knocking sound during hard braking when coming to a stop. It reminds me of the knocking sound of the cam tensioner at start up. The knock calms down quickly when the bike stops, but during those last moments of hard braking, it's pretty noticeable. Does this description make sense?

whatcha think????

danke'

[jdiaz]

Originally posted by knary
I've noticed that my GS has an interesting knocking sound during hard braking when coming to a stop. It reminds me of the knocking sound of the cam tensioner at start up. The knock calms down quickly when the bike stops, but during those last moments of hard braking, it's pretty noticeable.
Is it your crotch contacting the back of the gas tank? :)

Where is your oil level? Is the oil light coming on when you are braking this hard?

[knary]

Originally posted by jdiaz
Is it your crotch contacting the back of the gas tank? :)

Where is your oil level? Is the oil light coming on when you are braking this hard?
Oil level is right around the dot. The oil light doesn't come on - that I've noticed. I'll go for a spin and see, but I don't think it's coming on.

[knary]

The oil light is not coming on when this happens.

I think I'll get it checked out by a local guru (the guy doing the work for the local BMW rep instead of the local BMW shop). I'm so new to oilheads that I still start sweating whenever it gets a bit hot and thus a bit noisy. :)

[r1dinman]

Sounds like the ABS doing its thing

[knary]

Originally posted by r1dinman
Sounds like the ABS doing its thing

I know that sound well. It's definitely not the ABS - setting, cycling, etc. This is a sound eminating from the engine.

[gsr]

MY 1150GS KNOCKED BADLY AT IDLE WHEN FULLY WARMED UP. DEALER IN KANSAS CITY KEPT BIKE OVER FOUR MONTHS. SAID DID COMPLETE TEARDOWN AND ENGINE FOUND TO BE IN SPECS. AFTER REASEMBLED NO KNOCK! THEY DON'T KNOW WHAT FIXED IT! RODE IT FOR ABOUT 400 MILES AND KNOCK WORSE THAN BEFORE! NOISE IS FROM RIGHT/THROTTLE SIDE OF ENGINE/TRANSMISSION AREA. DEFINITELY NOT ABS OR VALVE TRAIN NOISE, DEALER AGREED. SOUNDED MORE LIKE CAM TIMING CHAIN TENSIONERS DO WHEN STARTING. TOOK QUITE A WHILE BEFORE DEALER WOULD ADMIT THEY HEARD A NOISE. BIKE IS NOW OFF WARRANTY. NOW I SUPPOSE ALL KINDS OF PROBLEMS WOULD BE FOUND! HAS ANYONE FOUND THE SOURCE OF THE NOISE AND THE REMEDY?

[knary]

gsr,

1. don't type so loud. :D

2. some oilheads appear to knock quite loudly, especially when out of synch (throttle bodies) and Very warm. Have you balanced the throttlebodies recently? it should be done, in theory, everytime you adjust the valves.

3. I believe I solved much of my bike's knock 'problem' when I discovered a cut in the left throttle body vacuum line. With that cut, the left cylinder would have been running much leaner and, generally, just been all out of whack.

I wish I had a clear answer for you...

[gsr]

Dealer replaced both throttle bodies and adjusted valves. Bike performance is very good, just hammers at idle. Can also feel it in bars and pegs. Milage is between 45-50 mpg. Engine pulls hard to red line in the lower gears etc. I would have to say the bike is perfect if not for that loud knock at idle. Bike did not have this knock until 13,000 miles or so. Scary to think that the dealer says it has a bad problem but, doesn't know what it is or how to fix it. I have listened to several r259 engines and have found none like mine! The area rep and bmwusa rep just keep punting back to the dealer. Am going to persue this a little longer then, if it can't be solved, I will own my first non bmw motorcycle in 48 years.

[jdiaz]

Originally posted by gsr
RODE IT FOR ABOUT 400 MILES AND KNOCK WORSE THAN BEFORE! NOISE IS FROM RIGHT/THROTTLE SIDE OF ENGINE/TRANSMISSION AREA.
Its your right-hand throttle body. Start your bike at idle, then place your index finger on the cable wheel....my guess is that the butterfly shaft bushing has loosened and its bouncing off the stop. My wife's RS did that.....just needs a new right-hand throttle body for $110 or so.