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I am just curious what the high-pitched sound is on these bikes. My CBR600RR did not have this. Sounds cool but just wondering what it is... Highly technical responses are okay 
What is the high-pitched whining sound from the bike?
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1,607 Posts
Forced air induction.
Sounds sweet huh?
SPECIFICATION
Engine Type Liquid-cooled, DOHC, in-line 3-cylinder
Capacity 675cc
Bore/Stroke 74.0 x 52.3mm
Compression Ratio 12.65:1
Fuel System Multipoint sequential electronic fuel injection with forced air induction
Ignition Digital - inductive type - via electronic engine management system
Sounds sweet huh?
SPECIFICATION
Engine Type Liquid-cooled, DOHC, in-line 3-cylinder
Capacity 675cc
Bore/Stroke 74.0 x 52.3mm
Compression Ratio 12.65:1
Fuel System Multipoint sequential electronic fuel injection with forced air induction
Ignition Digital - inductive type - via electronic engine management system
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201 Posts
The 'turbo' type noise that you hear is the ballancing shaft, designed to reduce vibration....Mike
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1,707 Posts
If you look inside the motor, it is the noise from the timing gears, kind of like a gear driven water pump on a big American V8, but for the timing.
While at Laguna Seca, Triumph had a 675 that was cut apart to see the internal parts of the motor. It has three gears that were connected to the clutch, crank, and balancing shaft??. (at least that was what I remember seeing)
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The forced air induction only "forces" air in when the bike is moving. Kind of a fancy way to dress up the name of the intake!! The faster the bike goes, the more the air is "forced" into the motor. There is no "extra" motor or anything that forced air into the engine. If there were, it would be called a turbo, which would cause a similar whining noise.
While at Laguna Seca, Triumph had a 675 that was cut apart to see the internal parts of the motor. It has three gears that were connected to the clutch, crank, and balancing shaft??. (at least that was what I remember seeing)
The forced air induction only "forces" air in when the bike is moving. Kind of a fancy way to dress up the name of the intake!! The faster the bike goes, the more the air is "forced" into the motor. There is no "extra" motor or anything that forced air into the engine. If there were, it would be called a turbo, which would cause a similar whining noise.
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1,886 Posts
oh if thats the cause the cure for that is a quick wheelie! :lol:Eclipze said:
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Thanks for the explanation and the photo triple grrr. By the range of responses, seems like we do not all have the same understanding about what causes the sound, but your response seems very logical, and I can see it in the picture.triple grrr said:If you look inside the motor, it is the noise from the timing gears, kind of like a gear driven water pump on a big American V8, but for the timing.
While at Laguna Seca, Triumph had a 675 that was cut apart to see the internal parts of the motor. It has three gears that were connected to the clutch, crank, and balancing shaft??. (at least that was what I remember seeing)
![]()
The forced air induction only "forces" air in when the bike is moving. Kind of a fancy way to dress up the name of the intake!! The faster the bike goes, the more the air is "forced" into the motor. There is no "extra" motor or anything that forced air into the engine. If there were, it would be called a turbo, which would cause a similar whining noise.
It does sound cool but I think the exhaust coming in the mail this week will drown most of that out
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it does, unfortunately. i'm especially disappointed at the fact that my 675 no longer sound like a jet while sitting in it. oh well, a decent tradeoff i guess.[email protected] said:It does sound cool but I think the exhaust coming in the mail this week will drown most of that out
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39 Posts
I hear this on my 'Tona but not all the time. I usually only hear it while I'm passing "faster" Japanese bikes.[email protected] said:
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1,707 Posts
Same here, but I have a little more commitment with this one, And she keeps coming back....lol, much to my surprise that she still puts up with me and my neediness!
At least I know my wife doesn't read these!!!!
Just Kidding honey. (In case she does read these!!!)
At least I know my wife doesn't read these!!!!
Just Kidding honey. (In case she does read these!!!)
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2,884 Posts
HA HA awesome!chedachee said:
I love the psuedo-supercharger whine of the 675! A quick blip of the gas from idle sounds very similar to a blower and can tease the ear of some motorheads at stoplights! Almost all motorcycles have geardriven primary-drives but they're helical cut gears, where on the 675 they're straight cut on the clutch and balance-shaft which gives that distinct sound. Some twins will sound like that due to the timing belts.
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