What makes the high pitched mechanical whine?

[Bigslim]

First, I'm an automotive gear head, have worked on cars for 10 years now but this is my first bike and I love to understand what is mechanically going on. Especially with my mechanical things. lol

The sound I'm reference is not a problem, my bike is brand new and I hear on just about all crotch rockets. It rises and falls with revs and is not related to the transmission as its present when the bike is not moving and/or the clutch is engaged. It's 1 of the 2 main noises the bike makes, there's the exhaust the high pitch sound. What is it? Doesn't quite sound like induction noise to me but again I am basing that on my automotive knowledge. Is it something in the valve train? And finally, why is it so prevalent in bikes but not cars?

Thanks

 

[Tree Doc]

I'd guess you're identifying the ol' Yamaha Stator whine?

 

[exskibum]

Don't know for sure, but I've always assumed that prominent whine is the intake tract as it sucked air at varying velocities into and through the air box.

 

[Bigslim]

I'd guess you're identifying the ol' Yamaha Stator whine?

I don't know, that's the whole problem. lol

Do most Japanse performance motors have stators and how does a stator differ from an alternator?

 

[wmadoty]

If I am not mistake the balance shafts are gear driven. The sound I think you are talking about sounds like every Gear driven timing system I have put in small block v-8's. I think it is the balance shafts.

 

[J Paul]

The balance shafts turn at twice crank speed-at least the ones I deal with on diesels-and are driven by spur gears which are noisy. Jeff

 

[FJRONAMISSION]

I know when it came to bustanut ..... when he rode fast in the twisties!!!... his sphincter made a whining sound!!

so .... at least thats what D carver told me......

Just say'n

 

[FarWestFastEddie]

FJR's are not crotch rockets, we have evolved and sit upright, per Brian, its easier on the hemmies....

Most of the inline-4's with shorter stroke do make distinct motor noise related to the smoothness of the

RPM cycles, not found in the high carbon V-Twins..

And thank you for asking a well thought out question.. watch out for the answers relating to the bearing speed differential with hydraulic thrust plates and

friction cohesion for the rat on the treadmill, they may be yanking your proverbial chain..

FWFE

 

[Constant Mesh]

You're hearing the two balancers turning 2X the crankshaft speed. One front left driven off crankshaft. One right rear driven off the clutch housing. Also the primary gear drive between crankshaft and clutch housing.

All three of these gear drives use spur gears (straight teeth) which are very noisy.

 

[Bigslim]

I most certainly agree the FJR is not a crotch rocket, it's sporty nature combined with livable ergonomics is the reason I chose the bike.

I only referenced crotch rockets because I also often hear a similar sound on other crotch rocket bikes and not on V-twins or cruisers. I'm assuming it is something fairly common to high performance fours.

 

[Bigslim]

You're hearing the two balancers turning 2X the crankshaft speed. One front left driven off crankshaft. One right rear driven off the clutch housing. Also the primary gear drive between crankshaft and clutch housing.

All three of these gear drives use spur gears (straight teeth) which are very noisy.

Gotcha. I figured it might be a straight cut teeth issue, just didn't know where. Knew it wasn't the transmission as it's rev related not speed dependant.

And by the way, I do like the sound.

Thanks for the input everyone.

 

[lnewlf]

Stators can't whine-they are static [don't move]. Definitly the balance shafts..I remember that the early '80s Yammie 900 Seca made a similar whine..don't recall if the had balance shafts or not?

 

[garyahouse]

I noticed that gear whine the first time I test drove my 05. Since then it has become music to my ears. It may be my favorite instrument in the FJR symphony.

Gary

darksider #44

 

[Island_FJR]

I'm kind of relieved to read this - I had started to wonder if there was a problem with my bike because of the whine. I'm still kinda of new to it!

 

[juniorfjr]

Hmmmm. I always thought it was the turbine.

 

[Harald]

Hmmmm. I always thought it was the turbine.

Nope, it's that damn car tire on the back! :lol:

 

[juniorfjr]

Hmmmm. I always thought it was the turbine.

Nope, it's that damn car tire on the back! :lol:

No, that was there before the tire. You non believers. <_<

 

[joebiodiesel]

Stators can't whine-they are static [don't move]. Definitly the balance shafts..I remember that the early '80s Yammie 900 Seca made a similar whine..don't recall if the had balance shafts or not?

I respectfully disagree. Stator whine is well documented and easily reproduced on anything with an alternator. You can identify it easily by changing the load on the charging system.

Joe

 

[John d]

Alternators can whine, but its the rotor in it that spins within the stationary stator. Applying additional electrical load can't make it spin faster because it is mechanically driven by the engine.