Jump to content

I have an engine sound that starts at 2900rpm. Carbs?


Josh1234

Recommended Posts

I have a video with some sound, but I'm betting someone will know what the problem is without the vid. (I'm not sure of an easy way to post it).
 
The sound can be described as a chattering sound, or a mechanical flutter.
 
With the clutch pulled in, or the bike in neutral, I can still hear the sound, so it doesn't matter if the bike is moving or not.  As I rev the throttle, the sound starts at about 2900 RPM.  If I let off the throttle, the sound STOPS happening at about 2400 RPM (~500 rpm lower).
 
While riding, I think it goes away around 4K or 5K rpms, although I can't be sure, since by then engine & wind noise may just be drowning it out?
 
This is NOT the tweety-bird sound, air intake, or the sound from the straight-cut gears, which are all common & noticeable mon a YZF600R. They're also enjoyable & music to my ears when I ride :)  I sound like the car from the Jetsons, actually. But this fluttering or chattering sound is annoying at slow speeds, like cruising through a parking lot.  It's very noticeable and I do not remember my previous YZF doing it.
 
It was present when I bought the bike, and I've put several hundred miles on the bike since then.
 
Is it somehow carb related?

 

 

p.s.  If I could change *1* thing about my bike, I'd want fuel injection!

Link to comment
Share on other sites

Could be vibration in the fairings....The fact that it's at a certain rpm leads me to think that something is resonating at that rpm and vibrating. Turn your idle up till it a at 3k and start pushing on things until you feel the vibration or hear it stop.

Link to comment
Share on other sites

Thanks guys.

 

Can a cam chain tensioner go bad even if the bike only has 7K miles on it?  Can a cam chain tensioner go bad based on time, not miles?  

 

I did some looking, and apparently a yzf600r has a resettable CCT.  It's under the tank, but apparently you can unbolt it, hold down a spring so the "teeth" will move the other way, and reset it.

 

I also had someone else on the yzf600r forum mention it might be fairings.  I'm a little suspicious since the RPM at which it happens is very consistent, but that might be easier to test.  In my digging, I found out where my idle screw is, so maybe I can set my idle to where it turns on, and then press on some different panels and see if it stops.

Link to comment
Share on other sites

Your tensioner should be automatic but it's possible it has stuck. Very easy job but I would check for rattles in the body work mirrors etc first. You can also tell if the sound is coming from the cam chain by using a screw driver as a stethiscope. Put the handle to your ear and the tip to the cam chain. If it amplifies the noise, you've found it.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...