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Discussion Starter · #1 · (Edited)
I'm curious about a noise that happens when my bikes engine is between 4800 and 5000 rpms. The best I can describe it is a sort of chatter. My throttle bodies have been synced, the valve clearances are within spec, the chain is also properly adjusted. I'm wondering if it is possibly a preignition/detonation problem at that rpm range or could this just simply be normal. Any Ideas?

Edit: the only engine mod I've done is to remove the Secondary Air system with a block-off kit because those parts are no longer available
 

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How many miles on the motor ?

Could it be your cam chain ?
 

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Discussion Starter · #5 ·
Fox: I don't have a way to record the noise
Rolex: it has 52,000 and I'm kinda leaning towards the cam chain explanation
Gert: Yes but they are all tight

Thanks guys!
 

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I would not expect that level of cam chain noise at 52k unless a tensioner failed. I would sooner suspect resonance from a loose bolt somewhere like the subframe. If you give each passenger handhold a good yank and listen, do you hear anything strange?

I assume the noise happens in neutral with the bike stationary?
 

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Do you have engine guards (crash bars) / sump guard (skid plate) fitted? I'm thinking along the lines of a possible vibration from a defective bracket / joint that resonates at a certain rpm?
This is where my money is. Panniers and carriers are notorious for resonance at specific RPM. Has this noise always been there? Did you change any equipment recently? Has your riding style changed (RPM range)? Did you stop wearing earplugs?
 

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If you suspect anything loose rap a ratchet strap or a bungee cord around it and try a test ride.

The Givi crash bars are a well known point of noise.

Where they join at the front the short tube that fits inside can rattle even if the bolt is tight & on a mates bike I found the triangular mounting plates had countersunk bolts coming in from the rear they had worked loose.
 

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Discussion Starter · #9 · (Edited)
I appreciate all the ideas. I've been very sick the last few days and haven't been able to do any trouble shooting. As soon as I feel up to it, I'll try some things and report back

Edit: I went and took a look and I discovered that the O-Ring where the Givi Crash Bars meets in the middle has broken and is just hanging on. When I feel up to it, I'll remove the skid plate and crash bars and take it for a spin and see if that's the problem. I'd like to figure this out before I install my new center stand
 

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Discussion Starter · #11 ·
I'm surprised you old guys missed it. Gen1 650 has that chain/ countershaft bearing clatter that emits from L side engine area. Steady or increasing throttle.?
Before you replied, I got fed up with feeling bad and made the stupid decision to put on my gear and go for a ride paying attention to where, when and how it sounded. It definitely is contained between 4800 and 5000 rpms regardless of holding, accelerating through or deceleration. It sounds like a metallic/chain chatter/clatter type of sound. It seems straight down rather than one side or the other
 

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Use some silicone to replace that O ring & on the tube there is a very big chance that is where the noise is coming from at those RPM's
 

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Discussion Starter · #14 ·
This morning the wife and I installed the center stand because It wouldn't interfere with removing the skid plate and the crash bars. While it was on the rear stand I cranked it up and used my throttle lock to hold it at a rpm that created the sound and I grabbed the crash bars where they join and the sound dampened. I appreciate everyone's response and help!
 
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