When my 99 CBr 600 F4 is engine braking/decelerating in RPMS while in gear, I'm getting a loud tapping sounds coming from right below the tank, so presumably the engine. At first I thought it might be that my chain is currently a bit loose and was bunching up as the front sprocket was slowing down, but I was pretty sure it wasn't coming from THAT far down in the engine. So I'm wondering if the sound might be coming from my valves... It doesn't sound HORRIFIC... but it doesn't sound great.

Any ideas gang?

 

Is it a tapping or does it kinda sound like slapping? If it's more of a slapping it might be that the cam chain tensioner failed.

 

I have this same issue. I've been told Cam Chain Tensioner (as this is a very common problem), however my noise is most apparent on the Left side of the engine. Can you tell which side of the engine your noise is coming from?

 

Is it just one single rubbing/slap noise? Cause mine just started making a rubbing/slapping noise when i close the throttle sometimes.... but its just one single short noise.

 

To make things more confusing for you guys, it was kind of a combination of the two

Finally got a swing arm stand from FlynCycle (40 bucks! Not bad!) and serviced the drive chain. It had a heinous amount of slack. It's the stock chain and I just ticked over 16k miles a few days ago so it's definitely time for it to go. After adjusting it to a point where the slack was reasonable, it put me well into the "replace chain" section of the wear indicator. Yikes!

While I was doing this I also took off the front sprocket cover and revealed a DISGUSTING amount of buildup along the metal surfaces across from the front sprocket from crap getting slung off the chain against the housing. It was literally almost touching the sprocket... that's how bad the build up was! Scraped that all out as well as buildup along the rubber chain guide on the top of the swing arm.

Lastly, cleaned and lubed up the chain, made sure I was all torqued up in the rear axle bolt, and went for a spin.

First of all the bike is riding like heaven compared to before... but most importantly, the sound is gone!

Glad this is all over! Just gotta order a new chain and sprockets. I think I'm going to tooth down 1 on the front sprocket... Exciting

I'm also glad that my first guess (that the chain needed to be adjusted) was correct. The only thing that led me to believe that it could be a valve was that the sound was LOUD and it was difficult to tell if it was coming from a particular side of the engine. But since it was ONLY happening while IN GEAR, and since the transmission felt fine, and since the motor wasn't losing power, I figured the chain was a good place to start.

Jinx, I THINK my problem started out that was and got progressively worse pretty quickly. So if the same happens to you, check your chain slack/wear and check for any buildup along the guide or around the front sprocket. If that doesn't fix it then you probably have a bigger, or at least different, issue.

 

I regularly clean the inside of the counter sprocket cover, and the only time it was as bad as you said yours was, was when i first got the bike. Apparently previous owners dont clean their **** very well?

My bikes got over 16k on it, and its getting to the replace chain indicator, i just cant decide how i want to go with the sprockets. If i want to keep them stock or go +2/-1, and have my guages all messed up...

Anyway the problem was gone when i adjusted my chain. I took my friend for a ride, and afterwards i was looking at my chain, and it was ridiculously loose. What it looked like happened was the chain was rubbing against the footguard part of the fairing that is below the left footpeg. I don't know if it got that loose that rapidly because i had an extra 110 pounds on the back, or what. but its gone. I'm back to the only noise being the damn cam...