I noticed a sound yesterday that I don't normally hear as I am usually wearing ear plugs and listening to my MP3 player. At very low RPM, idle and maybe a touch higher, I am hearing a very soft thump-thump-thump. It isn't the clacking I heard from my CCT (I only changed the front one so far, so not ruling out the rear one yet). It also sounds like a rod knock...very deep, not a clacking sound. It concerns me, but it doesn�t get louder with higher RPM, it isn�t even audible with the increased RPM as the exhaust may drown it out.
What do I look for? I am having a hard time pin-pointing the source, and I haven�t heard of many internal Engine problems. I REALLY don�t want to have an issue, so ignoring it bothers me. The sound appears to be the same in Neutral as in gear with the clutch in. Once moving other sounds mask any noise it might be making.
The bike has 27K miles, and has not have a valve check. Not sure if this would possibly create noise such as this.
[image: View Post]thereisnospoon, on May 14 2009, 06:10 PM, said:
I'll go with "nothing because these engines just don't do that"...
I just finished replacing the engine in my '04 because of mechanical failure at 10,192 miles. I bought it with an engine noise. It was at a Honda dealer for diagnosis and recall work when I bought it. The Honda tech and myself both thought it was a lifter noise on the rear head, and we suspected a VTEC lifter because it still had perfect compression and ran well. A loose CCT also crossed my mind, but no such luck. It was a sharp intermittent tapping sound at idle, and I dare not rev it over 3000 for fear of doing more damage. It turned out to be a spun rod bearing. I didn't hear rod knock, what I heard was the piston hitting the head because the bearing was so loose. I know these sort of things aren't common, but they do happen. I don't know what the previous owner did to cause it, but I suspect he wasn't being easy on it.
[image: View Post]CBR600F4i, on May 14 2009, 11:04 PM, said:
[image: View Post]thereisnospoon, on May 14 2009, 06:10 PM, said:
I'll go with "nothing because these engines just don't do that"...
I just finished replacing the engine in my '04 because of mechanical failure at 10,192 miles. I bought it with an engine noise. It was at a Honda dealer for diagnosis and recall work when I bought it. The Honda tech and myself both thought it was a lifter noise on the rear head, and we suspected a VTEC lifter because it still had perfect compression and ran well. A loose CCT also crossed my mind, but no such luck. It was a sharp intermittent tapping sound at idle, and I dare not rev it over 3000 for fear of doing more damage. It turned out to be a spun rod bearing. I didn't hear rod knock, what I heard was the piston hitting the head because the bearing was so loose. I know these sort of things aren't common, but they do happen. I don't know what the previous owner did to cause it, but I suspect he wasn't being easy on it.
I sometimes get a noise like that when the bike is warmed up, and I'm starting to move from a dead stop, just letting the clutch out with a little bit of engine load on it, light throttle. I doesn't happen with the clutch all the way in and no throttle or with the clutch out, bike in neutral. Only when I start to load the clutch and start moving (RPMs starting to bog when letting the clutch out). Once I get rolling and the clutch is completely out (engine is not bogging the clutch), the noise goes away. I think it seems to me to be a CCT. It seems to occur more so when the bike is nearing an oil change. I'm going to change oil brand at the next change and see if it goes away. Someone mentioned on here that Valvoline oil quiets the CCTs on these bikes or at least on their bike.
Thanks for the idea Mark....I think tearing it down at Rons place is a great idea. Suppose we can rebuild it in 4 hours? :goofy:
It is definantly not related to the transmission or the sprockets...I only hear it when idling, and mostly in neutral. Maybe I am just hearing things, or being over cautious.
Put it up on the center stand - run it up through the gears sitting there. see if you can determine when you hear it. Might help to narrow down the options.
Edit - just saw your post about only in neutral..... I got nothing.... sorry.
End of thread · 15 posts recoveredWayback Machine snapshot 12 Apr 2010