Noises at idle when running hot

[Phonics]

Hi there, has anyone experienced knocking / loud noises at idle after running at high revs for an extended period? It seems to have developed but admittedly have only recently been taking the motorbike at speed so maybe its a normal cooling noise. Would be interested in others opinions if it is normal.

Thanks!

 

[m in sc]

that hard knock in the middle of the vid? or the overall noise? have you checked your oil level?

 

[Phonics]

The hard knock in the middle of the vid. Oil levels are sitting where they are meant to be. The hard knock continues in idle until the engine is turned off - usually ~10 seconds spacing. The overall noise also

 

[m in sc]

I'LL BE HONEST, it sounds pretty 'tinny' or sheet metal-ish. Ive owned and worked on a LOT of motorcycles and never heard anything like that from a motor. check to make sure the heat shields on the exhaust, particuarily the lower front one is tight, and that the skid plate isnt missing a bolt or loose. the only othe rthing i could possibly thing it is is the cam chain, but thats just wild speculation.

 

[dmonkey]

How many miles are on it, and any engine mods? Any issues with engagement of the centrifugal clutch coming off idle, or issues shifting?

I have heard that same type of hollow knock sound from my CT125 before when actively shifting Neutral to 1st Gear with the shifter clutch out of adjustment, never just sitting at idle without interaction though. A loose oil spinner can sound a bit like that but the only times I've heard that it's been more frequent, and on the manual clutch bikes that don't have a centrifugal clutch with shoes in the spinner like the CT does.

 

[Cpd419]

Maybe the clutch.

 

[Little_Thumper_Boy]

Run it again with exact same conditions, warm up, prep etc as you did in the video. Then idle it in neutral while pressing down on the shift lever firmly (disengages the clutch) and see if the noise changes. Repeat with the bike in gear (on center stand), repeat in gear with enough pressure on shift lever to disengage clutch while applying rear brake. Noise?

 

[JPMcGraw]

If its any help that sounds a lot like my bike when the clutch needs adjusting or after i adjust it wrong. Its got the same tone and gives a pop when i lift off after a shift, just not constantly at idle. Id troubleshoot that like others have said to rule it out.

 

[Pittsburgh_Bob]

My brand new Trail just started doing this last night! I took it for its first ride yesterday. I put about 80 miles on it. It used to idle like butter but last night it made popping sounds just like in the video. About 3 minutes ago I started it. Heard the pops then miraculously they went away and it’s idling quietly again. Weird!?