Uhoh this don't sound good!!!

[Roscoe]

Hard to tell but it sure sounds like a connecting rod spun a bearing. Do you get a double knock when giving a little throttle? I wouldn't run it for long if it is a bearing because it will chew up the crank and rod end.

Pull the filter and cut it open to check to see what's inside. If it is a bearing, you should see some swarf....

Motor still runs smooth as a babies bum.

 

[Roscoe]

Sounds like a clutch spring tower or a clutch spring bolt broke and the spring is hitting the cover. Not far from catastrophic failure. Open, change, ride, now if you're dropping the sump like @Mittzy said, drop it straight. Clutch spring bits and pieces of aluminum in the front of the pan under the basket, clutch problem. Debris in the rear left screen area and no teeth; Torsional damper. Debris generally everywhere and signs of gear teeth the the noise is probably gear dogs too close because a circlip is on walk about. Just thinking out loud

So if I open up the front and it is the spring like you are think and I am too...... will I still need to drop the sump and do a clean up?

 

[Roscoe]

I wonder if there's any kind of vibration on the clutch lever when pulled in?

No the lever had pressure sort of a bit maybe but I had to rock the bike back n forth to get it to neutral so I could push it. Lever felt fine just that it did nothing had to lock the back wheel up to stop it as I couldn't change gears.

 

[warp9.9]

So if I open up the front and it is the spring like you are think and I am too...... will I still need to drop the sump and do a clean up?

It will depend on how bad it is. If it were me id spend the 20 bucks or less on a gasket and drop the sump amyway just to clean and inspect the sump screens.

 

[mr hunt]

Drop the sump...better to be sure now than at 120 on the highway 2hrs from home...

 

[Roscoe]

Yeah true....... oil only a week old too lol..... actually had a call from a mate who builds triumph race engines offered to fix it for me for cost of parts. Coooool.... my disability doesn't allow me long hours working with anything.

 

[Gregger]

Roscoe, hope it is restricted to the clutch area. If you have a stethoscope or a long screw driver you should be able to hear exactly where the noise originates. I'd still drop the sump as the fellows suggested. Glad you have someone knowledgeable to check it out for you.

As to con rod bearings, I don't think I've seen any posts of someone loosing a bearing on a Rocket so it's highly unlikely you have that problem. The noise sounds similar to the many vehicles I've heard with spun bearings in the auto industry in the 70s when we would have a plethora of Chevy small block engines fail with the first -40F temps of the season. Guys would fight to start the engine, then get it going and rev the cr-p out of them resulting in that double knock noise or a hole in the side of the block. Changed a lot of short blocks, cranks and rods back then.

 

[Roscoe]

FOUND IT.

Wow, when the detent spring broke the hook end that broke off went into the teeth of the clutch basket and was smashed into the bottom of the groove between two teeth. Wish I had taken a foto of it in there but we were puzzled as to what the hell it was and took us near 5 minutes to get it out with a hammer and a chisel. Foto of the hook attached. This explains the noise in line with a timing and quickening when I revved it, the basket spins in time with the engine on the crank. It was by fluke we found it putting the clutch back on it was impeding us getting it on as it was lined up with the opposing cog.

Covid has stopped us working on it this year only just free this weekend to continue work.
Also of maybe the dogs on 4th and 5th looked like they had only just touched each other........

 

[Gregger]

Thanks for the update. Love good news stories.