Anyone know what this sound is?

Hey guys, first post here. I've been on the forum for a while as a resource, and I finally decided to join about a month back.
My bikes making a pretty loud clunking noise. Maybe it's a bent rod, bad wrist pin? I also think that it could even be ignition timing or mixture. I've clean the carbs when I first got it. needles and pilot, but I ran it without fuel filters for a while. Is this what pinging sounds like? I've only found videos of pinging cars. Watch video

You can use a 2' or so small diameter PVC pipe or 2' stick or something and try to find the source of the pinging. Put one end of the pipe/stick on the suspected area and the other end near your ear. Narrow down where the sound is coming from. Sounds like it may be a sticky valve. But where the sound is coming from will help you diagnose what component is suspect.

It's a thumper!

Is it running on both cylinders for sure?

Yeah definitely. Just learned that trick the other day from a friend. Using a long screw driver with the handle at ear, it sounded like the transmission area. I should probably try it again at more points. Thanks for the reply.

Yup, it's running on both for sure. I've pulled the plugs one at a time while running. Both spark. I've notice something strange between the two cylinders. Here in Nevada, our winter temperatures are usually 15-30 degrees in the day time. While cold, the left cylinder has way more condensation smoke than the right. I'm pretty sure the left had the more compression too. would this make a difference? Thanks for the reply.

Yes a tired cylinder would make it run rough,but that sounds more like mechanical noise to me.
It wouldn't hurt to run a compression test on it though I guess

Did the noise change when pulling the spark plug wire off of each cylinder? Cylinder getting unloaded from combustion force.
It sure sounds like your going to be either looking for a good used motor, or tearing into that one. If you had the carbs gunk up, it may have gone lean and damaged a piston. But he noise sounded load under the oil sump/ pan, like a lower end bearing. If you drain out the oil and filter into a clean pan, you can see if there is any bearing metal. Sure looks like bad news for the motor.

was it okay before you cleaned the carbs :blink: . both head pipes same temp/heat. Does the noise go away if you pull in the clutch lever. :blink: I've seen some out of synch carbs make em sound like a single. the cylinder streaming mist when cold may be loafing or have an internal problem. I know the twins make more noise than the 4's. Hard for me to diagnose by video/sound. :dry:

Wireman- I'll try and find one on ebay, or maybe ask to borrow a friends. A cold, compression test with a little amount of oil in each cylinder showed 90psi in the left and then 60 in the right. ( This was before I had the bike running) If I remember correctly.

Motor Head- You know, I had the header off on the right side,( being the low comp side) and notice alot of caked on green flakes inside the exhaust ports. There wasn't any carbon in there. I looked like a barge covered in barnacles and sea scum haha. the other cylinder was carbon and looking right. Maybe I'll snap a picture.

WOW! I feel very embarrassed. I pulled the plugs and found out that I was only running on my right cylinder. Bad connection on the plug wire. I knew it sounded more distinct for the past few days. That also explains why my comfortable idle went down so low. the lowest I can normally go is 1000-1100. Unfortunately I am still having the noise issue. Just not as loud.
I should of given more back story to began with..
I fixed this problem once before by adjusting my mixture screws. There a little out of wack again from frantically adjusting them to make up for one cylinder missing spark.

Turboking- A friend borrowed one of those temp guns from work and shot them. They both were the same temp. Don't remember the degree. I couldn't tell you if they heated up at the same rate or not because it was after a ride. Thanks for the reply.

Funny, but my twin will only run on the right cylinder when the left is unplugged. The left cylinder can't keep the bike running. you can tell that it's trying too. It will only last about 5 seconds before giving out.

Sounds like I'm having a couple problems. Any advise for setting mixture screws? I understand that you are checking and setting after referencing the color of the plug to that cylinder.

If it has only 1 screw on each id start with 1 1/4-1 1/2 turns out from seated as a baseline to see what it does

I kind of wrote off checking to make sure that the cylinders really were both firing because I'm always pulling plugs and what not. Sorry to everyone who suggested checking. I get a little stubborn and at the same time overwhelm my self with thoughts to the point where I start to disregard the simple things.