I'm hoping to get some opinions on what this engine noise could be. I know I've had a few threads recently but I'm trying to separate them based on the issue. Let me know if that's not the best approach, mods.

A little history:
In 2012, I burnt up an exhaust valve which resulted in a catastrophic failure. It pretty much sat until last year. Last year, I rebuilt the engine with a new head and Wiseco piston. I got it running this year and installed a VM36 carb, Versy cam chain tensioner, Versy head plug, and a Barnett clutch. Stock exhaust and air filter. Running Rotella T6 15w-40.

After several rides and one big pull in particular, I started to hear this knocking and/or rattling type sound. The engine doesn't perform ANY different, but I obviously have concerns.

https://imgur.com/a/wU3WupY

To rule some things out, I have installed the modified cam chain tensioner, and I have triple checked my valves. This sounds dumb, but it's something I noticed; I had it idle for a second with the valve inspection covers open as well as the timing plug cover open (honestly didn't think about this one). While oil did splash a bit, I noticed that the sound was much quieter with the left-side timing plug off.

I talked with Dave, and have the flywheel puller tool rental in motion to verify that my flywheel nut isn't loose. I'm a little worried it might be a bad crankcase bearing or maybe an issue with the wrist pin on the piston. Maybe it's piston slap? I know some other guy had an issue with the balancer in the crankcase that was making a knock. Honestly, I feel like I don't know what noises are normal and what aren't at this point. Not sure what to check without tearing the top-end down again, but if I have to, I must.

Robb++, view the video I just posted regarding a loose flywheel.  While your engine is running, throttle it up and listen to your noise.  See if it is similar to mine.  It might be helpful.

My compliments.  You got it runnin.  As I recall, that engine was a mess after a valve snapped off.  You worked a miracle.

Welp, I got a lighter flywheel and got it all back together. Same horrible knocking sound. Feeling discouraged. Might light the whole thing on fire.

justin_o_guy2 wrote on 08/26/22 at 13:18:10:

You don't have to do that. You can just light one end of it and when it gets to the tank, it'll finish it for ya.

That's some helpful info right there.

Rob, you are going to have to isolate the source of the noise, otherwise you'll be throwing parts at the bike in a hap hazard way. It could be a big item like a rod bearing, or as simple as a loose engine mount bolt. They can sound the same from the riders position.

These types of noises are much easier to find with a few helpers. And sometimes people who don't know a dang thing about motorcycles are the best helpers because they don't have a preconceived notions about the way things are supposed to sound.

Finding the source of your noise by listening to the engine will be extremely difficult.  It's air-cooled and rigidly mounted.  I suggest you try the process of elimination.  Let's face it, to eliminate the noise, or at least be comfy with the noise, you will have to disassemble stuff.

The noise you are hearing is like a rattle, a steady clicking, or clacking, or clunking, or slapping, etc., am I correct?

It makes the noise when you are running the engine in neutral.  Is that correct?

It doesn't make any difference if you pull the clutch lever in, it still makes the noise.  Is that correct?

If I am correct on all three of those points, then you can rule out the transmission output shaft and output gears, the transmission input gears, and the speedometer drive.

I remember you found chunks of non-magnetic material in the crankcase.  When I read your old posts, they suggest that you completely disassembled the engine.

Did you completely disassemble the engine?  Like split the crankcase so you could see all the transmission gears and the crankshaft and the balancer drive gears and the balance shaft?

Did you check the rod bearing clearance as outlined in the manual?  If so, what was the side clearance and how much did the rod swing?  Did you try to check the rod for excessive radial play by using the method outlined in the manual (pull up on rod, slap with palm, listen for loud clunk)?

Did you verify that all three timing marks on the balancer drive gears were correctly aligned?  Was the balancer drive gear pin in place?  Was the pin tight?  Were all the cushion springs installed and none broken?  Was the drive key in good condition?

Are you sure you retrieved ALL the chunks of metal out of the crankcase?

Did the oil pump turn smooth with no evidence of binding or debris inside?

As I recall, you had one #ell of a time getting this thing lit off.  You mentioned valve adjustment problems and an extremely low compression pressure reading (like 100 psi).  You posted that you went back into the valve adjustment and found some sort of issue with tight valves.  It was like you had to back off the adjusters a LOT to get things corrected.

Are you comfy with your valve adjustment?  Are you sure that your cam is timed correctly (100% confident)?  Are you sure that you didn't run your valves into the piston again due to the adjusters being grossly too tight or the cam being out of time?  That compression pressure was grossly low.  Valves being bent or held off the seat would explain that super-low compression pressure.  Did you hold the throttle wide open when you were doing the compression test?

Let's talk about your piston and cylinder some more.  You had a big failure.  Did you use the old cylinder, the one that was subjected to the failure?  Did it have dings and scratches from the debris?  Did you use a hone to clean up all those little dings and scratches?  Did you try to remove ALL of the little dings and scratches?

Or, did you pick up a used cylinder off ebay or in the marketplace.  Same questions regarding the hone.  I'm looking to find out how much honing was performed.  Folks have a natural inclination to hone out ALL of the imperfections.  ALL used cylinders have little scratches and such.  You can make things really loose if you try and clean up every last little scratch and/or pit.  Loose pistons slap, and the noise they make gets louder the looser they are.

Tell us everything you can about your cylinder.

Don't get discouraged.  Many of us have been exactly where you are right now.  This is a good opportunity to learn a lot.  

If you don't have the tools or gear that you need, consider buying the stuff.  It's not as if you are pouring more cash into the bike.  The tools and equipment will be with you for a good long time and will be used on many more bikes and cars.

Removing the clutch cover, alternator cover, and head cover are easy jobs.  If you dig back into the thing and carefully verify that everything under those covers is as it should be, and don't find the source of your noise, then you will have to remove the cylinder.  That's a little more work, but still a relatively minor endeavor.  You did it once, you can do it again.

As you go through all the stuff under those covers, post pictures and explain what you find.  You give us enough info we can help you, but keep things organized and don't be embarrassed to give us all the facts.

You can start by doing your level best to answer all the questions I have asked.  Don't skip any, answer them all.

Good luck.