How loud can a exhaust leak sound?

knocking as everytime it changes direction.

 

Oh yes. I’ve only ever had one engine with a wrist pin knock. Not a common issue

 

Could that kind of noise even come from a pulley/drive belt?

 

No, sure not on Toyo. esp.

I'd rule out everything else first.

Dirt bikes were terrible about that but always sounded much different. More of a SHSHSHSHSHHSHSH as it smacked the head.

 

Could if a bolt were backing out and touching a pulley.

edit: listening again doesn't rule out anything.

again though, I don't think that's going to be hard to find. It's too loud and nearby

 

Drive accessories can cause many odd noises. When you have the belt off make sure the crank pulley can’t be pulled in and out too.

 

Have you had the camshaft out? There's a scissor gear that might no be preloaded anymore. I did that once and it was a fast tick. Not that loud though.

 

Definitely not an exhaust leak... sounds too loud to be a lifter. Maybe timing chain stretched and is slapping? Pulling the belts will be a good place to start.

 

We don't have lifters. We do have shim over bucket and it certainly is possible for a shim to get dislodged but this sounds to fast to be a (as in one) valve. Too fast to be 1 of anything. Makes me think it's something ancillary to the engine

 

If a shin was making this noise it would be a misfire too

 

Probably true.

It does sound terrible, don't blame you OP for much concern.

Really could be anything though and probably will be something strange.

The only way I see a broken piston is from detonation but it certainly does happen from that. I hope not for you.

 

Never had camshaft out.. replaced harmonic balancer acouple months ago I could have done something wrong re-assembling not sure. Going to take off the belts when I get a chance. If the noise is still prompt what should be my next step?

 

And even with this noise it idles at a constant RPM doesn’t misfire and drives perfect. Just with that horrible noise..

 

OK the harmonic balancer or something attached to it is now suspect #1
empty lord is also right to check crank freeplay.

 

Check if the crank pulley has wiggle room?

 

Yes forward to back, if it does pull the inspection plate for the transmission and pull it back and forth and see if the flywheel moves too. If it does then there’s bad thrust bearings.

Kinda doubt this is your issue. But it’s something to check