Ring failure is NOT a common issue... Is the metal soft like bearing or hard like cylinder wall.. Is is ferrous ( magnetic ) or non ferrous aluminum ? You didn't say if you also had metal on the drain plug magnet...
I would definitely start with the compression test and the borescope.. Can't hurt..If there is really something wrong, It should be obvious..
Does she seem to run on three cylinders ? Or does she run normally and justs bang ? The alternator drive can be pretty noisy on these things...Especially if you're running a bunch of extra electrical stuff..
About the only way I can think of to get your oil diluted with fuel is with a stuck injector...That might also give the noise you are hearing.. Then maybe a busted ring or cracked piston from hydraulic lock..But that's pretty extreme for an LT...And I would think at that point, The bike would not be rideable...As in NOT running well at all...
I had a computer failure that lead to an injector being continuously open...
On my Ford Focus... Not on the bike...
I'm assuming that one side of the injector will be hot all the time.. The computer fires the injector by switching the ground side of that electrical circuit...A shorted transistor in the computer will keep the injector grounded and cause fuel to flow continuously.. It could easily be the reverse of this, But most engines switch the ground..
You could troubleshoot this by putting a pressure gauge on the fuel rail....Key on, Fuel pump runs, Pressure comes up to the regulator's release point and should stay there.. If it falls off as soon as the fuel pump stops running, You've probably got an injector stuck, leaking,or constantly commanded to be on.
Then unplug the injectors one at a time to find the culprit..Measure the voltage at the injector terminals.. If you can read +12v across the injector connector that means the computer is shorted... If not, Then an injector could be stuck..
Of course a short to ground of that particular injectors ground wire would cause it too..
You'd have to unplug the connector at the computer to verify that..
You've got some troubleshooting to do...Get back to us..