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What is this part under the crankshaft nut called? Part number? Where to get ine?

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rabbie6

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Taking the timing cover off I discovered this 23mm nut with a 10mm nut inside it holding a metal plate to the crankshaft and it looks stripped…

Looked at a parts fische but couldn’t find the part number - is is easy enough to replace?

Also found an alarming amount of metal in the #3 carb intake port and the electrode on the spark plug crushed - expecting the worst for piston #3

Dropped the oil pan and saw a piece of metal in bars I was using; but may not have been from the oil pan…

Cannot get the rocker cover off with the motor in the bike so removed all the front and back bottom motor mounts hoping to pivot it forward to get it off but motor won’t budge - suggestions? Just pull the motor entirely?
 

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That is part of the advance mechanism for the ignition no.7 in the pic , so you will need another advance unit . Someone must have thought you could undo the 24mm nut when it only sits in a keyway and is actually held on by the 10mm . Sounds like no.3 could have dropped a valve and unfortunately , you have to remove the motor to strip it . If you dont have a hoist , lay the bike on it`s right side and lift the frame off .
 

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hinksy said:
That is part of the advance mechanism for the ignition no.7 in the pic , so you will need another advance unit . Someone must have thought you could undo the 24mm nut when it only sits in a keyway and is actually held on by the 10mm . Sounds like no.3 could have dropped a valve and unfortunately , you have to remove the motor to strip it . If you dont have a hoist , lay the bike on it`s right side and lift the frame off .
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thanks! got the motor out now and the valve cover off but cannot get the head off

yes, valve dropped! the exhaust valve stem on #3 is broken at the seal
not looking forward to seeing what the top of the piston looks like as I found larger chunks of metal in the oil pan...

and I found an extra vale adjuster nut loose in the intake valve area - free parts!

the PO used silicone heavily on the alternator cover so I suspect he has used some sort of glue on cylinder head gaskets also - used a torch and banging with a mallet for a couple hours and still nothing
 
Ouch ! That has to hurt , but it was on the cards . I hope it didnt do too much damage to the cylinder . Dont forget to go thru the entire oiling system and thoroughly clean it . So all off the galleries/jets , engine cases and cam towers aswell as crank shaft . And most important , check the oil pump , it may be toast now after eating metal if the piston holed and shared it`s goodness thru the engine . Be carefull wacking the head as those fins wont take much to deform or worse , snap ! You do have all of the head studs off yes ? Even the ones under the cam towers ? My original F2 in 77 used to have the annoying habit of the number 3 exhaust adjuster undoing itself , but by the sounds of it , the PO was a butcher and he somehow droppped the adjuster and just fitted another . He and you are lucky it stayed put . I just had to redo/replace my whole topend last year . So all new valves/guides/seats/pistons/bearings/seals/gaskets oof da may !
 
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