Topic: Who knows 550 transmissions?

[MetalHead550]

So, finally got around to dealing with the trans. problem in my 78 550k project.  Problem was 3rd gear was dead, like hitting neutral but you could bypass it to 4th.  The engine's out and upside down so I could pull the pan and investigate the situation.  What Ive found is that on the countershaft, 4th gear's dogs have been broken off.  These dogs are what the shifter forks plugged into the countershafts 3rd gear, thus the false neutral since theyre gone.  Im hoping some of the more experienced members can help me with my plan of attack.  First off, obviously the cases need to be split so I can swap out the countershaft and gears with another(which I dont have yet).  I can see that there are 10 long-assed bolts that go through the bottom crank case and run all the way through the jugs and head where they are torqued with nuts.  These of course will need to be removed to split the cases but will the rest of the engine more or less come appart when I do?  I would like to avoid disconnecting the cam chain and tackling this from the bottom of the engine if possible.  Is it?  How hard is it to disconnect the primary chain since I see that as being the main obstical, working from the bottom.  Anyway, any advice would be very appreciated:  can I do it from the bottom, what special tools will I need, what things do I need to be carefull with,  what else should I definitly replace while its apart?  How much beer will I need?   Thanks guys!

[Kevnz]

Gidday there.
I have just had the same problem with my 500\4 except not so bad. It would surge in 3rd as the dogs would jump in and out of mesh.
Tha cases have to be split. I don't have a manual but from my experience it looks like you need to remove the head and barrel and ALL bolts in the top and bottom cases. Problem is you can't remove the crank from the bottom case without removing the primary chain so you have to lift the topcase up which means the pistons have to be removed from the rods.Also have to remove clutch basket and gearselector linkages and probably oil pump.I just kept unbolting things until the cases felt like they would separate.
Once cases are apart the gear shafts lift straight out of the bottom case and you will see the faulty parts. Replacing the gears is easy and when reassembling the cases I threaded a piese of cord through the conrod eyes so I could keep the rods vertical as the cases went together. Then tilt rear of cases upward so you can poke a screwdriver in to get the selector forks in the right slots, centre fork goes forward, other 2 rearward. Make sure gear cluster and selector shaft are both in neutral. The forward left and rearward right needle bearing housings have dowel holes that mate with dowels in the upper case. Make sure they line up before trying to clamp the cases together.
Before doing every thing up make sure you can select all gears and that the cam chain is free and the crank spins freely. Piece of piss.
Kevin

[MetalHead550]

...yeah....sounds easy.... .  Oh well, I figured it was all comin apart.  The engine has 20 some thousand on it and ran really tight, no smoke or sounds, but what are some components I should go ahead and replace while its in peices?  Would threre be any point in honing the cylinders and replacing the rings?  Dont have the cash to hop it up right now, or at least my priorities lie elsewhere, just a standard rebuild might be in order though?  Thanks Kevin, and others in advance!

Oh yeah, any ideas for a simple engine stand? 

[bryanj]

You DO NOT need to take the head off to remove the bottom case PLEASE GET A MANUAL. Everything is in that