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Discussion Starter · #1 ·
Ok, I'm far from a mechanic but I am going to give this a shot anyway. Rebuilding the motor on an 84' Z50R. I'm ok with doing the heads, but what parts typically need to be replaced in the case?
 

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I just did the motor on my 83 Z50, they seem to be pretty hearty.The only thing I replaced was the piston rings and clutch plates. Had the cylinder honed, then just looked over and cleaned everything else.
 

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You'll want:



a complete gasket set,

a complete seal set,

the mesh oil filter is usually destroyed,

clutch plates; heavy duty springs for an adult; a new clutch nut (you'll figure out why when you get there).



Other than that the bottom end is bullet proof. Under normal wear and tear there should be no need to split the cases.



Top end you'll need



Rings /



perhaps piston,

Piston Pin,

Piston Pin Clips,



timing chain and sprocket kit



Aside from catastrophic failure there's no reason not to rebuild these engines.
 

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On a pair of '71 Z50AK2 motors I've got, both of which have been through a couple generations of kids before spending the last 18 years with me, one's never been opened up at all and runs fine, with no attention other than oil changes and tuneups. Might be time to clean the oil filter sludge trap thing in the clutch.



The other one was lightly seized when I got it, because a mouse was storing soybeans in the intake, and some fell past the intake valve into the cylinder, where presumably the combination of soybean moisture and mousepiss cause a little cylinder wall rust. I honed the cylinder, replaced the rings, and lapped the valves. Still runs fine. Might be time to clean the oil filter sludge trap on that one too.



While you've got the top end off, gently check the connecting rod for side to side rocking/tilting freeplay and end to end freeplay (which would translate to radial play at the big end bearing). You can probably get away with slight rocking play and almost certainly won't be able to feel radial play. I couldn't on mine. If you can, you might want to consider a crank replacment/rebuild. But I bet you won't. There's a spec in the manual where you can check this with a dial indicator, but in my experience a stock motor can live with some pretty horrible conditions and keep on ticking.
 

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Discussion Starter · #6 ·
LoudFastUgly said:
You'll want:



a complete gasket set,

a complete seal set,

the mesh oil filter is usually destroyed,

clutch plates; heavy duty springs for an adult; a new clutch nut (you'll figure out why when you get there).



Other than that the bottom end is bullet proof. Under normal wear and tear there should be no need to split the cases.



Top end you'll need



Rings /



perhaps piston,

Piston Pin,

Piston Pin Clips,



timing chain and sprocket kit



Aside from catastrophic failure there's no reason not to rebuild these engines.


When you say "heavy duty springs for an adult" are you talking about the springs on the back end, or somewhere in the clutch?
 

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Discussion Starter · #10 ·
LoudFastUgly said:
Those are for a manual clutch, not auto.




Yea, I realized that after I sent it. Hey, let me ask you this. I have one engine where the clutch seems to slip? Or maybe not go into gear correctly. Sometimes on the 1st down shift it won't go into 1st gear and you have to down shift again. Sometimes it appears to be not hitting the right gear. What would cause this?
 

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Possibly a bent shift fork or worn dogs.



Transmission is an early Latin word, meaning: "to be fixed by others" or "not to be tinkered with". These little Honda's have one of the simplest tranny's ever.



Beware, if your not overly handy, this is not your territory.



Ps, did you get your fenders yet?
 

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Discussion Starter · #12 ·
LoudFastUgly said:
Possibly a bent shift fork or worn dogs.



Transmission is an early Latin word, meaning: "to be fixed by others" or "not to be tinkered with". These little Honda's have one of the simplest tranny's ever.



Beware, if your not overly handy, this is not your territory.



Ps, did you get your fenders yet?


Well, I have a junker that I'm learning on so I won't mess with this one until I learn. If all else fails, I have a local guy that rebuilds these things for a living. Haven't gotten the fenders yet, the tracking info says they are in my coutry though. Should get here in a few days.
 
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