Z1OwnersClub GB

Hi,
My engine (Z400J) is being put back together again, I've a query about the order to do things.

My thinking is to put the rings on the pistons first, then fit the pistons to the conrods, then insert the 12 engine studs.
Is there anything wrong with doing it this way? Seems easier to me, but I've no previous experience so I might be missing something.

All the pics in the manuaI seem to have the studs installed before the pistons are fitted, and then rings fitted to the pistons already fitted to the conrods. But maybe that's because of the order they come apart?

As usual, thanks for any advice.

Best way is rings on pistons first ( once they've been gapped in the bores if new) and then fit to rods.
Doesn't matter either way if the studs are put in first or last if the pistons etc don't interfere with their installation and the base gasket slips easily over the pistons, which it should.

Great, thanks Zed1015 (again!).

Hi Kwackman

I've restored a Z400J a few months ago. Just let me give you some advice.
Put the rings on the pistons, the opening of the top ring should point at the front, the opening of the second ring should point to the rear and the opening of the oil ring should point to the front.
Put new circlip rings in the pistons on one side.I mean a new circlip in the first and second piston on the right side and on the third and fourth piston on the left side.
Put the piston rods halfway in the pistons , piston 1 and 2 from the left side, piston 3 and 4 from the right side.
Install the studs on the cranckcase, you can see how deep they're in and they act as a guide for the cylinderblock.
Install pistons 2 and 3 first and put new circlips in, then install pistons 1 and 4 on the conrods.
Now comes the tricky part! (Don't forget to put a new gasket between the cranckcase and the cylinderblock!)
Slide the cylinderblock over the studs, making sure that the camchain is out of the way and secure it one way or another to prevent it from sliding back into the cranckcase.
Turn the crackshaft by hand to rise piston 2 and 3, keep in mind that piston 1 and 4 go down and might touch the cranckcase , so do it gently! Guide the camchain by hand.
Slide piston 2 and 3 into the cilinders. Be carefull a piston ring can snap suddenly! Work the rings in one by one and use lots of oil or even WD40 to make them slide in.
Once those two are in, you can gently turn the crackshaft so that piston 1 and 4 rise, taking care that piston 2 and 3 don't come out of the cylinders. Again, guide the camchain by hand!
Slide in the pistons 1 and 4, one ring at the time. When the four pistons are in the cylinders press the cylinderblock down to the cranckcase and secure it with the nuts.
Now you can check if the pistons are OK by very gently turning the cranckshaft by hand, once again keep in mind that the camchain has to be guided allso in order to prevent it from sticking around the cranckshaft!
I tried to put the four pistons in the cylinders all at once and snapped a piston ring and it was not the first time I installed pistons in the cylinders.
So be carefull, do it gently and take your time.
I hope my explanation is clear and I wish you all the luck you need!
Greetings from Belgium
Philippe

Wow, thanks for that Philippe, very much appreciated.
Cheers,
Kwackman

Hi Kwackman

you're welcome!
Philippe

Hi,
I'm about to fit the 12 studs back into the upper crankcase.
Does anyone know if these need to tightened to a particular torque, and should I use any thread lock with them?
I looked in the K workshop manual and the haynes but can't see any references to the studs.
Ta for any info.
Davy

Hi Davy

I 've looked it up in the service manual and there's no torque mentioned; I think it has to be more than 2,3 m/kg as that's the torque of the cylinderhead nuts. It is mentioned though that you must apply a non permanent locking agent.
Oh yes, before I forget: there's a free download of the service manual on "manuals lib". It covers the z400, z500 and the z550.
Good luck
Philippe

Philippe wrote:Hi Davy

I 've looked it up in the service manual and there's no torque mentioned; I think it has to be more than 2,3 m/kg as that's the torque of the cylinderhead nuts. It is mentioned though that you must apply a non permanent locking agent.
Oh yes, before I forget: there's a free download of the service manual on "manuals lib". It covers the z400, z500 and the z550.
Good luck
Philippe

Thanks for your help again Philippe.
I have that manual, but I've obviously missed the "use a non permanent locking agent" bit. Must try harder next time!
Your advice on fitting the pistons was helpful- I managed it without dropping any circles into the crankcase!
Cheers,
Davy