Rebor

[Wayne1960]

Is it possible to have my Z900 A4 rebored and still keep the same pistons? is there an acceptable limit?

[zpower]

Simple answer is no you will require new pistons after a rebore.

[PAULJAC47]

Unless you have new liners put in !

[Wayne1960]

What's the next size up and I guess ZPower stock the pistons and rings?

[Mark Tiller]

Take it up in capacity....no substitute for cubes

[Wayne1960]

Can you get new liners? can i fit them myself?

[DogsbolloxofZ1B]

Hmmmm
It should be possible to re-cross hone your bores and keep within the serviceable limits, but not re-bore as other state. Modern X honing from companies like SERDI UK is done to within microns using inline auto honing machines. You'd have to measure the bore using a bore gauge, pistons and work out if you had enough meat left in the bores. If you do, get some new rings and re-gap correctly. Plenty of ass grease and away you go, rings should lap themselves in after a few tens of miles.

Mike

[chrisu]

why do you think it needs a rebore ?

have you measured it ?

as zpower says - rebore = new (different) pistons.

if you do go down this route price up a wiseco set of pistons against the standard kawasaki ones.

[Wayne1960]

Chris

Smoking on 1 & 2 !! 3 & 4 fine checked plugs on 1& 2 and wet.

[z1bman]

have you measured to piston to bore clearance? is the bore scored? what are the piston ring end gap clearances when installed in the bore ? are the valve guides in good condition & fitted with new quality valve stem seals

[Wayne1960]

Hi Zed
Engine feels like it's running well now but when I had the problem with the piece of metal in the chamber I spent the day with Buzzard.
We tidied up the head so I could use it to get the bike finished which I have. However we established that the bores were scored and the valve guides shot.
Ian keen to keep the engine 903 original spec so the first thing I need to do is sort out the cylinders.
Pistons measured ok and rings all new so I'm guessing the scores are causing the problem.
So can I swap the out for new?

[Gavin]

Give it a compression test before stripping down, it may just be valve stems seals

[chrisu]

Another set of barrels?


But get the valve guides/seals done before you put it back together

[Wayne1960]

Ok I'll do another compression test which I did before and I had what I thought was good compression about 8 on each.
In fact the worst was was cylinder 3 and that and 4 doesn't smoke at all it's only 1&2
Don't really understand why but Buzzard did say it would smoke but it should smoke on all 4
Say I've got good compression! I have already confirmed the plugs are damp.
So can I buy new cores and keep my block if I need to?

[ADRIAN H]

You can buy liners here. Think this is priced for one liner.

http://japan.webike.net/products/2505366.html

Or ask Zedhead on saisei-europe.com.