TOPIC:

Keep in mind while doing a rough overbore.. Without having the new pistons in the hand of your machinist. That you should take out as little material as needed to do the bore cleanup.
Your machinist can then check the actual size of your new pistons to then finish bore or hone your cylinders to the exact right size to achieve the recommended piston to cylinder wall clearance
Dave

.4mm over bore is a fine idea. That will allow you to see if the bores clean up and still allow a few thousands for the final hone to size after you get the pistons.
I'm pretty sure you will be fine with .5mm.

gordone wrote:

ThatGPzGuy wrote: I got a set of the IMD pistons for my KZP. I believe they are made in India. Seem to be of decent quality, at least my machinist thought so.

Where did you purchase them +0,5mm ?

eBay. stores.ebay.com/imdpistons/

No eBay APP ID and/or Cert ID defined in Kunena configurationI`m so grateful for your feedback !

I have good references on the machinist person, cross my fingers 0,4mm is enough

If so is the next question what oversize +0,5mm piston I shall purchase...

And there are only one option as I understand?

I seem to recall partzilla having them as well. For more dinero, of course.

I hope the imd piston work well, I found them expensive enough

Have you found +0.5mm piston on Partzilla now also ?

As you already suspect / know, the only way you should re-use a cylinder is if there is no visible damage or wear beyond the recommended service limits, If your cylinders show a line of pitting (like the pictures) or deep scoring on the cylinders or piston skirts, a simple "de-glazing" hone and a set of new rings typically isn't enough. The cylinders will require re-boring and oversize pistons and rings installed. The 0.4 mm clean up bore (test) is a good idea before buying a 0.50 mm over piston kit....those pits look pretty deep to me....the 0.50 pistons mean only 0.25 mm is cut / honed from the sleeve wall, and that might not be enough.....

Daftrusty (KZR member) used a set of those Cruzin Image pistons in his 750 and they seemed to work well for him....

I delivered the block to a local engine specialist, he think +0,25mm piston is enough, but to be sure he will take of metal step by step to figure it out....

My questions is, I have been given link to imdpistons who are +0,5mm, is it possible to get +0,25mm?
I guess no, since nobody have talked about that earlier here?

I have crated a separate thread for the big bore:
www.kzrider.com/forum/2-engine/607514-up...e-to-bigbore-pistons

No, most ADDED - AFTERMARKET oversize pistons for Japanese bikes come in only two overbore sizes, at best. So only 0.5 mm and 1.0 mm over stock are typically available. Don't confuse "oversize" with "big bore" pistons - oversize are meant to repair slight damage and return stock performance (most of the time). Big bore is usually associated with increasing performance / power.

I think have descied to go for overize +0.5mm pistons.... combination of norwegian regulation and possibility of coming into new problems with my bike... I want to run nice for the summer and I`m happy with exssitign power for now...

I have started a fresh threat about finding the best option of pistons, when it comes to +0.5mm pistons.

kzrider.com/forum/2-engine/607519-750cc-oversize-piston-0-5mm

When I talked with the engine workshop earlier these week, he had a theory engine has been standing for a while at some point, and it had started to corrod (corrosion) in the cylinder, and when you start up you have kind of dust combine with the heat... Could be the reason for these damage.

Condensation.
Steve