Help identifying high compression pistons please

[LondonZ1]

Am gradually getting my Z900 engine apart and my latest discovery is that it has an overbore with high compression pistons. They are aluminium and the underneath of the crown is marked Alcoa and MTC. There is some scuffing on the skirt but I am not enough of an expert to know whether the pistons are salvageable. They measure 69.5mm diameter with my verniers.







Anyone help with the identification? Or offer an opinion on whether they are scrap or not? The bike also has aftermarklet camshafts and I would like to reuse these bits if I can.

thanks, Peter

[z1000puddin]

MTC Link
http://www.mtceng.com/

Scuffing looks not too bad,
Better to measure the bores/to piston & the pop the rings off & place into the bore about 1/2" - 3/4" down & use a feeler gauge to check the ring end gap.

I'm not sure what the gap should be on the MTCs, but you should be able to find out from the link.



Stu

[hillbilly]

if you dont want them,im intrested.

[Ginger Bear]

Joe Hooper does a lot of MTC stuff.

http://stores.ebay.co.uk/pitstopperformancestore

[Z1parR]

Blimey you were quicker out of the blocks than Pigford then Brent

[Ginger Bear]

Spoke to Piggy earlier........ He's had to take the wife out!

So make "Hay while the sun shines" ladz!

[kennym]

Yes I would contact Joe Hooper, He supplied me rings for my 30 year old MTC pistons, 70mm diameter and advised me how to widen the oil ring grove to 2.8mm so latter model oil rings would fit as they stopped making the narrow 2.5mm oil rings years ago

[LondonZ1]

Thanks for the helpful replies. Have contaced Joe Hooper as suggested and am sending him the dimensions. The lower ring is 2.45mm thick so it sounds like I may have to get the groove widened if I want to reuse the pistions with new rings. He also sent me a very well written guide to taking a Z1/900 engine apart and rebuilding it. Much clearer than a Hynes manual even without the (awful) photographs.