Identify pistons

[Guest]

hey im having issues determing what pistons the old owner installed in my gs750.
can someone help with this ?

print on top
H4717

and

4035ps xc

on bottom

4035

and what appears to be a W in circle

20190523_235236.jpg20190523_235236.jpg

[franchizai]

topside
20190524_083346.jpg

[franchizai]

Pin side
20190523_235240.jpg

[GregT]

The ID marks are characteristic Wiseco. What's the bore size ?

[franchizai]

The ID marks are characteristic Wiseco. What's the bore size ?

ahh sorry forgot to mention theyre 69mm

[Steve]

69mm bore with a stock stroke makes it an 843.

That is the same as a stock 850.

.

[franchizai]

69mm bore with a stock stroke makes it an 843.

That is the same as a stock 850.

.

Yes but these are running in a 748ccm cylinder which i bored up to 69mm. 20190523_234753.jpg

now that i have everything apart i was considering installing new piston rings while im here. even though they actually seems fine.
but i really wanted to make sure what origin these pistons are. i presume theyre from wiseco. as it looks like a circle with a w in it on the bottom of the piston
and i have seen that same marking on other wiseco pistons i found picures off on the web.

i have no idea what the letters and numbers on the piston top means though.

[sharpy]

I googled this but didnt find any page that would open to verify exact same thing.. K844 GS750 2V 69mm 4035PS

https://www.google.com/search?q=K844+GS750+2V+69mm+4035PS&oq=K844+GS750+2V+69mm+4035PS&aqs=chrome..69i57.781j0j8&sourceid=chrome&ie=UTF-8

[Nessism]

Wiseco for sure. XC could be the ring type. You might want to call Wiseco.

Maybe these...https://www.ebay.com/itm/WISECO-2717...-/232398177733

[franchizai]

Wiseco for sure. XC could be the ring type. You might want to call Wiseco.

Maybe these...https://www.ebay.com/itm/WISECO-2717...-/232398177733

Now that im pretty sure its wiseco pistons it was easy to find the rings needed on their website. and yes it should be exatly those the 2717xc rings.

thanks for the input i will order up some of those

[Steve]

69mm bore with a stock stroke makes it an 843.
That is the same as a stock 850.

Yes but these are running in a 748ccm cylinder which i bored up to 69mm.

It does not matter whether you bored it to 69mm or Suzuki bored it to 69mm. The mathematics of the situation say that with the stock stroke and a 69.0mm bore, you will have 843.6cc displacement. That happens to be exactly how the 850 left the factory.

.

[hannibal]

It does not matter whether you bored it to 69mm or Suzuki bored it to 69mm. The mathematics of the situation say that with the stock stroke and a 69.0mm bore, you will have 843.6cc displacement. That happens to be exactly how the 850 left the factory.

.

It's probably easier to say the stock stroke (56.4mm) that Steve's referring to is the same on the 750 and 850. This implies that the 850 gets its additional displacement from the larger bore (69mm vs 64mm).

Do you really think his comment suggested that the same bore and stroke has different displacement depending on who or when those dimensions were created?

[kochic]

This is a wiseco piston, piston number 4035m06900, rings, 2717xc,(64to94mm, 1mm top ring,1.2mm 2nd ring and 2.8mm oil ring).
Marc