Yosh pistons, GS750ES

[QuaiChangKane]

There's a set of Yoshimura GS750ES pistons on eBay in the UK right now...

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ih=013&sspagename=STRK%3AMEWA%3AIT&viewitem=&item=230045897166&rd=1&rd=1

DIBS d4mnit!!!!


It's a bit misleading with the year range, but the bore and stroke are the same for the 1st & second-gen 16v 750's, AFAIK.

They're first overbore, so only minor changes to displacement. My question is does anybody know what benefits there would be to these pistons??? They're kinda pricey, and as much as it would be cool to have them just to have them (100% pure unobtanium), it would be nearly pointless unless there was some gain. Lighter? Taller? Made of Flubber???

(Please don't snipe me!)

Thanks,

-Q!

[oldschoolGS]

67mm is stock, I have run a 69.4mm bore (1982 GS1000SZ) Katana 1000 pistons that gave 802 cc, so 70+mm is not a small increase in bore size. 1st oversize should be in the 1mm overbore range, not a 3+ mm overbore.

With that center dome, good luck on street compression. I was at 11.25-1 with the 69.4 mm domed setup and this was very strong but required a mixture of pump/race fuel.

For comparison, The 816 cc Wiseco kit is a 10.25-1 compression 70mm bore kit.

Good Luck, Ed.
1983 GS750ED
2005 GSF1200SZ
1992 Duc 900SS

[QuaiChangKane]

Sweet. Guess I should have read up on my specs first.


Oy, what to do. May buy 'em and shelf 'em for the spare "one day I'll build this thing up" motor.... :-D



Thanks for the heads up.


-Q!

[hp1000s]

You might be able to fly-cut the piston crowns to reduce the compression dome...any engine builder machine shop could do the calculation and the machining.