www.zxrworld.co.uk

My race engine has a polished crank and rod set with the rods bearing 1173.
I also have a spare set of polished rods, though don't know how much work they have done which are also 1173.
Then I have, what looks like a stock unpolished crank and rod set with 1208 on the rods, and the rods look like they have bigger webs.

I am tempted to rebuild with the spare set of polished rods on the polished crank....but...Were the smaller 1173 rods slightly weaker but spin up faster?

the 1208's (or is it 1209? i forget) are L9 rods i think,..

yes, they are heavier, yes they are stronger.. I believe L9's also had a heavier crank..

I think there were three types of conrod, in order they're : 1151, 1173 then the 120*

how much the strength/longevity differs i have no idea.. I've always been under the impression that the parts were made heavier to improve torque and midrange, rather than to make them stronger.. (not many rod failure on zxr's compared to fzr's etc, and it took them 10 years to change them) but its a logical conclusion that the later heftier parts would be a better base for modifications.

irrespective of this.. my racebike runs a stock H1 crank and rods, and rev's happily to 15500 rpm.. maybe it'll break.. maybe it wont.