Hi MC, i have an engine with RC crank and rods and ported head, bigger valves, {ex drag bike from the early eighties in perfect condition} and was looking at Jays 970 cc pistons, with 1000cc size {OD} sleeves this leaves me room to rebore if needed but its the reliability thing that has me a little concerned. I am just after heaps of torque for the street so high revs aren't really a concern. What are your thoughts?
Mick
First realize my firsthand experience is with the 888cc. A solid motor. A shop I was at dragraced some 915cc motors but that's a different world.
Reliability has to do with expectations and applications. Do you want it to last like a 736cc in a touring and occasional romp thru woods application?
With a balanced crank and rods, and a cam for torque, keeping the revs below 8k, I would bet the 970/1000cc motors, with HD cyliner studs and bottom end studs, would hang together like a 736cc. And gobs of torque.
Its usually roadrace applications, high revs, that shorten life spans, assuming everything else is built up for the extra ccs.
My only engine failure was with a 750cc (Yoshimura hi-comp slipper pistons) high rev cam, yosh head, Weber carbs, pipe, stock rods. I bent a rod, lucky it didn't break.
I was thinking its still a 750, I don't need rods. Oops. strength first, HP second.
But to answer your question first hand, someone else must come forward. I defer to the proper engine builders on the board.
There is a member with a high mileage 1000cc kit. Can't remember his name, may be on this thread. Is using MTC alloy rods I think. If I didn't already have my cylinders and pistons, I would be making this same decision as you. THinking that I'll never put as many miles on this motor as when I was younger and only had one bike, I'd pop for the 1000cc.