I'm building a pro-street Kz900 and have a few crank related questions.
1) How much power can a small pin crank take. Can a balanced/trued/indexed/welded '73 small pin crank handle 1428cc/13.5:1CR compression and power.
2) How much can the stock con-rods take, as well
I'm planning on running HD studs and a main cap plate.
My crank in my bike which is 1428cc 13.5/1 and 7" slick is a Z1 item and has lasted a few years stock rods as well, but mine only had 143hp at the wheel.
I am changing to a GPZ crank this year though as the Z1 crank is a bit tired.
The Mk2 crank or the GPZ ones are a better bet of course but i've heard of funny bikes using Z1 cranks with stock rods.
Ive got a kz 1075 making about 300hp. it has a stock Z1 900 crank and rods(welded)ape studs and nuts throughout with a steel bearing support. the clutch hub and basket are stock. the trans was undercut with an orient express 2nd gear and MRE lock-up. M/T ET street tire 26x10.5, stock starter and charging system. stock cams degreed 108int/112exh Star mild portjob with o.s. ss valves. it is in an old topgas chassis (72") and I weigh about 270lbs. the bike has been together for about 6 years and 4000 hard (very hard) street miles on it with absolutely no problems (other than oil leaking from the front of the head) Oh yeah, it wouldn't make that much power if it wasn't for the Mr. Turbo set up running 24psi of boost and the 60hp NOS fogger and VP C-16 fuel!!!! Good luck with your pro-streeter and dont worry about those 30 year old parts. If I cant killem on the street, nobody can. Its like a 350 Chevy!