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Discussion Starter · #1 ·
Hi all, im from nz, been riding for nearly 50yrs, ive been going over my bikes for about 35yrs, current bikes are fully modded XR650r, and fairly extensively modded gsxs1k, its mtr is mostly k7 gsxr1k, with early style rods (16mm pins) steel valves in a k7 cyl head, mild cams, heat exchanger vs air cooled oil cooler with galleries to suit ( so cases will suit drag race eng builders) early models didnt have cyl vent holes between 1/2 & 3/4, bores are 73.4mm, comp ratio is 12.2:1 stock, piston deck height is 10 thou sub deck, oil pump is k7, cam buckets are k7, clutch basket is k7 but no slipper clutch, crank has grooved mains, gearbox is k5-8,
Ive built race headers and ported cyl heads for awhile now, (ex m/c tech) ive done bolt ons, ecu flash, pair mod, milled cyl vents, had crank lightened/bal, epoxy ported head, 5 angle int valve seats, radiused ex seats, v&h s/steel valves, ive tried retimed stock cams, k8 cams, and some local kelford speedway grind cams, gsxrk3 springs, coated std pistons, then had new stock rings installed as it had 26k on it by then, but....the sole nikasil shop here stuffed up my cyl by diamond honing without without torque plates + too high an ra surface for suzuki rings, so consequently had to find out where all my comp went..., ive had 12 thou off head, and run 18thou cometic gasket, but my mtr lost 30psi after the re-ring, cyl- piston was still under 1.5thou, so i was a perplexed as to why i had such bad blowby, and only 180psi , vs 210psi stock, after much reseach i found info about torque plating and they admitted not foing that before "straightening" my bores via diamond bar hone, do i called millenium, they answered all my questions, and diagnosed probable out of round bores, too rough a honed surface and likely cause of lost compression.
So now im doing a new build with 76mm custom JE's, , ape cyl/mains studs, a k8 cyl head, s/steel valves, sae oil pump upgrade parts, modded lower oil gallery to run k8 oil cooler, new crank brgs, stock rods with new bolts , kelford cams 396/254 & 354/[email protected] 40thou, gsxr750k3 shimmed springs on intake, stk gsxs sprigs on ex, , fully tapered header & my own design muffler
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