www.zxrworld.co.uk

pulled my SP apart last night because its been doing my head in with weird running/setup issues and the occasional odd noise..

was looking at the intake cam (mostly as it was timed in 1 tooth retarded) and something caught my eye.. grabbed a ZX4 intake and compared it (it should be the same except for the sprocket) it was easy to see that the SP cam had less duration than the ZX4, so i grabbed my calipers and had a quick measure up..

all relative to ZX4

lobe height 1mm less
base circle smaller
visibly less duration

also, as the base circle is smaller, it should need larger shims to compensate.. but it hasnt, its got normal 3.1foo ish shims and ok clearances

reprofiled ?
weird OE cam ?

Are they stock pistons and rods??

I have one similar and it came out of my totally original 93 jap spec bike. Along with 30.5mm carbs and flat top pistons. 1mm was the exact same difference on mine with visibly different duration...put it str8 in bin or smack it with a hammer so u don't use it by mistake lol...most I got outta that bike was 55bhp

interesting .. i believe some mid-late JDM L models had wanky cams, as from ~1993 they were meant to be restricted to 53bhp, like all JDM 400's, (infact i had an L4 import with the same spec as yours shaggy69 but only got as far as doing the carbs and ignition) but i believe the SP kept the same cams, and gained a restricted ignition.. which i've probably got.. i know none of this for sure though as its really hard finding tech specs on the SP's, and the manual's dont mention the changes whilst the microfiches note differing part numbers but obviously dont describe the differences.

what i need are 15 all original bikes spanning ZX-4 to L9 including SP's to strip and check

mine after several phone calls and some more measuring would appear to be "probably" reprofiled SP cams by Kent, although the chap at Kent Cams (who was very patient bless him) said he obviously couldn't say for sure without seeing them, but he would be happy to ID them if i sent them over..

oh yeah, for anyone wondering how a stock sp cam with 280' duration can be bettered by a KC re-grind with a duration of 244'..

its all in the lift at which the duration is measured, kent use 1mm, kawasaki use 0.2mm (according to the very patient man)

Does it have adjustable sprocket on it or fixed?

they are adjustable..

I used to have some genuine M3 cams but sold them (and never thought to take a picture of them) so cant actually tell if the sprocket assembly is OE kwak or Kent as nothing to compare to

Ps kent usually weld the sprocket on and always engrave or teap a number onto the sprocket

the end of both the cams is stamped "KC" and "8082" which confused the man at kent cams no end .. the kc bears out, the 8082 meant nothing to him.

I thought Xanthius as they are less aggressive but aren't adjustable , never had a good look at my J1 cams though

PS: Power restrictions in Japan change all the time , at peek a 400 can be 59ps and some years they go back to 54ps - just your donald duck if you choose the right one lol ( crank PS BTW ) However I think for the latest 400 they have moved it to 62ps - need to check again as didn't pay much attention as the modern stuff doesn't float ma boat