weird cam in SP engine .. ideas ?

There seems to be more and more members appearing that are racing the ZXR400 so i've created a special section just for you to show off results, discuss meets etc etc.

Moderator: Moderators

Post Reply
zimm
zxr400 oc member
zxr400 oc member
Posts: 2320
Joined: Tue Oct 10, 2006 12:32 am
My Bike: ZXR400-M4, ZX4, ZX6R.
Location: Herefordshire

weird cam in SP engine .. ideas ?

Post by zimm »

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 ?
Last edited by zimm on Sun Sep 07, 2014 4:42 pm, edited 4 times in total.
User avatar
RedexRobB
Site Admin
Site Admin
Posts: 7212
Joined: Fri Aug 30, 2002 7:37 pm
My Bike: ZXR400L3
Location: Ipswich, Suffolk

Re: weird cam in SP engine .. ideas ?

Post by RedexRobB »

Are they stock pistons and rods??
shaggy69
Posts: 63
Joined: Sat Jun 18, 2011 8:10 pm
My Bike: ZXR 400 Racebike

Re: weird cam in SP engine .. ideas ?

Post by shaggy69 »

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
zimm
zxr400 oc member
zxr400 oc member
Posts: 2320
Joined: Tue Oct 10, 2006 12:32 am
My Bike: ZXR400-M4, ZX4, ZX6R.
Location: Herefordshire

Re: weird cam in SP engine .. ideas ?

Post by zimm »

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 :pmsl

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)
Last edited by zimm on Tue Sep 09, 2014 11:04 pm, edited 1 time in total.
shaggy69
Posts: 63
Joined: Sat Jun 18, 2011 8:10 pm
My Bike: ZXR 400 Racebike

Re: weird cam in SP engine .. ideas ?

Post by shaggy69 »

Does it have adjustable sprocket on it or fixed?
zimm
zxr400 oc member
zxr400 oc member
Posts: 2320
Joined: Tue Oct 10, 2006 12:32 am
My Bike: ZXR400-M4, ZX4, ZX6R.
Location: Herefordshire

Re: weird cam in SP engine .. ideas ?

Post by zimm »

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
Last edited by zimm on Tue Sep 09, 2014 11:07 pm, edited 1 time in total.
shaggy69
Posts: 63
Joined: Sat Jun 18, 2011 8:10 pm
My Bike: ZXR 400 Racebike

Re: weird cam in SP engine .. ideas ?

Post by shaggy69 »

Ps kent usually weld the sprocket on and always engrave or teap a number onto the sprocket
zimm
zxr400 oc member
zxr400 oc member
Posts: 2320
Joined: Tue Oct 10, 2006 12:32 am
My Bike: ZXR400-M4, ZX4, ZX6R.
Location: Herefordshire

Re: weird cam in SP engine .. ideas ?

Post by zimm »

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.
User avatar
Mori Man
Blingmeister
Blingmeister
Posts: 1976
Joined: Thu May 10, 2007 3:30 pm
My Bike: ZXR400J2
Location: JAPAN

Re: weird cam in SP engine .. ideas ?

Post by Mori Man »

I thought Xanthius as they are less aggressive but aren't adjustable , never had a good look at my J1 cams though :smt017

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 :smt019
Nothing worse than having an H and not being able to scratch it !
Living life on the edge, SuPposedly
Post Reply