troyboy Posted June 14, 2009 Share Posted June 14, 2009 hi guys and girls! sorry 2 bring up the dreaded exup valve again but ive looked every where for a decent answer to this question, so many different opinions on this! i have a yzf 750 sp, the exup valve is working fine but im after a few sneeky torques of maybe a horse or 2! some poeple rave about wiring the exup valve fully open and leaving the servo so you dont get the error code. is it even worth doing this? i have a carbon micron tail pipe on the bike already, should i bite the bullet and buy a new header and junk the exup valve completly? i use the bike for 1/4 mileing and road rideing i dont really want to cause trouble by gaining more top end and loosing out at the bottom end with stinking great flat spots! OR should a leave well alone and spend me cash somewhere else on the engine! (standard). any help would be appreciated, thankyou. Link to comment Share on other sites More sharing options...
steve m Posted June 14, 2009 Share Posted June 14, 2009 some poeple rave about wiring the exup valve fully open and leaving the servo so you dont get the error code. is it even worth doing this? ed, thankyou. Try it,, see what you think ? if it`s not for you then put it back " as was" you only need to disconect the servo cables from the exup valve (no need to remove them) wire the valve open and se how it goes........... Ps, make sure you make a note as to which cable goes on which side of the pully, better still take a picture .. Link to comment Share on other sites More sharing options...
rf9rider Posted June 15, 2009 Share Posted June 15, 2009 If you wire the valve open, you`ll have a big flatspot under 3500-4500 rpm. If you get the exup free headers, expect to do a little re-jetting. There is quite a weight saving with the new headers, about 7-8kg if i remember rightly. I have them fitted to my Ace, but the cam overlap is different between the Ace and YZF`s, so theres no need for re-jetting the Ace. The only reason i fitted them was the Ace headers are made from cheap metal and rot quickly, and theres no need to worry about servicing the exup valve. If you don`t mind servicing the valve, spend your money elsewhere as i don`t feel theres any power gains with the new headers. And if you have flatsides on your SP, might be a nightmare setting them up correctly? Link to comment Share on other sites More sharing options...
troyboy Posted June 16, 2009 Author Share Posted June 16, 2009 thanks for the help guys. that has thrown a bit of light on the subject. Link to comment Share on other sites More sharing options...
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