ninjette.org - View Single Post - Comparing the 250 & 300 motor/engine (Version 2)

micoulisninja · May 29th, 2014, 09:02 AM

Hi everyone... it's been quite a long time I haven't been around... things here in Greece are getting tough...
anyway, this is the kind of post I've been looking for in a long time.... congrats to the.... author !! very thorough !!

However a couple of things to mention and ask...
1. the 250 piston is kind of "narrower" by some hundredths of a mm....ahh... sorry of an inch I mean... that's because it "needs" more clearance compared to the one in the 300's aluminum block since heating and working conditions 9and heat dissipation of course are different...

Well, now for the good part... I am about to put a 300 crank and rods to a whole new big bore kit (67mm), this
:http://www.ebay.com/itm/Kawasaki-Nin...a6e68c&vxp=mtr
for an engine of 345cc in 250 cases with the 300 head, 300 throttle bodies and my 250 full racing yoshi exhaust system as well as my "electronic equipment" (250 ECU with 1000 extra rpm, PC V, autotune etc)
so I have a few questions unanswered yet...
1. can I fit a 300 fuel pump along with its base in a 250 tank?
2. 300 fuel injectors are "larger" in fuel output compared to the 250's?
3. can I fit the 300 slipper clutch in the 250 cases ?

If- eventually- for some reason I change my mind and choose to use the 300 cases can I fit my 250 rotor and stator for more energy ? if yes, does the 250 side rotor cover fit the 300 casing? (I am worried about the position of the advance timing sensor being in the same position -the angle related to the rotor etc. Can I fit my 250 gearing altogether in the 300 cases?

So far -as some of you might remember- I have a modest 250cc engine with widened intake ports, camshafts my design base CR of 13,8:1 and yamaha T-max 31mm throttle bodies (apart from the exhaust and electronics mentioned above for a 39,6 hp on a superflow dyno... it's about time I build something close to 50....naturally aspirated...
any help, advice and relative experience is welcome...
thank you all in advance and especially Alex ...ahhh... cuong-nutz for this excellent modifying manual !!

P.S. anyone knows another kawa model with stiffer valve springs than oem's that I can fit to the 250/300 head ?

May 29th, 2014, 09:02 AM	#14
micoulisninja modaholic junkie Name: Nick Location: Athens, Greece Join Date: Sep 2012 Motorcycle(s): 2001 ZX-12R, 2009 ninja 345cc and plenty of others in the past... Posts: 438 Blog Entries: 2	Hi everyone... it's been quite a long time I haven't been around... things here in Greece are getting tough... anyway, this is the kind of post I've been looking for in a long time.... congrats to the.... author !! very thorough !! However a couple of things to mention and ask... 1. the 250 piston is kind of "narrower" by some hundredths of a mm....ahh... sorry of an inch I mean... that's because it "needs" more clearance compared to the one in the 300's aluminum block since heating and working conditions 9and heat dissipation of course are different... Well, now for the good part... I am about to put a 300 crank and rods to a whole new big bore kit (67mm), this :http://www.ebay.com/itm/Kawasaki-Nin...a6e68c&vxp=mtr for an engine of 345cc in 250 cases with the 300 head, 300 throttle bodies and my 250 full racing yoshi exhaust system as well as my "electronic equipment" (250 ECU with 1000 extra rpm, PC V, autotune etc) so I have a few questions unanswered yet... 1. can I fit a 300 fuel pump along with its base in a 250 tank? 2. 300 fuel injectors are "larger" in fuel output compared to the 250's? 3. can I fit the 300 slipper clutch in the 250 cases ? If- eventually- for some reason I change my mind and choose to use the 300 cases can I fit my 250 rotor and stator for more energy ? if yes, does the 250 side rotor cover fit the 300 casing? (I am worried about the position of the advance timing sensor being in the same position -the angle related to the rotor etc. Can I fit my 250 gearing altogether in the 300 cases? So far -as some of you might remember- I have a modest 250cc engine with widened intake ports, camshafts my design base CR of 13,8:1 and yamaha T-max 31mm throttle bodies (apart from the exhaust and electronics mentioned above for a 39,6 hp on a superflow dyno... it's about time I build something close to 50....naturally aspirated... any help, advice and relative experience is welcome... thank you all in advance and especially Alex ...ahhh... cuong-nutz for this excellent modifying manual !! P.S. anyone knows another kawa model with stiffer valve springs than oem's that I can fit to the 250/300 head ? __________________________________________________ If noone has tried it before, I will !!! Last futzed with by micoulisninja; May 29th, 2014 at 10:33 AM.