Kawasaki Ninja250R spark timing

Johan921 · February 14th, 2020, 12:19 PM

Hey there. I am a total noob at how 2 cylinder engines work. I have a 2012 Ninja 250R engine that i want to build into an old Kl250. The question i have is how does the cdi and ignition system work on two cylinders. I understand that the cdi wiring is on the same standard as for a single cylinder engine. According to my knowledge the pistons move at an angle of 180 degrees. How does it split the spark? Or does it fire in both cylinders at the same time on both top dead ends?

DannoXYZ · February 14th, 2020, 01:32 PM

Hi Johan! Wellcome to Ninjette!

The Ninja 250 triggers ignition from 2 sensors on flywheel 180-degrees apart. Then it ignites two cylinders 180-degrees apart. Due to arrangement of pistons 180-degrees apart, firing order is not even.

0-degrees = ignition on #1 cylinder
180-degrees = ignition on #2 cylinder
360-degrees = exhaust #1
540-degrees = exhaust #2

Since there's no cam-sensor, ECU doesn't know which TDC is compression or exhaust. Spark is also ignited on exhaust stroke aka "wasted-spark" configuration. #1 cylinder fires @ 0 & 360 degrees and #2 cylinder fires @ 180 & 540 degrees. If you swap 250 engine into different bike, take matching harness and ECU as well.

Another way to do this is have both pistons go up & down together. Then you can have evenly-space firing order 360-degrees apart. However, you have bad primary balance and lots of vibration

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Removing spark spark plugs?	tsdexter	2008 - 2012 Ninja 250R Tech Talk	3	June 26th, 2013 03:48 PM

February 14th, 2020, 12:19 PM	#1
Johan921 ninjette.org newbie Name: Johan Location: Secunda South africa Join Date: Feb 2020 Motorcycle(s): Kl250. Ninja250. Nc50 express Posts: 1	Kawasaki Ninja250R spark timing Hey there. I am a total noob at how 2 cylinder engines work. I have a 2012 Ninja 250R engine that i want to build into an old Kl250. The question i have is how does the cdi and ignition system work on two cylinders. I understand that the cdi wiring is on the same standard as for a single cylinder engine. According to my knowledge the pistons move at an angle of 180 degrees. How does it split the spark? Or does it fire in both cylinders at the same time on both top dead ends?

February 14th, 2020, 01:32 PM	#2
DannoXYZ ninjette.org certified postwhore Name: AKA JacRyann Location: Mesa, AZ Join Date: Dec 2011 Motorcycle(s): CB125T CBR250R-MC19 CBR250RR-MC22 NSR350R-MC21 VF500F CBR600RR SFV650 VFR750F R1M ST1300PA Valkyrie-F6C Posts: A lot. MOTY - 2018, MOTM - Nov '17	Hi Johan! Wellcome to Ninjette! The Ninja 250 triggers ignition from 2 sensors on flywheel 180-degrees apart. Then it ignites two cylinders 180-degrees apart. Due to arrangement of pistons 180-degrees apart, firing order is not even. 0-degrees = ignition on #1 cylinder 180-degrees = ignition on #2 cylinder 360-degrees = exhaust #1 540-degrees = exhaust #2 Since there's no cam-sensor, ECU doesn't know which TDC is compression or exhaust. Spark is also ignited on exhaust stroke aka "wasted-spark" configuration. #1 cylinder fires @ 0 & 360 degrees and #2 cylinder fires @ 180 & 540 degrees. If you swap 250 engine into different bike, take matching harness and ECU as well. Another way to do this is have both pistons go up & down together. Then you can have evenly-space firing order 360-degrees apart. However, you have bad primary balance and lots of vibration