ninjette.org - View Single Post - '09 250 Drops to 1 cylinder on highway, I'm stumped.

atxninjette03 · October 16th, 2023, 09:06 AM

Hey yall I'm a little bit stumped here and would like any ideas or suggestions. Randomly and infrequently (every 20-50 miles), only at high speeds such as on the highway, my 2009 Kawasaki Ninja 250 drops a cylinder. It runs only on one with a top speed of about 60 and when I come to a stop it usually dies. It won't start back up immediately but after a couple of minutes of sitting there (and with some choke) it briefly comes back to life for another chunk of time. I don't think it has ever lost it at less than 8k rpm and always at constant throttle. Works incredibly well and then boom, randomly down to one cyl.

Here's what I've done to try and fix it:
- Full carb cleaning and rebuild
- Leaned the bike out slightly
- Brand new spark plugs
- Checked plugs, boots, coils etc for cracks, none I could see. The connector between the coil and boots was maybe a little iffy, but everything reseated
- Swapped the left and right coils for shits and giggles

I've run out of easy things to test and try other than to just start replacing components and hoping for the best. I don't think its fuel anymore and am suspecting something electrical overheating and failing. Would love any kind of thoughts.

October 16th, 2023, 09:06 AM	#1
atxninjette03 ninjette.org member Name: Brian Location: Austin Join Date: Aug 2023 Motorcycle(s): 2009 Kawasaki Ninja 250R Posts: 10	'09 250 Drops to 1 cylinder on highway, I'm stumped. Hey yall I'm a little bit stumped here and would like any ideas or suggestions. Randomly and infrequently (every 20-50 miles), only at high speeds such as on the highway, my 2009 Kawasaki Ninja 250 drops a cylinder. It runs only on one with a top speed of about 60 and when I come to a stop it usually dies. It won't start back up immediately but after a couple of minutes of sitting there (and with some choke) it briefly comes back to life for another chunk of time. I don't think it has ever lost it at less than 8k rpm and always at constant throttle. Works incredibly well and then boom, randomly down to one cyl. Here's what I've done to try and fix it: - Full carb cleaning and rebuild - Leaned the bike out slightly - Brand new spark plugs - Checked plugs, boots, coils etc for cracks, none I could see. The connector between the coil and boots was maybe a little iffy, but everything reseated - Swapped the left and right coils for shits and giggles I've run out of easy things to test and try other than to just start replacing components and hoping for the best. I don't think its fuel anymore and am suspecting something electrical overheating and failing. Would love any kind of thoughts.