ninjette.org - View Single Post - Right-Hand Cylinder not firing

Haynix · September 27th, 2018, 02:22 PM

Seemingly at random my right-hand cylinder will go into a phase of either not firing or flooding. It will struggle to get past 5k RPM, and when idling it will very slowly die. The right exhaust will very clearly smell of unburnt gasoline, and will backfire. It runs fine 90% of the time but will have a spell of this. Usually after bike has been ridden awhile, but has happened when cold. I can't discern a clear pattern. When issue is occuring, right exhaust will sometimes smoke but I honestly can't tell what color.

This is a new-to-me (and first bike!) 2007 ex250R with 4000 miles. Previous owner let bike sit in garage and gas crystalized. Other than that, it's in excellent shape.

I cleaned carbs and replaced gaskets / float needles with a kit. Properly adjusted float levels with micrometer (twice). Mixture screws at 2.5 turns (360+360+180). Cleaned/dried gas tank and petcock. Only used Ethanol-free gas since then. Added a K&N KA-2586 Air Filter. Added generic In-line fuel filter from Autozone. Changed Oil and filter with Rotella. Lubed chain (and cables).

Recently bought new NGK spark plugs which seemed to fix the issue but it has returned after about 150 miles. The original right spark plug was significantly more blackened than the other.

I have done basic vacuum test with Starting Fluid sprayed on the carb boots, but it didn't seem to affect it. Maybe a couple hundred RPM. Have not done compression test. Normal operating temperature is about halfway between dead-center and the first warm mark... fan rarely turns on. I am concerned the fuel line from tank to carb might be affecting it, I didn't have the exact right size hose clamps when installing the fuel filter so it's a bit loose. Fuel filter is usually about half or 3/4 full (on its side).

I put a moderate amount of Seafoam in the gas (maybe 2-3 ounces per gallon) but it doesn't seem to have affected anything.

Considering the strong smell of gasoline from 1 exhaust, it seems to be no-spark or rich/flooding.

Next Steps: considering replacing the coil on right side. Will pull plugs this weekend to check for fouling.

Any ideas?
(Also, should I rejet with that air filter?)

Fuel Filter:
https://www.autozone.com/ignition-tu...2_953903_17721

K&N Air Filter:
https://www.knfilters.com/search/pro...x?prod=KA-2586

K&L Carb Rebuild Kit:
https://www.ebay.com/itm/2-NEW-KAWAS...72.m2749.l2649

NGK 2086 Spark Plugs:
https://shop.advanceautoparts.com/p/...hTerm=NGK+2086

September 27th, 2018, 02:22 PM	#1
Haynix ninjette.org member Name: Adam Location: Durham, NC Join Date: Jul 2018 Motorcycle(s): 2007 Ninja 250 Posts: 10	Right-Hand Cylinder not firing Seemingly at random my right-hand cylinder will go into a phase of either not firing or flooding. It will struggle to get past 5k RPM, and when idling it will very slowly die. The right exhaust will very clearly smell of unburnt gasoline, and will backfire. It runs fine 90% of the time but will have a spell of this. Usually after bike has been ridden awhile, but has happened when cold. I can't discern a clear pattern. When issue is occuring, right exhaust will sometimes smoke but I honestly can't tell what color. This is a new-to-me (and first bike!) 2007 ex250R with 4000 miles. Previous owner let bike sit in garage and gas crystalized. Other than that, it's in excellent shape. I cleaned carbs and replaced gaskets / float needles with a kit. Properly adjusted float levels with micrometer (twice). Mixture screws at 2.5 turns (360+360+180). Cleaned/dried gas tank and petcock. Only used Ethanol-free gas since then. Added a K&N KA-2586 Air Filter. Added generic In-line fuel filter from Autozone. Changed Oil and filter with Rotella. Lubed chain (and cables). Recently bought new NGK spark plugs which seemed to fix the issue but it has returned after about 150 miles. The original right spark plug was significantly more blackened than the other. I have done basic vacuum test with Starting Fluid sprayed on the carb boots, but it didn't seem to affect it. Maybe a couple hundred RPM. Have not done compression test. Normal operating temperature is about halfway between dead-center and the first warm mark... fan rarely turns on. I am concerned the fuel line from tank to carb might be affecting it, I didn't have the exact right size hose clamps when installing the fuel filter so it's a bit loose. Fuel filter is usually about half or 3/4 full (on its side). I put a moderate amount of Seafoam in the gas (maybe 2-3 ounces per gallon) but it doesn't seem to have affected anything. Considering the strong smell of gasoline from 1 exhaust, it seems to be no-spark or rich/flooding. Next Steps: considering replacing the coil on right side. Will pull plugs this weekend to check for fouling. Any ideas? (Also, should I rejet with that air filter?) Fuel Filter: https://www.autozone.com/ignition-tu...2_953903_17721 K&N Air Filter: https://www.knfilters.com/search/pro...x?prod=KA-2586 K&L Carb Rebuild Kit: https://www.ebay.com/itm/2-NEW-KAWAS...72.m2749.l2649 NGK 2086 Spark Plugs: https://shop.advanceautoparts.com/p/...hTerm=NGK+2086