During my inspection, noticed that the #3 cylinder (counting from left to right) is cold. I checked all the cyclinders and they are all hot except for the #3. Maybe theres no combustion happening inside #3. Please review my troubleshooting data..and help me with the solution. 1. battery ok. 2. fuel system ok 3. spark splugs > all brand new (nippon denso) 4. Ignition coil for #2 and #3 cylinders > primary coil> resistance ok secondary coil>resistance ok 5. Cap plugs> resistance ok 6. Wire harness for 1,4 and 3,2 > with continuity> all ok Additional Infos: a)all resistance value are within limits as per fzr250 specification manual b)I dont have any difficulty starting the engine c) The bike easily overheats unlike before. >when oveheating, the engine stalls and when i start it again it starts on low revs. then after 1 min the engine dies. >If i let the engine cools down for 10 min. the bike starts smoothly again. d) charging system is fine> no discharging of battery e) engine stalls after high revs at lights Ignition System troubleshooting. I took off the cap plug for #3 cyclinder and attached a used spark plug and ground the spark plug body. Start the engine. I saw a continuous spark so i guess theres no problem with the ignition system. CDI>Please correct me if im wrong with this> i think theres no problem with the CDI since the combustion inside cylinder 1,4 and 2 is working properly. I guess the problem is in the other system but i have no idea where to begin hunting. Need help with this..thanks in advance
You are getting spark, so there are only a few more things to check: Compression: Check the compression in that cyclinder, heck check them all. Valve Adjustment: You may have a valve that is not seating all the way prohibiting combustion. If you are in here, check all clearances and adjust accordingly. Carb Cleaning: Check the respective carb for gummed up passage ways. If you are already in there clean them all any way. Then clean them a second time. I'm serious, go through the whole process twice. Let us know how you get along...
ground the spark plug from that cyl & make sure it sparks right- i had a bad head gasket letting water in cracked all 4 plugs (hot plugs don't like water) other suggestions are right too
If it is the valve clearance...at least it will be hot (not hotter than the others). It will have combustion but lower compression but the cyclinder #3 is completely cold. But i think il follow your advice regarding carbs.thanks
To brad, I also suspected the head gasket before but when i drained the coolant..theres no trace of oil. I removed the spark plugs and theres no trace of water (it was dry) I got a sample of oil and thers no water nor fuel.
So you can start the bike up from cold and let it idle ok? And the header is completely cold or warm? If all the cylinders are running at idle but it overheats and #3 is only warm you may have a blockage in the one of the main jets. The stalling after high revs and the general unwillingness to start when hot was solved after I synchronized my carbs. This could also be the cause of the overheating. Instead of all the cylinders sharing the load it is concentrated on the remaining 3 that are getting more mixture. It’s worth a shot before jumping right to the head gasket and rings etc.
i meant testing the plug from the cyl- too many ppl told me there are a few bad plugs out there- even new ones
