I'm having trouble keeping my Honda 1989 NX250 running. Some days it will start just fine and run all day with no problems. Other days it will never crank or stall while I'm riding.
Here's what happens when it wont crank:
- Starter motor is good and turns over
- Sometimes it will fire and rev when I crank with throttle open and choked but immediately dies
- Sometimes will backfire (yes a real backfire through the air intake) sometimes "backfire" (impropper fuel burn) through exhaust pipe
Here's what I've done and know:
Battery is new and charged
- The fuel is fresh, clean, and has a new inline filter to carb
- Carb has been completley broken down and cleaned, all jets are unclogged, all o-rings are good, accelerator diaphragm is good, throttle needle is not damaged, float is good no leaks
- Spark plug is new and has been tested, gives nice blue spark
- There are no leaks from the air cleaner to the carb (new air filter) and there is good air flow
I originally thought it was a fuel problem - carb bowels were empty. One day when I turned fuel on it started pouring through the overflow. I took apart the carb and cleaned out small patch of goo that I think was causing the float needle to stick (both open and closed). After that it never overflowed. I cleaned the carb spotless even though there it was already very clean. I thought the problem was the carb because some days the bike runs just fine and other days it will never crank. When it is running sometimes it will die when I'm riding at speed (throttle open 3/4), I've noticed mostly when I'm going uphill. I'll pull off the road and it will turn over a few times than crank, other times it won't start unless I let it sit for a few minutes sometimes it take hours. As I said, I can't find any fault in the fuel delivery, no blockages or clogs (that I can find in fuel line, tank, or carb). I was wondering if it's a valve clearance problem, but it runs perfectly half the time. It never overheats after 30 mins of riding and there is not ratteling sound or rough running. I'm kind of lost from this point forward as to what to try and what to test next. Any thoughts or suggestions