sipma02
XS400 Enthusiast
Fuel. Air. Spark. Timing. Its simple right? This is the XS400 set up with the Arduino ignition, and its actually going decently well. The left cylinder is working great. The engine starts more or less right up on just that cylinder! But for some reason, when I hook the other coil up, it WILL NOT start. Or even pop. This engine/carbs ran great 3 years ago. I currently dont have an airbox or exhaust on it. Ive re-cleaned the carbs multiple times. Assuming these are 180º engines, i only have one pickup sensor triggering both coils. (wasted spark) Ive swapped coils, spark plugs, Ive taken both spark plugs out and made sure both are sparking. They are. Put my thumb over the spark plug hole. Plentyyyy of compression. When i squirt a bit of gas in the spark plug hole, I miiight get a backfire through the carbs. So something is going on in there.Then, I disconnect the right cylinder and it fires right up (as well as an engine can with one cylinder.
I seem to remember reading that these bikes have an asymetrical airbox, and different sized jets in the carbs, is that true? Is that causing my issue? The thing that confuses me is that when i have both coils connected, it WILL NO do anything. As soon as I disconnect the right one, it fires right up. Which makes me think its a spark issue.
Any ideas? Or anything I can try?
I seem to remember reading that these bikes have an asymetrical airbox, and different sized jets in the carbs, is that true? Is that causing my issue? The thing that confuses me is that when i have both coils connected, it WILL NO do anything. As soon as I disconnect the right one, it fires right up. Which makes me think its a spark issue.
Any ideas? Or anything I can try?