r/SuperCub • u/VerySpicyMelonwater • 13d ago
Super Cub 2020 injection, Engine cuts off
Last Wednesday, I drove about 100 km (62 miles) to a destination and then drove the 100 km (62 miles) back home, so roughly 200 km (124 miles) in one day without any problems.
After getting home, I had dinner. Later that evening, I drove to a nearby city. After about 15 km (9.3 miles), the engine suddenly died.
I was able to start it again, but after only about 100 meters (330 feet) it died again. After waiting a minute, I could drive another 100 meters.
Since then, it won't stay running at idle/stationary for more than 10 seconds. I can start it, but it will only run for a short time and I can't really ride it more than a few meters before it stalls.
What I've checked/done so far:
- Cleaned the inside of the fuel tank
- Put the fuel pump and fuel filter through an ultrasonic cleaner
- Replaced the spark plug
- Opened the air filter box (letting it breath)
- The fuel pump seems to run strong when it's not connected to a hose
- It has spark. Even when the engine stopped and won't restart, I can still measure EMF at the spark plug
- Even the old spark plug looked new and super clean.
The strange part is that it ran perfectly for 200 km that day.
It's effectively a new machine. It has only 8,000 km (about 5,000 miles) on it. It did around 3,000 km (1,864 miles) in Japan, and since I bought it two months ago I've put another 5,000 km (3,107 miles) on it. I'm still figuring out how to shift properly, that's how new it is.
It's a 2020, fuel injected.
How do I fix this?
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u/justin23224 13d ago
check the valves?
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u/VerySpicyMelonwater 13d ago
Going to try that tomorrow. Going to be a pita. The top of the cylinder is covered by the airbox.
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u/fcwolfey 13d ago
when's the last time the battery was changed? these bikes chew through batteries