Post by tatertots on Dec 23, 2020 23:55:31 GMT -5
Hello all!
I've got an issue with my scooter and was looking to see what some solutions were. The scooter that I have is a Yamaha BWS Zuma 2008; it's my first scooter and I've been working on for a few months now. Currently on the scooter, I've got a 70cc Malossi engine, a Malossi Flip Exhaust, and a TPR Variator Kit with rollers to go along with it. The rest of the scooter is stock (including the carburetor) with some normal service items changed out - including the brakes/brake fluid and the gear fluid.
After my most recent mod where I modified the throttle cam (like what is shown here: Link), the scooter hasn't been able to ride smoothly when revving the engine to a little bit past the idle speed. Once the scooter has revved to a high enough point, it seems to start choking out and eventually it'll cut itself off (though sometimes it will recover). Prior to modifying the throttle cam, however, the scooter was able to ride pretty normally, without any issues that I noticed myself. Whether this issue could have been present before the mod is not to my knowledge. I'm guessing that because the throttle can open up further, it's causing the engine to run much more leaner than before. Some things I noticed that led me to this conclusion included the spark plug becoming fouled (dry carbon) as well as the engine going 'runaway' - where the engine wouldn't stop running even after hitting the kill switch.
Some things I have tried as well as the results are as follows...
- Checking for Air Leaks: The scooter seems to hold it's pressure well (and I didn't notice any bubbles coming from the usual places using soapy water). The only thing I've changed out was the intake boot clamp as the original one didn't close properly anymore.
- Cleaning the Carburetor: I've cleaned the carb at least twice already, but those were done a few weeks ago.
- Upsizing the Main Jets: I've tried some jet sizes between 92 to 102 with nothing seeming to fix the issue. Higher jet sizes, however, seem to make things just a little better (i.e. it allows for the scooter to rev higher, though it could just be my imagination).
Please let me know if any additional, information, images, or videos are required.
Thanks!
I've got an issue with my scooter and was looking to see what some solutions were. The scooter that I have is a Yamaha BWS Zuma 2008; it's my first scooter and I've been working on for a few months now. Currently on the scooter, I've got a 70cc Malossi engine, a Malossi Flip Exhaust, and a TPR Variator Kit with rollers to go along with it. The rest of the scooter is stock (including the carburetor) with some normal service items changed out - including the brakes/brake fluid and the gear fluid.
After my most recent mod where I modified the throttle cam (like what is shown here: Link), the scooter hasn't been able to ride smoothly when revving the engine to a little bit past the idle speed. Once the scooter has revved to a high enough point, it seems to start choking out and eventually it'll cut itself off (though sometimes it will recover). Prior to modifying the throttle cam, however, the scooter was able to ride pretty normally, without any issues that I noticed myself. Whether this issue could have been present before the mod is not to my knowledge. I'm guessing that because the throttle can open up further, it's causing the engine to run much more leaner than before. Some things I noticed that led me to this conclusion included the spark plug becoming fouled (dry carbon) as well as the engine going 'runaway' - where the engine wouldn't stop running even after hitting the kill switch.
Some things I have tried as well as the results are as follows...
- Checking for Air Leaks: The scooter seems to hold it's pressure well (and I didn't notice any bubbles coming from the usual places using soapy water). The only thing I've changed out was the intake boot clamp as the original one didn't close properly anymore.
- Cleaning the Carburetor: I've cleaned the carb at least twice already, but those were done a few weeks ago.
- Upsizing the Main Jets: I've tried some jet sizes between 92 to 102 with nothing seeming to fix the issue. Higher jet sizes, however, seem to make things just a little better (i.e. it allows for the scooter to rev higher, though it could just be my imagination).
Please let me know if any additional, information, images, or videos are required.
Thanks!