Stuttering/bogging/loss of power in certain situations

[sasquatchms]

Hey everyone. Recently bought my scooter (all the specs are in my signature...I am running premix at 33:1 ratio, keeping cyl. head temps under 400 deg. and running BP 93 octane).

It ran fantastic and strong up until a week or so ago when I noticed sometimes it will stutter/bog down/lose power in certain situations. It happens when I start off from a standstill (at a stop light for example) above 1/4 throttle and until WOT.

I can usually prevent it from beginning to stutter after taking off by staying under 1/4 throttle or going WOT. If I back off on the throttle, I can get it to stop stuttering. If I quickly go WOT, I can get it to stop stuttering. But 1/4 to 3/4 throttle seems to cause these issues. It starts fine. It idles fine. It hasn't died on me (yet?). Seafoam in the tank did not help.

After searching around here, I plan to do the following to begin diagnosis:

• Inspect, replace spark plug, gap at 0.024"
• Inspect reeds. If damaged, replace
• Inspect float to make sure it's moving.
• Remove and clean pilot and main jets.

I am looking for guidance from you fine people because I am new to these machines, and new to carbs as well.

Thanks!
Seth

[sasquatchms]

Okay I replaced the spark plug. Didn't notice a difference is behavior but I plan to do a longer ride tomorrow.

The plug I removed was a BR6HSA (left) and the one I installed is a B8HS (right).

[sasquatchms]

Also, I have one of the Polini air filter pods, which has a removable cover. I have been running it with no cover but when I attached the cover today (looked like rain was coming) the issue is MUCH more pronounced and occurs at a wider range of throttle positions. I am assuming this cover is restricting airflow and thus enrichening my air/fuel mixture. Removed the cover and the issue returned to how it behaved prior to adding the cover.

So perhaps I am running a bit rich?

[Wheelman-111]

Greetings:

That would seem to support the too-rich theory. Try jetting down a size?