Modern Vespa

Any ideas on what next? Issue with cold start. Carb clean, plug ok, valves ok. Takes a loong while to start when cold. Throttle position seems to make no difference. Except that dies if i try to open throttle when the motor first engages.

I just went through this with a Big Ruckus, and it ended up being a clogged bystarter jet. Scooter would start and idle fine as long as it was 55 or warmer. When the temperature dropped, it was a bear to start. I pulled the bystarter and measured it's resistance and throw length. Both were in spec. I was able to clear the opening from above without removing the carb by pushing a length of plastic water dispenser tube into it and filling it with carb cleaner. I did this a couple of times, and let it set overnight. It's working fine now.