Modern Vespa

I changed my exhaust gasket on my 300 GTS. Thanks to a spacer tool, the seal fits perfectly into the tube, but to push it onto the collector is much more difficult, the first half of the length fits easily but the rest is very difficult.
How do you do ? Do you have a tip?

Did you buy the Vespa oem gasket? There is a Yamaha part # floating around that has a slightly smaller i.d. than the Piaggio part. It was impossible for me to fit the header tube into it. Take a piece of 120 grit sandpaper and clean the header up thoroughly. Watch Robot:

Thanks for the video. I do it exactly like this. I do use a Vespa OEM seal.