This does happen every week at Scootertronics where a consumer who has placed an order online or over the phone which it really happens very little over the phone.
When an order is placed I have built software that tells me what the consumer has searched for and the reference site they were to get to Scootertronics, so when I see a consumer looking for a two stroke part and they order a four stroke I contact them. When they order several parts for a Ruckus and then order parts for GY6 50 I contact them, I catch almost every order that need help.
One of the biggest errors made when placing an order online is consumers ordering the wrong part product for their scooter. There is a difference for some parts between models and brands. This happens more with what people read on a forum then order what someone else says works.
Know what brand, model and most of all the size engine and whether its two stroke or four stroke when dealing with a 49cc (50). A common mistake is when ordering for a Honda Ruckus. It’s not a GY6 motor and CAN NOT have a cylinder upgrade.
Another common mistake is ordering parts for GY6 50 when you have a two stroke scooter.
Also the two stroke models have several different engines. Mineralli and Franco Morini are most common with Morini being used in TGB and Hyosung and some older Aprillia models. Al Yamaha and Chinese scooters use the Mineralli engine with the Yamaha having different crank tapper and wrist pin size for most upgrades, there are some older Ventos with 10mm wrist pin and Baccio uses 10mm wrist pin. The starter are also different from Yamaha to 40QMB engines in Chinese made and Twainese scooters.
Another misconcepition is engine swaps. Although anything is possible dropping a 150 in a 50 is not going to be that easy. Although of course its been done and of course there is a video but these just like the Honda Ruckus swaps are all custom work.
All of the above is spelled out on Scootertronics plus every part that can be confused is mention in part description and page for the scooter. I have not found other sites to even mention any of these differences. And when they do its very vague. Everyday I get the call that a consumer bought something from another site and need help on why it will not install on their scooter.
Although I could go on with this all day so please know your scooter and know what you need to get the performance and repair correct. FYI your vin plate says what your scooter is and engine numbers are on the engine. Besides trial and error in the shop this how I learned everything.