Fairly lightweight, very easy to route due to the short hose length needed. To install on the 501 you need to remove the header, disconnect the airboat, remove all engine bolts save for the bottom most bolt. Tilt the engine back and slide out your charcoal filter. Easier than it sounds. Plus you get to clean and grease those corroded engine bolts.

Unless you have the jug off

I bought this overflow compensation tang when I bought my 2019 KTM 250 XCW Tpi . \nTook it to the dealer but there was a lot of work involved in installing it. They recommended me to wait until the first piston/rings change. So I stored it for a year. So 112 machine hours later it was installed when they changed the piston . I was wondering how it works. When the radiator fluid pressure is out of limits the cap spring recedes and allows the vapor to escape. It goes through the overflow tube and into this reservoir. And it is stored there. Lets say 100 cc of vapor escape. When it cools down the liquid returns to its normal volumen and then a vacuum is created. So this sucks back some of the liquid. I use a radiator fan and in tight trails like to leave the bike running in iddle just a moment lo allow it to cool down. But is an inexpensive extra caution that can be added. Just bear in mind to buy it and install it when you have to change your piston the first time. I just changed bike and will get one in order to install it on the firt piston chhange of the new bike ( also 250 KTM Tpi) and this will remain in the 2019 250 TPI that was handed down to my son. Great product neat fitting. Inexpensive extra insurance. And dont forget to install a fan its a must on TPIs to have a fan.