020avp

I looked at media cat, but I dont see an oil tank vent listed in the crankcase or the filler cap. My filler cap is oem, but solid with no duck bill or ball check with spring. Mine is a TS202 and came sans oiler, but has a 1/4" chainsaw sprocket (odd). Anybody know where it should be, or is it...

Anybody have any knowledge on what else I'm missing to make this exhaust handlebar heater work on this? I saw an 020AVH in this book,and saw this funky casing on eBay. I figured it had to be for a heater.