I have plans on putting a motor on a Columbia tank bike will I be able to keep my tank because that is what makes my bike I know that is where you mount the gas tank just wondering thank you for any info
You can rear rack mount the kit fuel tank. You can mount a cylinder shaped fuel tank under the seat and it looks pretty cool. I can't remember who sells the under seat tanks. maybe venicemotorbikes.com.
The cheapest way would be to simply add a pipe to the back of your seatpost and mount the kit tank there.
There are also rear rack style tanks available.
Those "tanks" were meant to hide the batteries for the headlight and to imitate the look of motorcycles. It was never intended to actually be used as a tank.