Take a look at this bike. You probably see this and think, “Did they just weld the engine and tank to the frame?” Some have taken that approach, but a majority of the time it’s impossible to repair them once they’re permanently attached to a frame. So what are you supposed to do? You’ll need to drill into the frame. Now, before you go thinking we want you to take a drill bit to your frame and poking holes out of it, take another look at that frame. It’s pretty unusual, right? Normally, if you have a frame that’s a little big on end or another you can make your own motor mounts. With these types of frames, that’s not really a possibility, and that’s why in these instances you’ll need to drill into parts of the frame in order to properly fit an engine on to it:
To mount a gas tank on a frame like this you’ll need to drill 2x holes that are about a ½”-1” wide (depends on the width of the gas tank brackets). Insert the gas tank brackets into the new ports you drilled, align the tank bolts with the bracket, and bolt the tank to the brackets as high as the brackets will go (this will usually make the bracket a V)
You’re going to do the same thing as you did for drilling those tank mounts, only it’ll be one port and it’ll be 10mm (most brackets are 6-8mm, so you want to make it slightly bigger than that). Once that’s drilled, slip the u-bolt into the port, install your motor mounts into the u-bolt bracket, tighten down, and you’re ready to ride!