Since I've had more than a few questions about this, here's a quick 'n' dirty thumbnail sketch of what's involved in the F2 tank and Monster seat mods I've done. I'm putting them together mainly because I did them both at the same time, and it so happens that they work together swimmingly. This advice can be extrapolted to each mod individually, but since I haven't done each one individually, I can't offer direct advice, though. For that, go bug Ross Dale, Robb Zimdars, Chis Mulhall or Mike Pescetto.
What you need for the tank mod:
-An F2 or F3 tank. They're identical. Don't worry about paint, since you'll need it repainted when you're done with the mods.
-A modern Harley replacement petcock. A used Harley part will work, or a new off-brand. They're around $25 new and as low as $5 used. Harley owners feel the need to cast off their stock pieces for $75 Pingle units, for some reason unknown to me.
-Your Hawk gas cap will work without modification.
-About ten minutes of a welder's time.
-Large ball-peen hammer.
This is the only modification needed to the F2 tank when used with a Monster seat: an extension of the front mounting tab of roughly an inch, center to center. A little trimming of the side of the tab to make it fit in the slot, and it's good to go.
The bottom:
I should've freshened that paint while I had it off. One more little item: my metalworker friend who did the welding on this project was concerned about the front underside of the tank contacting the frame. I don't honestly see it as a problem, since the tank's steel and the frame is aluminum, but since we're dealing with the potential of leaking gasoline, I decided to go with his word. I pounded in the tank in the two spots where it would rub until I could see light through the gap when the tank was on the bike, and to be double sure, I epoxied some heavy duty inner tube patches at the points of possible contact. No problem to date, about two years in.
Speaking of leaking gas, here's something worth mentioning. Be sure to mock up the tank location on the bike with the petcock installed on the tank. The tank needs to sit back far enough so the petcock completely clears the rear cylider head by at least 1/4". If not, the petcock will vibrate against the head, fatiguing the metal on gas tank, and eventually wearing a hole in it. I didn't have the petcock when I fitted parts, and my tank wound up about 1/8" too far forward. This is the only part of the job that I had to clean up later, as the pinhole didn't wear until about two years on. And in my case, all I had to do was open the mounting holes a little to gain the clearance necessary. No big deal, but it's even easier to do it right the first time. Learn from my mistake.
You'll also need to discard the bracket that holds fuel lines and such that sits under the stock tank, but rerouting that stuff is cake.
The reason this tank/seat combination makes so much sense is this:
That bracket doubles as a rear tank mount and front seat mount. The tank, clearly, sits on top, and the two tabs on the front of the seat slide under it. It functions exactly like the bracket on the OEM Hawk subframe, it's just a couple inches higher and further forward. The mounting tab of the rear of the tank is untouched.
Here it is on the other side:
It's pure seredipity that this bracket work so perfectly. Or maybe I'm a born fabricator...
What you need for the tank mod:
-An F2 or F3 tank. They're identical. Don't worry about paint, since you'll need it repainted when you're done with the mods.
-A modern Harley replacement petcock. A used Harley part will work, or a new off-brand. They're around $25 new and as low as $5 used. Harley owners feel the need to cast off their stock pieces for $75 Pingle units, for some reason unknown to me.
-Your Hawk gas cap will work without modification.
-About ten minutes of a welder's time.
-Large ball-peen hammer.
This is the only modification needed to the F2 tank when used with a Monster seat: an extension of the front mounting tab of roughly an inch, center to center. A little trimming of the side of the tab to make it fit in the slot, and it's good to go.
The bottom:
I should've freshened that paint while I had it off. One more little item: my metalworker friend who did the welding on this project was concerned about the front underside of the tank contacting the frame. I don't honestly see it as a problem, since the tank's steel and the frame is aluminum, but since we're dealing with the potential of leaking gasoline, I decided to go with his word. I pounded in the tank in the two spots where it would rub until I could see light through the gap when the tank was on the bike, and to be double sure, I epoxied some heavy duty inner tube patches at the points of possible contact. No problem to date, about two years in.
Speaking of leaking gas, here's something worth mentioning. Be sure to mock up the tank location on the bike with the petcock installed on the tank. The tank needs to sit back far enough so the petcock completely clears the rear cylider head by at least 1/4". If not, the petcock will vibrate against the head, fatiguing the metal on gas tank, and eventually wearing a hole in it. I didn't have the petcock when I fitted parts, and my tank wound up about 1/8" too far forward. This is the only part of the job that I had to clean up later, as the pinhole didn't wear until about two years on. And in my case, all I had to do was open the mounting holes a little to gain the clearance necessary. No big deal, but it's even easier to do it right the first time. Learn from my mistake.
You'll also need to discard the bracket that holds fuel lines and such that sits under the stock tank, but rerouting that stuff is cake.
The reason this tank/seat combination makes so much sense is this:
That bracket doubles as a rear tank mount and front seat mount. The tank, clearly, sits on top, and the two tabs on the front of the seat slide under it. It functions exactly like the bracket on the OEM Hawk subframe, it's just a couple inches higher and further forward. The mounting tab of the rear of the tank is untouched.
Here it is on the other side:
It's pure seredipity that this bracket work so perfectly. Or maybe I'm a born fabricator...
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