It will be awhile before the tank project is complete. Have to wait untill I get some more extra money before I can get the petcock and gas caps. Once I get those I will mount the tank on the FireLizard. With full pics (better pics than I posted) and instructions.

Here is some better pics.

Your Road King tank sits a lot lower on the frame than my SoftTail does. I envy you the lower seat. Mine was $50.00 as an insurance repair swap-out from Harley though so I can't complain.

The petc0ck and filter is probably the cheapest part you'll ever get to buy from them. Make sure you ask for a vacuum one as they do both gravity and the sucker kind like we use. They have a nice OFF setting between the fuel and the reserve setting and a big ol' lever to do it with. Easy to find too when she starts to sputter after those 300+ mile runs.

For the spacers for the bolt through the front mounting flanges I used a roll of washers wrapped in black electrical tape on each side. You just put on as many washers as you need and once you know the number you just wrap about six layers of that nice stretchy plastic electrical tape on 'em. Mine have been out in the weather for two seasons and over 11,000 miles with nary a problem. No tape peel at all.

You may find that, like me, you'll need to re-route some of your wiring under the tank. I also had to move the compression starting solenoid, horn and electronic module that's on the end of the spark plug wire. And I took the chrome off the top of the engine for the extra clearance
and so there wouldn't be any more heat than need be close to the tank. Gasoline expands a lot and nothing feels quite as nice as a gas soaked thigh when the vented gas cap starts to spray you. So don't try to get every gallon in there that it'll hold. Don't ask.

I noticed on your first pictures that you too have a little metal tube coming down on the bottom front of your tank. Make sure you block it on the outside, I used a short rubber fuel line clamped on it to fit with a short bolt clamped into the other end. Harley runs their fuel gauge and/or speedo cable through the tank near as I can figure and gas will pour out of there. Again, don't ask.

As for filling that big hole in the middle, I fond a clock that fit perfectly in there on mine (different size hole), but the vibration kept making the hands fall off inside it. So I ended up filling it with a gas proof filler you mix 'cause the hole in mine was open into the tank. I just put a plate in there about an inch down form the lip and then filled it in. If yours doesn't have a gas problem you could just use bondo if you're going to paint it. Sand it down and spray away. If you go the powder coat route as I did you'll need something that can take the heat of the process. I forget the name of what I used but it's available at WalMart, lots of hardware stores and auto parts stores.

Until you get the gas caps you want you can do a cheapo thing in the mean time. I went to an auto parts store and got a screw in locking cap for a car that fit the right side of the tank. It's basic black and looks pretty good on my yellow tank. The right side hole on mine was for a gas gauge and had a bigger, left hand thread so I just used the filler to permanently mount another cap that matched the first one. Both caps together were around $15.00. I won't be changing mine 'cause I like the look okay and I'll never be going for the "bike beautiful" look. I use my bike hard so dings, dents, etc. are going to be a major part of it's life.

Jack

This is probably going to be a stupid question, but you guys should expect that from me by now.    Was that big center hole in the Road King tank used for the speedo?  If so, couldn't an OEM speedo be dropped in there?  I know it's a "Harley" part so it's probably VERY expensive, I was just wondering.

No, the Road King tank has only one filler hole.

Yes, I believe the center hole is for the original Harley speedo and instrument panel.  

Oh, just to clarify, the tank is 2008 Harley Road King tank. Just wanted to let ya'll know what year it was.

Before you scrap plan A, I just got back from the Harley shop. (parts guy there knows his stuff)

Harley fuel gauge will not work, the wiring harness is too weirded out compared to our relatively simple one. So, just do what Jack did and find a clock or something to fill the gauge hole. By the way, no gas ever comes through the gauge hole, no extraneous sealing required. That tube is for wires only. The gauge sending unit is actually connected to the fuel pump for fuel injection.

Speaking of fuel injection, found out the real differance between carb and injected tank. Injected tank the hole that looks like it goes for the petcock is actually to plug a fuel line directly into. However, Harley does have an adapter to allow use of a petcock through that hole. Also, according to the Harley shop, a vac petcock is dang near 200.00bucks while a standard on/off/reserve is 20.00bucks. No problem, just seal vac nipple at carb.

I made a plate/cap to cover center hole in tank out of 1/8in aluminum that I will bolt over it with a gasket and small o-rings under the screws. That will insure no gas leaks.

And finally, my Suzuki stealership can still get the tach cable for a GT250 for 20.00bucks, so speedo relocation will be easy.

I just need to get a tap so I can create threads to bolt the aluminum cap into place.

You're right, the thread I got the info from said 750, oh well, it's not like I have already ordered it. But since they can get the 250, they should be able to get the 750 as well. Thanks for the clarification Max.