VIDEO: Sportster Gas Tanks 101 - Gas Tanks, Petcocks, Gas Caps and What Fits 1986-2003 Harley Sportsters
In this video you will learn about the many options there are when it comes to customizing your 1986-2003 Harley-Davidson Sportster gas tank. Changing the look of your bike drastically can be as easy as changing your gas tank or handlebars. Tyler gives you the knowledge on what to look for when it comes to choosing a Sportster tank (which are sometimes called a peanut gas tank) for yourself and what features to steer away from.
At Lowbrow Customs we offer a wide variety of Sportster gas tanks and we try to make it even easier for you to do change out on your bike with little to no modifications when utilizing our Gas Tank Adapter Brackets.
Tyler also covers just a few styles of gas caps we offer at Lowbrow Customs and the differences between them. In addition, he gives you the rundown about the differences between motorbike petcocks, pricing differences and even how to install NPT fittings correctly. Don't forget for a little extra reassurance while on the road, grab one of our Fuel Reserve bottles and Carriers because when you need it, you need it!
Everything you need to know about custom Harley Sportster Gas Tanks
*Editor Note* at 10:13 Tyler accidentally reversed the information about how the reserve works on a petcock. Please run your bike with the petcock "ON" and when you feel it sputtering move it to reserve to get the last few miles out of the tank.

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Sportster Gas Tank Examples In Action
This is Tony's Sportster here at Lowbrow. He is using a Stock Style Harley Sportster Gas Tank, a Gasbox Frisco Style Gas Tank Lift Kit and a Pingel 22mm Petcock.
This Harley-Davidson Sportster found at Cycle Showcase in St. Louis is using a Lowbrow Customs Narrow Frisco Mount Sportster Gas Tank.
Here is an example of a Harley Sportster using the Lowbrow Customs Frisco Mount Sportster Gas Tank.
Chris Drew has an Axed Dual Cap Gas Tank on his Sportster chopper. (GPS Not included)
Virgina Cagney's 1996 Sportster chopper "Heywood" has a Cycle Standard Narrow Axed Gas Tank with a single filler cap.
Jacq Brandt converted our King P-nut Gas Tank to fuel injection using our Weld-in EFI plate for her 2017 Iron 883.
Lowbrow Customs Good Luck Fuel Bottle and Carrier 2.0 combo will give you a peace of mind and will save you on the road from having to push your bike to the next gas station.
You can read the full transcription of this video here:
Hey, everyone. I'm Tyler with Lowbrow Customs and I'm going to talk to you a bit about gas tank options for your Harley-Davidson Sportster.
We've got a variety of tanks here and there's many more available at Lowbrow Customs that will fit your Sportster, but I wanted to go over a few in detail. Then also, we're going to talk about different style gas caps so you understand the difference between cam style, thread in et cetera and also different petcock sizes and thread in style so you need to know the parts you need to customize the Sportster that you've got in your garage. This first tank is a stock style 1986-2003, it's a bolt-on direct fit gas tank.
What's nice about this is it's a flat bottom, while a lot of tanks end up having a larger radius here, smoother looking at the bottom which is a more modern style. These are an excellent gas tank to replace your stock one. It gives it a little bit more of a classic vintage style, or if your tank's damaged or you don't have one, whatever. You can see here, these are stock mounting points here, they will fit directly to your '86-2003 Sportster using all of the stock hardware.
This gas tank actually comes with a full set of mounting hardware or you could reuse the hardware on your bike if you'd like. You can see the petcock bung here, that's what we call a 22-millimeter petcock bung which is a stock Harley-Davidson petcock. We can get more into that a little bit later. It also takes a very common thread in Harley style gas cap which would be '86 and up, though pretty much any aftermarket tank, they use the same filler.
That's your stock option. Excellent tank, looks great, easy to install. Something that we have exclusively at Lowbrow because it's our design, our gas tank adapter brackets. These fit the same year range, 1986-2003, and you can see the larger holes here for the rubber mount hardware. These come as you see them and you use your existing hardware to mount these to your motorcycle. What's interesting about these is the threaded holes.
The rear bracket has two different dimensions, so it allows different center to center lengths for the mounting tabs on various gas tanks we offer and more than half a dozen. What's neat about these is these brackets bolt directly to your bike, and then custom gas tanks will bolt directly to these brackets. Instead of having to weld on your frame or do any fabrication work, we give you the solution that's really straightforward and allows a variety of gas tanks to be mounted to your Sportster.
Using these brackets, you can mount any of these three tanks and there's a variety of others at lowbrowcustoms.com. This is one of our most popular gas tanks. You can see it's actually using the same tooling as a shell of the stock gas tank but this is a Frisco mount. Frisco mount means that it's going to have a shallow tunnel and it's going to sit up higher on your backbone while a stock tank sits down low with the backbones deep into that tunnel. Something that I want to point out, these tanks, it's got Lowbrow Customs stamped right on the bottom.
We don't just resell tanks, we spend a lot of money and a lot of time developing our own gas tank designs, so there's reasons that our gas tanks are different from any that you'll find from other people out there. For instance, on our Frisco mount gas tank, we've got the petcock bung, the 1/4" NPT petcock bung here at the back. Many other gas tanks, most that you'll see available, have the petcock bung in this area on either side.
The bad thing about that is when this is mounted on your frame and your petcock is way up here, that means all the gas in this rear section of the tank is unusable because the lowest point that gas is going to drain from is from up here. By putting this petcock bung way back here on a Frisco mount gas tank, it allows you to use all of your gas. We also on this tank move the filler from the center up to the far right.
That way when your bike is on its side stand, gas is going to leak out from the cap and again, with the tank mounted higher, it lets you fill up your tank further than if you have a standard center mount cap. Those are some of the details that we know because we build bikes, we chop bikes, we ride bikes that we know how to design a gas tank that actually works properly, that gives you the full capacity. This gas tank will bolt directly to a 1986-2003 Harley-Davidson Sportster using our gas tank adapter brackets.
This is the standard width tank, it gives you a little more capacity. We also have a narrowed one and then a super narrow. Depending on what profile you're looking for, we've got a variety of tanks that will bolt directly to your Sportster. Moving on, this is a traditional gas tank called an axed gas tank, or sometimes referred to as an alien head. You can see there with the filler are the eyes, they're on the alien if you didn't know that. This tank will also bolt directly to our '86-'03 gas sink adapter brackets.
This one has a deeper tunnel and it's got two different petcock bungs, gives you an option. For left or right side, you've got a 3" NPT and 1/4" NPT whichever petcock, whichever side you decide to run it on, you would just plug the other side with a pipe thread plug which we have available at Lowbrow Customs or you can find it at a good hardware store. The fourth tank I'm showing you here, this is a Lowbrow Customs King P-Nut tank.
We've got a line of P-Nut gas tanks we've been making since 2010 that are very popular. Excellent tanks, but they don't fit well on a late model Sportster. This tank has a wider tunnel and tabs at the proper dimension to work with our gas tank adapter brackets. Again, because this is a Frisco mount tank and it sits high in the backbone, we have 1/4" NPT petcock bung here at the rear and the filler cap which is included with this tank is way upfront.
This gives you the most capacity you can get out of this size tank. That will again bolt directly to an '86-'03 Sportster with no modifications to your frame. You can always unbolt the tank, unbolt the adapter brackets, put your stock tank back on and put it right back to how it was. That's a little overview of some of the styles of tanks that we have. I want to discuss quickly the different style gas caps available. Many tanks are going to have a Harley-Davidson thread in style filler, and we have a few versions here of caps.
This is a black one, also available in chrome. These are inexpensive, common just like a stock OEM Harley-Davidson cap. These caps ratchet, you can tighten it down till it clicks, undo it, vented, they don't tend to leak, great all-around cap design. This is the same style of thread in but this one is a Lowbrow Customs USA made machine cap. This is a solid brass dome cap, same exact deal that- these don't ratchet but you just go ahead and snug it down. It's vented, it works perfectly on your Sportster. Also available in aluminum.
Here's another Lowbrow Customs cap. These are an investment cast aluminum finned cap and again, fits the same style bung. These ones ratchet and the ratcheting mechanism allows you to tighten it and then back it. If you're OCD and you want those fins to line up perfectly, you simply tighten it and then put it right back where it goes and you're good to go. Really neat looking cap, available in polish as well as black.
That's it for the thread in caps, they're pretty straightforward. The alien head tank has what's known as a cam style cap, or uses a cam style cap also known as a bayonet cap. This is earlier Harley-Davidson styling. You can see the underside of the bayonet cap there and the difference in the bung and how it looks. This is a vented cap, really basic. Just push down, turn and that's it. On these dual filler alien, it's also available in a single filler version, but the left side's a dummy meaning it looks like there's a filler there but you basically put the cap on and leave it on.
That's when it's on the side saying gasoline is not pouring out of the filler. If you're looking at a gas tank and it says it takes a cam style or a bayonet style, that's the style cap you want. Thread in, we've shown you very common and widely available. Then in the case of the King P-Nut, the cap is included. It's a 1 5/16-12 thread filler cap and we do have a variety of different style caps available that'll fit this tank that's the same size as a filler on Lowbrow Customs oil tanks and Mooneyes oil tanks.
There's interchangeable cap options available. Talking about petcocks, petcock is simply a fuel valve. It's just on and off valve. It's when you're not running your motorcycle, it's how you keep gas from leaking into your carburetor. It's just a fuel valve. There's different options available. It's not that daunting, I'll go over them with you now. 22 millimeter is a standard late model Harley petcock. This here is an inexpensive, around $20, 22-millimeter petcock.
One thing I wanted to point out, at Lowbrow, for instance, we carry typically various price ranges of parts because depending on your budget, depending on your priority, the priority of motorcycle is in your life or what quality of parts you want to buy, you might want something different than someone else. These petcocks work well. Generally, we don't have any problems with them. They can leak eventually. We have midpriced options and then you get to the high-end options like a Pingel or a Golan petcock, which are great and essentially are going to be trouble-free and last your whole life, but are over $100.
It just depends on what you're looking for. This petcock though, to show you this is- it's got a filter screen on here. There's a stand off tube because there's a reserve. If you're running your bike on reserve, what that means it'll start sputtering for running out of gas and you can go to on. It starts bringing gas in from the hole that's here and that gives you that extra half a dozen miles or what-have-you to get to a gas station before you run out.
This petcock fits this tank here, this stock style tank. You can see that style 22-millimeter petcock bung and it simply slides in there and tightens on with a wrench, very straightforward. Now, if you are running a tank that says quarter NPT, that's National Pipe Thread, which is a tapered thread. If you look closely at this and it's also, 1/4" NPT is larger diameter than actual 1/4" but you can see there's a taper to it. NPT-threaded bungs tighten as you go in.
You're not necessary trying to bottom those threads out, you just want it to get in there nice and snug and tight so it doesn't leak. Some people run tough line tape on the threads. I like Hylomar or something specific like that which is a fuel resistant thread sealer, but you're going to tighten that petcock in there. You can carefully get a wrench onto a body like this but you definitely don't want to over tighten it or you'll snap your petcock off.
Also, you want to be aware when you're tightening it up that you stop at a point where you want the handle or the outlet. This is a 90-degree petcock and I would be running a straight out petcock on this tank, for example, but you don't ever want to tighten it up and then back it off because then you're going to get a leak. With a tapered thread like that, think while you're doing it, don't be looking over your shoulder BS-ing or drinking a beer or something, get it snug up right where you want it to ensure you don't get a leak.
Then in cases of the axed tank, there's two different sizes. 3/8" NPT same exact idea as the 1/4" NPT, it's just a larger diameter. Same thing though it's a tapered thread. You don't want to over tighten and have to back it off, nor do you want to over tighten it to the point that you fricking rip your tank in half or snap the petcock off. Just something to keep in mind.
That pretty much covers all the basics. If you're looking to change the look and style of your '86 to '03 Harley Sportster, this will give you all the basic knowledge to get you started and know what you need when you're purchasing a gas tank. What features to look for, what features to avoid, what petcock you need, what gas cap you need. Another thing I wanted to mention, it's not a gas tank but somewhat related. We've been making fuel reserve bottles for many years.
These are very handy on any motorcycle honestly because when you need it, you need it but you can have some extra fuel in hair here. It saves me all the time. I know many other people, same thing it saves you from walking or hitching a ride. We also have our fuel reserve bottle 2.0 carrier, super simple, cinch top, molle webbing on the front here, nylon strapping. You can mount that to a shock. You can mount that to a fork tube.
You can put a carabiner on it and throw it on your bag. Extremely easy fast convenient to stow and it's very cheap insurance. Like I said, when you need it, you need it. You can check out all of these parts the gas tanks, fuel reserve bottle carrier, and bottle, petcocks, gas caps, all that stuff at lowbrowcustoms.com. We have the largest selection of custom gas tanks in the world and we've got all the knowledge.
If you've got any questions, you want to make sure something will fit your particular bike, you're not sure what petcock you need et cetera, hit us up. We're always happy to help. Comment, open a support ticket, give us a call and we offer free motorcycle tech support. Or watch one of our other videos. We have lots of videos available showing you different installs, product reviews all that type of thing. Thanks for watching and be sure to subscribe. Check out our next videos, we're always working on them and go to lowbrowcustoms.com for anything you might need. Thanks.