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BUYING HARLEY GAS/FUEL TANKS
This is an addendum to the addendum to the FXR series, but applies to all Harley tanks purchased through non-OEM outlets. I have purchased a few tanks on eBay, and learned some hard lessons which I shall share with you.
The emphasis here is upon practical usage, rather than "show bike" mods. I ride approximately 20,000 miles per year and have done so for the past 28 years.
FITMENT
First, lets talk about fitment issues. As referenced in my addendum on the FXR series, the model years 1981 - 1992 had hand-welded frames with unusual configurations which are no longer employed by Harley. Dyna tanks with not, generally, fit on the FXR frames for those years without a bit of metal-work. The FXR, FXRS, FXLR and FXRT all used the same or similar one piece tanks. There is no easily obtainable kit to mount flat-side tanks to an FXR, but there are custom builders who can weld mountings to the FXR frame, although usually they go the other route and weld FXR fittings to FLT's because the FXR tanks tend to be smaller and they like that. Go figure -- its what they do.
Most "extended" tanks will not fit on the FXR without significant modifications to the seat.
There are three tanks that have been mounted on FXR's. The early models up to the 90's had a center fill elevated spout with a hole for the sender unit immediately forward of that. The dash was a chrome unit with rubber gaskets on its base and around the fill-spout. The tank came with a needle fuel gauge and a black plastic fill cap. PART NUMBER 61044-82C.
The other tank version, found rarely (because it was used only for 1.5 years on a single model), had a flush fill hole on the right and a dummy fill on the left which held the fuel gauge. Wiring to the fuel gauge ran under a center dash which had several configurations as Harley used up available parts. Tank capacity for these varies wildly as these were tanks modified by Harley during the final days and hours of the FXR lineup. The fuel gauge on these was reportedly difficult to see when riding. PART NUMBER 61421-88A.
There is an FXLR smooth top tank with no place for the dash or the fuel guage. The filler is on the right side. These tanks are not rare, although it is very common for sellers to claim so; you can find them all over the place as this type was a common third party fabrication. Although the tank looks bigger, its capacity is the same as all of the FXRs due to a large vented air space that runs down the center. PART NUMBER 61006-87A.
TANK CAPACITY
Tank capacity is universally mis-reported for the FXR, from the reviewers to the comparo guides to Harley itself. You cannot even trust the original Owner's Manual. The reason for this is that Harley measures the tank capacity by logical volume with the sender unit removed and the tank off the bike. When the sender unit is installed, a full half gallon is subtracted right away. Lean the bike on its side stand with the tank mounted and yet another subtraction caused by air trapped in the forward half of the right-hand shell occurs, resulting in the effective loss of nearly a gallon in total. California models have an emissions vent that is supposed to go to a carbon canister, typically removed by most long-term owners. Filling the tank to the lip on these models will result in extra gas flowing out the vent tube concealed under the chrome dash onto the ground.
The maximum effective capacity of a standard mounted FXR tank is 3.5 gallons. The "reserve" is typically unreliable with the stock petcock, by the way. "Smooth top" tanks hold 4.0 gallons if filled right to the brim. There is no such thing as a real 4.2 gallon tank for an FXR. The Owners Guides are wrong. The Factory Shop Manual from Harley is wrong. The articles in the Performance Portfolio are all wrong for each of the years reported. The Clymer Manual is wrong as well.
No one has done what I did (it seems): Take several tanks, set them on a shelf, and one by one physically test them all by using calibrated jugs, then empty them into measured containers to double check capacity.
DINGS AND DENTS
Most of the older used tanks on eBay come with dents of various sizes. A dent puller will perform poorly on a tank designed to hold combustible fuel, so don't try it -- unless you got something against the guy on whom you plan to fob this dangerously patched and repainted monster. A dent puller consists of a corkscrew that drills the sheet metal right through, plus a winch of some kind which yanks the metal into place. The finished job is then filled with Bondo or some equivalent, sanded and painted. Works well for car panels and such, but not so good for things that need to withstand atmospheric pressures caused by either gasoline vapors expanding, or vacuum caused by fluid displacement as the tank empties. Thats why reputable third party suppliers ALWAYS say, "test, pressurize and seal." This applies to ALL fuel tanks, not just Harleys.
How then to handle the ding? Well, you can just fill it with metal epoxy and paint over it, or you can get someone to pound it out from the inside. Which probably will still need a surface epoxy treatment and repainting. Or you can have a welder cut the tank in half, which is what I am going to do with mine. More on that and why in a bit.
SENDER AND "DESCENDING" UNITS.
The FXR sender unit is a simple variable resistor with a float; you could make one yourself out of simple parts available from Radio Shack. A constant current is supplied to the sender unit through a voltage limiter from the battery. As the float sinks, resistence increases on the path to the dial, causing the current to the guage to decline and thus allowing the needle to fall towards the red zone. The principal has been around for scads of years, and a nice description of operation is on the site dedicated to Ford Mustangs.
THERE IS NO SUCH THING AS A "DESCENDING UNIT!" Obviously, don't buy a tank from any fool who claims the tank comes with one. That seller is scamming you or worse, does not know what the blankety-blank he is talking about.
And another thing: there are sellers on eBay who have not even SEEN the product being sold to you. You think these "Power Sellers" with over a thousand sales actually LOOK at what they are selling? Gimmee a break. They typically are being middlemen in the exchange of goods between two independent people. Even the shipping is handled by a third party. Sometimes the photo is not even of the product itself, but a stock image of what the item is SUPPOSED to be. I got a nice inspection cover that way; the entire surface had been stickered over with fake identification numbers. Once cleaned up, it looked OK, but it sure had no resemblance to the image posted on eBay. And it was not, as advertised, a chrome piece.
The rule is, go by part numbers, and definitely use reputable sellers who at least employ correct spelling in their ads.
SEALING
OK kids, repeat after me: EVERY DINGED TANK AND EVERY USED TANK ON EBAY MUST BE RESEALED. Well, there are maybe two out of the 25 tanks currently listed which probably do not need resealing, due to their extraordinary pristine condition.
If it is dinged, the inside seal has broken. You must scour it all out and recoat. There is no other way.
Sealer comes in two colors: epoxy grey and pale blue. Sealer is NEVER bright yellow or any other primary color. I got a tank shipped to me which positively glowed from the inside. Either the seller, or the original owner, saw a lot of rust caking the inside of the tank, and instead of acting honestly, poured enamel paint into the tank, coating it thoroughly. The time spent doing that scam job could have been better employed using a proper tank liner after scouring the tank with acetone or battery acid. Costs about $25. KREEM costs about that, comes in a three stage kit with clear instructions, and is the industry standard. It's what I use and it works well. Heck its better to sell and buy a tank lined with rust than do what that moron did to me.
Unsealed tanks will rust every place gasoline is not touching, plus some. You cannot overcoat a Harley liner that has decayed -- you must removed it, and the Kreem process is the only reliable way to do it. Here's a tip: the cork from the 1800 Gold tequila bottle works perfectly to stop up the spout where the petcock goes. Kept sulphuric acid in a tank for 36 hours without leaking a drop!
If you have one of those Red Devil paint mixers, you can toss a few handfuls of gravel in the tank and let 'er rip. That will work really well to remove rust layers as well and is the most friendly to the environment as Kreem tank cleaner and most rust removers are pretty toxic. I know a father/son team that just puts in their workout with a tank like that. When one guy is tired shaking the thing, he passes the tank to the other.
Every used eBay tank I have seen listed will require etching with acid, followed by coating with a proper liner and most new tanks must be lined as well. Those tanks must have the storage grease washed out of them, which is another process.
THE FXR CAPACITY AND RIP-OFF SOLUTION
So, as mentioned above, we got a tank lined with bright yellow enamel that gasoline will surely break up in a matter of days, if not hours, clogging fuel lines, carburetor, and the engine ports. It is dinged. The capacity is the notorious 3.5 gallons. There is no sender unit -- the guy bolted a plate over the sender unit mounting hole and simply lied about it. The seller feigned ignorance; and he probably is pretty ignorant, too. What to do?
The welder shop is your best friend. In fact, any number of welder shops are experienced in doing exactly this kind of work, as this problem is so common. They will cut that tank on both sides, use a sandblaster to get that ridiculous enamel off, and with the open shell there easily use a hammer to pound out that ding. Then, the shop will add metal strips to the sides, weld the halves back on and -- presto! -- new 6 gallon tank!
Cost around here is about $200.00 for the job.
Take any old sending unit from any tank and mount that sucker right up. Sure, the level will lie for the first 80 miles or so, but its the last 20 miles we are concerned about, not the first.
Of course the welds will be visible under the new coat of paint no matter how much you goop it on -- did I mention the guy sent a tank with a yucky surface? -- but frankly, a usable tank is better than no tank at all. And there are all sorts of things you can do creatively with those welds. Why not add shark fins and paint the tank accordingly? Add fake rivets maybe. Those TV bike builders sure lack imagination sometimes. Heck, maybe I'll turn the tank into a mallard duck . . . .
Comments are welcome. Lets ride herd on the scammers out there and get them off off eBay!
This is an addendum to the addendum to the FXR series, but applies to all Harley tanks purchased through non-OEM outlets. I have purchased a few tanks on eBay, and learned some hard lessons which I shall share with you.
The emphasis here is upon practical usage, rather than "show bike" mods. I ride approximately 20,000 miles per year and have done so for the past 28 years.
FITMENT
First, lets talk about fitment issues. As referenced in my addendum on the FXR series, the model years 1981 - 1992 had hand-welded frames with unusual configurations which are no longer employed by Harley. Dyna tanks with not, generally, fit on the FXR frames for those years without a bit of metal-work. The FXR, FXRS, FXLR and FXRT all used the same or similar one piece tanks. There is no easily obtainable kit to mount flat-side tanks to an FXR, but there are custom builders who can weld mountings to the FXR frame, although usually they go the other route and weld FXR fittings to FLT's because the FXR tanks tend to be smaller and they like that. Go figure -- its what they do.
Most "extended" tanks will not fit on the FXR without significant modifications to the seat.
There are three tanks that have been mounted on FXR's. The early models up to the 90's had a center fill elevated spout with a hole for the sender unit immediately forward of that. The dash was a chrome unit with rubber gaskets on its base and around the fill-spout. The tank came with a needle fuel gauge and a black plastic fill cap. PART NUMBER 61044-82C.
The other tank version, found rarely (because it was used only for 1.5 years on a single model), had a flush fill hole on the right and a dummy fill on the left which held the fuel gauge. Wiring to the fuel gauge ran under a center dash which had several configurations as Harley used up available parts. Tank capacity for these varies wildly as these were tanks modified by Harley during the final days and hours of the FXR lineup. The fuel gauge on these was reportedly difficult to see when riding. PART NUMBER 61421-88A.
There is an FXLR smooth top tank with no place for the dash or the fuel guage. The filler is on the right side. These tanks are not rare, although it is very common for sellers to claim so; you can find them all over the place as this type was a common third party fabrication. Although the tank looks bigger, its capacity is the same as all of the FXRs due to a large vented air space that runs down the center. PART NUMBER 61006-87A.
TANK CAPACITY
Tank capacity is universally mis-reported for the FXR, from the reviewers to the comparo guides to Harley itself. You cannot even trust the original Owner's Manual. The reason for this is that Harley measures the tank capacity by logical volume with the sender unit removed and the tank off the bike. When the sender unit is installed, a full half gallon is subtracted right away. Lean the bike on its side stand with the tank mounted and yet another subtraction caused by air trapped in the forward half of the right-hand shell occurs, resulting in the effective loss of nearly a gallon in total. California models have an emissions vent that is supposed to go to a carbon canister, typically removed by most long-term owners. Filling the tank to the lip on these models will result in extra gas flowing out the vent tube concealed under the chrome dash onto the ground.
The maximum effective capacity of a standard mounted FXR tank is 3.5 gallons. The "reserve" is typically unreliable with the stock petcock, by the way. "Smooth top" tanks hold 4.0 gallons if filled right to the brim. There is no such thing as a real 4.2 gallon tank for an FXR. The Owners Guides are wrong. The Factory Shop Manual from Harley is wrong. The articles in the Performance Portfolio are all wrong for each of the years reported. The Clymer Manual is wrong as well.
No one has done what I did (it seems): Take several tanks, set them on a shelf, and one by one physically test them all by using calibrated jugs, then empty them into measured containers to double check capacity.
DINGS AND DENTS
Most of the older used tanks on eBay come with dents of various sizes. A dent puller will perform poorly on a tank designed to hold combustible fuel, so don't try it -- unless you got something against the guy on whom you plan to fob this dangerously patched and repainted monster. A dent puller consists of a corkscrew that drills the sheet metal right through, plus a winch of some kind which yanks the metal into place. The finished job is then filled with Bondo or some equivalent, sanded and painted. Works well for car panels and such, but not so good for things that need to withstand atmospheric pressures caused by either gasoline vapors expanding, or vacuum caused by fluid displacement as the tank empties. Thats why reputable third party suppliers ALWAYS say, "test, pressurize and seal." This applies to ALL fuel tanks, not just Harleys.
How then to handle the ding? Well, you can just fill it with metal epoxy and paint over it, or you can get someone to pound it out from the inside. Which probably will still need a surface epoxy treatment and repainting. Or you can have a welder cut the tank in half, which is what I am going to do with mine. More on that and why in a bit.
SENDER AND "DESCENDING" UNITS.
The FXR sender unit is a simple variable resistor with a float; you could make one yourself out of simple parts available from Radio Shack. A constant current is supplied to the sender unit through a voltage limiter from the battery. As the float sinks, resistence increases on the path to the dial, causing the current to the guage to decline and thus allowing the needle to fall towards the red zone. The principal has been around for scads of years, and a nice description of operation is on the site dedicated to Ford Mustangs.
THERE IS NO SUCH THING AS A "DESCENDING UNIT!" Obviously, don't buy a tank from any fool who claims the tank comes with one. That seller is scamming you or worse, does not know what the blankety-blank he is talking about.
And another thing: there are sellers on eBay who have not even SEEN the product being sold to you. You think these "Power Sellers" with over a thousand sales actually LOOK at what they are selling? Gimmee a break. They typically are being middlemen in the exchange of goods between two independent people. Even the shipping is handled by a third party. Sometimes the photo is not even of the product itself, but a stock image of what the item is SUPPOSED to be. I got a nice inspection cover that way; the entire surface had been stickered over with fake identification numbers. Once cleaned up, it looked OK, but it sure had no resemblance to the image posted on eBay. And it was not, as advertised, a chrome piece.
The rule is, go by part numbers, and definitely use reputable sellers who at least employ correct spelling in their ads.
SEALING
OK kids, repeat after me: EVERY DINGED TANK AND EVERY USED TANK ON EBAY MUST BE RESEALED. Well, there are maybe two out of the 25 tanks currently listed which probably do not need resealing, due to their extraordinary pristine condition.
If it is dinged, the inside seal has broken. You must scour it all out and recoat. There is no other way.
Sealer comes in two colors: epoxy grey and pale blue. Sealer is NEVER bright yellow or any other primary color. I got a tank shipped to me which positively glowed from the inside. Either the seller, or the original owner, saw a lot of rust caking the inside of the tank, and instead of acting honestly, poured enamel paint into the tank, coating it thoroughly. The time spent doing that scam job could have been better employed using a proper tank liner after scouring the tank with acetone or battery acid. Costs about $25. KREEM costs about that, comes in a three stage kit with clear instructions, and is the industry standard. It's what I use and it works well. Heck its better to sell and buy a tank lined with rust than do what that moron did to me.
Unsealed tanks will rust every place gasoline is not touching, plus some. You cannot overcoat a Harley liner that has decayed -- you must removed it, and the Kreem process is the only reliable way to do it. Here's a tip: the cork from the 1800 Gold tequila bottle works perfectly to stop up the spout where the petcock goes. Kept sulphuric acid in a tank for 36 hours without leaking a drop!
If you have one of those Red Devil paint mixers, you can toss a few handfuls of gravel in the tank and let 'er rip. That will work really well to remove rust layers as well and is the most friendly to the environment as Kreem tank cleaner and most rust removers are pretty toxic. I know a father/son team that just puts in their workout with a tank like that. When one guy is tired shaking the thing, he passes the tank to the other.
Every used eBay tank I have seen listed will require etching with acid, followed by coating with a proper liner and most new tanks must be lined as well. Those tanks must have the storage grease washed out of them, which is another process.
THE FXR CAPACITY AND RIP-OFF SOLUTION
So, as mentioned above, we got a tank lined with bright yellow enamel that gasoline will surely break up in a matter of days, if not hours, clogging fuel lines, carburetor, and the engine ports. It is dinged. The capacity is the notorious 3.5 gallons. There is no sender unit -- the guy bolted a plate over the sender unit mounting hole and simply lied about it. The seller feigned ignorance; and he probably is pretty ignorant, too. What to do?
The welder shop is your best friend. In fact, any number of welder shops are experienced in doing exactly this kind of work, as this problem is so common. They will cut that tank on both sides, use a sandblaster to get that ridiculous enamel off, and with the open shell there easily use a hammer to pound out that ding. Then, the shop will add metal strips to the sides, weld the halves back on and -- presto! -- new 6 gallon tank!
Cost around here is about $200.00 for the job.
Take any old sending unit from any tank and mount that sucker right up. Sure, the level will lie for the first 80 miles or so, but its the last 20 miles we are concerned about, not the first.
Of course the welds will be visible under the new coat of paint no matter how much you goop it on -- did I mention the guy sent a tank with a yucky surface? -- but frankly, a usable tank is better than no tank at all. And there are all sorts of things you can do creatively with those welds. Why not add shark fins and paint the tank accordingly? Add fake rivets maybe. Those TV bike builders sure lack imagination sometimes. Heck, maybe I'll turn the tank into a mallard duck . . . .
Comments are welcome. Lets ride herd on the scammers out there and get them off off eBay!
Guide created: 03/15/07 (updated 08/07/08)
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