Sportster Fuel Tank Modification

[81xs400UK]

Anyone out there have info on modifying a Harley Sportster Tank to work on an xs (xs400 in particular)? I am wondering if much has to be done as the Carbs are vacum carbs (whatever those are). There is also some sort of Tampon filter at the top of the petcock into the Stock tank, does this need to come over to the new tank?

Any help appreciated.

[drewpy]

Anyone out there have info on modifying a Harley Sportster Tank to work on an xs (xs400 in particular)? I am wondering if much has to be done as the Carbs are vacum carbs (whatever those are). There is also some sort of Tampon filter at the top of the petcock into the Stock tank, does this need to come over to the new tank?

Any help appreciated.

I've seen xs400's for sale with the tank on so it can be done. If you can keep the vaccum tap on, keep it, otherwise go with the harley one and put an inline fuel filter on the fuel line. don't forget to blank off the vacumm pipe though!

carbs are fine leave them if they work ok

[81xs400UK]

I've seen xs400's for sale with the tank on so it can be done. If you can keep the vaccum tap on, keep it, otherwise go with the harley one and put an inline fuel filter on the fuel line. don't forget to blank off the vacumm pipe though!

carbs are fine leave them if they work ok

Blank off the vacumm pipe? Is that simply plugging the hole in the carb with a rubber seal? Do the carbs work normally sans the vacumm hose? It seems my bike has a inline filter on the fule line and the stock intank tampon. It was set up like this when I bought it. Overkill? Why is the filter necessary? Gas is cleaner 30 years later, no?

Thanks for the advice.

[Cy Welch]

Blank off the vacumm pipe? Is that simply plugging the hole in the carb with a rubber seal? Do the carbs work normally sans the vacumm hose? It seems my bike has a inline filter on the fule line and the stock intank tampon. It was set up like this when I bought it. Overkill? Why is the filter necessary? Gas is cleaner 30 years later, no?

Thanks for the advice.

It's because of what can and will get into the tank. The stock filter if in good condition (the tampon in the tank) does a good job, but going in any way aftermarket you NEED an inline. I have found that an inline AND the in-tank cause too much restriction for me, so I took the inline out since the in-tank filter is in like new condition.

[Cy Welch]

Blank off the vacumm pipe? Is that simply plugging the hole in the carb with a rubber seal? Do the carbs work normally sans the vacumm hose? It seems my bike has a inline filter on the fule line and the stock intank tampon. It was set up like this when I bought it. Overkill? Why is the filter necessary? Gas is cleaner 30 years later, no?

Thanks for the advice.

Yes, its just plugging the fitting with a rubber cap. The fitting is to turn the fuel flow on so if you use a non-vacuum petcock you need to cap it. The vacuum carbs can be tricky to modify or adjust, but when working right provide very good fuel control for a carb.

[drewpy]

Blank off the vacumm pipe? Is that simply plugging the hole in the carb with a rubber seal? Do the carbs work normally sans the vacumm hose? It seems my bike has a inline filter on the fule line and the stock intank tampon. It was set up like this when I bought it. Overkill? Why is the filter necessary? Gas is cleaner 30 years later, no?

Thanks for the advice.

its not the gas that is cleaner, its the sediment from your tank, the gas stations tank (especially after a tanker has delivered fuel) I never buy from a station if I see a tanker there!!