Hi I’ve just purchased my first Harley and the fuel gauge wasn’t working. On taking the sender unit out of tank (it’s a 2007) we have found the inside of tank has been coated with a sealer of some sort, it’s a yellow colour like spray foam. In some areas it is started to break up has anyone had to remove this coating, what solvent or method did you use, I was thinking acetone? The bike was repainted a couple of years ago so don’t want to ruin paintwork if I can help it, not sure why coating put in but maybe corrosion. Thanks for any help

 

All Harley tanks are internally coated and it's recommended new tanks are coated as well.
Cleaning out a tank is a long arduous process.

 

Tank coating can be a "do-it-yourself" thing that a lot of folks have done to their bikes. One brand I've seen around a lot is KREEM. There may be others. I cannot comment on how or when the Motor company may have coated factory gas tanks. I removed the factory tank on my 1985 FXRS just a couple years after I brought her home, in 1985. It was replaced with an aftermarket "Quick-Bob" tank that didn't have any kind of liner in it, and I never tried to add one. I'm still running that tank, without any kind of liner and never had a problem. A lot of folks have had "issues" when their tank lining material started to peel off and clog things up. The only successful way I've heard of to remove old liner goop is to put steel ***** inside the tank and tumble..a LOT. If the bike is running and the liner is not causing an immediate problem... I would recommend adding a clear inline fuel filter that you can monitor to see if bits of the liner are getting into the fuel line and catch them before they shut you down.

 

if it is fuel injected, a filter will do you no good. DIY liners come and go but personally i never had one to hold up. the ball method might be good to remove failing material but you will have a lot left and it must come out if you plan on coating the tank again. the only way is a chemical strip and yes, difficult if you want to save the paint but it can be done. you need to get or make blanking plate for fuel pump hole and a sealing fuel cap, make sure the plate has a drain port so you can flush from the top.
aircraft epoxy remover probably will do the job as acetone probably won't work.

 

I’m too old school on bikes to know anything about fuel injection systems on them. OTOH... I have a fuel injected 250 HP Yamaha outboard that has several fuel filters between the fuel tank and the injectors. Wonder why bikes are different??

 

I am curious about not using fuel filters on EFI bikes. Cars/truck use "inline" fuel filters and most are high pressure systems. The only thing to be aware of is the use of F.I. hose clamps.

 

for one, the pump is immersed in the fuel and the inlet should have a type of screen/filter. now if it gets fuel from the outside, then an inline filter would help. however, you are only helping the injector side. all said, IF it gets past the pump inlet, it will get past the external filter also and that leads to injector screen plugging up too.
when ever i get the first pump failure on my truck, i go with an external pump/ filter system, beats dropping the tank or raising the bed which is easier. but you MUST get the correct pump as most are pushers and do not work right trying to lift fuel.
if you notice a lot of the newer vehicles, they do not have an external filter, totally rely on the pump inlet sock.

 

This is true the fuel pump is immersed in fuel inside the tank, it also has a micro screen attached to it. But until very recently also so had a external filter. Working for Chrysler I have changed many. The. point of the filter was like having a second line of defense against anything that made its way past the tank screen. The only draw back to adding a second filter that I can see is the danger of proximity to engine heat.