[Froth]

Wow that filter looks gross, I’m looking at the diagrams for the fuel system and it seems there is no other filter anywhere in the system other than in that swirl tank type setup for the fuel pump which means anything that goes in the tank will feed down to that pump filter, on the carb models with a petcock they usually have a pre-filter over the tube in the tank and also an in-line filter. Definitely something the EFI guys need to check every now and then with only one filter in the system.

 

[Froth]

An after the pump filter is high(er) pressure so the inline filter clamps could become a leak point, and the clamps/filter must be high pressure rated/compatible.
A filter there though mean the smooge has gone thru the pump and could have damaged it before the filter.
Seafoam is good but Techron is for injectors so use Chevron gas if you can because Techron is in it.
Techron is sold at part stores though, and even Walmart.

I've had my single carbed 750 shafty over 100mph many times and I'm no light weight.
Your top speed may improve as those additives work their magic over time.

Seems that the fuel pump is actually in a little swirl tank/surge tank under the seat area on that model and not inside the fuel tank itself. As I understand the system there is an inlet line that feeds into the little tank which contains the pump/filter and then that has the high pressure outlet from the pump. The under seat tank inlet seems to be gravity fed from the main fuel tank so in theory a simple inline filter same as the carb models have before the pump may be able to be installed if there is enough room. Only my thoughts from looking at the technical drawings of the system though, not sure If it’s actually possible in practice.