TWIN AIR: http://www.twinair.com/usa/twin-air-fuel-filters - "Sorry, we do not offer a fuel filter for that model Husky."
SPLIT-STREAM:
http://www.split-stream.com/products/splitstream-fuel-filters - "We do not have a fuel filter which fits the Husqvarna TR650 ! Met vriendelijke groet, With kind regards, Mit freundlichen Grüßen,"
PROFILL-AUSTRALIA: http://profill-australia.com/e-store/STORE.html
"thank you for the email and photos.
A filter is unable to fit in a fuel tank like this.
The reason is because of the locking fuel cap and the way it gets pushed down... and the locking teeth of the fuel cap that expand out in to the tank.
It is these locking teeth that stop any normal filter from fitting.
This is the same problem as all other Road bikes with metal fuel tanks that have a locking fuel cap.
All our filters (and our competitors) need to have a round hole in the tank and some smooth area to seal the filter, and then we 95% of the time need to have a screw on fuel cap that will not stop the filter from fitting.
Normally in for bikes like this (KTM990 690 BMW 800 1200 Yamaha teneree ) all seem to have very similar fuel caps, and the only thing we can offer is for them to buy a filter and insert it in to the tank, to be used while filling the bike with fuel and then putting the wet filter in to a container or ziplock bag and store it under the seat or in luggage.
On our website we normally recommend that they buy the STD0001 or the SAF0001 filter, because of its large size and length of filter.
We sure do wish we could make a filter for bikes like this.
The only possibility we can see is to make a filter attached to a very thin mount ring... and that mounting ring was placed in between or inside the gasket Number #2 and fuel cap mount number #3
But to do this we would need to know the measurements of the hole in the fuel tank, the measurements of all parts of #2 and #3
This is what we are currently working on for the KTM990 and attempting to make a filter that fits under the #3 part of the tank."

These are the answers form fuel filter manufacturers.
Can you accurately measure this parts?
2: 8000H7041 - Gasket
3: 8539045 - Fuel cap ring nut