Please help find.1994 british championship mx winner

Hello.
My brother is rebuilding a 500cc husky 4 stroke for the son of a departed friend of ours.The bike has been sitting in the mezanine of the workshop for over 8 years now.New tyres have been fitted and bearings and cleaned up...
We are trying to find an air filter that fits but we cant seem to find one.
So im writing this that someone might know where we can purchase one.The original is pretty (dissolved)
What we thik we know about this bike is that it won the british chapionships in 1994..its a 500cc 4 stroke..I may be wrong with this info but i have a few pictures you can look at.....(hope i can download them)

Any help will be appreciated...Thank you....Janos
more pics on next insert

a few more pics

That filter is husky part # 800069783 and it should be readily available. Several companies also make replacements as well, like twin air. It look like you have and air cooled 510 motor (1986 and earlier) shoved in a later model frame (1992-1993) from the looks of the swingarm, sub frame, and rear disc brake. The exhaust looks very nice and custom maybe. It is a very nice looking bike.

VIOLA,found it and ordered two of them....Thank you for the quick repy.I knew this forum would help.
I purchased them for 12.95 euro each..from this shop(link)...some cool oldtimers he has.....Thanx again
http://www.enduroklassiker.at/en/

Here is a pic of the finished bike...finally.decals etc
thnx again......Jan

Awesome bike, lets hear it... any videos of that thing?