Well this is a dump find, haha, Not quite sure what it is other than a 340,...any ideas?
http://img378.imageshack.us/img378/7038/hpim1374qd5.jpg
http://img180.imageshack.us/img180/6891/hpim1373eg1.jpg

Looks like a sl338

Twin carbs were only on early GP models and the heads are angled wrong for a fan cooled (maybe?). but the fan housing
has been cut down and the fan left on ??? a little strange.
also has a impulse fuel pump to run mikuni type carbs .
Clutch looks ordinary and oil injection looks normal ..so it
wasn't likely a racer .
Maybe an older btm end with GPX jugs ???
My 2 cents of a guess
Ron

It looks to me like a 1969 SL-351 some of them had twin Mikuni carbs and a belt driven oil pump with the fuel pump in that location. But it looks like someone has taken off the air shrouds.

WOW! I wish there was something like that in our local dump!