would anyone have a picture of what this looks like so i can fabricate one?

or better yet one they can sell me?

thanks,

Martjn

You would want to include a pic of the top of your box. I've encountered two different styles and the one I think you have is the harder one to find. Yours probably has two elongated corners on the rear and more normal standard radius corners on the front. At least I believe that is correct. Those are the ones on my Rt1B and DT1E. Yamabob down in Texas on here had one 6 months ago that he wanted to sell. Come to think of it he sent me one for my bike for the cost of shipping.

FWIW...Here are a couple of air cleaner pics from the service manual found in the tech library along with a pic of the same area of my old DT1-C. Hope it helps.
 

That's the one!
if anyone has one for sale please let me know so I can avoid having to make one. 

 

Yep that's the hard to find one with the elongated rear corners. Good luck...if You find two I'll buy one for a spare box I have.  

This is what's on my '71. Is it original? Not even sure, my bike seemed/seems to be an amalgam of a few DT1's.

Apex .
Pretty sure that airbox is off a DT2/3

hunting down the parts is helf the fun, right!?

Is the cover for the one i have designed to sit tight against the housing - e.g. no air ducted in?  I think so since there are two downward facing inlet ducts...once i know i will endeavor to make one.

i appreciate everyone's help!

 Another oddity of this bike is that the splined shifter shaft extends out of the right hand side clutch cover in addition to left crankcase. If it was to provide support then there was no reason for Yamaha to bore all the way through, spline R side of shaft and install an oil seal so I am thinking that somewhere in the world the DT1E came with a R side shifter?

The reason for the right hand spline extention is a bit simpler .
50 years back , many riders grew up with british bikes , which shifted
on the right side . Many Japanese bikes came with shifter splines on
the right , and offered adapter kits , to change the rear brake pedal to the left .
Kawasakis of the same vintage , offered the same option .
The 71 Yamaha enduros were the last to have this option .