Hi Simon,
You'll probably find that the carb will run 'ok' as it is, perhaps a little rich on wide open throttle.
But in the interest of fuel economy....
Changing the jets on a dmtl is pretty easy, whip the air cleaner off to expose the top of the carb, You'll see 4 brass 'screws' between the two venturi's, these are the jets. Unscrew and swap them 1 at a time to avoid a mix up. There's an idle jet for each venturi and a main jet for each venturi.
When you unscrew and pull out the brass screw, you'll see the jet attached to the end of it. the top half of the screw is the emulsification tube, be sure to give these a blow out from any bits of crap that may have got in there. The jet part simply pulls off the end of the screw.
Setting up the choke cable is also very easy. Fit the choke cable in the stock position, remove the little cover to the lower left of the steering wheel. Once you've got the cable in and through the bulkhead (there's a perfectly positioned grommet in the bulkhead above the clutch pedal), Put the choke lever in the fully off postion, ensure the carb choke is fully open, then just nip the cable up.
