I recently purchased a set of brass throttle and air levers for another bike and the lower (throttle) lever is bent out of position.  Attached is a picture of the bent one and a picture of a proper one.  Any thoughts on how best attempt to straighten it?  The lever is from the late teens to mid twenties.

Hi Friends
                 Just thought this may help all those suffering with mild insomnia. So instead of counting sheep try counting the greasing             
                 points on your MK series Dougies? more than ten ****.   Regards Phil.

Changing the casting would have required altering the pattern and several core boxes. That requires time and equates to money, so presumably they figure it was not cost justified. Particularly for a cinder track machine where aesthetics was secondary. Who knows how big a stockpile of left over castings were on hand. And even if not a massive stockpile, they could have had a situation where when they ran out, then figured just running off another quick batch of castings would see them through. At some point they would have realized this dirt track phenomenon might stick around for a while. The more likely reason is you could still buy a I.o.M./TT model in 1928, and while the 1929 catalog shows the I.o.M./TT model as using the Dixon twin cam engine, I have my doubts that model ever went into production. So a 1929 I.o.M. model (if they sold any) would have likely been the same as the 1928 model. So it would behoove them to keep the pattern around unaltered, in which state it would suit either model.

I had a look though my collection of images and could not find one where the second carburetor control shaft was installed.

The tall airbox for the DT was drawn up in October 1929. There must have been an earlier drawing for the I.o.M./TT model, but it has not survived. Had it done so, it probably would have dated to around November 1925, when the 1.o.M./TT airbox lid was drawn. The 1929 drawing still has the features for the mechanical oil pump drive (see above rational), though the boss for the oil pressure gauge is not shown. The small airbox was drawn up in November 1930. Drawings seem to have been created after initial production was underway, and September-November was a popular time for such drawing work judging by surviving drawings.

The hole in the bottom of the tall airbox for the throttle shaft return spring is clever in its simplicity. They dropped a cotter pin (or split pin) through the hole and bent the tails over. Then used the eye of the cotter pin to hook the spring to. Quick and cheap to manufacture.

-Doug 

The WD/23 stamp on the timing chest is interesting: one of the bikes I listed above https://www.vintage-motorcycle.com/en/motorcycles/archive-sold-bikes/douglas-350-cc-1923 is identical, and has some interesting documentation with it suggesting it never went into military service. I wonder if yours was similar? What's the first date in the reg record?

Re value: It has all the makings of a lovely thing. A sensitive deep clean and polish, as suggested by EWRon, and assembly, plus whatever mechanical tweaks required, would bring to the top of the pile for a 1923 TS. As it stands, it would have to be a "mid-range" price - higher than a project or an average restoration, but some way from the top because it is not together and running.

If you like a bit of fiddling, keep it for yourself. You can deep clean it without disassembling it: just take the screws and bolts out one at a time, clean, oil and refit. It's very relaxing and satisfying.

Cheers

Leon

Thinks for the pics. Does look to be in good condition.
If that was my bike, I'd be giving the black enamel bits a dust off and a wax and polish.
But maybe you don't want to anticipate what a new owner may want.
A dust off wouldn't hurt though. !

Ze moderator will likely be along shortly, to fix the aspect ratio.

There are spiral fittings fitted into the cylinder head tops that I have not seen on any other similar machine.

Those are called fir cones.
They were (mostly) an accessory, fitted over the exhaust valves.
Allegedly to provide extra cooling.
Not sure if there is any data to back this up.
I've not seen them on a Duggie before either.