So some progress being made, not all in areas available in photos as yet. Gas tank has been sent out to Fuel Tank Services in Ft. Lauderdale for rust removal and lining. They use a very proprietary electro-chemical process to remove any bad liners and then rust. Had them do 2 tanks for me last year on bikes that had really decent original paint, and they came out great, so off this one went. Expensive but worth it IMHO.

Cylinder is at the machine shop having the bore checked over (it looks very good, some hone marks still visible, so it may be able to stay at 1st O/S with new rings). They also have the original stator plate to see if they can extract the broken 4mm screws I broke off. I am sure they have a better setup than I have, plus steadier hands.

While I was there, I asked him if he could reproduce the swingarm bushes in bronze, and he said he can get oil-impregnated bronze stock. I have looked several times but have never seen any available for the DT1s. So I am considering having a couple of sets made up, one for the DT1, and another for the TY250 as they are the same # (pretty sure on that, but I will check before anyway). I have a new set of OEM bushings I will hand him for sizing. I can hear some would say 'not necessary', but if I can make an upgrade here it might be worthwhile. I did it on the 360A already, using bronze RD350 items.

Thoughts?

Had the carb vapor blasted also when I sent the cases etc., out, and was able to get some bench time in. The vapor blaster did a good job cleaning them, and I am thinking he may even have ultrasonically cleaned them, but I washed them up in my tank anyway, then used carb cleaner. Good thing, as the small jet for the enrichening circuit that lives at the bottom of the float bowl was still blocked. Took me awhile to get it cleaned out. Carb cleaner and compressed air, pipe cleaner and then the smallest jet wire from my set did the trick. The pen tip points to where it lives.

First class work!

Thanks for the reminder. Easy to forget about the starter jet.

A few years ago I managed to get a photo of the tiny non-removable starter jet that lives in the bottom of that well and can cause so much grief with starting.

I had a full Keyster carb kit for the bike, which had almost everything. I did buy a new needle jet (0-2) as well. The kit had a new needle, and that pair can wear due to vibration. Since everything else should be up to snuff I wanted those to be new as well. The pilot jet, needle, and other parts were all the same numbers, (i.e.- 35 for the pilot), but the main jet was a number lower at 150 (manual indicates 160 as standard). The main that was in it was a 170, so larger, and the clip on the needle was in the second slot, lowering the needle. So, richer on the jet and leaner on the needle. Not sure what to make of that. Can't make any judgment until things are moved further on. So I used the new 150 main, and set the clip in the middle slot (#3), and will go from there.

Anyone have feedback on what they are running on these?

Float level setting was at 12-13 mm. Spec was 15.8mm. I have it at a solid 15mm, and the tabs look level with the bowl mount surface on the carb body.



Lastly, I note that the idle adjustment on this carb body is not what I recalled from my 1969 DT1, which had a screw arrangement coming up through the carb top. This one has a more normal (to me) screw that lifts the bottom edge of the slide. The parts manual (which is a reprint) has the kind I remembered, but the service manual (used OEM) has a drawing of what I actually have. So there must have been another change made during the first year run.

Careful with the Keyster "calibrated" parts like the slide needle and jets.

If they don't have the Mikuni "square in the corner of a square" they can be stamped with the same number as original but likely aren't the same.

That is an absolutely incredible photo of the starter jet.
I know I'm not supposed to, but I have on occasion poked around a bit in that dungeon of a well with a cut off violin E string and had good success. It's about .024-.026" unless you're using something costing under a dollar...

Would there happen to be a number stamped in that carb? Maybe on the upper edge of the mounting flange?

From Enduronut:

Carb flange stamping
1. E1 = 1968 to serial # DT1-002850
2. E2 = (Domestic) was only used in Japan
3. E3 = 1968 # DT1-002851 through 1969 # DT1-015829
4. E4 = 1969 # DT1-015830 through 1971


From what I've seen on the forum, I think the 68 carb through early 69 (first 829 or so according to EN) was supposed to be the type with the idle rod and then later in 69 they switched to the more common idle stop screw in side of carb like you have

P.S. According to a post by Enduronut, the 1968 had a 150 main

Thanks for the reminder on Keyster. I had actually heard that before, when I was rebuilding the 360A. I was able to get OEM for that one. This time around I actually tried to do the same, and had gotten both the needle and jet off eBay ahead of time. Once I had things apart, of course the needle is completely wrong, too long, etc., and way past time to get it corrected. Intent is to try to get OEM for that circuit at least. The jet is definitely OEM and a dead-on match for what was there.

And that is absolutely an awesome photo of that tiny jet! I took my time and was eventually able to get the smallest wire from a set of jet cleaning wires through it. Another go-round with an ultrasonic setup would have been my next step (and still may happen).

There is a small number stamped on the top of the mounting flange. It is "214" and under it "E4". From EN's post it would appear that the carb is from a later year then??? Will get a pic of that when I can.

On to the petcock as it was right on the bench and I had the bits (all OEM it seems). I dove right into it without taking any "before" photos, so nothing for comparison. Oh well

The thing really was pretty grotty. Dark black crap all around the main tube and reserve filter. Came apart easy enough. Everything inside had a hard reddish film/varnish that resisted the soft wash tank fluid. Tried carb cleaner which barely affected it. Wound up working a pick at it carefully and the stuff came off in pieces. It was like an M&M, it had a 'hard candy shell', but on the inside. Got as much as I could, will get it ultrasonically cleaned at my local shop, he's pretty cooperative.

Unfortunately the reserve filter gauze could not take it, so I will look for something I can work with to replace it. I swear I have seen similar on a site somewhere. The back of the lever that controls the fuel (last pic), with the 1/4 slot for on/off/reserve was completely flat. Had to dig for some minutes to extract the stuff packed in there.

Monofilament fishing line works good too. Many choices from ultra light to heavy weight.