It's taken some time but the manifold is ready and the carb mounted on the bike. When I got the bike it would hardly start (you could say it wouldn't start) and the 2 times I got it running it died after a few seconds. I had not expected it to run with the new single carb setup, and of course it didn't...
Then I followed some good advice from different forums and changed the spark plugs. That actually did the trick!
I haven't changed anything to the carb yet, so I put it on as I got it, with a 45 pilot and 165 main jet. I adjusted the idle and just turned out the fuel mixture screw 1 turn because it seemed to be running a little better that way. The AP isn't working so I have to fix that because I have the "bog issue" when I open the throttle fast. But when I somewhat gently open the throttle the bike actually responds pretty well. Even though the spark plugs look OK, I do have the feeling the bike could use a little richer mixture. But that's something I have to fix by setting up the carb correctly. But at least it starts and runs idle steady, and responds to the throttle so I'm happy for now.
Like I said the manifold is glued together. The glue doesn't take temperatures over 100 degrees celsius (I tested that by heating a piece of glued aluminium with a blow torch). So using glue to attach flanges to the manifold to bolt onto the cylinders was out of the question, as the outside of the cylinders will get hotter than that. And taking cxman's comment on the too sharp edges of my first design into consideration, that made me redesign the manifold and use the stock intake boots. By turning them around they face eachother at an angle of 20 degrees. So now I only had to make "sharp" edges at an angle of 10 degrees each, which I smoothed out on the inside as best as possible. the rest of the downward angle into the cylinder is now taken care of by the boots which are rounded on the inside so should make airfow much smoother than with the sharp edges. Added bonus is that I now have a thermal insulator between the cylinder and the manifold, which prevents the manifold from getting too hot and breaking the glued connections. Besides that the rubber boots also take up some vibrations and give a little room to play in case the manifold isn't "spot on" sized. All in all this manifold has cost me less than € 30,- in materials and tools I had to buy, and it actually seems to be working. So I'm quite happy
Anyway, I've put up a short clip on youtube of the bike running. You can see it here:
https://youtu.be/EURuICOtIgY
And yes, I know I should have put on an air filter but I haven't got that yet and was eager to test the carb setup
In the movie you also see the mounted KTM front fork, which was more or less a bolt on solution with the pyramid parts bearing replacement set (both top and bottom 48x30mm). The wheels will be replaced by spoked ones which I already have. Front will be and 18" (which is roughly the same outside diameter as this 90x90x19, so both engine and ground clearance don't seem to be issues) and rear the standard 15" for now at least. I managed to get hold of a 535 rear wheel that included the drum brake at a bargain. The only problem with that wheel is that you can't mount it in the rear fork without taking the final drive off, because it's like 0,5 cm too wide to slide it in. And mouting the drum brake when the wheel is already on the final drive doesn't work either. But that's something I'll have to figure out or learn to live with. It's not a lot of work unbolting the finl drive and I hardly ever take out the rear wheel anyway...
Here are some pics of the manifold: