I have a 78 IT400 and no carb. Any suggestions on a aftermarket replacement. Maybe something from a current or more modern bike. Anyone done something similar? IT400 carbs are hard to find and most want big bucks for junk. Thanks!

Suggest you check on the price of a new genuine Mikuni. they are not that bad and you are starting with new instead of worn out 45 year old carb. Unless you are looking for those " original #s". Also original cable, boots and fuel line will fit

How deep are your pockets?! 

This seller certainly gives me parts envy! 

original Ersatzteile Yamaha IT400: 1x MIKUNI Vergaser carburetor 1W6-14101-00 | eBay

You are right AL that seller is out of his mind. With age comes patience and I can wait for a better price. There are so many pirates on fleabay, that I have trouble believing any Mikunis on there are genuine. You have done so much on a low budget per bike. I have watched all of your posts. You and GFrench have shown us all some pretty unique repair ideas. On high wear items, like carbs and clutch baskets, I would just rather start new. Going to try to move some old inventory at the PVR bike show tomorrow for my next new purchase.

Mace6772, who would you recommend that sells these carbs new?

I am curious, has anyone bought a universal genuine mikuni vm carburetor, and bolted it on without altering the jetting? They say they are calibrated for 2 and 4 stroke engines, but I don't see how the jetting could be even remotely right on a random engine. Anybody tried this? I will go the used route because I usually end up spending 50 to 100 for brass anyway. The slide would be the biggest wear part in these carbs, and that can be replaced as well.

It MIGHT have been member racerclam that sells and sets these up. Sorry if I got that wrong, but someone here has certainly done so in the past. I think the only(?) issue was drilling a hole for the oil feed but, of course, this only applies to the later bikes. 

SUDCO (USA Mikuni Distributor) used to sell pre-jetted Mikuni's for many different bikes.  They still might. 

(The best pre-jetted carbs I've ever seen used to be sold by Klemm Research.  They were meticulous about fine tuning the best needle and all the other components through testing.  I think Harry is/was a member of this site...  not sure if they ever sold kits for the Enduros but if they did, he might still have the specs.)

Mikinioz. I bought from them