I was unfortunate to do some work on one of these Indian bikes a few years back, it was a WD 16H. The owner had paid a lot for it and when he got it home could not start it. I had to sort it out for him, a really an impossible job as near everything was bodged. One of the worst things was that all the cycle threads had been tapped out to UNF or metric. I got it running and he tarted it up and it went through an auction house. Be carefull with these Indian bikes as when they were over in India a few years ago they were worth nothing and kept running by the use of very basic tools mostly big hammers and blunt chisels. Saying that a lot of bikes over here had the same treatment in the 50s and 60s when they were worth nothing.
Look at the link to this 16H in this thread and look at the cylinder head and the absent of fins worn away with heat. Maybe taking the mag off with a big hammer caused the damage to the cylinder fins.
I couldn't agree more with that...I've rebuilt two ex India bikes and one ex N. Africa bike and they were a total nightmare...
Most UK based bikes got mistreated as their value fell, as Tim noted, but many also spent a lot of time in sheds doing nothing. I think most of the ex middle east machines spent the bulk of that time being worked and bodged to death...
Personally I wouldn't have another in my workshop and wouldn't recommend one to anyone else either unless they wanted a real challenge...The fact is by the time you've rebuilt one there will be little of the original machine left...
On the basis there might be the occasional example that is worth rebuilding and you're looking for it, approach them all with EXTREME CAUTION..!!!!!....Ian