thanks for all the help and info
a couple of days ago I did an email to Hatrick the Mikuni people in Queensland, I asked for a recommendation, they came back telling me that the information I wanted was on their website, it was hard to find at first, and here it is step-by-step:
On the Hatrick website
1. Go to the left hand drop down menu and select VM carburettor
2. That drops down menu and you select the size you want say 38 mm
3. That gives you pictures on the right-hand side - the different 38 mm carbies and a few other related parts including "tuneup kits"
4. You will see several different tuneup kits, for example you might see "for 4 stroke engines" or "for 2-stroke engines up to 250cc" or "for 2-stroke engines above 250cc", so you select whichever one suits your bike.
5. Then you get a drop-down arrow with a list of "old bikes" and there are a lot of them there, if you order one of those kits it will give you all of the parts so that you can "set up" your standard 38mm VM to suit your bike, some of the kits just have a couple of jets, some of them have jets and needle, and some of them have jets, needle and needle jet.
But of course KTM/Penton 400 from 1977 was not there, hatrick advised that I should pick something of similar performance/design to my engine and that would be a good starting point, but that's a bit tricky in itself.
OZKTM, yes I had a look at the Penton site, that's where I started to get confused because there were 4 different threads with 4 very different sets of recommendations.
