Take a look at page 9 of 20 (identified as pg5) and see if you can make sense of the starting circuit jet. For some reason it sounds rich. If it were me, I'd try to find some leaner ebay jets and swap it out for the next size down and learn if that gets you on the right path.

The pdf is here in our tech library under "other tuning manuals"

www.yamaha-enduros.com/index.php/other-m...-super-tuning-manual

Well it looks like yesterdays tinkering and suggestions above have had the desired effect.

The bike started and ran well today! OK not on the road yet but that will be down to further tuning when I get the bike legal.

Like TresCuatros suggested above I thought the bike to be too rich so I tried a new starting procedure.
Choke down (so full on) 2 kicks to get a bit of fuel to the motor and then choke off and it starts either first or second kick.
I tried this several times and this method worked each time.

Then I wanted to warm the engine up fully so I started it as I had previously and then let it warm up with full choke.
Choke off and there was a decent idle @1500 rpm on yesterdays settings.

Fine adjustments of fuel and idle screws and I had a good idle at 1300/1350 rpm and a good crisp response.

To say I am pleased is an understatement!

Thanks for the link to the Mikuni manual, didn't have a copy previously, a good read.

Good approach with the choke on for a couple then off.

Congrats on getting closer to sorting this out! Hopefully it'll be streetable in no time so you can enjoy the fruits of your labor.

I've forgotten where I learned this, but I know it's true with my 360 bike. If temp are over 70 degrees Fahrenheit, it does not need choke to start, and will quickly flood of the choke is used and not immediately shut off.
and by choke, I mean the enrichment circuit.

Registration document arrived today so all in all a very good week!