1984 KDX 200 has a hard time starting when hot?

[linny]

Hello all,
So after having a hard time find parts for the OEM carburetor (VM32SS) I went 2mm bigger with a Mikuni VM 34 carb. The bike starts a lot easier than it did, but every once in a while it seems to have an issue starting when it gets hot. Wife and I were out riding and she couldn't kick it over and get it started. When I pulled the plug it did seem to be fouled up a bit. I cleaned it up with a wire brush and away we went. It also can get fussy without fouling. The plug it has in there is an NGK B9EG, manual says it's supposed to be a B9ES. Not sure if it's a hotter or cooler plug than what it's K range is supposed to be. I'm still playing with the carb to figure out a good jetting set up as it's not an OEM carb. I'm thinking I will have to lean it out. Anyways I'm trying to figure out what is causing the fussy starting when hot.
-Linny

[GI_JO_NATHAN]

I'm not a 100% sure for all years. But I know the BR8ES is recommended.

[Adamnb1]

if it were me I would stick with what the manual recommends, Br9Es - going from an S to G won't affect heat range. Perhaps best to sort out the carb before trying to fix the problem by altering plug heat ranges. My first thought is that is sounds rich..as you were speculating. If it's rich you would have an easier time starting when it's cold, but when the bike heats up that same mixture would be too rich.