KDXRIDER.NET

So I have a 1985 KDX 200. Currently in the process of restoring it. According to previous owner the original 32mm Mikuni Carb (VM32SS) was somehow destroyed. in a crash maybe? And he replaced it with a carb from a 1986 KDX 200. And it never ran good since then. Luckily my Clymers manual shows me proper carbs for both years, and the proper specs/jets of each carb. So if the previous owner was correct, he installed a VM34SS, which is a 34mm Mikuni. The correct jetting of this carb is a 300 main, and a 35 pilot. However, the correct jetting of the original 32mm carb is 260 main, and 40 pilot.

Should I install the correct jetting of the 32mm carb into the 34mm carb? Or should I install the correct jetting of the 34mm (considering I don't know what jets are currently in it). Or should I buy a 32mm Mikuni off of ebay (slightly different model number) and install the correct jets into that?

I'd install the jets the 34 calls for and go from there.

Check that the slide ID cutaway & needle ID are the same in the 32mm as they are in the 34mm ....
Run the stock jets , needle & slide that are in the 32mm & use them in the 34mm & go from there....given the age of theses carbs you may find that they may need replacing with new due to general age, wear & tear..... You can still buy new carbs so it shouldn't be a problem just a matter of cost.