I bought two motorcycles, an 86 and a 93 ninja 250. I took parts off of the 86 to make the 93 run. I rebuilt the 93 engine and have it completed except for one little problem. I had to use the carbs off of the 86, which are a larger size. I had a professional clean, install, and sync the carbs and when he did I believe he used the jets out of the 93 carbs and put them into the 86 carbs. During the summer the bike wouldn't idle and it would always die, unless i set the idle to 5,000+ rpm, but as long as i gave it a little gas it would run fine. Now that it is winter I use the choke to start it up like normal and when it warms up and i take the choke off, it idles fine at low rpm. I was wondering would would cause this. Could the i need a smaller pilot jet, perhaps the original that came in the carbs, to offset the the change in air temperature?