by silkeysak » May 24, 2011 10:50 am
Hey Speed, I got the info you wanted. Some thing you want to keep in mind. The low and midrange orafices are not delivering fuel. They restrict air flow. The larger the orafice, the less fuel you get because more air (less vacuum) is created. That huge mid range orafice you have is causing a very lean (no gas) condition in your midrange by allowing too much air flow, and probably causing your lack of throttle responce. Less air flow bypassing through the low-mid orafices creates more vacuum on the hi (fuel jet) coming of the bowl. That jet is the only source of fuel. I have two sets of carbs. The big bores have #14 low, #20 mid, #65 hi. Carb # 397574. I checked the spechs, and these air the right orafices for these 1986 carbs. The throat is 1 5/8 diameter, the biggest they made. The other carbs are the mid size, and have #31 low, #47 mid, #65 hi. Again these are the right jets, but often low and mid orafices were changed to correct lean or rich idleing and midrange conditios. That is the main problem with the fixed jet carbs. Sending pics of the big bores. Hope it helps. Check you PM
Hey Speed, I got the info you wanted. Some thing you want to keep in mind. The low and midrange orafices are not delivering fuel. They restrict air flow. The larger the orafice, the less fuel you get because more air (less vacuum) is created. That huge mid range orafice you have is causing a very lean (no gas) condition in your midrange by allowing too much air flow, and probably causing your lack of throttle responce. Less air flow bypassing through the low-mid orafices creates more vacuum on the hi (fuel jet) coming of the bowl. That jet is the only source of fuel. I have two sets of carbs. The big bores have #14 low, #20 mid, #65 hi. Carb # 397574. I checked the spechs, and these air the right orafices for these 1986 carbs. The throat is 1 5/8 diameter, the biggest they made. The other carbs are the mid size, and have #31 low, #47 mid, #65 hi. Again these are the right jets, but often low and mid orafices were changed to correct lean or rich idleing and midrange conditios. That is the main problem with the fixed jet carbs. Sending pics of the big bores. Hope it helps. Check you PM
