24-04-21, 07:33 AM
The reason Ivan took the unusual step of enlarging the pilot circuit bypass holes was to allow more fuel to pass through them just off idle. In his testing, he found that turning the mixture screws out as far as they would go (about 5.5 turns) wasn't enough to give him the richer a/f ratio he wanted ... the size and placement of the holes was the limiting factor.
To check if Fazer carbs have been 'Ivanized' simply remove any carb top and look at the slide spring. If it has been cut at one end to shorten it, it will be obvious. If you go on to remove the slide and inspect the needle, you'll find that Ivan's needles have changes in taper that are visible to the eye. Stock needles are straight-edged along the whole length of the taper. If you remove the needle from the slide, you'll find that stock needles have SD-130 or SD-129 stamped around the top.
To check if Fazer carbs have been 'Ivanized' simply remove any carb top and look at the slide spring. If it has been cut at one end to shorten it, it will be obvious. If you go on to remove the slide and inspect the needle, you'll find that Ivan's needles have changes in taper that are visible to the eye. Stock needles are straight-edged along the whole length of the taper. If you remove the needle from the slide, you'll find that stock needles have SD-130 or SD-129 stamped around the top.