dingy Posted May 24, 2010 Author #26 Posted May 24, 2010 I got my beast running (Vmax cams and springs in 1300). I have the stock 1200 (1985) carbs on it at this time. The carbs have new diaphragms and have been cleaned within an inch of their life. Although it starts and idles great, when I blip the throttle it hangs before returning to idle. This appears to be a lean condition. How did you decide on 140 main jets? (stock is 117.5) Why did you also add spacers to your needles? I was at .072" on needles. I was getting a nasty hesitation if I would be at about a steady 6,000 rpm and crack throttle wide open. Red line is around 8,500, and I have hit 9,000 a couple of times. Reset needles to .102" and that got rid of hesitation at 6,000. I also backed the mixture screws out another half turn. (about 3 turns now). The roughness I was having at 3,000 cleared up quite a bit with the mixture screw. It was somewhat rough at a steady 3,000 before. For the most part it isn't bad. I am considering pulling carbs off and trying a larger main to see what that does to it. I've got #140's in it now. Used that size upon Squeeze's learned opinion as to a size to start with. Reason I am thinking about larger mains is Vmax's are running #150's, plus they are dumping even more fuel in when the V-boost kicks in. I have a hundred more CC's than a Max, but no v-boost. Squeeze wants me to get an air/fuel reading but I don't have anyone around I know that can do that cheaply. Gas mileage is in high 30's for the most part, which I am satisfied with. I have on a stock set of mufflers that have all but the forward most baffle removed. I was hoping to get SkyDoc on it at MD, but that may not happen with his condition. I like a second opinion on how its running. Gary
GaryZ Posted May 24, 2010 #27 Posted May 24, 2010 I research the specs to compare the three bike carbs; VR1200 VR1300 Vmax 1200 Main Jet #117.5 #125 #150 Main Air Jet #65 ø2.0 ø2.0 Jet Needle 5GLZ37 5DZ3-1 5EZ43 Needle Jet X-6 Y-0 Y-0 Pilot Air Jet 1 #80 #80 #90 Pilot Air Jet 2 #180 #180 #170 It looks like Squeeze was right having you start with a #140 main jet. What does it take to replace the main jets?
dingy Posted May 24, 2010 Author #28 Posted May 24, 2010 (edited) I research the specs to compare the three bike carbs; VR1200 VR1300 Vmax 1200 Main Jet #117.5 #125 #150 Main Air Jet #65 ø2.0 ø2.0 Jet Needle 5GLZ37 5DZ3-1 5EZ43 Needle Jet X-6 Y-0 Y-0 Pilot Air Jet 1 #80 #80 #90 Pilot Air Jet 2 #180 #180 #170 It looks like Squeeze was right having you start with a #140 main jet. What does it take to replace the main jets? Pulling the carbs out of bike. Splitting carb rack in half. Taking float bowls off of each carb. Picture below of main jet, it is on the right side of picture. Also there is a diagram of the flow patterns in a Vmax carb which is very similar to Ventures. Gary Edited May 24, 2010 by dingy
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