Adjusting Idle air mix on CV with backing plate installed.
#1
Adjusting Idle air mix on CV with backing plate installed.
I put bigger jets in my CV because it was danger lean after installing drag pipes in place of the stock exhaust on my 99 Night Train. I drilled the vacuum slider thingy and added the spacer to the needle doojigger and clipped a coil off of the slider return spring.
Install carb and bike runs great. Excellent throttle response and pulls like a freight train. Since I absolutely cannot leave well enough alone, I must find the sweet spot on the idle air mix. BUT, with the stock backing plate ( plate is a misnomer as this is made of some sort of plastic and "plate" usually refers to something more substantial). Without the plate installed there is nothing to hold the carburetor in place other than the friction of the rubber ring gasket.
So, The only way that I see to adjust the idle air mix is to remove the plate, make an adjustment, reinstall the plate, start the motor and see if it runs well on the new setting. That is obnoxiously inefficient and I reject the idea that this is a valid solution.
What am I missing?
As an aside, I did remove the plate, unscrewed the idle air mix 1/6th of a turn "fatter" and buttoned everything up. On my way home I noticed an improvement in throttle response and it "seemed" to pull better. The initial adjustment after making the mods was 2 full turns out from zero.
eta: I have filled the fuel tank 3 times since putting Omega on the road. I am averaging 39.6 MPG.
eta2: When I first purchased this motorcycle, I had to use the enricher to get it to start and run. Once warm I could release the enricher and it would idle as usual. Since I have installed bigger jets (48 Idle and 185 main), I cannot use the enricher at all to start the motor. The new procedure it to twist the throttle about 1/8th of a turn, hit the starter button and it roars to life. I open the enricher about 1/4th and let the motor run for a minute. After that I close the enricher and it idles properly.
Install carb and bike runs great. Excellent throttle response and pulls like a freight train. Since I absolutely cannot leave well enough alone, I must find the sweet spot on the idle air mix. BUT, with the stock backing plate ( plate is a misnomer as this is made of some sort of plastic and "plate" usually refers to something more substantial). Without the plate installed there is nothing to hold the carburetor in place other than the friction of the rubber ring gasket.
So, The only way that I see to adjust the idle air mix is to remove the plate, make an adjustment, reinstall the plate, start the motor and see if it runs well on the new setting. That is obnoxiously inefficient and I reject the idea that this is a valid solution.
What am I missing?
As an aside, I did remove the plate, unscrewed the idle air mix 1/6th of a turn "fatter" and buttoned everything up. On my way home I noticed an improvement in throttle response and it "seemed" to pull better. The initial adjustment after making the mods was 2 full turns out from zero.
eta: I have filled the fuel tank 3 times since putting Omega on the road. I am averaging 39.6 MPG.
eta2: When I first purchased this motorcycle, I had to use the enricher to get it to start and run. Once warm I could release the enricher and it would idle as usual. Since I have installed bigger jets (48 Idle and 185 main), I cannot use the enricher at all to start the motor. The new procedure it to twist the throttle about 1/8th of a turn, hit the starter button and it roars to life. I open the enricher about 1/4th and let the motor run for a minute. After that I close the enricher and it idles properly.
Last edited by Hebrew Battle Rifle; 06-26-2016 at 12:18 AM.
#3
I had this problem too. You have two options. Buy a backing plate just to use for adjustment or do it with nothing attached. I used a stock one and cut the entire bottom off. I ended at 2.5 turns out. eBay has them cheap enough. I tossed my hacked one if I still had it id give it to you. Removing the entire airbox to turn the screw is a pain. They do sell ezjust mixture screws but for something you'll only adjust once it's pricey
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Hebrew Battle Rifle (06-26-2016)
#4
I had this problem too. You have two options. Buy a backing plate just to use for adjustment or do it with nothing attached. I used a stock one and cut the entire bottom off. I ended at 2.5 turns out. eBay has them cheap enough. I tossed my hacked one if I still had it id give it to you. Removing the entire airbox to turn the screw is a pain. They do sell ezjust mixture screws but for something you'll only adjust once it's pricey
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#8
But I do like the idea of cutting up a spare one for tuning purposes. YD
#10
I would like to know how it works for you. I am in the process of changing out from butterfly to cv carb and am using a stock backing plate and round air cleaner cover. I like the look of the stock setup much better than other cheesy crap. But there is no way to get to the easy just cv performance idle adjust screw. If it works I will buy a cv carb support bracket.