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 Popping = too rich or too lean?
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Joined: Dec 2005
Posts: 50
Member
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OP
Member
Joined: Dec 2005
Posts: 50 |
Hi,
I've been reading around and some say to richen the idle screw, turn out, to stop popping.
Some say the bike is running too rich and therefore should turn the screw in.
I'm confused! as usual!
Bikes great, loads more power.
130's 42's and thruxton needles. Uni drop in, AI's removed.
3 turns out and its popping.
Is she too rich or too lean?
Please help,
Jon
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Re: Popping = too rich or too lean?
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Joined: Jan 2005
Posts: 3,753
Loquacious
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Loquacious
Joined: Jan 2005
Posts: 3,753 |
(Former)05 BA tbike pipes, ai removed, Freak, mikuni hsr 42's, 904, ported/polished head, 1mm oversized valves
NOW-2010 silver and black tbird
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Re: Popping = too rich or too lean?
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Joined: Aug 2005
Posts: 265
Adjunct
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Adjunct
Joined: Aug 2005
Posts: 265 |
Frank is right, Popping indicates a lean condition. The basic science behind it is that a lean mixture burns hotter, therefore when the exhaust valves open, the unburned fuel/air mixture is still hot enough to ignite in your exhaust manifold/pipes. A rich mixture, will burn cooler. Seems like it is backwards, but it is how it works.
Wendell
"Reality is for people who lack Imagination"
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Re: Popping = too rich or too lean?
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Joined: Jan 2005
Posts: 8,639 Likes: 3
Old Hand
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Old Hand
Joined: Jan 2005
Posts: 8,639 Likes: 3 |
Usually lean. Possibly slightly rich combined with an air leak.
It is not likely to ever happen with the electromagical ignition system on these bikes, but a combination of a low density mixture (closed throttle deceleration) and lots of ignition advance will cause popping too. Anyone old enough to remember the pre-49 Fords with the vacuum brake distributer?
Let's hope there's intelligent life somewhere in space 'cause it's buggar all down here. -- Monte Python
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Re: Popping = too rich or too lean?
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Joined: Oct 2005
Posts: 312
Adjunct
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Adjunct
Joined: Oct 2005
Posts: 312 |
splodge,
I have thruxton needles as well and couldnt' stop the popping until I put 2 shims on them. After that, I had no problem setting the mixture screws correctly. I have a Freak installed and have 45 pilots, so our setup is a bit different, but the shims might help you.
'05 America - Tec 2-1 (from a Thruxton)/ 4 pot caliper/ Kurt's Rearsets /
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Re: Popping = too rich or too lean?
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Joined: Jan 2005
Posts: 655
Adjunct
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Adjunct
Joined: Jan 2005
Posts: 655 |
Under throttle, pops out carb = lean, pops out pipes = rich.
Slowing down, pops out carb = get new valves, pops out pipes = idle/pilot circuit.
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