| carb question [message #138872] |
Sat, 13 August 2011 11:34  |
chasingsummer
Messages: 434
Registered: May 2011
Location: asheboro, nc
Karma: 0
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i see where trottle opens front flap, i see that thru linkage, once front flap is opened wide enough that there is a lever which moves which unlatches rear flap. i also see vacuum piece just forward of choke ( mine looks like original choke) it seems that this vacuum piece which gets vacuum from front of carb closes rear flapp, what i can not see is what opens rear flap, please assist my light bulb to burn ,
thanks bgk
brian
asheboro, nc
75 eleganza, 74 build
119k miles and counting,
DOG HOUSE
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| Re: carb question [message #138881 is a reply to message #138872] |
Sat, 13 August 2011 12:42  |
Craig Lechowicz
Messages: 541
Registered: October 2006
Location: Waterford, MI
Karma: 0
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Senior Member |
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The shaft on the rear air flap is offset. So, increasing air flow opens the rear flap. There is a small spring that closes the flap. The "vacuum piece" in front of the carb is the choke vacuum break. Its primary function is to open the choke a set amount on 1st startup. It's secondary function is to keep the secondary flap from opening too quickly with rapid throttle opening. With wide openings, the vacuum to hold the vacuum break pulled in goes away, and an orifice controls how fast it relaxes. Through the linkage, that prevents the rear air flap from opening too quickly. (especially if the windup spring is set too loose). If the rear secondaries open too quickly there will be a bog or sag in the throttle response.
Craig Lechowicz
'77 Kingsley, Waterford, MI
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