Topica Loopframe_Guzzi Archive


Subject: RE: carbs

Author: sund-@olywa.net

Date: Jul 4, 2001, 1:42 PM

Post ID: 1707368829


Slide carbs give positive control of the mixture at any throttle position.
The combination of slide cut-angle, needle taper, needle height, and
needle jet make it possible to get the right mix at any throttle position.

Butterfly carbs only control the butterfly opening as the throttle position
changes. The mix is dependent on other factors that are harder to change
and control.

Yamaha used a hybrid Mikuni carb that had both butterflies and slides.
There was a vacuum controlled diaphragm on top where the cable
would normally enter to raise the slide, and then there was a butterfly
at the narrow end of the horn. The butterfly position caused a given
amount of vacuum that would raise the slide the right amount for the
engine load and rpm. It made the old Yam 650 twins very nice to operate.
I actually have a pair of these that I was always going to try to adapt to
the 700.

BobG

 
Is there any particular advantage to using slide carbs versus butterfly
carbs? I have always wondered why all Guzzis use the slide type.
Ciao!
Chris in NC

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