Dellorto DRLA question

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Spike Jones
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Joined: Tue Apr 08, 2008 2:19 pm
Location: Texas South Plains

Dellorto DRLA question

#1 Post by Spike Jones »

Re: Dellorto DRLA carbs
I have read that screwing in the air bypass screws opens them, allowing more air to bypass the butterflies.
How many turns out from bottom are they completely closed?
I can't seem to find any definitive answer, even in the Tomlinson book. :?:
Spike Jones
'58 Cab

Tim Berardelli
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Re: Dellorto DRLA question

#2 Post by Tim Berardelli »

Spike,

Turning the screws IN not OUT reduces air flow- you will be able to see the change if you have an air flow meter on top of the carb. throat you are adjusting. The systems is the same as found on Weber carbs, only the adjustment screw is not exposed outside the carb. base and does not use a lock nut.

Spike Jones
356 Fan
Posts: 306
Joined: Tue Apr 08, 2008 2:19 pm
Location: Texas South Plains

Re: Dellorto DRLA question

#3 Post by Spike Jones »

Tim, thanks for the response.
In the Tomlinson book, re : air bypass screws, I read " Opening the screw, turning it clockwise, increases the flow of air around the butterfly."
Is that incorrect? You seem to be saying the opposite. I'm confused. I also see the term "base setting" referred to with no explanation of where the setting is or how to achieve it.
Spike Jones
'58 Cab

Tim Berardelli
356 Fan
Posts: 665
Joined: Wed Apr 30, 2008 7:02 am
Location: Washington DC Area

Re: Dellorto DRLA question

#4 Post by Tim Berardelli »

Spike,

Easy to check-with the engine up to temp., put an air flow meter on any carb. throat- try and turn the bypass screw in (CW)-if it moves note the change in air flow on your meter-if fully seated when you begin turn the adj. screw out (CCW) and note the change.

Spike Jones
356 Fan
Posts: 306
Joined: Tue Apr 08, 2008 2:19 pm
Location: Texas South Plains

Re: Dellorto DRLA question

#5 Post by Spike Jones »

Sounds too logical, but we'll try it.

Thanks again
Spike Jones
'58 Cab

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