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Dellorto jetting?

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Old Hutcho Officially Full-On Dubber

281 posts · joined Jan 2004 ·

#933519
Just picked up a pair of 36 dellorto DRLA carbs. Going to run them on a 1916, stock bottom end, Engle 100 cam, Bandido heads (Next size up from stock valves). Looking for driveability on the street. I am using twin Kads at the moment and they will take the engine to almost 6000 rpm, but it runs out of breath about there, and that is plenty enough revs for an old guy like me.

I am going to pull the Dells apart and rebuild them. Can anybody point me in the right direction where I can research the jetting that I will need to get me in the ball park for these carbs please.

Any info on line??

regards

Old Hutcho

Bizarre Moderator The artist formerly known as blue74l

12,789 posts · joined Aug 2002 ·

#933532
the Dellorto Supeformance book is a great place to start

http://www.cbperformance.com/ProductDetails.asp?ProductCode=0101

Next best place is AC.net
http://www.aircooled.net/vw-carburetors-jetting-102/

Jon Connolly od AC.net articles are mainly about Weber carbs
Same same - but different

Idles are generally 2 sizes bigger and totally differ E tubes
Vents, mains and airs work the same

Another good place is Alfa1750's web site

http://cgi3.ebay.com/ws/eBayISAPI.dll?ViewUserPage&userid=alfa1750


Whatever - this is pretty much my recomendation

DRLA 36
Vent 32;
Main 132;
E tube 9164.2;
Air 180;
Idle 58;
pump 33;
needle 150
Futue te ipsum!!!

Bizarre Moderator The artist formerly known as blue74l

12,789 posts · joined Aug 2002 ·

#933533
That all said - I would be amazed if you will get more revs bast 6,000 with that cam
Futue te ipsum!!!

matberry Moderator Go hard or go home

8,114 posts · joined Mar 2006 ·

#933563
^^^^ 👍👍👍
Matt Berry Motorsports...air cooled advice, repairs and mods Ph 0408 704 662
OFF-ROAD,CIRCUIT,DRAG,STREET,ENDURANCE

vwo60 Veteran Volks Folk

2,036 posts · joined Feb 2007 ·

#933579
Buy the CB tech book on delorto's, there will assist you with the tunning across the board, cover's how to set them up, float height, how to work out the jetting and choke size for the initial set up and any issues with the tunning once it is running. I have a set of 48 MM delortos on a 2276 and are very happy with them, they will be a big step up from the kadrons.

Old Hutcho Officially Full-On Dubber

281 posts · joined Jan 2004 ·

#933585
🤘

Thanks to the other guys for the very useful information.


regards

Old Hutcho

Old Hutcho Officially Full-On Dubber

281 posts · joined Jan 2004 ·

#933939
OK, did the strip down and clean jup and this is what Ive actually got.

30mm venturis.
Mains 140
Emulsion tubes 9164.2
Airs 195
Idels 55.

I dont know a hell of a lot about these things but it seems to be an odd mix? Someoby please correct me if I am wrong and feel free to offer advice. I have to buys some new jets anyhway because I am not 100% convinced some of these havent been drilled.


regards

Old Hutcho

Bizarre Moderator The artist formerly known as blue74l

12,789 posts · joined Aug 2002 ·

#933945
Rough rule of thumb is vents x 4.2 = mains
My guess is a 125 main is needed or 34 vents

I would go for 34 vents and keep the mains

I reckon the idles would be right to tight
40's take 60 or 65's

The E tubes are right

The airs "could" be too big - but I would put it on a dyno before changing
Futue te ipsum!!!

hellbugged 48's and straight cuts

5,080 posts · joined Apr 2003 ·

#933947
Yes the emulsion tubes are correct

I'd look for 34mm ventures....140 + mains to drive nice up to the 6000 rpm

If you stick with the 30 vents, look for 125-130 mains, it will still be a nice drive with these, but have more bottom end driveability and not such a burst up top

Definitely get 180 airs and make sure they're the tall ones... 195 is too big

The 55 idles should be okay, although 60's might be called for

I'd just get a range of main jets from eBay (alfa??? As above) and as said the
dellorto book is a must have

Plenty of jets, idles and airs here if you need a loan

matberry Moderator Go hard or go home

8,114 posts · joined Mar 2006 ·

#933948
^^ yep, bigger vents or no rev 🙂
Matt Berry Motorsports...air cooled advice, repairs and mods Ph 0408 704 662
OFF-ROAD,CIRCUIT,DRAG,STREET,ENDURANCE