How to tune a 2lt

[Colin Edwards]

Hi Joe,
The choke or main venturi (depending on which school you went to) is held in place by the auxiliary venturi.  The auxiliary venturi has to come out first.  On the side of each barrel is a lock nutted grub screw - pretty well in line with the delivery nozzle.  A little bit upstream of the mid way point along the barrel  This grub screw is about 5mm in diameter and features a flat blade screwdriver slot.  The locknut must be loosend first.  Then the grub screw can be removed with a flat blade driver.  The grub screw features a pointed end.  This point engages a dimple machined into the outer wall of the auxiliary venturi.  Once the pointed end of the screw is clear of the dimple the auxiliary venturi can be pulled out.  Then the main venturi or choke can be pulled out with you finger.

When reversing the process DO NOT screw in the grub screw tightly.  It only needs to be very lightly nipped up.  The lock nut should then be done up firmly while preventing the grub screw from going in any deeper. A little dab of low strength loctite should be applied to the underneath of the locknut before tightening. 

[joestram]

Hi Bonno and Colin, thanks for the info!

My kids decided to have a lunchtime sleep today so I ducked outside to have a bit of a tinker.

I was able to locate the screw and Nut and removed them, however, the damn things still wouldn't come out!

I have posted a picture.

Am I missing anything?

I didn't want to apply too much force/pressure to avoid damage but wanted to double check I wasn't missing a screw that needed to be loosened.

Thanks again everyone!





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[Colin Edwards]

Hi Joe,
Try repeated applications of a good penetrant for a couple of days.  Leave the carbies standing upright as in your second photo.  Squirt some penetrant into the grub screw holes as well. 
Grab the wifes hairdryer and heat up from the outside just one barrel at a time.  We want the carby body to expand away from the auxiliary venturi.  If you apply heat for too long the auxiliary venturi will expand as much as the carby body.  We dont want that. 
The auxiliary venturi is a very close tolerance fit in the bore of the carby body.  I hope moisture hasn't got in there and started oxidation!

[bonno]

Sounds like Colin has had to do this several times in the past. I suggest that the possible cause for difficulty, is the tendency to over tighten the lock screw holding auxiliary venturi (refer to Part 2 video).

[Colin Edwards]

I don't think its possible to install the Dellorto auxiliary venturies arse about.  Locating tabs on the venturies are provided at about 1:30 on the l.h.s barrel and 10:30 on the r.h.s barrel.   These tabs locate in recesses provided in the carby air box / plenum mounting flange. 

I however don't recall these tabs being on every Dellorto I've played with.  if you put the auxiliary venturi in arse about and looked into the locating grub screw hole you wouldn't see the locating dimple. 

The Dellorto DHLA and Weber DCOE are both works of art and certainly not for the faint hearted or ham fisted!!

[joestram]

Thanks again for the replies Colin and Bonno.

Colin - what type of penetrant do you recommend? Will carby cleaner suffice or wd40?

I hope they aren't oxidised either!!

Joe


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[Neil Choi]

As a Guru showed me, INOX is really really good.  Get some Joe.

[joestram]

Thanks Neil!!


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[Colin Edwards]

Hi Joe,

I've heard good reports about INOX, however never used it myself.  I usually use Penetrene (from Blackwoods) or a 50:50 cocktail of Acetone (from Bunnings) and auto transmission fluid / power steering fluid.  Its curious that Penetrene is the same colour, smell and consistency as the above brew!

CRC carby cleaner is great stuff but very aggressive.  Its usually my weapon of choice if brake cleaner isn't up to the job.  Both are great for cleaning but not as penetrants - they evaporate too quickly.

You may however need to spray carby cleaner onto the inner surface of the auxiliary venturi to cool / shrink it while heating / expanding the carby body with a hair dryer.  Don't let the carby cleaner come into contact with the rubber gaskets!

[carlo rossi]

sorry guys been in italy
and i have to admit i havent been looking at my computer
but it seems you are in good hands
as they said clean clean and then clean
but it looks like it had a service of sorts
A truely amazing piece of work the dellorto /weber and solex
not to
upset anyone
so I recommend to  the start with  34mm chokes
158 ( 155 -160) mains 210 air corrector  f8 emulsion
and if you can accelerator jet 40 not overly important this one

[Colin Edwards]

sorry guys been in italy
and i have to admit i havent been looking at my computer
but it seems you are in good hands
as they said clean clean and then clean
but it looks like it had a service of sorts
A truely amazing piece of work the dellorto /weber and solex
not to
upset anyone
so I recommend to  the start with  34mm chokes
158 ( 155 -160) mains 210 air corrector  f8 emulsion
and if you can accelerator jet 40 not overly important this one

Will the Weber F8 emulsion tube actually link between a Dellorto air corrector and main jet and work?

[carlo rossi]

no what I meant to say is 7772.8
but as the original sequence of 7772 is for all generally just the last number is quoted
sorry been in europe for last 5 weeks
hows it going Joe

[carlo rossi]

well Joe its been 1, 1/2 years of tuning have you finished the tune up

[joestram]

Hi Everyone,

Sorry it has been a while since my last post.

I had some personal matters that took priority, however, now have time to get this thing started again.

The Chokes came though, however, I was never able to get the original ones out.

I replaced all the jets and tried to give the carbs a quick clean and replaced the O rings etc.

I have started to bolt the carbs back on and am finding that I have lost a few screws and nuts so I am on the hunt for these.

In the mean time, I have just moved house and I need to arrange the car to be moved so if anyone has a trailer please let me know - happy to pay for your time

I'll keep everyone posted on the tune

Joe

[bonno]

Happy New Year Joe
I am pretty sure a local fellow Alfisti  will be able to help with moving the Alfetta to the new location. If not, try your local tilt trailer guy who would be able to provide this service at a reasonable fee. With regards to the carburettors, the loss of some parts and the inability to remove chokes, may I suggest you get onto carby  specialist in Melbourne who will be able to service them off the vehicle (you remove and re-install then adjust). Provide details of the cams fitted to the vehicle as this will assist in jetting and choking (all covered in this thread so a copy of the post would assist).
cheers
bonno