I have just aquired a DHLA 48mm dellorto sidedraft. It is used, and I rebuilt it, going through it completely. I replaced all gaskets and o-rings, and upon installation, noticed it leaks fuel out of the choke. I have been trying to figure out why it would do that, but so far have been unsucessful.

I did notice that the plastic cap that covers the emulsion tubes and the breather holes for the choke seemed to be a bit warped, and figured maybe that was it. So as an experiment, I made a thick peice of aluminum plate to cover the emulsion tubes and left the choke side wide open, to see if the fuel was maybe leaking from the emulsion tube part instead, but this did not solve the problem.

The only thing that comes to mind that could be the problem is when I was rebuilding the carb, and comparing it to a teardown that I printed out of it, I found no pump jet weights over that ball bearings (they're supposed to be under the two little brass caps next to the starter emulsion tube). Could this have something to do with it? I know I found the teardown from a VW designated site, so I am wondering if this is one of the things that RB changed for the RX7's. anyone know?

 

CHECK YOUR FLOAT LEVEL , AND YOUR FUEL PRESSURE , 3 PSI IS PERFECT FOR DEL. SIDEDRAFTS

 

+1 to check float level and fuel pressure. I use 2.25psi.

RB did not have pump jet weights in theri dellorto kit. Every RB dellorto I've rebuilt did not have them. I tried two different weights for grins and ended up removing them; drove better w/o.

 

[+1 to check float level and fuel pressure. I use 2.25psi.

RB did not have pump jet weights in theri dellorto kit. Every RB dellorto I've rebuilt did not have them. I tried two different weights for grins and ended up removing them; drove better w/o.
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Thank you so much. That was something that has been bothering me for a while. The guys at Racing Beat didn't have a clue as to whether that was something that they had modded for the RX's since they had thrown out the specs something like ten years ago or so.... I will def try lowering the fuel pressure.

 

Had the same problem with a Mikuni I rebuilt, they like 4.5 psi. At 12 psi, fuel pours out of the venturi, even on a fresh rebuild, at 6 psi, it only dribbles, lol.

 

I just obtained a 48 DHLA myself (waiting at home, only three more weeks!). Where did you buy your rebuild kit? I found a VW site that has the kits but I am not sure if they will have what I need for a rotary application. Also, you can try this site for diagrams/info on rotary prepped Dell'Ortos: http://www.gruntled.com/Dellorto/

While I am at it, I have seen where people put in an aftermarket fuel pump for these carbs. I have also seen where the pressure put out by the '81-83 pumps is sufficient. Which is best?

Thanks for the help.

 

Here's a list of resources from Vintage Rotaries:

Racing Beat Weber jetting

Weber Carbs (was Redline Weber Carbs) - Replacement parts, jets, gaskets, etc.

CB Performance - With a customer base in the aircooled VW scene, they have access to TONS of Weber and Dellorto rebuild kits, jets, and throttle linkages (Also a good source for "Gorilla Studs" if you want to stud your hubs).

Pierce Manifolds - Another MASSIVE Weber dedicated webpage, EVERYTHING you would want to buy

Total Performance - Yet another online store that's stocked with carbs, jets, and nearly everything you could need.

Inglese Induction - A great write up on the weber hisory, streetability, tuneability of ther Weber

RotaryShack - Great outfit to support carb turbo hats and carburetor parts

The stock fuel pump is barely adequate for the stock Nikki when new. Pick up a low pressure carb pump that puts out around 70 gph. You will also need a good fpr and pressure gauge.

 

Thanks trochoid. I just joined over there, guess I need to spend more time on it.

 

I got my rebuild kit from CB Performance. Everything seemed to be in order, except for the needle and seat, and the carb to manifold gasket. The needle and seat had a smaller internal diameter than the one that was on the carb when I took it apart, so I got a bigger one from a guy named Cory Siler since I am using the carb for a blow through application, and I didn't want to hurt my fuel flow capabilities. I found him on a VW Forum called thesamba.com, but if you need to get anything from him you can just email him. He was super helpful to me through this project, and quick with return Emails. I had him make my turbo emulsion tubes, too. His email is corysvdub@yahoo.com if you want to give him a try. I wouldn't have been able to get as far as I have without him.