Re-Jetting Carburretors and changing engine to asperated for MOT

17th March 2010
The jetting of the Dellorto DRLA 40 Carburetors was fairly simple as the main jets are easily accessible from the top of the carburetors. and can be located by removing the air cleaners if fitted.

Unfortunately one of my main jets was stuck in the left carburetor . I could remove the air corrector from the carburetor but this left the emulsion tube and main jet stuck inside the carburetor. Furthermore one of the idle jet holders in the other carburetor the idle jet holder had verdi-grease on it. I decided to remove the carburetors and do a basic clean them up.

Stuck jet stacks can be a really problem to remove and great care is required to dislodge them. I filled the jet up with carburetor cleaner and found a small screw driver that would fit snugly in the emulsion tube. I gently rocked this in its seat from site to side. Eventually this gentle movement freed the emulsion tube and main jet. This was also covered in Verdi-grease. I cleaned off the verdi-grease and replaced the jets. I had ordered new fuel line and was waiting for this to arrive so that they could be refitted.

For the 1600 I went for:
9164.4 emulsions
112 mains.
180 air.
52 idle.

MOT time looming again

28 Feb 2010
The turbo buggy was becoming a slow process again as the realisation of the fact that the engine would not fit was a major blow as I had two major hurdles to overcome before the engine could go back in.

I decided that the best option was to take the turbo modifications off and revert to the 1600 basic engine in an attempt to run the engine in and get the MOT ticket . This was annoying as I new it was going to be another year of modifications. The major of these was a 3" body lift kit. I had been asking on several websites about the Bugpack kit but had been told that it was not as strong as a box section version. This meant that I had to have one made which would take some time to be fabricated. The good thing was at least my engine would be run in prior to the fitment of the turbo. It would also allow me to fit an electric fuel pump in front of fitting the turbo and check the systems work.

After reading a for sale post open eBay for a turbo Dell IDF carburetor I was surprised to see that if it was jetted back it would still function well as an aspirated version. With this in mind I decided I needed some new jets 28 vents, 9164.4 emulsions, 112 mains, 180 air, 52 idle. Fortunately my trust box of Dell tuning parts came up with most of the parts including the 52 idle jets but no 112 main jets. I started removing the turbo and exhaust from the engine and started to clean up and paint the previous exhaust I had used. the Carplan VHT paint was fantastic and bought the exhaust up like new. I hoped the new main jets could be located soon but would have to wait to source the parts. I found the new jets and continued to paint up the rusty exhaust. There would be some fitting issues possibly with the braketry but this would have to be sorted out after fitting. I hoped my new body mount would not be obstructing the old exhaust as it had been modeled to fit the drag exhaust. The fitting or changing of the exhaust from the turbo collector was undead a problem The no3 cylinder J tube was tight on the Heavy Duty Gearbox cradle and at first would not move. This eventually came free with the help of a friend John and the next problem was also evident. The new body support I had built was right in line with this new exhaust. I decided as as I was trying to have the 3" body lift kit made that this would have to change anyway as the whole body would rise 3" making the support arms the wrong length and angle. I removed them and refitted the drag link bars that now fitted. The bracket that held the oil filter was also directly in the path of the new exhaust. I made a new bracket that placed the external oil filter lower by using the old one i had manufactured as a template. The resulting bracket can be seen left. With the bracket made I could now refit the oil filter . I now needed to start work on the electronics to run my electric fuel pump. The electric design had been given to me by a VIZI member and I was intended to fit the new electric pump I had bought with a return flow to the tank ready for the turbo to go back in.

Dellorto DRLA40 carburetor non linkage return Issue.

27th October 2009
I had been noticing that my left carburetor was not returning to its stop since the rebuild process for the turbo seals whilst I was installing the new linkage kit. I was not entirely happy with the shaft when I put it back during the turbo rebuild and it appeared now I was right and the non return issue on my left carburetor was due to the spindle being bent. This resulted in the shaft rubbing in the carburetor. The only solution I found was to renew the shaft. Its quite tricky to do as you need to be comfortable with stripping the carburetor. The best way to do this is to photograph each stage if you haven done this before. You need to remove the paraphernalia on the top of the carburetor Air cleaners or trumpets. There are 4 screws on the op of the carburetor that hold the float cover on. If you remove these you will most definitely need a new gasket so don't skimp. With the top loose gently remove the top carefully as the float is underneath put these items somewhere safe in a backing tray.

Next remove the two screws either side of the carburetor this locate the spray bar it only goes in one way make sure when you take it out you recognise this. The screw is usually held with a locking nut. With this out the chokes can be removed sometimes these grow in here and will need carburetor cleaner to get the loose and maybe a soft tap. Again look at the orientation how the come out. Record everything

Next remove the nuts on the spindle and remove the control arms these must go on the right way round. Its important that you note which side the longest part of the spindle protrudes from it is imperative it is put back exactly the same for your linkage kit to work.

Next turn the carburetor over you should see the two butterfly valves two of them in each carburetor throat they are held with two brass screws which are peened over on the back so they don't fall out. Once you have the screws out you can twist the spindle vertically so that the butterfly can be removed by sliding them out of the slot. Repeat 4 times noting which way round the butterflies come out and which hole and which way up they will only come out one side. With the butterflies out Put one of the spindle nuts back on the spindle and use a soft rubber mallet like a camping one to remove it. The bearing may come out too don't worry. Use a thin screwdriver to drive it all the way out. You can knock out the bearings whilst your there and remove the plastic covers with a small watchmakers screwdriver and grease the bearings replace the plastic cover.

Put it back is same as dismantling it. Make sure the new shafts the right way round (imperative) I used a couple of sockets or tubing at ether end of the spindle to drive the bearings into their correct seating.

The butterflies can only be inserted from one side of the spindle they wond go in from the other side. Use 4 new brass screws for the butterflies. Peen them from the other side once their tightened by putting a screwdriver across the back of them and tapping the screwdriver with a light hammer ensure you support the shaft underneath with something so as to not bend it again.

Now I did this I now need no springs at all. A carburetor schematic can be found on the www.dellorto.co.uk web site you can buy parts here or on ebay.