OZZ240 Posted August 22, 2009 Share Posted August 22, 2009 The BIG Question is can I and is it ok to make a set of Triple Carbs from two sets of twins which are of the same size, manufacture and model type? I've been offered a made up set of triple 40mm Dellortos for $250 which I think is cheap. These will be going on a stock L28 for now with a mild cam and set of headers to come. The carbs are off either a 1.8 and/or 2liter Alfa motors which are very close bore, stroke and valve size to the L28, the carb specs are 40mm with 32 Venturs I'm guessing the will need to have a rebuild plus jetting changes to suit the L28. Is there anything I should look out for? Thanks Ian Quote Link to comment Share on other sites More sharing options...
Tony D Posted August 24, 2009 Share Posted August 24, 2009 Absolutely, I regularly took Toyota 18RG and 2TG Solexes and mated them to Tripple manifolds. The most you may have to get is a proper bellcrank for the applicable side of the carby to mate wit hthe tripple bellcranks and etc... But a fully made up set of 40's for $250... that's a steal. Have him send them down to me in Newcastle/Dora Creek if you don't snag them! LOL (working in the general area...) Quote Link to comment Share on other sites More sharing options...
OZZ240 Posted August 25, 2009 Author Share Posted August 25, 2009 Thanks for that will grab myself a bargain Quote Link to comment Share on other sites More sharing options...
PanzerAce Posted August 25, 2009 Share Posted August 25, 2009 should be good to go. Just make sure all the jetting is the same, and be sure to sync them. Quote Link to comment Share on other sites More sharing options...
brokebolt Posted August 25, 2009 Share Posted August 25, 2009 Is there anything I should look out for? Yes, you should look at the progression hole count and size, idle mixture screw type, and the idle air bleed type. Their are two types of both the last two and I don't know how many types of the first item. The first item is the progression holes, they are located under a slotted brass 'slug' (meaning it has a "-" {minus} on the head and uses the same type screw driver to remove it.) This slug is sometimes steel with a coating to prevent rust which may look gold-ish or at one time looked gold-ish in color and I have found is always a phillips head (meaning it has a "+" {plus} on the head and uses the same type screw driver to remove it). The 'slug' is easy to located in front of the idle mixture screw which is located toward the back side of the carb (where the butterflies are located on the carb body), on the top of the carb, located by the carb mounting surface to the manifold. Their are three bass things in a row on the carb. First is the accelerator pump jet holder the second is the brass slug and the third is the idle mixture screw. The hole count and size need to match. For example you may have a large hole and three smaller holes. I would not suggest you mix and match carbs of different progression holes, as it will effect the characteristics of the progression phase of the carb. Second their are two types of idle mixture screws. The first idle mixture screw is a fine thread if it is encased by the aluminum carb body. The idle mixture screw is recessed into the carb tower a bit. The other type is a course thread where the idle mixture screw is somewhat exposed and the tension spring is 100% exposed with no aluminum shroud around it. I guess you could mix and match these but I wouldn't suggest it, as the idle mixture may vary between the carbs. Third you need to make sure that they are either the non-adjustable air bleeds that have the air bleeds located in the carb body or the other type has the air bleeds on top of the idle jet like how Mikuni, Weber and others have done it. Locate the jet cover, usually black or orange plastic, sometimes aluminum, remove it, and pull the idle jet from the carb body. The idle jet (two per carb) is the smaller two of the four brass parts located under the cover. The other two are the main jet, E-tube and air corrections jet (or air bleed jet). Their are two ways to tell. First if their are numbers stamped on the side (like 7850.1), or second if you have two rows of holes drilled in the jet holder; one row above the threads and one below the threads, than you have the idle jet version, if not then you have the carb body version (no stamped numbers, and only a single row of holes drilled above the threads). The idle jet is located on the bottom of the idle jet holder on either version. The carb body idle air bleed vs. idle air bleed jet isn't an issue other than to make sure that you have three carbs that have the same type. If not, I do believe that the carb body is drilled slightly differently for it's passages and this may effect the idle characteristics of the two types of carbs. Not sure though, I have never mixed them before. I would not suggest it, as it may effect the idle and just off idle characteristics of the carb. If the tuning parts are not identical, no worries man, you can always pick them up from several sources, like VW performance shops and some still sell Dellorto parts. Dellorto DRLA and DHLA use many of the same parts. Auxiliary ventures maybe the hardest to source and cold start parts too. But you really don't need to use the cold start function for performance minded personnel. Happy motoring. Quote Link to comment Share on other sites More sharing options...
Drax240z Posted August 25, 2009 Share Posted August 25, 2009 Yes, you should look at the progression hole count and size, idle mixture screw type, and the idle air bleed type. Well put. This applies to Weber's as well. I've seen mismatched webers cause nothing but idle/low speed issues due to progression holes being different between them. Quote Link to comment Share on other sites More sharing options...
brokebolt Posted August 25, 2009 Share Posted August 25, 2009 This applies to Weber's as well. I've seen mismatched webers cause nothing but idle/low speed issues due to progression holes being different between them. I didn't know Weber did this as well. Good to know. I am no Weber expert so this helps out a bunch, I do dabble with them from time to time. And yes, I agree with Drax240z, he is absolutely correct about causing issues... Dirt (straw, crud, debris, etc.) will cause issues too, gotta keep them holes clean! Quote Link to comment Share on other sites More sharing options...
OZZ240 Posted August 26, 2009 Author Share Posted August 26, 2009 Thanks guys this is the info I was looking for and will check them thoroughly before buying Cheers Ian Quote Link to comment Share on other sites More sharing options...
PanzerAce Posted August 27, 2009 Share Posted August 27, 2009 Oh damn.....this thread just reminded me I'm syncing and re-tuning the idle on my mikunis on friday....not looking forward to that (looking forward to actually being able to idle though....) Quote Link to comment Share on other sites More sharing options...
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