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Triple Dellortos ready to install

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yes warren thats definatley one thing is i noticed there is little difference when i wind the mixture screw out, as i understand it the procedure is

1: make sure linkages are operating corectly - Done

2: balance the carbys with air metre - Done

3: set the mixture for each carby by letting the motor idle and then richening each carby until the revs of the motor drop slightly and then its Qtr turn back to lean. - NO GO

 

I havent been able to achieve step No.3 yet. I bought new softmounts aswell as a new manifold to try and elimate air leaks. As a rule i dont gasket clue the intake manifold on so i dont have to get a new gasket every time i take the inlet manifold off. I shall do it tomorrow and see how it goes. probably where its leaking  :-[

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Much better day today, took the manifold off, put some goo on and bingo i can tune it and the popping has stopped. Took it for a quick run and no hesitation anywhere. I should have know better about tuning these carbs after playing with little nitro cars for awhile where air leaks a critical. Thanks for your help guys :) much appreciated.

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Very Good, glad to hear it is smooth.Now you can start experimenting with different jets and emulsion tubes to try and get the best mixture and throttle response.

 

Warren

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Hi Warren,

 

Yer give me a call Tuesday if you like. Drop by and check out the big hole (soon to be garage) I have in the back.

 

Good to hear you've made progress Glen. I keep hearing about air leaks with tripples and the problems they cause. I've been pretty lucky on that front.

 

Sachi, hold on to the 46's for as long as you need to.

 

Cheers,

Sulio

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Glen,

 

I take it the carbs are working well now since you found the air leak. Are these the final settings and how do you feel it's running now? I copied and pasted from your post a few back, I just want to update that spread sheet I've got running.

 

L26

DHLA40

Chokes 30mm

Idle holder/emmulsion tube 7850.1

main jets 132

air correctors 180

emmulsion tubes 7772.5

idle jets 45

air bleeds dont need to be restricted on my carbys

Acc pump jets 40

 

Oh and Scoota, I've got your final jetting on you 45's but can't find the 40's any where?

 

Cheers,

Sulio

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Hi sulio, there will do for me time being but if it was my permant setup then i wouldnt recomend it as there is some funny hesitation going on like its flooding but it does clear. They are running much better since i put the manifold back on but i wouldnt say this combination is all that great either.

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Well Glen I'm not sure when you're back at work but I'll be stuck in the office next week. If you're still on holidays drop in during the day and we can pull out all my jets etc and try the lot in your carbs. Just call me if your free I'm in Notting Hill.

 

Cheers,

Sulio

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Sulio, i have got your 46 idle jets. Unfortunately the setup Warren and i tested (and worked so beautifully when testing) wasn't so hot on the way home.

 

emmulsion tubes 7772.5

 

 

Sach

 

I tried the 7772.4 Emulsion tubes and it was Shite. The 7772.5's are towards the rich end of the scale. I went back to the 7772.10 which is the leanest you can get, they work great and are the suggested starting point.

The 7772.4's came with the new 45MM Dellortos i got but it was setup for rally which made it great for 3000rpm upwards but not for the lower half of the rev range.

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Hey Glen,

            A bit off topic but I saw your mention of air leaks on nitro RC cars. I am having problems getting mine to run properly at the mom. Could you please PM me the areas you need to look at when the car is not running properly. Thanks.

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I've started to have a play with my triple dellortos (emission type), mainly to see what bits I have, and what I need. Where does everyone buy their dellorto parts? I've found the UK dellorto website, and a US ebay shop that seem alright range/price wise.

 

Anyway, one of the my carbs has no main or idle jet assemblies. The other two have 145 mains with 7772.10 emulsion tubes and 240 air correctors, and 55 idles. All three have 32mm chokes and 7848.3 axillary venturies. I figure for a start, i'll set the third carb up the same as the other two. Jets seem pretty cheap, so I might grab some idles either side of the 55, and some lower mains (based on Sulio's spreadsheet).

 

I've know fuel pressure is important, is it worth getting one of those variable regulators you see on ebay every now and then? Or should I be able to get the pressure about right with just a restricted fuel return?

 

I'll also need softmounts, and a new manifold gasket. The carbs came with a new one, but it was broken in transit. Are these off-the-shelf, or should I take my broken one in to a exhaust shop/mechanic to get a new one made from the sample?

 

With the idle jet air corrector, am I right in thinking the reduction from 2.0mm to 0.9mmis done with a small tube that down the centre of the idle jet holders? Can someone get me some dimensions on these?

 

Wow that turned into a lot of questions, should get me started... I'm in no rush to get these done (the Des Hammill book is very helpful), and it may be worth while waiting until after I get my exhaust upgraded.

 

Oh, and I should add they're DHLA40's and I'm running a stock L28.

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40mm Dellortos are most commonly ex Alfa Romeo. These carbies work fine on L series engines but require a modification to the idle circuit. Without this mod' the engine will 'hunt' under light load and at cruise. I some regards these carbies are better than Webers in fact my race car Built in 1973 used 3 x 50mm Dellortos producing 295 BHP and 244 Ft Lbs torque from 2700cc's.

 

Cheers

 

Gordon Dobie

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