Setting DHLA Dell'Orto Dellorto Float / Fuel Level

[barker_001]

Question now moved to its own thread...

Edited March 27, 2012 by barker_001

[jeremyf]

Great info. If doing this without moving the top cover and inserting a rod down the main jet stack, I guess I need to use a figure other than 27mm as the floats will raise the level when in the fluid - i'm getting something like 21mm. What is the ultimate aim here? Is it to get the float level as close to the duct without spilling over?

 

I've also thought that you must fill the fuel chamber with the pump after taking out the main jets as this changes the level too.

 

This is all a sharp learning curve for me

 

thanks

 

Jeremy

[frustorto]

This would be the ultimate, being able to measure the fuel level with floats and everything in place. What would you do, make a dipstick that located on the top of the casting?

 

Does the 21mm correspond to 16.5-17mm?

[frustorto]

I had forgotten I had written the above. I meant 27mm and does it correspond to 16.5-17?

Anyway I had reset the float height to 17 and the measured the fuel depth. It was 31mm to the engine side of the jet tower, about 33mm on the other side.

Taking all the folds out of the float bracket, the float height was reduced by 3mm down to 14. This was definitely not what the manufacturer intended. The progression is a lot richer (now too rich) though and the fuel depth is probably now around 28mm.

It bothers me a bit, that I cant think of anything that would make the floats ride higher than when they were made.

[hammerDown]

New member here, and hi everyone!

 

Unless I missed something in the prior float setting/checking "steps"...when removing the top cover with float attached, the fuel level will NOT be the prior mentioned "27mm" but some 4-5 mm lower, as > the actual weight of the float 'floating' in the fuel raises its level in the bowl.

 

A prior question asked and not answered, (reguardless of which weight float used) is it 'ideal' to want the fuel just below the two vents in the bowl which would be 27mm and possibly trickling in thos two vents?

Or, during vehicle operation is it even more desired to have the fuel even a tad further below those two vents to prevent fuel-drip into the ventures?

 

Great site, and always enjoy learing something new, Ray

[ChrisV]

I have also a question... The 27mm measurement should be done on the idle jet side of the stack, or the main jet side ???

 

When the carburettors are flat, it is pretty straightforward, and it does not matter as you will have 27mm on both sides, but when you have angle the main jet side can have the 27mm but the idle jet side will be lower.

 

My question is this : Does the idle jet need to have contact with the fuel ? If it doesn't and the side of the idle jet is lower, let's say by 2 mm, will the vacuum work as it is supposed to or it will draw air as well making tuning impossible ?

[awolhmv]

I just put in a new float and still have the same problem.

Right rear carb barrel is very wet and is spraying fuel up and out when rev'd.

What would be the issue? 

[DaveNotSoSideways]

Had a nice delivery from Italy Rocky SRL. Good for Dellorto Parts.

[anthonyfca]

So this may be an old post, but it's been heaven sent for me; thanks. 

By all means move this somewhere if it doesn't belong in this thread. It's about the 0.5mm gap there is supposed to be between the actuating leaver and the accelerator pump "button" which is actually a pole attached to/part of the diaphragm.

Here's the image everyone and me have found impossible to emulate because the required space is inside the solid metal housing:

 

[anthonyfca]

it appears editing is restricted so I will continue here.

Having dismantled it all I found that if I press on the diaphragm from inside, it pushes on the actuating lever, so gently pushing this to the point where the pole meets the end of its travel, having also pushed the actuating lever away, there is 0.7mm of the actuating lever protruding upwards (all this is done upside down to keep the lever resting on the pole). At this point the gap between the lever and the pole is 0mm (zero) because they are touching. So add 0.5mm to the movement of the lever away from the pole and we have the 0.5mm clearance required in that manual extract (reputedly from legendary "the" "Dellorto manual". 

In other words when 1.2mm of the lever protrudes from the housing (downwards when all fitted), we have the 0.5mm gap at the diaphragm.

Problem is I found the adjuster nut on it's vertical thread, runs out of thread significantly before it can be wound far enough up the thread to give the actuating arm sufficient angle upwards necessary to expose any, let alone 1.2mm protruding below the diaphragm housing. 

I can add pics if that helps. 

So I am interested (not least if anyone is still here) if anyone knows or even guesses why my Dellorto DHLA 45C does not seem to match the expected design. 

The relevance of all this to me has been an accelerator jet dribble problem on one of my two carbs pair.

Regards Anthony 

[anthonyfca]

apologies, I now see I had an original thread in 2023 about my dribble problem and the above two posts from me really belong over there.

[anthonyfca]

it may be 8 years later, but I have recently used this thread like a bible, thank you for it!

[anthonyfca]

I finally solved the dribble problem: two of the ball bearings in the pump jet circuit that should be underneath the long weight, were on top of it. Corrected that and the dribbling stopped. I also flipped all 4 weights the other way up as they all looked worn on the underside. Not sure whether that apparent wear is supposed to be there, but I have assumed not. - Anthony