Scoville

Removing the butterfly "rod"and floater in chamber.

34 posts in this topic

I need some guidance with removing the rod that runs through the carb holding the two butterflyvalves in order to change the bearings.

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PB160183.jpg?t=1289920564

How do I do it?

Also how do I remove the little rod holding the floater in the floater chamber?

PB080074.jpg?t=1289920701

Cheers Rasmus

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when I rebuilt my carbs I was going to remove the shaft and bearings. In the end I decided not to because what is the amount of wear really likely to be? Not much because its not like they are rotating at high RPM they only move about 90 deg. Even if there is a little play its not going to make much difference. Ok so I figured this out after I had tried to push them out. I found the shafts were bending even though I had heated the carb bodies in boiling water for 5 mins. There is info about how to do this in Des Hamils "power tuning Dhla carbs" book. So in the end I used a spray degreaser and re-greased them and they were good as new. On the float pivot you need to be really careful. They snap easily so if you need to have a good vice with flat top jaws. open the jaws so they are just wider then the pin. Or you could drill a hole a bit bigger than the pin in a peice of ally. Then with a smaller pin punch you drive the pin out. BUT YOU MUST DO IT FROM THE CORRECT SIDE. You need the split side down resting on your base and carefully drive the pin down so the split arms are being supported during the opp. If you do break them I can weld them back up.

Buddsy

Edited by Buddsy

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Best advice for the throttle butterfly shaft is: DON'T!! The bearings tend not to wear and you risk causing irreparable damage, to achieve nothing of any use. Agree totally about the float pin...as long as you do it properly, shouldn't cause any damage. It's retained by a splined section which fits into the split posts...once you habe pushed this bit clear of the split posts, the rest slides out easily. I've found it takes very little force to extract them.

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The only time you should have to replace those bearings is if they are allowing bypass air into the carbs. Very rare.

To remove the float shaft, press it out with a small drift - it is just a light friction fit.

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I've not had the butterflies out of a Dellorto but it is my experience that the set screws holding the butterflies are locked to the thread (knurled/bashed) to be non technical. This is to ensure they don't come loose and get swallowed, (expensive) so you need to know how the screws are held in, and you may not be able to get them out intact. But the major issue is to lock them back in again without risk of coming loose.

As above no air leaks, and bearings holding up, I'd leave well alone.

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Thanks all, the trouble is one of the bearings has one of the protective sidewalls come off and it sounds like old people having unlubricated sex (there is thought you won't get rid of soon). I just know since it is in pieces right now and the new bearing is on it's way from Dellorto here, I need/want to change it. I don't want to start cutting corners hours into starting a life long dream project, I just can't do that. I don't have OCD (yet) but I do feel I will regret NOT doing it and it will get worse with time since there is no protection from outside crud getting into it.

:detective:

/Rasmus

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Here in Coffs Harbour Australia I've found my local Ducati dealer very helpful and knowledgeable on Dellortos.

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Ducati916.jpg

Keep out of there Roger before you become a convert. This Ducati is still one of the most beautiful bikes made. A headturner after 16+years and so tempting to take up biking again.

Edited by DanR

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Hi Rasmus,

seems to be a challenging task to get the throttle shaft out and in again without destroying something.

The link to the pdf is nice but does not help you.

Spent the money and buy “How to build and Power Tune Weber & Dellorto DCOE & DHLA Carburettor” from Des Hamil. The prescription about removing the shaft and remounting it with new bearings has 9 pages!

I got my overhaul kit today with 2 x 4 shaft seals (ORings and rubber rings), 4 star washers and the 4 bearings from Eurocarb.

post-3590-0-07412200-1290284379.jpg

On the bottom of the pic to the left 8 new butterfly screws

A pressure test with 0,5bar on the carbs showed air leaks on all bearings, so I have the same work in front of me this winter. The seals are lasting not forever in the bearings, could be a good test for every turboesprit owner, escaping petrol/air mixture under load conditions in this area is not a good thing.

Have a look in carbs rebuild from ghe67, I remember that there was a pic with a dismantled shaft as he reworked his carbs. Ask him for advice, he was already in there.

Hope this helps,

Cheers Rolf

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Thanks Rolf, so flipping the problem then, how do I just the bearings out? You look to be in the same boat as me and I just can't wrap my head around how to get a grip on the bearings in order to pull them of the shaft...

Ok book ordered on Amazon. Better do this the right way I suppose!:sorcerer:

Cheers

So now to sit on my hands until the damn book gets here... Wait! What is this Fallout 3? HELLO!!!!

Edited by Scoville

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Just remember that the main gasket is a type of neoprene or rubber - if the one in the kit is a normal material type ,they got it all wrong ...........

OH ,BY THE WAY - DO ONE CARB AT A TIME ,IF YOU DON'T KNOW WHERE A PART GOEAS ,YOU HAVE A POINT OF REFERENCE (THE OTHER CARB)

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Removing the bearings is probably best done by heating the alloy carb body..hot air gun should do it, no more than 150C I should think...at which point the bearings might even fall out!! Otherwise, with the shaft removed, I think I'd use a suitable drift through from the other side of the carb and tap them out, gently, from the heated carb. No problem with applying force to the inner race, as you're replacing the bearings anyway. Fingers crossed for you!!

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Guys you do realise the book you are talking about is the same book in the PDF file?

The problem I had was pushing the shafts out from the bearings. Getting the butterflies out is easy. But I found even by setting the carb under a press, appling a force on the end of a brass shaft with a large slots in (for the butterflies) too much. I could see the shaft deforming and there was no way they would come out before breaking. Ok so I could just make some new ones or buy some but be prepared for that out come. Maybe yours will be looser than mine? Just keep an eye on them. And let us know how you get on?

Buddsy

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Hi Rolf,

did you solve the problem?

I have seen only now your email about the bearing/spindle issue.,let us know.

Cheers

Giorgio

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Hi Giorgio,

As I am short of time right now, the carbs will be disassembled after Christmas.

In the moment I organize a copper hammer, ultrasonic bath for cleaning and other helpful tools not in hand.

Want to make sure not to damage the carb body or the throttle shaft.

How to optimal prepare the throttle spindle to get it out of the carb body?

I plan to clean and oil the shaft, heat up the carb body end where the bearing has to leave the body, tap on the other side on the shaft gently with a copper hammer while the body is clamped in a vice between to wooden blocks, expect that the bearing comes out easily while the shaft has to be drifted through the tighter fit on the inner bearing race the longer way

How to get the star washers (turbo only, secures the Oring and sealing ring on the inner side of the body orientated to the accelerator pump lever) out of the body and new ones in?

Cheers

Rolf

:construction: Rasmus, any news from your side?

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I have paused until I get the book, I know it is on PDF file but Amazon was going to ship for me to have beginning of dec looks like march now so it looks like i will have to start off with the pdf file anyway. I am down to the butterfly shaft and the choke. Looks like a special tool to get into the choke. Family is taking up much time and I have burnt some mental fuses doing bumper removal etc...

Next week I should be removing the first of the two with pictures and hopefully minimal amount of tears.:thumbsup:

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The only time you should have to replace those bearings is if they are allowing bypass air into the carbs. Very rare.

Real world issue is boost pressure with fuel leakage OUT of the shafts. Bad bearing seals can allow this, and can be more common than one realizes.

Fuel smell at best, fire hazard at worst.

Edited by f1karting

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post-3590-0-52958000-1293481149.jpg

Tracing air leaks this summer I found the leaking bearings and that the plenum paper sealing is not fully air tight. Hylomar cured the plenum leakage.

Bearing removal:

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Heating up with a torch, slowly, wait until heat gets into the carb body, not much over to hot for the fingers

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Tap gently with a copper hammer, for the first move the nut protected the shaft end just for additional safety, no washer behind the big washer gives space for movement

post-3590-0-50666300-1293482787.jpg

Same with the other side and a special drift

post-3590-0-66947900-1293482872.jpg

Job done :thumbsup:

post-3590-0-03018100-1293482933.jpg

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Awesome!! Xmas and new years along with a whole bunch of family stuff has me swamped looking to do this just on the other side of the new year. The rod that you have laid out there Rolf what is that? I am scared to death of breaking something and I am rereading everything like four times.

/Rasmus

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I wonder if the new bearings will seal any better than the old ones..hope they do!!

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Hi Rasmus,

the rod is the punch for the bearing which stays inside the carb body. Slightly smaller diameter than the throttle shaft, I have choosen 7,75 mm and 6,5 mm for the step which goes inside the inner ring.

Don´t be to nervous about getting everyhing apart, the fun starts when assembling begins.

I just had to remove the shaft a second time as I damaged the metal side seal of the new bearing while punching it in without a protecting washer :blush: .

Two star washers are also on the learning list.

To press that O Ring + sealing ring and star washer inside again needs a lot of patience.

Hi John,

hope so too. When I ever get the whole bunch together I make a pressure test on the bench before reinstalling. The metal side seal of the new bearings looks good, no clue if it seals good.

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Awesomeness ROLF! I just had all of my relatives over for a family "outing" and everyone was just looking at my car going "That is NEVER going to drive again!". Having moments like that and looking at a part disassembled car is shattering. Now to refocus and take it a small step at the time. Did you have that made by a firm or is that a over-the-counter tool? I am learning as I go along so my build will take some more years then others (since I am changing the steering from RHD to LHD as well).

/R

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I am learning as I go along so my build will take some more years then others (since I am changing the steering from RHD to LHD as well). /R

From my own experience of driving my RHD Esprit since 4 years here in the LHD world I do not recommend to change the steering. It is not worth the effort IMHO, spending extra time and money, problems with parts availibility, changing all the cabling etc.

If you want to overtake with a RHD car, you have lots of power with the TurboEsprit and a long straight with enough distance to the car in front of you (gives extra visibility) or a slightly bended left curve, that´s it.

Why not focus to get the car running as it is and have some fun driving it? If you then figure out you don´t like it RHD, still possible to change it.

Tooling: The punch was made by a friend on a lathe. Check out a machine shop in the neighbourhood, maybe the trainee can make you one for a small tip.

Cheers

Rolf

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Reinstalling the bearings....a length of threaded rod and some nuts and washers ought to make a puller to ease them in...possibly better than tapping with a hammer!

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