 ATTN: Carb Experts!, Need Help with a Dellorto DRLA |
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| jr91472 |
  Apr 1 2006, 07:30 PM
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#1
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"I'm pacing myself sergeant..."  Group: Members Posts: 1,205 Joined: 2-August 04 From: McKinney, TX Member No.: 2,437  |
Ok, this winter I bought a pair of used Dellorto DRLA's, rebuilt them with all new gaskets, o-rings, etc. I put them on the motor and today started it up for the first time.
I will get to the point: On one of the carbs, fuel from reservor drains into one (only one) of the barrels and collects on the butterfly (i.e. makes a puddle and produces a rather rich mixture (IMG:http://www.914world.com/bbs2/html/emoticons/wacko.gif) ). I spent most of the afternoon troubleshooting this and call tell you that even with the motor off, once there is fuel in the bowl...it drains out and into one on the barrels. With the carb still on the motor, I cannot tell exactly where the fuels is entering the barrel, but it seem to be near the bottom (like one of the holes near the butterfly). While cleaning them, I didn't notice any cracks or wear, (IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif) I will be pouring over my Dellorto manual tonite and probably take the carb off the motor in the next day or so and go through it completely. But I thought I would see if anyone had any thoughts. This is my first dual carb experience, so be gentle and thanks in advance. |
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| tat2dphreak |
Apr 1 2006, 08:06 PM
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#2
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stoya, stoya, stoya Group: Benefactors Posts: 8,797 Joined: 6-June 03 From: Wylie, TX Member No.: 792 Region Association: Southwest Region  |
did you check the float adjustment? I had a similar issue on my webers... turned out the float was adjusted wrong and would overfill...
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| jr91472 |
Apr 1 2006, 08:17 PM
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#3
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"I'm pacing myself sergeant..." Group: Members Posts: 1,205 Joined: 2-August 04 From: McKinney, TX Member No.: 2,437 |
That was my first thought too. But if I simply pour some gas into the bowl till about half full, its starts flowing into the barrel.
It is coming out right above the butterfly, so Its not the idle port (which is below the butterfly), has to be the progression port right?? I got a bad feeling (IMG:http://www.914world.com/bbs2/html/emoticons/sad.gif) |
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| So.Cal.914 |
Apr 1 2006, 08:46 PM
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#4
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"...And it has a front trunk too." Group: Members Posts: 6,588 Joined: 15-February 04 From: Low Desert, CA./ Hills of N.J. Member No.: 1,658 Region Association: None |
That bad feeling is the money you are going to have to pull out of your butt, for a set of webers. (IMG:http://www.914world.com/bbs2/html/emoticons/smoke.gif) Crack detector is a dye you can mix with some fuel, it will tell you exactly where your leak is.
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| rhodyguy |
Apr 1 2006, 10:19 PM
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#5
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Chimp Sanctuary NW. Check it out. Group: Members Posts: 22,070 Joined: 2-March 03 From: Orion's Bell. The BELL! Member No.: 378 Region Association: Galt's Gulch |
the fuel is running out of the little tube directly above the butterfly? the accelerator pump jet? i always ask. what kind of fuel pump and/or regulator are you using?
if they were webers i would suspect the accellerator jet rubber diaphragm and the related pump jet fuel circuit. k This post has been edited by rhodyguy: Apr 1 2006, 10:23 PM |
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| olav |
Apr 1 2006, 10:34 PM
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#6
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Senior Member Group: Retired Members Posts: 1,107 Joined: 28-December 02 From: Los Gatos, CA. USA Member No.: 34 Region Association: None |
I had that kind of issue with my Webers. One of my needle valves was stuck open. Cleaned it out and problem solved for me.
I don't know if Dellorto's have needle valves. |
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| mikelsr |
Apr 1 2006, 10:36 PM
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#7
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Senior Member Group: Members Posts: 657 Joined: 2-January 05 From: Mahomet, IL Member No.: 3,390 Region Association: Southwest Region |
I don't have my books in front of me but IIRC there is a check valve at the bottom of each float bowl. Check them to make sure they are loose. I'll look at my book in the AM.
Mike |
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| jr91472 |
Apr 1 2006, 11:56 PM
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#8
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"I'm pacing myself sergeant..." Group: Members Posts: 1,205 Joined: 2-August 04 From: McKinney, TX Member No.: 2,437 |
I am using one of those rotory fuel pumps from CB. Got rid of the Fucet (too loud). Thanks everyone for the ideas. |
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| jr91472 |
Apr 2 2006, 12:07 AM
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#9
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"I'm pacing myself sergeant..." Group: Members Posts: 1,205 Joined: 2-August 04 From: McKinney, TX Member No.: 2,437 |
hmm, check valve? I have a accel pump valve at the bottom of the bowl, but it is one per carb. Also I have a Progression Port Inspection screw (2 per carb / 1 per barrel). But there isn't much instruction in my book about these. thanks for looking into it (IMG:http://www.914world.com/bbs2/html/emoticons/smilie_pokal.gif) |
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| mikelsr |
Apr 2 2006, 10:25 AM
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#10
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Senior Member Group: Members Posts: 657 Joined: 2-January 05 From: Mahomet, IL Member No.: 3,390 Region Association: Southwest Region |
I attached a jpeg. If you look at the circled (in red) part 30, intake valve. IIRC inside the intake valve is a metal ball that acts as a check valve. I took mine competely apart last year soaked everything and make sure that check ball was loose.
Mike Attached image(s) 
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| Jake Raby |
Apr 2 2006, 10:36 AM
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#11
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Engine Surgeon Group: Members Posts: 9,394 Joined: 31-August 03 From: Lost Member No.: 1,095 Region Association: South East States |
You have "Dellorto Drip", undoubtedly. Its an internal leak of the fuel passages arond the internal lead plugs.
It is repairable and Art Thraen at Aircooled Engineering in SLC Utah is the man. Tell him I sent you. This is common and can be fixed for a couple hundred bucks. Dellortos spank the pants off of Webers- I love them. OK, back behind the curtain I go- see ya |
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| jr91472 |
Apr 2 2006, 03:21 PM
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#12
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"I'm pacing myself sergeant..." Group: Members Posts: 1,205 Joined: 2-August 04 From: McKinney, TX Member No.: 2,437 |
Can't they just give me shot or something (IMG:http://www.914world.com/bbs2/html/emoticons/chairfall.gif) Seriously, thanks for the tip Jake. I will monkey around with it some more but probably call him on Monday. Beats starting over..... |
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| mikelsr |
Apr 2 2006, 04:51 PM
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#13
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Senior Member Group: Members Posts: 657 Joined: 2-January 05 From: Mahomet, IL Member No.: 3,390 Region Association: Southwest Region |
I hadn't heard that about the carbs. Thanks to the man who won't be on the non-club this month...
Mike |
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| jr91472 |
Apr 2 2006, 05:41 PM
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#14
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"I'm pacing myself sergeant..." Group: Members Posts: 1,205 Joined: 2-August 04 From: McKinney, TX Member No.: 2,437 |
Mike, I checked the input valve per your advice, unfortunately the little ball moves freely.
Looks like I got the drip. At least its repairable. |
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| jr91472 |
Apr 4 2006, 01:24 PM
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#15
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"I'm pacing myself sergeant..." Group: Members Posts: 1,205 Joined: 2-August 04 From: McKinney, TX Member No.: 2,437 |
Just an update for future "Dellorto Drip" victims.
I shipped my Dell 40 off to Aircooled Engineering for repair. Quoted repair price of $65. wish me luck (IMG:http://www.914world.com/bbs2/html/emoticons/beer.gif) |
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