So you want to rebuild your Webers?, Here is how I did RoadGlue's Weber 40 IDFs. |
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So you want to rebuild your Webers?, Here is how I did RoadGlue's Weber 40 IDFs. |
ThePaintedMan |
Mar 27 2013, 08:48 PM
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Advanced Member Group: Members Posts: 3,886 Joined: 6-September 11 From: St. Petersburg, FL Member No.: 13,527 Region Association: South East States |
Awhile back, Randy (RoadGlue) gave me the opportunity to rebuild his Weber 40 IDFs, and I thought I'd take the opportunity to document the process. I'm also going to try give a little insight on some of the tips and tricks I have learned along the way. Keep in mind, this thread is a work in progress, as Randy and I are still tracking down some of the parts these carbs were missing.
Now, I understand for most people, the process is fairly straightforward and many of you will think it unnecessary to give a step-by-step. After all, most rebuild kits only include a handful of parts and the location and function of most pieces are obvious. But there are some important additional steps that one can take to truly ensure the rebuild process goes smooth and that you won't have to do this over again immediately after reinstalling the carbs. Here it goes! First, I would like to outline the fact that not all Webers are the same. Not only are there different models of IDFs (the 36, the 40, the 44 and the much rarer 48), but there are "early" style carbs and "later" ones. I'll try to list some of the most obvious differences, which are to the best of my knowledge true in most cases, but may not hold true in all of them. Here are the tools you'll need for the job: -Carburetor rebuild kits (CB Performance or Redline are the most common) -8mm open/closed end wrench -10mm open/closed end wrench -11mm open/closed end wrench -19mm open/closed end wrench -Smaller flat tip screwdriver -Large flat tip screwdriver -Brass brush -Paint gun brush cleaning set -Small hammer -Brass punch set -Razor blade -Carb cleaner -B-12 Carb dip -Anti-seize -Shop towels -Compressed air source (preferably) -Clean workspace, preferably with white background Optional: - (4) 3/8 x 24 Brass Hex grub/set screws - Allen keys -SAE Tap and Die set Below is a picture of an early and late set of Weber 40 IDFs. Some of the characteristics of EARLY versions are: -Short emulsion tube holders -Short throttle shafts with little overhang outside of the carb body -Non-sealed, ball-in-cage style throttle shaft bearings -Cam-actuated, non-adjustable accelerator pump assembly -No ports for "ported" vacuum (still has 2 "manifold" vacuum ports) -76 degree bevel throttle plates (this may or may not hold true for every set of early carbs) -No throttle return springs installed from factory (thanks Kevin for clarification) -Most (all?) were made in Italy and are stamped as such Later style Weber 40 IDFs (Weber 40 XEs) are usually characterized by: -Taller emulsion tube holders which extend above the carb top -Longer throttle shafts -Sealed black throttle shaft bearings -Adjustable, spring cushioned accelerator pump assembly -One pre-drilled ported vacuum port in addition to two threaded manifold vacuum ports -78 degree bevel throttle plates -Factory installed throttle return springs -Made in Spain, but potentially also Italy and Brazil Please note that most of these instructions to follow are also true for 44s and 48s as well. The main difference being the way that the secondary venturis are designed. |
ThePaintedMan |
Dec 17 2013, 05:05 PM
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#2
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Advanced Member Group: Members Posts: 3,886 Joined: 6-September 11 From: St. Petersburg, FL Member No.: 13,527 Region Association: South East States |
Next, move on to the top of the carb. Remove the 19mm brass nut at the fuel line neck, which holds the mesh fuel filter. Clean out the filter and passageway thoroughly and reinstall the filter as well as the new red/orange gasket supplied in the kit. Don't overtighten this fitting, or you'll crush the gasket and ruin it. (Eventually I'd like to find a suitable aluminum style sealing ring to replace the cardboard ones.) You can add a small dab of grease to both sides of this washer to improve the seal and prevent tearing.
If you have not already done so, drive out the float arm pin and remove the float. Be sure to do this with an appropriately sized punch and hammer and with the carb top well supported and far away from a position where it could fall on the ground. If it does, you're likely to ruin the carb top and finding a replacement in good condition is very difficult. I prefer to drive the pin out in the direction outlined below. Sometimes the pin can have a knurled end to it and if that end is forced through the non-slotted end of the float pin tower, it may break. Once the pin is removed, remove the float and needle valve assembly. Install the new top gasket (after scraping any residual gasket material off of course) and the needle valve base. Note that there is a small aluminum washer underneath this base that should be replaced with the one in your kit. Also, ensure that the two holes for the idle circuit vents exist on your gasket and will not block the idle circuit vents on the top of the carb bodies. I like to open these holes up a little with a flathead screwdriver just in case. Clean the float of any debris and install the needle valve on the small tab at it's fulcrum. Install both into position and slide the pin back into position. Several taps of the hammer should be able to get it back into position. Again, note the knurled end of the pin and install it so the smooth end goes into the non-slotted holder first. |
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