Solex 32-34 PDSIT 3/2 Carburetor(s) rebuilt (Bus 73/74, early and late models).

(click on any pictures for a bigger view)

From my motorcycle mechanic years, I can tell you that those carbs are fine carbs, if properly maintain, seal and adjusted I think that they will be able to give you a few more years of work, maybe another decade!!! (and they have choke!)

This is a step-by-step carbs rebuilt procedure (not that difficult at all but time consuming), . Before you begin (it's a 15 hours job) you should check a few things such as if all moving parts are still in an acceptable condition.
Ex.: Is the main butterfly shaft too loose (this one could be rebuilt with a new bushing by a professional machinist), is the main pump injection twisted tube (see picture) still solid, this is a very fragile part (well, with some good old JB-Weld everything is possible), Also inspect the straight brass / copper tube for crack (mine was cracked), it is the one inline with the main / dual air mixture screw on the left carburetor (see picture).

Tool: 2 carbs rebuilt kit (available at www.cip1.com or www.busdepot.com ), an air compressor is a good thing to have, compress air is one of the best cleaning tool for carburetors, but it is not a must. Carbs cleaner in spray, old gasket remover spray, brake cleaner for cleaning the exterior carb body, degreaser. Some metal and nylon brush. A Dremel tool with wire brush is almost a must!!! And some normal tools like long nose pliers, fine screwdriver (absolutely NO Beer before the end of your job. He he he)
Step 1  Remove carb form the bus:
Remove air filter(s) element,  Remove / unplug every hoses from carbs (letters), check for leak/crack at vacuum (red arrow), unplug fuel hoses and block the hole of those one.
Step 2
Split the 2 main carbs body at screws "D", be careful with tube "E", check if "A" surface is flat and not pitted, check if screw "C" is tight, check end-play at butterfly shaft, if too loose have the shaft bushing redone by a pro. Start cleaning the lower body part. External and internal with carb cleaner and a small brush.
Step 3 (this si the right carb, they are the same, specifications for the left carb are at the end!)
Remove both "Jet" (air & fuel) with a GOOD flat screw driver, gently remove both JET, one is located at the green arrow (air) and the other one (fuel) is located at the upper red arrow, you will have to remove the jet plug / fuel drain plug (black arrow) to be able to remove the fuel jet (not shown on the picture). Clean everything and spray some carb cleaner in side the green arrow, carb cleaner  should go out in all red arrow location!!!! If you have compress air, use it now everywhere. (Picture show the acceleration pump removed - right upper side) Ckeck the jets to see if they are the same number??? mine were not!
Step 4
Remove the 3 screws that hold the choke element, remove the choke (the electric choke is the one with the spring-like flat metal wire inside and the 12V on it). Check if the choke cam is misplace (green arrow), the good position is shown on the picture. The 2 cam should meet at the 2 red arrows when the carb is at the close position and cold.
Step 5
To replace the choke to upper body gasket you will have to remove the choke plate (A), to do so, remove both choke plate screws (green arow), slide this one out. Check if the fuel pump injection tube is solid (very fragile part, Red arrow). Blow air / carb cleaner in the fuel pump injection hole (orange arrow), it should go out at the "A" hole.
Step 6
You can now remove the choke shaft, be carefull not to lose the 2 very small spacer (on the shaft - purple arrow) at each end of the choke plate (yellow arrow on step 5)), Inspect the choke shaft for excessive loose..
Step 7
Unscrew the 2 screws (purple arrow on step 4) and remove the choke body from the main upper body. Remove the old gasket and spray the red arrow hole with carb cleaner.
Step 8
Remove (3 screws) the choke diaphragm / shaft, take note of the spring position (red arrow), clean everything.
Step 8
Grease the NEW shaft diaphragm. put the new shaft back and be careful to align this one.
Step 9
Put the new gasket that joins the upper body to the choke body. Screw back the 2 parts.
Step 10
Put back the choke shaft and be careful to align the "click choke cam" so it can meet with the lower arm. Put back the choke plate with the 2 washer (IF THEY ARE STILL GOOD!!!!!!!!!!! IF NOT THEY WILL FALL INTO THE COMBUSTION CHAMBER) and 2 screws.
Step 11
Put back the choke element, align the 2 mark together!!!! Well, thats all depend on the choke element condition!!!! The most important thing is that it better be fully open when hot. Better safe than sorry!!!! The main problem with those sucker is that if you adjust those one so the cam "kick in" when cold, they don't fully open when hot (so you are stuck with a rich mixture). The only safe solution is to buy new chokes element!!!!!!!!!!! (the hell with that for me, i will keep my feet on the pedal)
Step 12
You can remove and replace the fuel level valve (part of the very complete kit)
Step 13
Change the fuel injection!!! pump (part of the kit), take note of the spring position and orientation. You will have (a bit later) to double check the lenght of the pump stem, the Bentley as a good description of how to do that. But it is very easy to understand the basic principle when you are that far in your carbs rebuilt steps.
Step 14
This is not really a step unless you have the late model (on the right) with a second hole, if so the new o-ring is included in the carb rebuilt kit.

Take note that the pump lever as a different hole for the stem assembly. The earlier one have a 3 pin hole adjustment and the late version as a screw type adjuster.
Step 15
This is a very important step, cleaning all the air/fuel passage (including the needle  fuel screw - green arrow). You need to blow air and carb cleaner in those small hole near the mixture screw. You need to TRIPLE check the carb mating surface (brown arrow) with the intake, this one needs to be flat like hell. Check the buterfly shaft fot loose (it is normal on a 30 year old carb that you have SOME loose but not to much) or excessive play, if to much the bushing need to be replace or you will suck to much air (red arrow). You need to gap the buterfly to .010mm max (orange arrow). Secure the barrel screw (purple arrow). Change the very important o-ring on the small screw (blue arrow) put them back together.
Step 16
Finish product!!!
Note about the left carb and central mixture
The left carb as a central mixture and idle control, you need to change the o-ring on both (mixture & idle) of those screws + the normal screw on step 15 (3 total). DOUBLE CHECK if the tube (green arrow) is not cracked or broken (mine was). Be careful with that tube and the twisted tube (red arrow) when cleaning the carb, they are fragile. Seal back the cut-off valve (orange arrow)
Basic adjustment
Put both (on each carb) needle screw on step 15 at 2.5 - 3 turn out, put the main (on left carb) mixture screw at 2.5 turn out, idle screw should be 4 turn out or more. Start the Bus and have some fun (get the bus to a very good mechanic who know about carbs and equiped to do a good adjustment!!!!!)
(more to come later, cheers, Ben)
 
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