Late Solex
Early Solex

Late Solex (15 Dec 2010)

These are a set of late style Mikuni Solex 44 PHH carburetors found on the U20 Solex package engine. These are how they looked when I purchased the engine.


Early Solex (15 Dec 2010)

Early style Mikuni Solex 44 PHH ...note the two screws on the jet block. These are the type I should use on my 67.5, but again it's a clone and I was told the late are easier to work with, so I sold my early style.


Linkage (15 Dec 2010)

Solex carbs show up for sale, but the manifold and linkage can be difficult to of the Roadster vendors made some beautiful reproduction Solex linkage (see vendor page).


Rebuild Kit (15 Dec 2010)

My carbs were very dirty, I considered a complete rebuild (if I had the $ I would have sent them to Todd at WCR), but since the butterflies and shafts were tight I chose to just purchase the rebuild kit from Dean as he provides an additional main gasket for the Roadsters carbs.

jet block area
fuel jet

Dried up Fuel (15 Dec 2010)

I started by removing the jet's hard to see in this bright photo, but there is lots of brown crusty junk at the bottom of the float chamber.


Starter Jet (15 Dec 2010)

Located at the bottom of the float chamber is a starter jet..mine was crusted over.


old fuel
crusty fuel

Nasty! (15 Dec 2010)

Well looking at the bottom of these carbs I can see why they ran so bad. The Solex carb has LOTS of small openings and ports and junk WILL block fuel flow...this is just years of old fuel and junk building up inside of these carbs.


Opposite Side (15 Dec 2010)

The same crud was on the bottom of both sides of the float bowl. Lots of Q tips, Pipe cleaners, and carb cleaner was used to clean these up.


float blockoff
pilot screw

Blocking Plate (15 Dec 2010)

This plate is installed on the opposite side of the float. The carbs look like they were designed to be front or back depending on where certain components are installed.



Pilot Screw (15 Dec 2010)

Rebuilding/restoring your own car certainly helps teach you about your parts. I found out there are actually two types of PHH carbs (homogeneous main system, and Independent main system) the two main systems are very obvious in the jet block area.

accel pump
more crust

Accelerator Pump (15 Dec 2010)

When you stomp on the gas pedal the fuel tends to lean combat this, the Solex carbs use an accelerator pump to inject addition fuel into the sytem. Here I am removing a REALLY small cotter pin from the pump rod.


What Can I Say? (15 Dec 2010)

Well since the accel pump is the lowest point on the carb all of the really nasty stuff settled and hardened here. I was actually removing chunks of foul smelling junk from this area.

all clean
accel pump bottom

Ready to Assemble (15 Dec 2010)

These are the major components in their basic order ready for reassembly. Notice all of the old dried fuel and junk have been completely eliminated.


Accel Pump (15 Dec 2010)

I installed new gaskets on the pump body.


pump diaphram
return spring

Diaphragm (15 Dec 2010)

The diaphragm fits right into the pump cover.



Return spring (15 Dec 2010)

A spring is installed between the diaphragm and the pump body. I installed a new gasket and carefully compressed the set together.

pump back on
final install

Accel Pump Install (15 Dec 2010)

The pump is installed on the bottom of the carb. There are 3 holes on the pump rod that allow you to increase or decrease fuel flow (the middle hole is standard).


Pump Completed (15 Dec 2010)

While still keeping the pump assembly compressed I tightened all six screws to complete the assembly.

jet blocks in
float cover

Jet Blocks (15 Dec 2010)

The Solex is tunable thru the changing of jets...there are several other things that can be changed out from starter jets to the venturi, but the three common adjustments are the Air, Main, and Pilot jets all located under the same convenient cover.


Float Cover (15 Dec 2010)

This is the underside of the float chamber cover.



needle valve
float holder

Needle Valve (15 Dec 2010)

I purchased new needle valves for the floats. I was told the Solex carbs are finicky about their float level and the fuel pressure to them, so I'm being very careful in these areas.


Float Holder (15 Dec 2010)

This piece slides in from the top and holds the float from the underside. The spring is very stiff and the entire plate is actually part of the float adjustment sytem.

float adjuster

Float (15 Dec 2010)

I installed a new gasket and slide the float into postion. It simply installs on a pin and must be 12 to 12.5 mm from the cover.


Float Adjuster (15 Dec 2010)

With a new gasket I installed the adjuster for the float. The adjuster pushes the entire float plate down (the picture with the small silver spring).

pump nozzle
fuel banjo

Pump Nozzles (15 Dec 2010)

The rebuild kit comes with new o rings and washers for the pump nozzles, but man are they small!


Fuel Banjo (15 Dec 2010)

The kit also had new crush washers for the fuel banjo bolts. There are small screens inside of this inlet.

1 down

Done! (15 Dec 2010)

This is the carb complete...the small circle above the jet block cover is the starter circuit...the Solex does not have a choke, but instead uses a starter circuit. The starter disk simply has holes/bypasses that divert fuel behind the butterflies so the car starts...after the engine warms the fuel is returned back to the main system.


Installed! (20 Dec 2010)

I installed the carbs and they ran very lean (backfiring thru carb with 160 fuels/140 air/55 Pilot) I ordered a few new jet sizes from Todd at WCR and currently I am running 60 Pilots, 140 Fuels, and 190 Air (see video on engine page) I still have a small backfire...lots of popping in the exhaust, but I am going to wait to get the engine on the frame and get a full exhaust installed before I make anymore adjustments.