This is a page I intend to fill up with some basic maintenance, common
problems and tips to help sort out the tuning of Solex/Mikuni
sidedraughts. These are in addition to and come from the information
contained in the Mikuni PHH Carburetor Service
Manual and
Here are pictures which identify the location of most of the parts used for and during tuning, shown on an S5 type. These parts and relative locations can be related back to all the other Solex/Mikuni types. A picture of a typical central balance arrangement found on 2T-Gs and 18R-Gs will come shortly.
There will be another couple of pages linked off this page with more tips and advice shortly as I re-learn how to add and edit the links.
When Mikuni sold the PHH40 and 44mm as a performance option they provided an initial jetting specification with each carburetor. This is a good place to start when applying the Solex and Mikuni to performance or competition use. Toyota and other manufacturers using the Solex had their own jetting tables which changed constantly, as required through the evolution of the motors using them.
From Mikuni's manual:
Description |
Size for PHH40 |
Size for PHH44 |
Main Jet |
140 |
150 |
Main Air Jet |
180 |
200 |
Pilot Jet |
57.5 |
57.5 |
Pilot Air Jet (fixed) |
140 |
120 |
Outer Venturi |
32 |
34 |
Inner Venturi |
12-16 |
10.5-14 |
Throttle Plate |
#165 |
#175 |
Jet Block Assembly |
5.8 - (6x2.5 & 4x1.5) |
OA |
Bleed Pipe |
T |
|
Fuel Needle & seat |
1.5 |
1.8 |
Pump Jet |
40 |
40 |
Idle Mixture/Pilot Screw |
1.0 turns |
1-1/8 turns |
There are now so many jetting sets out there that this can only be typical
examples. Please, if possible refer to the Service manuals.
Description |
Solex S5 40mm typically on 2T-Gs |
Solex Type T typically on18R-Gs |
Main Jet |
125/135 |
135/140 |
Main Air Jet |
150/180 |
200/140 |
Pilot Jet |
55/57.5 |
63.8 |
Pilot Air Jet (fixed) |
80 |
120 |
Outer Venturi |
28/32 |
32 |
Inner Venturi |
10.5-14 |
10.5-14 |
Throttle Plate |
#165 |
#165 |
Jet Block Assembly |
5.8 - (6x2.5 & 4x1.5) |
5.8 - (6x2.5 & 4x1.5) |
Bleed Pipe |
T |
M |
Fuel Needle & seat |
1.5 |
1.5 |
Pump Jet |
45/40 |
35 |
Idle Mixture/Pilot Screw |
1.0 turns |
1.0 turns |
RM Carburetors: Copyright 2015
Hosted by Red Rook
Updated 18/06/2015