installation guide for

installation guide for
HE JRC 26 or 30mm
Congratulations on your purchase of the JRC Flatslide carburetor. This carburetor has been
developed to give better starting, engine performance, and throttle control for your classic motorcycle.
The procedure to install it, depending on the level of experience of the installer, takes approximately
40 minutes to perform.
The Carburetor
The carburetor is detailed as in Fig.1
we Carburetor Body
1. Fuel agin
. Ar Sorew
rote Cable mn
O Ring in Saat
in A Ch
Jats - Pot and 4 Man
Fuel Overfmy Cutlet
Note: A cable operated choke is available for single, twin and 3 cylinder applications.
Tools Required
The installation procedure is simple and requires a Whitworth open ended spanner set (up to 1968
British motorcycles) or inch size spanner set (1969-82) and Philips style (Cross head) screw driver,
see Fig.2
Screwdriver ~ used 1 removing the Юр
housing of the throtlie sce
ta stiached the taratte
Spanner - usad to tighten up the
bolts at tha flange
© JRC Engineering
Installation Procedure
The first step is to disconnect the battery to ensure no lose sparks occur. Then remove the old
carburetors and gasket(s) and detaching the throttle cables. Be sure to take extra care with gasoline
during this step. Gasoline is extremely flammable and fumes may be ignited by appliance pilot lights
from a surprising distance. Be careful to work in a well ventilated area.
This will leave the manifold bare as shown. (Royal Enfield shown)
Step two involves attaching the throttle cable to the slide assembly. To do this unscrew the two
screws at the top of the throttle slide housing assembly taking care to keep a finger on the top as
once the screws are undone the spring inside will push upwards.
Removing the top cover, the spring, white collar, will leave the chromed slide and needle inside the
о Having removed the top cover, push the nipple
end of the throttle cable through the top cover
and down the center of the spring and through
the white retaining collar. Compress the spring
and hold it all together so as much of the cable
is showing as possible, Fig.4
Note: Return springs of different spring rates
are available from your dealer. © JRC Engineering
Now insert the end of the cable so that the
nipple sits in its place in the throttle slide, Fig.5
ane o
Fig.6 shows a close up of the throttle slide with
the cable end in place but not yet with the white
collar in position.
Insert slide into the throttle housing ensuring it is the correct way round. NOTE — there is only one
way it can be inserted, no force should be applied for this. Another way is to leave the slide inside the
ert the cable down the side and into its seat within the throttle slide.
Let the white collar and spring rest inside the housing securing
the cable in its place, and then re-position the top cover and
screw back into place taking care not to over tighten the screws,
NOTE —The weight of the carburetor should not hang from the
cable alone. Support the carburetor with a length of wire. O JRC Engineering
The next step is to ensure the ‘O’ ring is in its seat on the face of the flange and the gasket is on the
threaded studs. Mount the carburetor onto the studs fully and put on the washers and nuts and
tighten them up with the open ended spanner. Do not over tighten the nuts, Fig.8
Note: 1969 and later Triumph models delete the cupped steel and rubber washers and replace with
flat and lock type washers. Make sure to use the insulator block from the old carburetor on 1969-82
Final step is to fit the air filter. For illustration purposes, a gauze offset pancake air filter is shown
(also available from JRC Engineering, please see website or catalogue for details). In Fig.9 the
completed assembly is in place after fuel line has been attached. © JRC Engineering
The carburetor comes with extra jets, a pilot and four main jets. The jets can be changed easily whilst
the carburetor is mounted in place on the bike.
To replace the main jet, the bottom large nut at
the base of the float bowl can be removed, Fig.10
1 ; € (remember to turn off your fuel tap from the tank).
Pe pi | Some fuel will spill out so have a large rag or
i 3 2 bowl to catch it. A couple of small spanners will
i be needed to remove the jet.
For changing of the pilot jet, the float bowl needs
to be removed to gain access to it and this can be
done by removal of the two screws. NOTE — the
bowl needs to be gently maneuvered around to
release it as there are the floats and internal
structure inside. This must be done very gently
for both removal and re-installation. Fig. 11
shows what is there once the bowl is removed (in
the photo the carburetor is removed from the bike
and sitting on a bench).
The steps in this guide are just that, a guideline only. Anyone wishing to install the carburetor does
so at their own risk and JRC Engineering cannot accept any liability for any loss, damage or claims
arising as a result of any work or action carried out based on the information given in this guide.
It is suggested if you do not feel confident enough to perform the
installation procedure on your own that you engage the services of a
professional motorcycle technician to do so on your behalf. © JRC Engineering
Additional information on your JRC carburetor.
Accessories and kits available;
1. Cable operated choke assembly for single , twin , and 3 cylinder
Throttle cables for single , twin or 3 cylinder applications
Carburetor kits for Norton Commando single 30 or 32mm
Carburetor kit for TR6/7 to fit standard air filter box, 30 or 32mm
Carburetor kit for T140E 1979-82, replaces Mk2 Amal or Bing 30 or 32mm
Carburetor kit for new Royal Enfield 500, 30 or 32mm
Carburetor kit for Ural twins
9. O JRC Engineering
nm А = Trade Name
2 NE ARE Absorbed Base
3 FEE Float Com
4 FE Float Chamber
5 FUE TE Float Chamber Gasket
6 BUREN Nut for oil Leaking
7 02 O - ring
8 = fait Triangular oil needle
10 ARE Slow Jet
11 Mit Jet needle
12 nn Bar clip
13 BALA Throttle valve
15 HR Top Cover
16 le 2 Top Gasket
17 EPI Accelerator screw
18 API N Screw Spring Of Accelerator
19 an AE Throttie Spring
20 | mi: Oil needle spring
24 Wit Arm pin
26 + ME Main jet
27 aa Guiding Wire Adjustor
28 ¡EE Hexagon nut
29 TREE Air screw
30 TEME Air screw spring
31 #1 5 88 Needle clip plate
32 SE Screw of floating chamber
34 HARD Needle jet
35 ЗЕ РЕ Main jet base
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF