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The SR500 had three different OEM carburettors during its years of construction.
In the 2J4, the SR500 of the 1978-1983 model years, the MIKUNI VM34SS-2J4 installed.
From 1984 - ca.1990, the 48T of the MIKUNI VM34SS-48T installed. A characteristic feature of these carburettors is the choke lever, which is pressed down to operate it.
The 48T built between 1991 and 1999 was equipped with the MIKUNI BST-34 delivered. This has a round choke button that is pulled to activate it.
The KEDO carburettor program includes almost everything to keep the increasingly rare OEM carburettors alive.
For all those who want to get a little more power out of their SR500, we also have something in our program:
OEM-CARBURETTOR
TUNING CARBURETTOR
The "early" SR500 models, the 2J4 of the 1978-1983 model years, were equipped with the
MIKUNI VM34SS-2J4 .
The SR500 48T was produced from 1984-1989 with the only slightly modified carburettor VM34SS-48T provided.
The VM34SS is a fully equipped round slide carburettor with a 34 mm passage. A little more complex to maintain but with many advantages.
The VM34SS was slightly modified several times during its construction period.
On the 2J4, the pin of the accelerator pump diaphragm was changed from 1979 to 1980. In 1984, during the transition to the 48T, the shape of the idle mixture control screw was changed from a conical to a stepped tip shape.
From the outside, the VM34SS carburetors of the 2J4 and the 48T can be distinguished by a small "stamp" on the left-hand side of the carburetor in the direction of travel (see illustration).
With the 2J4 carburettors, there is either 2J4 or 2J2 to see.
The 48T carburettors have there 48T or 48U imprinted.
These variations must be taken into account when selecting spare parts.
In addition to seals and nozzles, there are three different diaphragms that are considered wear parts.
Today's gasoline can cause them to dry out and crack after just 6-8 months of use.
Common symptoms of leaking diaphragms are
The accelerator pump diaphragm was modified from 1980 onwards.
Please check the pin length here!
Item no.: 27986
Accelerator pump diaphragm of the 2J4 until 1979
Pin length 13.4 mm
Item no.: 28696
Accelerator pump diaphragm of the 2J4 from 1980
Pin length 12.0 mm
Although the OEM accelerator pump diaphragms used have different pin lengths, the "newer" diaphragm - the one with the shorter pin (Item no.: 28696) - can be used in all VM34SS carburettors without any problems.
In carburettors for the US market, the diaphragms of the safety valve were attached at four points.
Item no.: 28195
Diaphragm safety valve (4-point attachment)
US models ONLY: SR500'80-'81 US, XT500G'80 US, XT500H'81 US
During the transition to the 48T in 1984, the shape of the Idle mixture adjusting screw was changed.
Item no.: 28190
Idle mixture adjusting screw incl. spring + O-ring for 2J4 up to 1983
conical tip shape
Item no.: 28584
Idle mixture adjusting screw incl. spring + O-ring for 48T, 1984-1989
stepped tip shape
Of course, we also offer everything you need to overhaul the carburettor yourself.
The following is a small selection of the most commonly required products for carburettor rebuilds:
SR500 2J4 1978-1983
incl. choke piston, springs & ball, sealing ring for the actuating shaft
(Nozzle sizes: HD #300/LL #25)
SR500 2J4 1978-1983
Nozzle HD #300/LD #25, incl. choke piston
SR500 48T 1984-1989
incl. choke piston, springs & ball, sealing ring for the actuating shaft
(Nozzle sizes: HD #300/LL #25)
SR500 48T 1984-1989
Nozzle HD #300/LD #25, incl. choke piston
Carburettor with throttle valve. Less complex than its predecessor with correspondingly fewer spare parts required.
In the SR500 the successor to the VM34SS and the last carburettor before the design of the injection in the SR400FI
The carburettor is controlled via a throttle valve. A diaphragm controls the flat slide movement. The MIKUNI BST34 came from the Yamaha component shelf and was used in other models of the brand in the early 1990s. An appropriate successor to the VM34 - also with regard to the further development of the SR500.
In addition to the rebuild kit 94043 and the gas slide/diaphragm combination 10249 we offer the Air-Cut valve cover 29122-1 on. As the original plastic part ages relatively quickly and becomes brittle, a good replacement is important here.
Here is a small selection of the most frequently required products for the carburettor rebuild:
SR500 48T 1990-1999
For all those who want to have their carburettor professionally overhauled, we offer this as a service by our master mechanic.
SR500 48T 1990-1999
Mikuni BST-34 carburettor (jet sizes: #165/#45)
SR500 48T 1990-1999
For original BST34 carburettor
OEM-Vergleichs-Nr. 2LN-14940-00
SR500 48T 1990-1999
For Mikuni BST34 carburettor incl. small O-ring at the top and large O-ring at the bottom
We also offer the current flat slide carburettor from MIKUNI as an alternative carburettor for SR/XT/TT models in two sizes with 36 and 40mm passage.
This carburettor is definitely a tuning carburettor and shines with its spontaneous throttle response.
While the TM36 can be ridden with unmodified original components (intake, engine, exhaust) of the SR500, the TM40 carburettor is only suitable for top performance with heavily modified engines.
A precisely guided flat slide is controlled via a cleanly mounted mimic. Equipped with a choke and accelerator pump, both models are controlled in the same way as the original carburettor with an opener and closer cable. As with the VM36, the advantages come into their own in combination with sporty exhaust systems and racing air filters.
SR500, TT500, XT500
WITHOUT kit, Not street legal
Fuel/vacuum hose connections 8/6mm
SR500, TT500, XT500
WITHOUT kit, Not street legal
Fuel/vacuum hose connections 8/6mm
Here is a small selection of the most frequently required products for the TM36:
SR500-'89
SR500'90-
incl. connecting rubber to the air filter box
Mikuni TM36
4x idle jet #12.5-#22.5, 5x main jet #127.5-#140, choke jet #25
Mikuni TM36/TM40
Contains all gaskets, jet needle, needle jet, mixture control screw, float needle valve, bellows, but without jets
Mikuni TM36 & SR500, TT500, XT500
For TM36 flat slide carburettor and cylinder head without intake port machining, incl. clamp
Mikuni TM36/TM40
For TM36/40 flat slide carburettor and cylinder head with intake port machining, incl. clamp
Here is a small selection of frequently required products for the TM40:
SR500-'89
SR500'90-
for Mikuni TM36/TM40
This carburettor also comes from MIKUNI Japan.
Our technically uncomplicated and inexpensive alternative to the original carburettor of the the 500cc models
With a 36 mm passage, it certainly has a performance-enhancing effect.
The VM36 carburettor is only operated with an opener throttle cable centrally above the round slide. The diameter on the air filter side is an impressive 63 mm.
We have therefore developed an adapter ring for the 48T air filter box that enables problem-free installation.
Type B main nozzles are used for tuning.
For an SR500 with air filter box and performance manifold, you are in the range of a 220-240 main jet and a 25-32.5 idle jet.
Here is a small selection of the most frequently required products for the VM36-4:
Contains gaskets, nozzle needle, mixture control screw, float needle valve, clip, but without jets
SR500 (with Mikuni VM36 carburettor and vacuum-operated fuel tap)
SR500'84-'89, SR500'90-
The connecting rubber between the carburettor and the air filter box must be shortened; please order this rubber (item no.:. 28180) at the same time if necessary.
Whether special wrench, jet change tool, MIKUNI PocketTuner, tool tank or starting aid spray - here we have compiled special tools for working on the carburettor.
