Greate Info About Rx 135 Series from Karthik’s post at Gearheads

Here’s the must have info about the RX 135s

I am listing down some basic differences & similarities between 4-speed & 5-speed versions of RX135 (Includes RXG & RX-Z), which will help people to differentiate & learn more about these legendary series once produced in India.

1. Bore Kit (a.k.a Piston-Cylinder Kit / Barrel / Block)

4-Speed – ‘4TL00’ with OEM “ART” STD piston ‘4Y201’, Rating: 12BHP @ 6500RPM
5-Speed – ‘4TL10’ with OEM “ART” STD piston ‘4Y201’, Rating: 14BHP @ 7500RPM

Note1: To check the originality, the LH side of Cylinder (Gear shifter side) has ‘4TL00’ or ‘4TL10’ marking along with ‘132cm3’ (which is the displacement) and the RH side (Crank Kicker Side) has the batch of manufacturing, for ex., E1, E2, E3 or E4 (All of them have exactly similar performance, people who swear by performance of E1 being the best, is all crap.) Also if nothing is mentioned or some other type code is mentioned, then the Cylinder is a fake, except for ‘4Y201’ which is the original block of RX-K.

Note2: The Cylinder packing has the following description on it:

1. RX135 4-Speed / RXG / RX-Z 4-Speed: Cylinder Kit RXG”
2. RX135 5-Speed / RX-Z 5-Speed: Cylinder Kit 5-Speed”

Note3: Displacement calculation

For Std RX135 being a single cylinder engine, we have the following inputs,

Bore Dia = 58mm
Bore Radius = 58/2 = 29mm
Bore Radius Squared = 841mm2
Stroke Length = 50mm
Pi = 22/7 = 3.142857
Number of Cylinders = 1

Displacement in mm3 = Stroke x Bore Radius Squared x Pi x No. of Cylinder
= 50 x 841 x 3.142857 x 1
= 132157.143

Displacement in cm3 = 132157.143/1000
= 132.157 (Corrected upto 3 decimals)

2. Piston Kit

The OEM Piston kit for Indian RX135 series are from “ART” Japan. For Indian models piston sizes from STD to 0.5mm are available (in steps of 0.25mm). On careful observation of the piston, one can identify if it is original or not. Simply turn the piston upside down & inside we can see “ART” & “4Y201” clearly written. This is the proof for original piston. The piston kit essentially comprises of

· Piston (STD/0.25mm/0.5mm)
· Piston Rings
· Piston Pin
· Clips

Note: The pistons are the same for RX135 4-Speed, RX135 5-Speed, RXG & RX-Z.

3. Carburettor Assembly

The OEM Carb assembly for RX135 is Mikuni / UCAL Mikuni. The Carb assembly are different for both 4-Speed & 5-Speed versions.

4-Speed: ‘4TL 01’ with Main Jet = 165 & Pilot Jet = 17.5
5-Speed: ‘4TL4 20’ with Main Jet = 135 & Pilot Jet = 15.0

These are VM type of Carburettors manufactured by Mikuni & both are 22mm. Additonally VM24 & VM26 are used for RX available in South-East Asian countries (Like Singapore, Indonesia & Malaysia) and in South American Countries (Like Peru, Argentina & Brazil). The details of these are given below:

VM24: ‘2YA 00’ with Main Jet = 145 & Pilot Jet = 20.0
VM26: ’55K 00D’ with Main Jet = 210 & Pilot Jet = 22.5

These carbs (VM24 & VM26) are direct fit to Indian RX135s with some minor jetting changes required based on the Power output of the engine.

Note: The type code is mentioned just above the 2-T oil Inlet in the carb, with that the originality can be confirmed.

4. Head Assembly

The heads are also different for 4-speed & 5-speed. The type code is mentioned below:

RX135 4-Speed: ‘4TL5’ written on inner side (Top) of Head (For OE fitting Catalytic Converter type)
RX135 4-Speed / RXG: ‘4TL00’ written on inner side (Top) of Head (For OE fitting Chrome Silencer)
RX135 5-Speed: ’09L’ written on inner side of Head

5. Clutch Bell Assembly with Primary drive

The clutch bell assembly are the same for 4-speed & 5-speed RX135 (Including the number of Clutch plates), but it is different for RX-G. Below are the differences mentioned:

RX135/RX-Z 4-Speed/5-Speed: Main Bell = 74 Teeth
Primary Drive = 19 Teeth

RX-G : Main Bell = 71 Teeth
Primary Drive = 22 Teeth

6. Chain Sproket

The sproket (Front & Rear) are all different for entire RX series. Detailed info given below:

4-Speed: 16T / 34T
5-Speed: 15T / 38T
RX-G : 15T / 37T

7. Gear Box
The Gearbox are obviously different for 4-speed & 5-speed. Details below:

1st = 35/11 = 3.182
2nd = 30/15 = 2.000
3rd = 26/19 = 1.368
4th = 23/23 = 1.000

1st = 35/11 = 3.182
2nd = 30/15 = 2.000
3rd = 26/19 = 1.368
4th= 24/22 = 1.091
5th = 22/24 = 0.917

8. Engine

The engine may be classifed based on Top End (Included Cylinder+Piston & Head) and Bottom End (Includes Clutch Assembly, CrankShaft, Engine Bearings, Crank Kicker, Engine Cases, Clutch/GB Covers, Ignition coil, GearBox Assembly etc as major components). Most of these items are already covered in points 1 to 7 above.

Note1: The RX135 4-Speed & RX-Z 4-Speed share the same Engine, likewise RX135 5-Speed & RX-Z 5-Speed share the same Engine.

Note2: The CrankShaft Assembly is the same for RX135, RX-G, RX135 5-Speed & RX-Z.

Note3: We can identify looking at the Engine number if the Bike was a 4-Speed version or a 5-Speed verion. Check the details below:

1. RX135 (With Chrome Silencer as OE fitting): 1L5 XXXXXX
2. RX135 (With Catalytic Silencer as OE fitting): 4TL XXXXXX
3. RX135 5-Speed: 1L7 XXXXXX
4. RX-Z 4-Speed: 1L3 XXXXXX
5. RX100: 1L1 XXXXXX

P.S: The RX135 5-Speed never came with OE fitted Chrome silencer, the OE fit was the Big Hot-Tube type catalytic converter Exhaust.

Any comments/additions are most welcome.
Thank you.



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