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Converting a DS-7 roadbike into a TD 3 racer special.

There are a number of similarities between the DS-7 roadbike and the TD3 production roadracer which allow the roadster to be converted into a competitive racer. In 1972 Yamaha released a bulletin on how to complete this conversion. Below is essentially a transcript of that bulletin. Please note, a few of the parts mentioned are no longer available through Yamaha.

Please check the part numbers with your supplier before attempting to order.

 

 

A fine example of a DS-7 converted to a TD-3 roadracer.

 

 

 

 

Model: . . . . .                                         TD 3 (DS 7 Engine Used)

Displacement. .                                     247cc

Bore and Stroke:                                   54 x 54mrn

Number of Cylinders:                          2

Use: . . . . . . . . .                                     Road Racer, Drag Racer and Half Miler

Cylinder Head Volume: . . . . . . . . .     10.2cc   (Part No. 239‑11111‑00‑00)

Carburettor Size: . . . . . . . .                   VM 34 SC  (Part No. 329‑14101‑00‑00) 

Ignition Timing: . . . . .                         2.0mm BTDC

Spark Plug Heat Range: . . . . . .         NGK B 10 EN


Special Parts: (Road Racer only)

 

Rods: . . . . . . . . .                                   TD 3, Slotted                              (Part No. 328‑11650‑09‑00)

Bearings: . . . . . . .                                 Small end                                    (Part No. 93310‑21636‑00)

Big end (Silver cage) . . .          (Part No. 93310‑42255‑00)             

Crankshaft Main Bearings       (Special)

Tacho Idler Gear Set:                (Bearing: Part No. 93310‑21564‑00)

                                                                                                                     (Gear: Part No. 328‑15650‑00‑00)

                                                                                                                     (Washers ‑ two each:  Part No. 328‑15653‑00‑00)

                                                                                                                   (All tacho idler gear parts above must be installed as a set.)

Ignition System: . . . . . .                       CDI Magneto Assembly         (Part No. 328‑8500‑10‑00)  

Ignition Coil ‑ two each            (Part No. 328‑82310‑60‑00)

CD1 Unit Assembly                  (Part No. 328‑85540‑10‑00)

Clutch: . . . . . . . . .                                 Exposed, dry type                     (Part No. 328‑16301‑10‑00)

Clutch Primary Gear                  (Part No. 328 - 16150 - 10 - 00)  Use this gear with dry clutch only.

                                                               Covered, wet type                     (Part No. 329‑16301‑00‑00)

                                                               Clutch Primary Gear                  (Part No. 328 - 16111 - 10 - 00)  Use this gear with wet clutch only.

Transmission: . . . .                               TD3 Close Ratio transmission is available in 5 or 6 speed.

                                                                Transmission Shaft is a special for the dry clutch if used.

Expansion Chambers:  . . . .                  TD3              Left side:               (Part No. 329‑14610‑00‑00)

                                                                                       Right side:            (Part No. 329‑14620‑00‑00)


Optional Equipment:                                                                                                                                                 

Chassis:                                                  TD 3                Frame:           (Part No.  328‑21110‑00‑33)

           Swing Arm: (Part No. 239‑22110‑00‑33)

Wheels:                                                  TD 3                 28‑inch Alloy Rims

Brakes:                                                    TD 3                Drum Type:   Four Leading Shoes ‑ Front

                  One Leading, One Trailing ‑ Rear

Fuel Tank Assembly: . . . . .                                                                 (Part No. 328‑24110‑00‑00)

Front Forks Assembly . . . .                                                                (Part No. 328‑23100‑00‑00)

Fairing Assembly: . . . . .                                                                      (Part No. 328‑28350‑00‑02)

Note: When using TD 3 parts in a DS 7 engine, be sure to check parts book for interchangeability. Many individual parts are not interchangeable, and must be ordered and used as sets. 


Cylinders:

TD3 Roadrace cylinders used:                           Left side:               (Part No. 329-11311-00-00)

                                                                                 Right side:             (Part No. 329-11321-00-00)

 

 

 

All dimensions are in millimeters.

Tolerance: 0.5mm 

 

 

 

 


Pistons:

TD3 Roadrace pistons used:                                                               (Part No. 329-11631-00-96,97, 98 or 99) 


Expansion Chambers:

TD3 Roadrace expansion chambers used:         Left side:               (Part No. 329-14610-00-00)

                                                                                  Right side:            (Part No. 329-14620-00-00)

 

 

Material thickness 1.0mm

All dimensions in millimetres.

Tolerance 1.0mm            

 

 


                                            
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03/23/08 07:15 AM +1000    

This website Greg Bennett 2002.