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  6. KTT Valve Timing No. 24 Cam

As used in K.T.T. engines up to KTT270.

The valve timing is best carried out by fixing a disc to the sprocket side of the crankshaft, marked out in degrees; a pointer should be fixed under the cylinder base nut, this can be made of a piece of stiff wire.

Set Exhaust and Inlet Tappet to .012 clearance.

Now set the disc on the crankshaft to show--.0 degrees on the pointer when the piston is at the top or bottom of its stroke.

Remove inlet Rocker, turn the engine round until the exhaust cam comes against the rocker, this should be brought firmly against it, sufficient to take all slack; the reading on the disc should be between 65/70 degrees. Now turn the engine backwards, and test the reverse side of the Cam, the reading should be 45/50 degrees after the piston has reached the top.

It is only necessary to check one valve to arrive at the correct timing. To check the inletIt is only necessary to check one valve to arrive at the correct timing. To check the inletvalve, the exhaust rocker should be removed, and then proceed as before. Inlet should beopen 38/42 degrees before the piston reaches the top, and close 54/58 degrees after itreaches bottom.

To check timing by piston movement, test the overlap.

The inlet valve opens before top of stroke 3/8" approximately.The Exhaust Valve closes after top of stroke 9/16"

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  • Velocette Documents
    • GTP Manuals
      • F40/5R GTP Instruction Book 1951
    • KSS, KTS Manuals
      • F236/4R Mk. II OHC Instruction Book 1950
      • F42/3R OHC Models 1925-1931 Instruction Book
    • MAC Manuals
      • F469/4R MAC Service Guide 1965
      • F466/2R MAC Owner's Handbook 1955
      • F50/7R MAC Rigid Frame Service Manual 1955
      • F50/4R Supplement
    • MOV and MAC
      • F131-3R Instruction Book 1937
    • MSS Manuals
      • F477 Owners Handbook 1954
    • Venom, Viper, MSS
      • F485/1R Owner's Handbook 1956
      • F484/9R Service Guide 1967
      • F484/11R Service Guide 1971
    • Valiant Manuals
      • F62-1R Service Manual