TS125 conversion to 150

Forums Technical Two Stroke: Help needed TS125 conversion to 150

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    • #4387

      Hi everyone.

      I am restoring a ’79 TS 125 and wonder how easy a conversion to 150cc would be.

      Do the engines share the same bottom end?
      Can a 125 barrel be bored to 150?
      Is the head the same?
      Does the 150 need a larger choke carb, or simply a re-jet of the 125 item?

      For those with experience of riding both, is the extra oomph of the 150 worth having?

      Many thanks!


    • #4402
      Peter Gunnee

      Hi Drew
      I have done the conversion, by swapping barrel,piston, head and carb.
      All the bottom end is the same , apart from the final drive sprocket which goes up a tooth on the 150.
      The heads are different, combustion chamber is smaller on a 125.
      The inlet stub and carb are smaller on a 125, they may work on a 150, but I think it would reduce the power.
      The result I was very pleased with, the engine was much smoother when running, ( possibly the engine balances better as a 150), and although performance was not much quicker the whole feel of the motorcycle was that it was not being “thrashed” quite as much. Definitely worth doing.

      Hope this helps


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