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CR125 HPP, Altering the Exhaust Valve Timing

A recent modification on a '98-'99 Cr125 bike that alters the exhaust valve timing. A simple spacer made on the metal lathe that adds some preload on the governor spring hence retarding the engagement with the exhaust valve linkage. This mod can help for enduro use or with bigger carbs.
I mostly followed the instructions from the below link though I made the spacer slightly thinner at 2mm thick.
Link at :
Honda 125 - HPP setup TIPS & TRICKS & TUNING @


  1. You don't have to make a shim,just press the outer spring holder on as far as you want to preload,no taking anything apart,There will be no coil binding on the spring,I have gone as far as 4mm

  2. Hi, did it work? Have you tried 3mm as well? Would appreciate a brief review! Thanks


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