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Discussion Starter · #1 ·
Hi all,
Any help, my nephew bought 1993 TZR 4HX and on the way home conrod lower bearing gave up on full throttle. I promised to fix the engine.

I have replaced crank bearings, new conrod, new piston, carburator cleaned multiple times with ultrasound washer and power valve cleaned and adjusted. Bike runs very well on idle and below 10krpm but starts cut around there. Also spits a bit oil from exhaust. I'm almost out of ideas. Thinking to replace igniton coil next.
I have tried new plug and lock the PV to open position.
Any ideas?
 

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Make sure the YPVS (the power valve) is adjusted correctly.

Also factory jetting in the carb could be off. Its not a guarantee that its perfect as it was, or that it hasnt been tempered with. Alcohol in fuel makes the micture lean!
 

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Discussion Starter · #3 ·
Make sure the YPVS (the power valve) is adjusted correctly.

Also factory jetting in the carb could be off. Its not a guarantee that its perfect as it was, or that it hasnt been tempered with. Alcohol in fuel makes the micture lean!
I have adjusted the ypvs and also locked it in open position so I'm pretty sure that this is not YPVS problem. Jetting is could be one, Feels that it's too rich on top than lean. Next I try another coil and jetting.
 
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