KTM 300 SX need some help

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11/21/2020 12:29 PM

After 60 hours it’s time for a new piston on my 300 SX 2019
Previous owner used the OEM KTM Piston 55630107000. 1 with 71,925 mm which is not availeable the next weeks also not the 55630107000. 2 with 71,935mm

If i Look for Aftermarket Wössner -ProX or Wiseco i found Sizes from 71,94 to 71,96 ?
What Zylinder -Piston gap works for the 300 and what Piston Brand/Size you use ?


11/21/2020 4:22 PM

The size is going to depend on your cylinder bore size, but if you don't have a inside bore gauge to measure, I would just go with the 71.4mm. If the cylinder is worn, then go with the 71.95 or 71.96. Again, without an inside bore gauge you can't measure it properly, don't try to use a regular caliper and measure across the top of the cylinder bore, it won't get you a good enough measurement when you are looking for that .01mm.

But if the cylinder still looks good, just go with the next bigger size, the 71.4mm.


11/25/2020 12:49 AM

Same as the person above said