Piston after 60 mth.

[skiba_14]

Hi,

is it normal that piston is worn like this ? What cause such wear on the bottom part of side wall ? Piston - Wossner A, brand new cylinder, GAS GAS EC 250 2012

[Neil E.]

Looks perfectly normal to me. 60 months is 5 years of use. Add up the hours and see what the total running time has been. The wear pattern is similar to what I get since I lug the bike more than I rev it.

[Davehuge]

I agree, looks perfectly normal wear.

Replace piston kit and keep riding.

[Jacob 'Berg]

Yep. Looks normal. You are going to see some scuffing on the piston skirt as the piston rocks in the bore of the cylinder a bit.

[Jakobi]

What they all said.. Piston can rock a bit on the pin given tolerances.. Some polishing is to be seen. Wear looks minimal..

[Jakobi]

Here's one of my 250 slugs that I ran well past it's good point.. 110hrs (70hrs is about right for me and my riding).

Top ring: 0.88mm
Bottom: 0.63mm

Intake Side


Exhaust Side




A bit of excess blow by on one side.


Lots of blow by.. rings end gaps flogged.. cylinder still in spec. Lesson learnt! 110hrs too much for me.