Bottom part of the piston broke off

[ricmonro4]

Hey,
I got a 250r with the hondaline 300r kit on it and I've seemed to brake off the bottom side of the piston when it was at WOT. I opened it up and this is what I found. Plus pieces of the piston all over inside. I can't kick it. The kickstarter is stuck. What caused this and how would I fix it. Is it common ?

[Samjp22]

Theres no picture.... could've been caused by a number of reasons and you fix it by rebuilding it, and you probably can't kick it cause theres pieces of piston in the bottom end or the bottom ends hurt real bad

[onformula1]

To help we need pics and more info.

Examples-

Type of premix & ratio?
What kind of gas are you running?
Time on the piston & rings?
Time on rod & lower end bearing & wrist pin bearing?
Is it jetted correctly?
Did it have a air leak?
Where were you ridding?, Paddles?, sand?, hot day?, cold day?, towing?

[Degoragon]

Hopefully, nothing else is damaged. If you're lucky, you will need just a new piston. Most likely the wrist pin got loose or sheared. How is the wrist pin, does the piston head have a lot of side to side movement?
Id inspect that engine thoroughly for damage, but if you caught it early, you may have only a piston to deal with. Had it happen on a Kawasaki trail bike.

[just ben]

The skirt breaking off is caused by excessive cylinder wall clearance causing "piston slap" you will need an over sized piston to fix it right.

[ricmonro4]

212968

This is the piston. Sorry for the late post

[ricmonro4]

What do you guys think. I have never done a top end before but I have the original service manual that take it step by step

[muthey]

I can tell you right now just by looking at your piston that your cylinder needs to be bored and you need to go to a over size piston

[atc300r]

Oem pistons are hard to find. There are no direct install after market pistons available. Some guys send there cylinder to racerstoystore to get a new piston for a liquid R big bore and have the cylinder machined to fit it.