250-500cc WR300 - piston life

How many hours/klm/miles are you getting before you do a top end?

I ride every weekend and have racked up 70 hrs.

All second and third gear tight single/hills and logs etc.

Engine still feels and sounds like new but I suppose I have to consider a top end freshen up because all the KTM guys are telling me they do theres at 50hrs...

A mate has 150 hrs on his WR250 but is only more of an average rider.

What are your thoughts and experiences?

My 92 360 had more than 600 hours on its piston.

Stu

100 hours easy unless you WFO all day. i do mainly your type of riding but a bit of wide open stuff too & am comfortable at 100 hours(bout to do second top end 191 hours-hope bottom end holds out another 100!). got a compression comparison from new to now stu? another 10-20 hours & you may start to feel it gettin weaker but as its gradual its hard to tell til you put a new heart in her then you remember how it should go(flipped mine in the backyard mucking around after first top end-funny stuff or so my missus thought)!!! my mate used to do his ktm300 at 50 hours too, waste of money i reckon. you know the drill mate, full syn oil, clean filter, jetting(lectron!) & avoid taking her swimming too much(im guilty of this numerous times!). im sure you could push these oem vertex pistons(forged more so again) a fair bit further but why take the risk, if you got it apart to do rings a new slug is bugger all extra. hate for it to crack up & lunch ya bottom end! 600 hours on the 360 is crazy man, they are tractors though!

then again at the prices these things are going for atm might be financially better to just ride it till it dies then leave it in the bush & go buy a newy!!!

What's 100 hrs in tanks of fuel? I have no idea of hours. My 09 wr250 is running as good or better than the day it was born and every time I peek at the piston it looks perfect.

Just put a fresh piston in mine at 2500K's probably 125 hours. The old piston was in great shape but the rings were worn and compression had dropped over time to 165 psi. It's now got the bottom end grunt it always did.

As long as you have it tuned right and good oil and fuel, I don't see a reason to put on a new top end in only 50 hours. A buddy of mine's KTM 250 has over 200 hours on his top end and he runs a 100:1 oil ratio.