Rotax Evo 125 Seizure at PFI Onboard

We had an engine seizure with our Rotax Evo while testing at PFI. Luckily we had the race engine with us and swapped it out in a few minutes and finished off the test day. When we got home I stripped the top end for a look at what went wrong. It looks like the piston failed and broke away from the conrod. The barrel and piston are gone but initial inspection I think the Bottom end and crank have survived. We will split the cases and have a proper look later.

[@YszapHun]

This is pretty suspicious, I don't think this was caused by lack of lubrication or lean mixture. Judging from the sheer amount of damage I'd guess that maybe the top end needle bearing has failed and that led to other parts exploding, or maybe material fatigue of the piston skirt.

[@samlloyd8687]

could be due to the temperature in the engine if its below 45 for s period of time the piston seizes

[@weofnjieofing]

The needle looked intact on the piston pin so I’d agree it was the piston shattering from stress fatigue.
A good reason to remind ppl never to just change the ring but the whole piston itself.
What was the CHT, EGT and water temps like? Was this straight out of the pits? What fuel/oil ratio did you use?

[@exup35]

Running lean maybe and engine overheat?

[@MeltingRubberZ28]

​@exup35 usually you can see a melted section on the piston if failure due to lean condition

[@IggySport1388]

How many hours did it have on the piston up to that point?

[@mymodel6]

That'll buff out....

[@robertwalker8023]

I take it that's not a standard barrel from Rotax is it??

[@gregw6748]

That’s not a seize.

[@rudyfarkas5461]

R I P ,

[@MaxVerstappenGlazer]

Did you run too lean?

[@svisser79]

Rip

[@wolfgangbaran340]

Na,da lag wohl ein kleiner Wartungsstau an...

[@leonardobaccaglini]

You did the impossible

[@vincentrobinette1507]

It looks like the piston shattered, breaking at the wristpin journals. There were no mistakes made, "That's just racing"

[@serchmarc]

is it better to buy a new engine or new cylinder kit?

[@Wheelshots]

we rebuilt with a new cylinder etc.

[@serchmarc]

@@Wheelshots how much in parts?cylinder,piston,rings,etc
no handwork.

[@Wheelshots]

@@serchmarc It was about £600 inc new bearings and seals.

[@michaeldecker2725]

You lose power in a turn and you stop on the track, why?

[@cynnf3406]

if he’s stop on the grass he’s risk damaging it more as the grass looks pretty wet so he just stopped off of the racing line

[@hendrox1]

In Brazil the engine locks the axle, At the end of the straight only Jesus to save.😂😂😂🏎🇧🇷🏁

[@K66192]

JAJAJAJAJAJAJAJAJAJAJAJAJAJAJA 😐

[@PlasticBoi]

hmmm looks like the end of that engine then

[@bartjr.notten626]

jeeeeezus

[@brandonlloyd1826]

i love the video i just wish it was slower
bloody hell george hahaha

[@spice3767]

Normal day in x30 🤣

[@CarlPearce]

I think i know whats wrong with it. It's got no gas in it.

[@BK-it6te]

There is only one word for this CAPUT
Why you think it Broke?🧐

[@KRM42-B]

I've never seen it happen with rotax, I've seen it happen with iames, kz's, parrilla... but never rotax

[@silasbluhm]

thats because Rotax are way more reliable than all the others but things like this can still happen

[@Aviopic]

There has beena problem with early Evo's cylinders, this was corrected in 2018/2019 which new cylinders via a special Rotas upgrade deal.

[@SirAlbertoAcrt]

oioioioioioi o mama