Luck was on my side this time

[250rRoostmaster]

211869211868211867

The pic tells all, it cracked all the way through to the wrist pin then started to burn a hole and pop. Could have been real bad but luckily she held together. Cylinder and head look perfect still! Whew! Last ride out at Florence my buddies bansheet took a crap about 2 miles away from camp and i had to get him back as 3 different people declined to help us... Towing with a 2 stroke is always kinda sketch but in the sand it's much harder on things and towing a fat quad didn't help either. This piston has only about 25 hours on it. It's a Pro-x which have a pretty good reputation but after this it's only forged for me. I run weisco pistons in my YZ250 and love them. My motor builder liked the pro-x and said he's never seen them fail really so against my better judgment i went with it. I'll put up some pics of the cylinder and a better shot of the piston later.

[petesatc]

happened to me about 10 years ago ......the piston cracked completely in half...mine was a OEM piston on original bore....i put out down to washing the bike down before the engine was cool enough??? changed the piston never had a problem since....

[250rRoostmaster]

We had to go through a few water crossing which may have contributed to the cracking. Hard to say.

[yaegerb]

211869211868211867

The pic tells all, it cracked all the way through to the wrist pin then started to burn a hole and pop. Could have been real bad but luckily she held together. Cylinder and head look perfect still! Whew! Last ride out at Florence my buddies bansheet took a crap about 2 miles away from camp and i had to get him back as 3 different people declined to help us... Towing with a 2 stroke is always kinda sketch but in the sand it's much harder on things and towing a fat quad didn't help either. This piston has only about 25 hours on it. It's a Pro-x which have a pretty good reputation but after this it's only forged for me. I run weisco pistons in my YZ250 and love them. My motor builder liked the pro-x and said he's never seen them fail really so against my better judgment i went with it. I'll put up some pics of the cylinder and a better shot of the piston later.

Woah, that sucks. God was on your side my friend. I don't know that I have seen a piston do that, but anything is possible. Are you going back with a wiseco? I hear the Wossner pistons are of high quality.

Haven't seen your bike close up before...I like it and still jealous of your LED pipe

[250rRoostmaster]

Woah, that sucks. God was on your side my friend. I don't know that I have seen a piston do that, but anything is possible. Are you going back with a wiseco? I hear the Wossner pistons are of high quality.

Haven't seen your bike close up before...I like it and still jealous of your LED pipe

Haha thank you sir! It had a cast Pro-x piston, so i will be going with a weisco moving forward.

[Dirtcrasher]

That is a beautiful trike!! So glad you didn't grenade the whole cylinder!!

Def not detonation, I bet it was the water. And I'd use a forged piston as well :D

[250rRoostmaster]

A few more pics to show how damn lucky I was... I put a lot of work into her so i appreciate the comments on my bike guys!

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[nd4speed]

Yeah your bike is sweet and that cracked piston is crazy ! At least it was not all bad in the end...

[Super350]

what made you check it out? Noise or just a hunch?

[250rRoostmaster]

what made you check it out? Noise or just a hunch?

It died, lost all compression about 5 mins in to the ride.

[onformula1]

I have seen this many, many times.

The problem happened do to inaudible detonation, (The silent killer) due to not enough octane at that time due to towing a boat anchor through sand.
To much load and lugging VS. the octane available. I have seen it a Glamis a ton of times...Towing trikes.

Your engine builder is correct stick with the Pro-X it has a better expansion rate that matches better with the cast iron bore, the Wiseco would have seized solid and probably bent the rod.

Polish the top of the cast piston lightly, (Don't change the exhaust port timing) it will help with stress risers in the crown casting.

[250rRoostmaster]

I guess that could explain it, I run 100% VP 112 octane race gas but i put a tremendous load on my motor that day in the sand. I will talk to Arlen (LED performance) this week when i take my stuff to him. Thanks for your input onformula1!

[hitmeup760]

This is good advice as this has happened to my brothers 250r, we were at Olds mobile and my cousins yfz 450 crapped out on him and he tried to tow him back to camp and in about 20min. Into the ride his 250r had the same thing happen as 250rRoostmaster, all power and compression was gone, he tried to kick start it and almost fell over with how easy it kicked foward, he was using an old piston though, rebuilt the top end with a weisco and all systems were a go, hope you get it running real soon.

[200X FT]

I got lucky also with my CRF 450. Pic below is of a CP piston that was in my bike. Went to start it up after sitting for the winter, and had no compression. Took the motor to my friend to check it out ( normally I would, but was on OT and had a race the next week). When I picked up the motor, that's when he showed me the piston. We both agreed I was lucky, especially since I just rebuilt the entire top end a year prior after breaking a valve. The piston was not new when I got it. The piston and the cylinder came from a guy at Crower cams who did some dyno pulls with it and took it off.211974

[oscarmayer]

sweet trike sir! O7
sucks about the piston, but as stated, glad it is an EZ fix and yea i would not be towing anything with that trike ever again. if you need to get yourself a crappy 200-250cc chinese quad you keep at the truck just for towing bikes back. they are good for towing stuff and cheap. or, get a big red :)