Piston/Engine Help!

[Rszeus]

Today my piston (wiseco)decided to scatted again. The rear piston skrit broke and shot down into the crank. This is the 3rd Time it has happened!(first time was my fault mixed 50:1). I had this piston in for roughly 3 months and boom. I am really getting fed up with it so i came here for help. For mods i am bored 20 over,V force reeds,14/40 sprockets,I usually mix my oil/gas mixer at 32:1,I do "beat" on it(i was also riding on snow in those 3 months),I have stock air filter, I have tried to change the jetting but i go bigger it just bogges to no end, I am on stock jetting,i have installed the tors removal(lost a piston to that),I have done a leak down test no leaks.Other than that everything is stock.

Is there something i could be doing wrong? I Dont think it has to doing with jetting. But if you have any ideas i would be glad to listen to them.

 

[Wheels]

Who has been doing your machine work?

 

[Rszeus]

Me myself and I

 

[Wheels]

Have you been measuring your piston and bore with precision tools to make sure your clearances are correct, or have you just been honing it and slapping in a 20 over piston every time?

 

[Awk08]

pics of shattered wiseco piston, and a 14 year old boring a cylinder.....or you're lying/trolling !

 

[Larry's Shee]

Explain what champhering the ports means. Then we will know more about your knowledge. What clearance are you setting your pistons
to?

 

[Blaaster]

You are running a stock #230 jet, mixing at 32:1 and running in very cold weather, you most certainly are on the lean side.

How did the plugs look after a plug chop.

Did you realise that forged pistons require a specialised warm up sequence, and really do not like being hammered in cold weather if they are not warmed up properly.

You say you usually mix at 32:1, what other ratios do you try, bearing in mind that every time you change the fuel/oil ratio you must change the jetting to suit the amount of fuel discrepancy in the mix.

You cannot just chop annd change the AFR and expect a piston to give you good service!

I think the problem lies with an operator stuffing around with things that they do not understand.

How on earth can you blame a TORS removal for the loss of a piston, adjust the idle and nothing esle has to be done, it must be operator error.

 

[Racer51]

eather his jetting is way off (and it probably is) or he dosent have enough clearance and the shattered skirt affected some movement in his crank (for the minisquel amount of time it was allowed to run with bits of metal down there). A shattered skirt is basicly a living nightmare for most. but checking diameter of the cylinder is kinda second nature. Have you been just throwing in 20 over pistons and hopeing it works?

 

[Wheels]

What happened to our friend Zeus?

 

[Larry's Shee]

What happened to our friend Zeus?

We weren't that rough on the kid

 

[Rszeus]

Sorry just finally got back to a computer and i may try my luck at rejetting. My jug bored ported and polish by aggressive porting. I have additionally gone though 3 whole new(used) motors. I may try different mix ratios. And the tors blew up a piston because it held open the slide and i never knew. And i may be youth but i have a good bit of knowledge about these.

 

[best]

Breaking skirts is usually from too much piston to cylinder clearance.
If you post pictures many of us old hands can give a more informed opinion.
I have run 50:1 quite successfully for many years, so I doubt that is your problem.

"Held open the slide and i never knew"? Normally the loud reving noise is a hint.

Forged pistons take careful warmup to prevent seizure.

If you have gone through 3 new (used) motors you should be looking doing somethings different. I'd suggest carefully measuring bore clearance, leaktests, and plug chops to set jetting.

Steve

 

[Blaaster]

"Held open the slide and i never knew"? Normally the loud reving noise is a hint.

Steve

Steve, let me show you what this comment caused.

 

[Larry's Shee]

Sorry just finally got back to a computer and i may try my luck at rejetting.Might as well try something, what you're doing now isn't working too good My jug bored ported and polish by aggressive porting. Is this what you call yourself?I have additionally gone though 3 whole new(used) motors. I may try different mix ratios. And the tors blew up a piston because it held open the slide and i never knew. And i may be youth but i have a good bit of knowledge about these.Seems as though you're on the wrong side of the learning curve

On another note, do you have a good right side case and counter balance gear? You must have spares 8-|

 

[best]

Steve, let me show you what this comment caused.

Ha! I've known that thrill myself on occasion!
My son had a close brush with death from just such an event.
I hope he doesn't mind me mentioning it, but he'd tell it himself and there is something to learn from it...

He was 15 I believe, just did his biggest rebuild to date on his YZ125 and he was excited to try it out.
Unfortunately the airfilter is held together with thermo-setting glue and came apart when he washed it in hot water (MAKE A NOTE!).
Anxious to try it out, he gave it a run with no filter and as best we can tell, some inhaled grit wedged the throttle slide stuck open at WOT. (NOTE THIS TOO)

Did you know a 2 stroke at full throttle will "auto-run" even with the ignition off or kill switch made?
Well MAKE ANOTHER NOTE because I have seen it many times. Red hot sparkplug electrode with act like a glow plug.
One quick shot on the gas and the bike unexpectedly carried on at full throttle across the lawn and into my thunderbird,
son frantically stabbing the kill switch and brake to no avail.
The rear brake will not stop a 40hp engine in 2nd or 3rd gear. So MAKE ANOTHER NOTE

Luckily he caught the front wheel of my Thunderbird instead of the house, and flew over the handlebars and car hood.
The collision bent a tie rod, stowed in the fender, crushed the air filter box, wrinkled the hood and darned near broke 2 femurs.
About $1200 worth of parts damage on the T-Bird. Remarkably, not a bit of damage to the YZ125.
Son's legs were badly bruised from the bars, thank God he was wearing a helmet! (MAKE ANOTHER NOTE!)

Another condition that will cause unintended accelleration is when the engine leans out.
Hill climbing on a near empty fuel tank will cause some exciting moments from this.

Steve

 

[Rszeus]

When i put this next piston in (gonna be a wiseco) and ill measure up the piston although with the cylinder. And if i go though this piston again(break skrit) ill probably end up selling it.

 

[frankin blaster]

Ha! I've known that thrill myself on occasion!
My son had a close brush with death from just such an event.
I hope he doesn't mind me mentioning it, but he'd tell it himself and there is something to learn from it...

He was 15 I believe, just did his biggest rebuild to date on his YZ125 and he was excited to try it out.
Unfortunately the airfilter is held together with thermo-setting glue and came apart when he washed it in hot water (MAKE A NOTE!).
Anxious to try it out, he gave it a run with no filter and as best we can tell, some inhaled grit wedged the throttle slide stuck open at WOT. (NOTE THIS TOO)

Did you know a 2 stroke at full throttle will "auto-run" even with the ignition off or kill switch made?
Well MAKE ANOTHER NOTE because I have seen it many times. Red hot sparkplug electrode with act like a glow plug.
One quick shot on the gas and the bike unexpectedly carried on at full throttle across the lawn and into my thunderbird,
son frantically stabbing the kill switch and brake to no avail.
The rear brake will not stop a 40hp engine in 2nd or 3rd gear. So MAKE ANOTHER NOTE

Luckily he caught the front wheel of my Thunderbird instead of the house, and flew over the handlebars and car hood.
The collision bent a tie rod, stowed in the fender, crushed the air filter box, wrinkled the hood and darned near broke 2 femurs.
About $1200 worth of parts damage on the T-Bird. Remarkably, not a bit of damage to the YZ125.
Son's legs were badly bruised from the bars, thank God he was wearing a helmet! (MAKE ANOTHER NOTE!)

Another condition that will cause unintended accelleration is when the engine leans out.
Hill climbing on a near empty fuel tank will cause some exciting moments from this.

Steve

i feel lucky knowing i was lucky enough that my plug didnt get to red so i was able to use the key to kill it note taken an saved to my hard drive.. even though after reading that i doubt ill ever forget it.. sorry about the car and glad your son was ok to could have been even worse..

 

[Blaaster]

When i put this next piston in (gonna be a wiseco) and ill measure up the piston although with the cylinder. And if i go though this piston again(break skrit) ill probably end up selling it.

No matter what piston you choose be it cast or forged it must be treated kindly.

Proper jetting, good oil at a respectable ratio, air cleaner, regular leak checks and all preventitive maintainence must be observed.

A motor must be warmed up well before riding to allow components to expand
gradually.

Riding before warm up is a guarentee of short piston life, and believe you me if you choose a forged piston you must adhere to the practice of proper warm up.

Rszeus, take note of my sig quote. Do not take the attitude of "I just wanna ride".

 

[Rszeus]

Ill keep the warm up sequence in mind. Ill let it warm up more. But hopefull This piston with Last longer. (long enough for me to save $90 for a new one )

 

[joeak47]

Ill keep the warm up sequence in mind. Ill let it warm up more. But hopefull This piston with Last longer. (long enough for me to save $90 for a new one )

Can you please post some pictures of the broken piston(s)?