Since I am a teacher I felt it oblivious this kid needs some visual aids to help him learn since he is unwilling to do self research and needs to be spoon fed.

and many other piston malfunctions

Please see "Shattered Skirt" which is cause by to much piston to cylinder wall clearance.

 

On the contrary what keeps the piston from turning sideways in the cylinder?

 

Hmmmmmmmmmmm, Come to think of it I have never heard of a stock engine blowing, wow how come I have never realized this!!!

NOOOOOOOOOOOOOOOOOOOOOOOOOOOT!

Get serious, stock engines blow too.

 

One dusty ride could potentially ruin a set of rings and a cylinder. I am glad you have had good luck with the K and N filters, but this still does not change the fact that they let unfiltered air pass by...this has been proven over and over. Why do you think K and N recommends a prefilter for very dusty conditions? Honda detunes their atv's for emissions? Please. So why does Honda have to detune their atv's to meet emissions while no other manufacturer has to? Your statement has no basis.
Gary

 

I had a 91 Lt250 that was bone stock and the piston skirt broke after 15hrs of riding. They do get defects just like any other manufactured part. Thay aren't all perfect like we wish they were. Press the dealer to warrantee it. It had to be a defective piston. I ran K&N's on all 3 of my bikes and only ride in the desert (doesn't get much dustier than that)as long as you use a prefilter it will work just fine. But if your concerned try a different filter setup next time. When used right they work well. IMO
Just my 2 cents.

 

K&N recommends outerwear to lessen the frequency of cleanings? Why? because you're supposed to chunk it after 25 washes. Wouldn't take long in dusty conditions and who wants to fork out $60 so often?

Emissions, yes. Why do you think you can change jetting and add up to 2 hp on a 400ex? They come slightly lean and it's not just Honda. No basis? Come on. You're a smart guy Gary. Use your head. The EPA and treehuggers will be after the 4-stroke recreational vehicles next. But Honda is a leader in environmentally friendly engine technology.

 

HONDA ATV FIRST TO MEET EPA 2006 OFF-HIGHWAY EMISSIONS STANDARDS

Torrance, CA - The 2005 Honda TRX400EX has just received the first Certificate of Conformity awarded by the Environmental Protection Agency, under the new low emissions regulations, adopted late last year, for recreation vehicles and engines, beginning in 2006.

Widely acknowledged as a leader in safety and environmental technology, Honda has a long list of "firsts" in applying new thinking and technologies to production vehicles.

"We're extremely pleased and excited to offer our customers environmentally-friendly machines that don't sacrifice anything in terms of performance and fun", said Ray Blank, American Honda Motor Co., Inc., Motorcycle Division Vice President. "We take a great deal of pride in being the first manufacturer to receive the EPA's certification for the 2006 regulations that apply to off-highway motorcycles, and ATVs, well before the new federal standards take effect."

The TRX400EX will be available for sale after the Honda dealer convention in September 2004, where seven additional 2005 Honda ATV models that meet the 2006 EPA regulation will also be announced.

 

The piston skirt brakes from too much piston to cylinder wall clearance. The piston rattles at the bottom of the cylinder and breaks the skirt off. The most common cause is the motor digested a lot of dirt through the air intake.

 

Also incorrect piston/cylinder fitment could cause this too in addition to your previous comments.

Also detonation prior to top dead center will cause the piston to rock having tow forces acting in opposite directions putting a lot of pressure on the skirt trying to keep the piston straight which can also cause skirt failure but detonation generally cause others problems before the skirt has time to be a problem.

 

I just think there would have been other evidence to support foreign debris or predetonation.