Jump to content
Sign in to follow this  

Piston exploded in cr250

Recommended Posts

So i am rebuilding my buddy's 2001 cr250. When i took the cylinder off i saw what happened. The piston was destroyed. What do you think was the cause? 

20140724_1357321.jpg

20140724_1308141.jpg

20140724_1357451.jpg

Share this post


Link to post
Share on other sites

There is no question what happened.. He ran the piston beyond it's service limits and the skirt let go. This happened to me end of March this year as well, also on my 2001 CR250.

 

It cost me over $700 in parts, with me doing all the labor, to fix it. A piece of skirt went into the crankcase and got wedged between the crank stuffers & the case halves and blew a chunk out of both case halves. I ended up having to get cylinder re-sleeved, new piston, new rings, rebuilt crank, all new bottom end bearings.

 

Ken O'Connor racing is who I used and I would HIGHLY recommend him. His work is awesome.

  • Like 2

Share this post


Link to post
Share on other sites

Looks like some serious detonation was happening too.

Edited by CamP
  • Like 3

Share this post


Link to post
Share on other sites

So i am rebuilding my buddy's 2001 cr250. When i took the cylinder off i saw what happened. The piston was destroyed. What do you think was the cause?

Very nice

Share this post


Link to post
Share on other sites

There is no question what happened.. He ran the piston beyond it's service limits and the skirt let go. This happened to me end of March this year as well, also on my 2001 CR250.

It cost me over $700 in parts, with me doing all the labor, to fix it. A piece of skirt went into the crankcase and got wedged between the crank stuffers & the case halves and blew a chunk out of both case halves. I ended up having to get cylinder re-sleeved, new piston, new rings, rebuilt crank, all new bottom end bearings.

Ken O'Connor racing is who I used and I would HIGHLY recommend him. His work is awesome.

I thoughtbu said you did all the work. I'm confused.

Share this post


Link to post
Share on other sites

The 92-01 motor will break the skirt if you run it past its time but like Cam said that motor had some serious detonation going on. Air leak, low octane fuel are some of the possibilities.

Share this post


Link to post
Share on other sites

dirty, I did all the LABOR..  I live in Houston & shipped my parts off to KOC. Ken O'Connor did the machine work, milling the head, re-plating the cylinder, rebuilt the crank-you know those things that we home-mechanics can't do at home..

 

I separated the case halves, sent them out to be welded by a local aluminum welding specialty shop, pulled & replaced all bearings, seals, gaskets, pressed all the bearings, put all the fresh parts back together.

  • Like 1

Share this post


Link to post
Share on other sites

Looks like some serious detonation was happening too.

Looks like some serious detonation was happening too.

Agree, That is a melt down condition. Lean jetting, Air Leak, Lack of octane in fuel. Some or all of the above.

Share this post


Link to post
Share on other sites

Looks like some serious detonation was happening too.

As you said and look at the silicone reed gaskets , probably lean too. 

Share this post


Link to post
Share on other sites

There is no question what happened.. He ran the piston beyond it's service limits and the skirt let go. This happened to me end of March this year as well, also on my 2001 CR250.

 

It cost me over $700 in parts, with me doing all the labor, to fix it. A piece of skirt went into the crankcase and got wedged between the crank stuffers & the case halves and blew a chunk out of both case halves. I ended up having to get cylinder re-sleeved, new piston, new rings, rebuilt crank, all new bottom end bearings.

 

Ken O'Connor racing is who I used and I would HIGHLY recommend him. His work is awesome.

Only shop that will touch my machine work and he will answer the phone  :thumbsup:

Share this post


Link to post
Share on other sites

Looks like this was caused by severe lack of maintenance and proper care.

Share this post


Link to post
Share on other sites

Hello again, so i have some shots of the cylinder and want to know if it is in good enough shape to hone and rebuild. Obviously i am no expert in this area so i will lean on you kind folks.

 

20140725_152057.jpg20140725_152108.jpg

 

20140725_152131.jpg20140725_152120.jpg

Share this post


Link to post
Share on other sites

Hello again, so i have some shots of the cylinder and want to know if it is in good enough shape to hone and rebuild. Obviously i am no expert in this area so i will lean on you kind folks.

 

 

 

 

 

If there are no grooves that catch a fingernail and no cylinder plating missing, you can reuse the cylinder after a little glaze breaker or scotchbrite work.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×