Jump to content
Sign in to follow this  

Please take a look at my cylinder & piston

Recommended Posts

I recently bought an '03 kx 60 for my son. He rode it for the 1st time this weekend. The bike ran well until my son rode it into a deep puddle and then dropped the bike on it's side. Unfortunately it was the side the airbox is on.

Long story short, muddy water got all the way into the crankcase. I'll be splitting the cases to clean all the silt/mud out and will put a new crank in.

Based on the pictures of the cylinder and piston, what happened to make those marks? Is it common for the exhaust side to wear faster than the intake? The rest of the cylinder and piston look to be in decent shape. The guy I bought it from said the top end had never been replaced.

Is there any hope for cleaning up the cylinder and putting a new piston/ring back in? Or does it need to be replated?

It really sucks that I just bought the bike and will now be rebuilding the engine. I don't want to cut any corners, but I'd like to not spend any additional money if I don't have to.

Thanks for any feedback.

DSC01370.jpg

DSC01369.jpg

DSC01367.jpg

Share this post


Link to post
Share on other sites

Those smudges look like oil to me:excuseme:

And if the top end has never been replaced and its a 2003, I'm surprised it looks that way. It should look worse.

Share this post


Link to post
Share on other sites

I can't feel the scratches with my fingernail. Do the marks that are showing up in the cylinder areas where the plating has worn off? I took a scotchbright pad and some carb cleaner and tried to clean the areas up and nothing happened.

Share this post


Link to post
Share on other sites

Is it a mark off of the KIPS? Seems like there is a plastic or rubber piece there that may make a mark if damaged or forced out too far.

That looks way better than sand damage.

-Kerry

Share this post


Link to post
Share on other sites

Is that scuff right over the exhaust port bridge? If it is then I don't believe the water damaged the piston. When the exhaust port bridge becomes too hot, like from an air leak between the pipe and the cylinder, it can cause scuffing like that. Wiseco pistons recommend drilling some holes in the piston in that area to allow some lube to get to the exhaust port bridge. If that is the intake side, then it was probably silt. You could flush out the crankcase with solvent, clean up the scuffs, and put it back together to see how it goes first before you rebuild the top and bottom end. It is only a 60 and your son will probably outgrow the bike pretty quick. The rest of the cylinder and piston actually don't look to bad to me.

Share this post


Link to post
Share on other sites

it tried to seize.... that's an exhaust port bridge scuff..... it means at least one time,it was too hot... you'll want to take all the normal precautions when it goes back together... cylinder plating inspect,carb jetting,crank seals,fuel mix,air leaks... e.t.c e.t.c.

  • Like 1

Share this post


Link to post
Share on other sites
Is it a mark off of the KIPS? Seems like there is a plastic or rubber piece there that may make a mark if damaged or forced out too far.

That looks way better than sand damage.

-Kerry

The 60's don't have a KIPS valve. If it was my bike I would get it replated and even bored out 2mm's. Depending on the size of your son and his riding experience build it to last. The 60's do like a fresh clean air filter every ride. My son's would bog out real bad and load up if we tried to ride on a filter a 2nd and 3rd time. Those little motor's scream like you would not believe. Do it right and do it once. That's my .02.:)

  • Like 1

Share this post


Link to post
Share on other sites
Is that scuff right over the exhaust port bridge? If it is then I don't believe the water damaged the piston. When the exhaust port bridge becomes too hot, like from an air leak between the pipe and the cylinder, it can cause scuffing like that. Wiseco pistons recommend drilling some holes in the piston in that area to allow some lube to get to the exhaust port bridge. If that is the intake side, then it was probably silt. You could flush out the crankcase with solvent, clean up the scuffs, and put it back together to see how it goes first before you rebuild the top and bottom end. It is only a 60 and your son will probably outgrow the bike pretty quick. The rest of the cylinder and piston actually don't look to bad to me.

+1

Try some super fine emery cloth to clean up the cylinder.

Oh, get some better shop rags, you got lint all over everything. They sell "box o' rags" that work great in the shop, kind of like heavy duty paper towels.

Share this post


Link to post
Share on other sites

instead of a scotchbrite pad try some 400 grit sand paper. Dont worry you wont hurt the plating. It looks like the piston seized to the exhaust bridge (as was said before) The plating is extremely tough and you can put some elbow grease into it. Of course the best way would be to get some muratic acid which melts (for lack of a better term) AL but be careful not to get it into any ports. Clean off the AL that you can see, put a new piston in it and run it, it will be fine.

Share this post


Link to post
Share on other sites
Have you tried to just hone out the cyl? It doesn't look to bad if you say the scatches in the cyl are not bad enough to feel with a fingernail. I would first try to hone the cyl. I would replace the piston/rings but make sure it has the holes on the exh bridge drilled into the piston.

If the scatches are still showing after having it hone, rebore and replace the piston/rings. And of course any seals and/or bearings in the crank/rod.

As you have found out.... the engine doesn't like water......

The KX60 uses an electrofusion coating on the cylinder. DO NOT hone electrofusion cylinders. Kawasaki's electrofusion coating is much softer than nicasil (Kawie uses molbydenum for their coating) and is easily chipped and damaged around the port windows when using a hone. If the seizure transferred some aluminum to the bore, miuratic acid, when carefully used, can clean it off of the bore surface. If there are scratches that you can see, or the cross-hatch is damaged, the cylinder needs to be repaired. Send it to a re-plater for new plating.

Even if you can't feel a scratch with your finger nail, it is still gargantuan as far as the rings and piston are concerned when running across the scratch at 14,000 rpm. A scratch in the plating will usually cause the plating to flake and peel at that point if the cylinder is put into service. If a Scotch Brite pad won't remove the scratch, it is too deep for the cylinder to be used.

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  

×