[efiles123]

Today I finally decided to take apart the top end on my 2003 klx 110 that has been ridden countless hours. The bike only had about 100psi compression and about 2/3 power of a fresh 110 so I was expecting to find some parts ready to be replaced. Here’s some questions:

1. Valves- as you can see in the pics the smaller valve is broken. I’m considering buying the parts and have a shop press the new valve. Are there any other components with this valve that should be replaced? Or just replace valve itself? Also should I replace other valve?

2. Piston-looks pretty worn on that one side as shown in the pic. Lots of burnt material on top. Fits loosely inside cylinder bore. I’m thinking it’s time to toss it.

3. Cylinder- the bore looks clean without any scratches or scarring. Thinking it might be worth having a machine shop measure although I’m also interested in starting fresh with a brand new oem standard replacement with new piston and everything else.

any help or advice I’d appreciated. Thanks

 

[tmas]

Have you looked into getting a big bore kit? Click here......
What is your budget?
tmas

 

[efiles123]

Have you looked into getting a big bore kit? Click here......
What is your budget?
tmas

I just wanna go oem with this bike. It's too old and tired to put any performance mods on it.

 

[chubbs]

If you're going to replace one valve...seems silly not to replace both.
If I recall correctly, you can buy OEM oversized pistons and rings from places like rockymountain, since you'll already be at the machine shop, have them bore and hone the cylinder accordingly.

 

[Falkon45]

The piston and head looks like it's been running rich. That scarring on the piston seems par for the course for horizontal engines with lots of hours/ miles. If it was ridden in dirt a lot with a cone filter instead of a foam filter, that could cause a bit of that also. Have the head inspected also. If the valve has been burnt through like that for a while, the valve seat may be damaged also. If it's okay, replace both valves and maybe some light port work to just clean up the flow a little. If the valve seat is bad, just go with a bore kit with head, as you'll be spending just as much to have the head repaired, and possibly more to get the OEM head and jug.

 

[efiles123]

Thanks for the good information guys. Gonna have the shop check it out tomorrow. Yes, oem oversized pistons and rings are available which would be a good option if possible.

 

[L.Holman]

From what I see, you will need 2 new valves, some lashing cream to re-lash the valve seats, .010-.020 bore, new piston and rings set, and something to break down the carbon on the cylinder head.

 

[efiles123]

From what I see, you will need 2 new valves, some lashing cream to re-lash the valve seats, .010-.020 bore, new piston and rings set, and something to break down the carbon on the cylinder head.

Got the head at the shop right now. they will install both valves. I'm gonna start with a fresh new standard oem cylinder and piston kit.