2004 KX 125 Rebuild

[DP3601]

Good news!  A rep from Athena called me to check on how things were coming out with the top end kit that I had asked questions about.  He told me that the cylinder for my 2004 KX 125 should only be using a flat top piston because of the clearance for the head.  When I pulled it apart the previous owner had put in a domed piston and used two base gaskets to try and make the clearance work out.   When I pulled the piston it had a ring around the top that was indented into the piston.  He suggested that it was possible that when I got it to the higher rpm it was hitting the head. 

Needless to say I put it back together to try it out with the correct piston before tearing the bottom end completely apart.  There is no vibration at all in the higher RPM's like before.   I rode it for two days pretty hard and it runs like really good.   I will eventually tear the bottom end down and replace bearings and seals since it has most likely never been done before.   

I still have some more rebuilding to continue to get it better in other areas but so far so good.   I will post some pics this week of progress.

Thanks again for all the info and suggestions from everyone that did.

[Foxx4Beaver]

wow....quite a turn of events...luckily that top end didn't grenade itself and really cause a mess.
have to remember those symptoms next time I or someone else comes up with a similar issue.

Roost on!

[DP3601]

Finally got some time to post a few pics of the KX 125 I have been working on. 

This is where I started, picking up a KX125 and KLX 110 for $1550 after talking to the seller.

[DP3601]

Making the trip home finally after a 4 1/2 hour drive south!


 


Not a bad bike to start with...


The forks were in bad shape, lower legs were pitted like they had been rode in gravel with out the fork guards and uppers were flaking off, rear shock was completely blown.

I took the suspension to Enzo to be rebuild and they said the forks would never hold a seal with the pits so thanks to Ebay I found this whole front end for half of what one lower tube would cost. 



Suspension Complete!

[Foxx4Beaver]

that 125 looks dam near new...

[DP3601]

Some more of the work in progress!

[DP3601]

The top end when I took it apart the first time. 

[DP3601]

I am looking in to cleaning up the cases, cylinder etc when I tear down the 125 next time.  What is the best process for getting that shine back on these parts?   I have read on here that there are a few good options.  I have always done the scotch brite pad route in my past but that becomes pretty time consuming.

[Foxx4Beaver]

send your stuff to Sandblaster....look through all 4 pages of this thread....
this is how your parts will look when he's done...

http://www.kxriders.com/forums/index.php/topic,13401.0.html

[Foxx4Beaver]

there's also soda blasting...which you can do right at home, for very cheap...but it'll never look as good as Sandblasters vapor blasting.

soda blaster...
http://www.aircooledtech.com/tools-on-the-cheap/soda_blaster/

[DP3601]

Wow that vapor blasting is amazing.  Better then factory!  Thanks Foxx4Beaver for the info.  I may try the soda blasting first on my sons KLX and see if I am happy with it then if not move to the vapor blasting. 

[Foxx4Beaver]

no problem.
be sure to take "before & after" pics, so we can see the difference.

[DP3601]

Has anyone ever used powder coating on your frame?  How durable is it or is it better to just repaint with the factory paint?  I have the motor pulled doing some work to it and figure this is about as good a time as any to do it.

[DP3601]

I pulled the motor to replace some oil seals and decided to pull the power valve cover to take a look. When I pulled the cover it was full of black oil. I cleaned this when I did the top end last time. What would cause this as I don't think this is normal. It has been smoking quite a bit but I have it jetted right on. Any ideas?

[Foxx4Beaver]

if it's "jetted right on", it shouldn't be smoking a lot.
there is a seal on the KIPS shaft...part number 92049-1238, and if it's worn/leaking, then it will show a little more black oil than normal when you pull the cover.

you could have a bad clutch side crank seal too...which would allow it to suck tranny fluid and burn it, causing the excessive smoking...a possibility.
and if it does have a bad crank seal, you'll never get it jetted correctly.