2004 KX 125 Rebuild

[DP3601]

I just replaced the front brake line with a steel braided line.  I have been doing the bleeding process to get the air out but I am not getting the brake to pump up with any pressure.  There is brake fluid running through the system and no air bubbles are coming out now.  Does anyone have any ideas on what I might be doing wrong or what the issue could be?

[Foxx4Beaver]

sometimes the fronts can take bit to pump up....I like to gravity bleed them for several minutes 1st, by loosening the bleeder, then just keep pouring fluid into the reservoir for a while, and let it run out into a clean jar from the bleeder....just don't let the reservoir go empty.
then after a few minutes of that, they'll usually pump up fairly quick.

[DP3601]

sometimes the fronts can take bit to pump up....I like to gravity bleed them for several minutes 1st, by loosening the bleeder, then just keep pouring fluid into the reservoir for a while, and let it run out into a clean jar from the bleeder....just don't let the reservoir go empty.
then after a few minutes of that, they'll usually pump up fairly quick.

Worked like a charm!  I should have ask sooner and saved myself an hour.   Thanks again

[Foxx4Beaver]

 
It's the only method I use ...on bikes, cars/trucks.

The plunger in the master is so small, that it takes forever to pump out all those tiny, tiny bubbles.

I do the rears the same way...but it's a bit more involved...as you need to put the bike on a stand, remove the rear wheel, and slide the caliper off the carrier, then rest the caliper on a brick/piece of wood , or whatever you have to keep the caliper from hangin by just the hose.

[144rider]

Two millimeters can make a pretty big difference.  It should slow the steering down and make the bike more stable.  Some models benefit greatly from this (such as the KX250F with 22 mm clamps), while others really change for the negative.  Of course it really depends on where you ride and what you want to accomplish.  My two cents would be if you like the bike now for the riding you are doing, don't make the change. 

Maybe KXDino has some more info on this.  He is very knowledgeable on different frames and years.

Going from a 25mm offset to a 23mm offset will have the opposite effect from what you describe.
The steering will be quicker and the bike will be less stable down long high speed straights and through braking bumps to the point you might experience head shake.

[DP3601]

Has anyone put the SSS forks off of a YZ onto the front of your bike?  These are always said to be some of the best forks.  Just curious what I can find for information on this or what anyone has done out there.....

[SuperWes]

I also have a 2004 kx125. Enjoyed reading your posts and I've also been reading
http://www.vitalmx.com/forums/Moto-Related,20/2005-KX125-Build,1295539?page=2 posts on Vitalmx. I'm currently slightly modifying mine. It already has a FMF exhaust with the stock muffler when I bought it, which I'll most likely keep on it. I'm installing a Boyesen Rad Reed cage and rejetting it. It had V-Force valves (first version) and has 12T front and 51T rear sprockets.
     Next upgrades: replace chain (w/ RK GB520MXU) and sprockets (don't know if I'll go with 12 or 13 tooth front), sliders and chain guide (w/ TM Designworks kit), and install Fasst rear brake return spring and brake clevis.
     I don't do much track riding anymore, mostly woods riding, and this has been a fun lightweight bike to ride. This bike makes my last bike, a '98 KX250, feel like a tractor.
     Next year, I'll plan on having my suspension re-done, probably by Pro-Circuit.

[DP3601]

I also have a 2004 kx125. Enjoyed reading your posts and I've also been reading
http://www.vitalmx.com/forums/Moto-Related,20/2005-KX125-Build,1295539?page=2 posts on Vitalmx. I'm currently slightly modifying mine. It already has a FMF exhaust with the stock muffler when I bought it, which I'll most likely keep on it. I'm installing a Boyesen Rad Reed cage and rejetting it. It had V-Force valves (first version) and has 12T front and 51T rear sprockets.
     Next upgrades: replace chain (w/ RK GB520MXU) and sprockets (don't know if I'll go with 12 or 13 tooth front), sliders and chain guide (w/ TM Designworks kit), and install Fasst rear brake return spring and brake clevis.
     I don't do much track riding anymore, mostly woods riding, and this has been a fun lightweight bike to ride. This bike makes my last bike, a '98 KX250, feel like a tractor.
     Next year, I'll plan on having my suspension re-done, probably by Pro-Circuit.

Its been a fun bike to work on.  I have plans for it now that we are in the new year.  I am looking at a new set of wheels, powdercoating the frame and getting some carbon fiber from lightspeed. 

I have found that I like the gearing stock but if I ride anything tight I do throw on a one tooth bigger sprocket to pull me around.  I am not your typical 150 pound 125 rider!

You cant go wrong with suspension from pro circuit but for less money I have been VERY impressed with Enzo.  It is some of the best suspension I have ever used.  It helps they have a local place I can drop it off and not have to ship.

[SuperWes]

I found out last month that my KX125 that I purchased as an '04 is actually an '03. It really bugs me when I purchase an ATV or dirtbike when there is no title or records available. I still enjoy riding it more than the old '98 KX250 I had. One way to distinguish between the '03 and the later models is that there's an extra hole in the swingarm in the later models where the suspension linkage hooks up. I'm still keeping an eye out for an '04 or '05 and this '03 that I have would make a nice spare bike and for friends to use.

[DP3601]

Wanted to see if anyone has an answer on this one.  The hose that comes off the side of the cylinder where the valves are is starting to pour out black oil.  I opened this up and it is full of oil.  Any ideas what would be causing this?

[KXDINO]

what your fuel to oil ratio , even at 40 to 1 a little bit comes out , not much though , is your jetting rich ?

[DP3601]

what your fuel to oil ratio , even at 40 to 1 a little bit comes out , not much though , is your jetting rich ?

I run it at 32:1.  In my racing days I always ran 40:1 with the engine work done.   The bike is bone stock except for a boyesen rad valve and power wing I was siding on the 32:1 to be safe.  Jetting is spot on.   Do you think I need to run it at 40:1?

[KXDINO]

It up to you of course ,32 to 1 is good myself i run 40 to 1 on all my 2 strokes from 144 to 500 , motorex oil , the 250 get a drop coming out of that pipe but no oil get to the back of the muffler , the 144 which is a 08 kx125 has had major porting and uses a wossner yz 144 flat top piston with a machined vhm head to suit , goes hard with a wide power band but it had to be jetted up to survive as more power = more fuel.

[DP3601]

It up to you of course ,32 to 1 is good myself i run 40 to 1 on all my 2 strokes from 144 to 500 , motorex oil , the 250 get a drop coming out of that pipe but no oil get to the back of the muffler , the 144 which is a 08 kx125 has had major porting and uses a wossner yz 144 flat top piston with a machined vhm head to suit , goes hard with a wide power band but it had to be jetted up to survive as more power = more fuel.

Thanks, I think I will try that at 40:1 and watch the jetting so I dont end up to lean.

[DP3601]

It up to you of course ,32 to 1 is good myself i run 40 to 1 on all my 2 strokes from 144 to 500 , motorex oil , the 250 get a drop coming out of that pipe but no oil get to the back of the muffler , the 144 which is a 08 kx125 has had major porting and uses a wossner yz 144 flat top piston with a machined vhm head to suit , goes hard with a wide power band but it had to be jetted up to survive as more power = more fuel.

Thanks, I think I will try that at 40:1 and watch the jetting so I dont end up to lean.

Thanks KXDINO, that cleaned it right up and running better and much crisper!!