KX125 Swingarm removal

[groenie]

I need to replace the swingarm bearings on a 1990 kx125. Looking at it, it should be straight forward but I cannot move the swingarm shaft (bolt). After removing the nut on the right the shaft should push out to the left, not so? I tried everything but it won't budge. Am I missing something?

Thanks for any help

 

[Senior KX Rider]

It should come out without to much trouble, but they sometimes get seized in there if the bearings have been allowed to go to long. You have to drive it out. Good luck. I would soak it with penetrating oil for a while and see if that frees it up any before I resort to brute force :)

 

[groenie]

Thanks. I sprayed some WD40 and left it. I will try again tonight.

 

[slo' mo]

I had to back the nut off several rounds then smack it with a hammer/socket to help dislodge it. Don't use a hammer only or you can trash the nut and not get it back on.

 

[Tom Cox]

Smack it!!

Yes try and use some lubrication, from what you describe the bolt is usually rusted to the bushings. Trying to get oil into the rusted area is really difficult. That doesn't mean you shouldn't try. Use plenty of your favorite penetrating oil over several days trying to get the oil into the rusted areas. Now, if you don't have a 1/2 to 3/4 inch in diameter brass drift about a foot long and can't borrow one, go to you local hardware or building supply center or where ever you can buy brass rod material in about 3 foot lengths. Buy whichever diameter rod that is as close to the outside diameter of your bolt as you can. When you think you're ready, use about a 1 foot long section and a 3 pound hammer. You're going to drive the bolt out. Brass is a softer metal than the bolt so it won't damage it. Hold the brass rod section with a LARGE pair of Vice Grips, so you don't hit your hand. I'm assuming you don't normally perform this type of work and I'd rather you beat up the Vice Grip with the hammer blow, when you miss the striking the brass rod than your hand. Now put one end of the rod on the end of the bolt (you've got the nut off of it right?) and smack the other end of the brass rod with the hammer, "Hard"!! Again, Again and Again. If after repeated blows the bolt isn't moving you can choose to soak it more with the penetrating oil and try hitting it some more or it's time to use an air driven impact punch. This will damage your bolt, but it should drive it out. :bang: :bang: :bang: :bang: :bang:

 

[groenie]

What I am using is a centre punch which fits into the centre hole on the shaft. That way I can smack it real hard and not damage the shaft. Still it won't budge. I am leaving a bit longer to try and soak and will try again. Unfortunately I don't have access to an air impact driver. My next move will be to try and cut the shaft between the frame and the swing arm. :yikes: Risky but looking at it last night it might be possible.

 

[Tom Cox]

Cutting????????

If you cut the bolt you will need to cut it 4 times. Either side at the frame and both sides of the engine case. Cutting it at the engine case will be the hard part. Remember this is a flush fit between all three items, frame, swingarm and engine. The swingarm bushings get pinched between the engine and the frame. Look to see what you'll be cutting. If you remove any base metal from either side of the engine or frame you will need to install shims to replace the metal you removed to correctly space and pinch the swingarm and bushings when replacing it to get a tight fit between the frame and engine. This is only my opinion but even if you have to pay someone to press or drive the bolt out, you will be ahead of cutting it out. Driving a punch into the hole in the center of the bolt, it may become stuck and doesn't effectively transfer the force of your blow to the bolt. Driving a punch into the hole directs part of your force to the side trying to spread hole opening larger. You need a flat surface against a flat surface.

 

[tennkx]

What I am using is a centre punch which fits into the centre hole on the shaft. That way I can smack it
Do not use a punch, it will spread the end on the bolt and you will not be able to get a nut on it. Trust me I learned the hard way.

 

[Tom Cox]

tennkx is right. Do not use steel on steel. Use brass, the brass is softer than steel and the brass will deform, not the steel.