How to change lower push rod bearing??

[colbyc28]

How to change lower connecting rod bearing??

Hello all, I have just started to re-build my lower end on an 89 YZ 250. I am doing this because the gear shifting shaft has badly worn splines on it. So I figure that while I am at it, I'll go ahead and replace all of the bearings and seals since I have to split the case and all. I do have a manual, but it is currently in the packed up in some boxes somewhere because I recently moved, it could be months before it re-surfaces. My question probably seems like a no-brain-er to the many seasoned pros out there but here it goes: How do I get the pin out of the crankshaft assembly that holds the connecting-rod and bearing in place? I have the crankshaft assembly totally out of the engine and in my hand. I see to little inserts that cover a hole, so I knocked one of those out and looked through there and I see no way that you can push that pin through. Am I missing something?

 

[Rotorranch]

Hello all, I have just started to re-build my lower end on an 89 YZ 250. I am doing this because the gear shifting shaft has badly worn splines on it. So I figure that while I am at it, I'll go ahead and replace all of the bearings and seals since I have to split the case and all. I do have a manual, but it is currently in the packed up in some boxes somewhere because I recently moved, it could be months before it re-surfaces. My question probably seems like a no-brain-er to the many seasoned pros out there but here it goes: How do I get the pin out of the crankshaft assembly that holds the push-rod and bearing in place? I have the crankshaft assembly totally out of the engine and in my hand. I see to little inserts that cover a hole, so I knocked one of those out and looked through there and I see no way that you can push that pin through. Am I missing something?

Yes, your manual. :whoa:

You will have to take the crank to a reputable shop, and have it pressed apart, to replace the CONNECTING rod bearing. It will then have to be reassembled, and trued, using special tools.

Rotor

 

[colbyc28]

Yes, your manual.

You will have to take the crank to a reputable shop, and have it pressed apart, to replace the CONNECTING rod bearing. It will then have to be reassembled, and trued, using special tools.

Rotor

Ahhhh, the lovely "special tools". (special tools=$$$). I will retrieve the manual this evening. I knew it couldnt be that easy! Ty rotor.

 

[Rotorranch]

:cool:

 

[Isobareng]

Hold on you do not need to split your cases to change a shift shaft. remove the clutch cover and the clutch basket the shaft should slide out from there.

D

 

[2strokerfun]

You are absolutely right, but chances are the '89 could use these new bearings anyway.

 

[colbyc28]

Isobareng, you're right. I did not know that until I had all ready split the case. I am learning as I go. Thanks for input. But as 2stroker says, I might as well do it while I have it apart now.

 

[Jasle]

if your going to change the rod bearing you might as well just order a rod kit. will come with rod, bearing, and the bushings that go on the sides. have it done professionally. yes there are those "special" tools you can do a job without. This is not one of them. If you happen to have a lathe lying around you can tru a crank yourself. but for the typical $40-50 you'd really kick yourself if you get the bike back together and it vibrates like heck. which is what it will do with a crank even a tad bit out of whack. I spent several years building motors for a living and it was more cost effective to have cranks rebuilt by the pro's.