Right side Crankshaft (drive) Seal and Spacer with Gears- Transmission Fluid Leaking into Lower Chamber with Crankshaft...?

Hey all! New to posting, but not new to the site.

 

My problem- For $60 I got a 1988 YZ250. Only catch is that the motor is in pieces. Anyhow onto my question:

 

I have the seal on the right side of the crankshaft (gear drive side to clutch) on properly (as far as I know?). There is a little spacer that goes on the shaft there followed by two gears on top, one for the clutch and the other for the water pump and or governor.. something like that... you get my point here.

 

This spacer doesn't fill into the seal and make a tight fit and there is an obvious space as can be seen in the pictures. I know this is the correct seal, but could the spacer be wrong? It was something that I thought was so obvious that I should try myself before asking as there just may be something so simple and right that I wasn't seeing it, so I put transmission fluid on the seal area and watched it flow through the bearing to the crankshaft. Again, this has been just a bucket of parts and may be wrong. That is why I am hoping some experts can chime in here. I will attach several images.

 

After many, many, upon many searches from different sites and Google images, I have come up with nothing (maybe I am just entering the wrong keywords so I apologize if this has been asked or is obvious). I turned to the owners manual parts list diagram and still coming up with nothing on what to do here.

 

PS: There is a big plastic washer thing that may go here too, as picture. Wrong place for it?

 

This manual doesn't quite match up with my bike even though it is the same year and model 0.o

 

Thank you all so much for your help and all the things I have learned from everyone contributing here. I hope to do the same as all of you someday (:

-Tyler

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I believe your crank seal is in backwards. It's hard to tell for sure though, so I'm not positive. Anyhow, even installed correctly, that ain't gonna stop that leak! You must be missing some kind of spacer that seals the crankshaft with an o-ring on the inside and is larger on the outside to sit tightly enough to seal to that crank seal.

I believe your crank seal is in backwards. It's hard to tell for sure though, so I'm not positive. Anyhow, even installed correctly, that ain't gonna stop that leak! You must be missing some kind of spacer that seals the crankshaft with an o-ring on the inside and is larger on the outside to sit tightly enough to seal to that crank seal.

I think you got it. It never occurred to me about the o-ring. I do have one that looks like it will fit in that area and take up the space between the spacer there. I will give that a try later today!

I would agree that the seal looks to be in backwards. The thrust washer in first a then the spacer. The primary gear should have a O ring in it where it slides over the crankshaft. Just make sure (I know from experience...lol) not to drive the seal in to far! I always put them in and rotate the crankshaft to make sure it's not rubbing the new seal. It's nice to know before reassembling the entire engine! I have some older YZ's and this looks very similar but continue to follow the manual. Good luck!

I would agree that the seal looks to be in backwards. The thrust washer in first a then the spacer. The primary gear should have a O ring in it where it slides over the crankshaft. Just make sure (I know from experience...lol) not to drive the seal in to far! I always put them in and rotate the crankshaft to make sure it's not rubbing the new seal. It's nice to know before reassembling the entire engine! I have some older YZ's and this looks very similar but continue to follow the manual. Good luck!

I have read several things saying the "castle" part (The bumpy part) goes down facing the crankshaft. I may be wrong and will triple check that then since you are all suggesting that. Anyhow, I will get back to work. You all are lifesavers! Thank you so much :D

Ugh I am becoming so frustrated... I tried what I thought you all were saying and apparently there is still a gap, a gap big enough where liquid can still get through =/

 

I attached an image so you can see where I am at-

 

Bottom: Thrust washer.

Next up: Main seal.
Inside main seal: Spacer thingy with the o-ring around it. There is still a gap there.

On top of that: Another thrust washer.

 

What is going wrong here? 0.o

IMG_20140507_215626.jpg

I would agree that the seal looks to be in backwards. The thrust washer in first a then the spacer. The primary gear should have a O ring in it where it slides over the crankshaft. Just make sure (I know from experience...lol) not to drive the seal in to far! I always put them in and rotate the crankshaft to make sure it's not rubbing the new seal. It's nice to know before reassembling the entire engine! I have some older YZ's and this looks very similar but continue to follow the manual. Good luck! 

 

 

To further add to what I just replied, I just realized that you mention of an O ring on the primary gear, not the spacer like I just showed. Here I have attached  a picture of the primary gear (Not mine but same year and model as I don't feel like going out and getting dirty in my shop at 11 at night lol). Looks like I will see how this works out tomorrow then...

$(KGrHqRHJFcFHoTkvDejBSC9gWu9Zw~~60_57.JPG

Edited by tylerlacasse

Sorry to keep bumping and adding to this but I just noted something-

 

The picture of the primary gear there points up with the raise in it, and then the other gear sits on top of that. No place for a o-ring there after all.

 

Still stumped here :(

Looking at the parts diagram from Bikebandit, there looks to be a seal in the collar? There is no call out for a O ring seal or any other but there needs to be a seal between the inner diameter of the collar over the crankshaft. The crank seal that seals over the outer diameter of the collar fits but there still needs to be a inner seal on the collar. The collar and the seal might be one in the same??

Can you get a good picture of the collar?

 

Also, you are correct on the crank seal. The ridge side or "castle side" goes towards the crank or faces towards the center of the engine.

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