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2007 kx250f oil in stator case

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So I rebuilt this bike a few months ago from a clapped out state to starting first kick. It was a budget build and I used a few used parts including the crank which felt tight. I installed everything properly with insert tools etc.

 

Anyway I was riding the bike on the track and it refused to turn over. I thought it was a heat seize at first but today I found out it was the crank. It turns rough and has a large amount of side to side play but no upward but it definitely is shot.

 

My question is how did it fail and taking into consideration the oil I found on this side of the case. How would it get there. My question is how is it contained with that hole there? Also my oil screens/filter or part 49065 had kinda crappy oil seals. My confusion is how does the oil flow through those or what is it doing. I did probably have too much oil but any insight is appreciated. Are the crank bearings ok? They have a new seal on the other side and feel good.

 

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Edited by Ride_Flip_Repeat

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Oil is coming from the head, whirling and splashing with the cams and cam chain.  It is normal to have oil on this side.

These diagrams may be helpful for figuring out what may be going on with the crank.

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When you say side to side movement are your referring to the crankshaft moving side to side or the connecting rod?

The crank is captured by the crank bearings and the case.  It cannot move side2side or up2down unless one or both of those bearings are shot.  OR the incorrect bearing was used for the rebuild.  For example if the installed bearing race is thinner than gem/spec, then the crank is not fully captured and can move side2side.

If the issue is the connecting rod.  Same thing.  The rod is captured by the crank webs.  If the big end bearing is worn and the rod big end is worn, then the rod can move side2side on the crank pin.  Some very small movement is normal.  An easy sloppy slapping side2side is not.  Connecting rod, big end bearing wear and burn up is common on 2strokes.  Not so much on 4 strokes.

When the engine was rebuilt, it is possible that excess case sealant has squeezed out in blocking oil system ports, galleries, pump, or screens.

The only way to know and get it fixed up is to pull the engine and take it apart, ensuring to be looking for these things as it is opened up so you can find something.  Often the evidence/cause of the problem is lost when taken apart if not watching for and looking for the possible causes.

For consideration; as not sure from your description which one of the two scenarios it is that you say is moving alot.

Edited by FaceDeAce
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When you say side to side movement are your referring to the crankshaft moving side to side or the connecting rod?
The crank is captured by the crank bearings and the case.  It cannot move side2side or up2down unless one or both of those bearings are shot.  OR the incorrect bearing was used for the rebuild.  For example if the installed bearing race is thinner than gem/spec, then the crank is not fully captured and can move side2side.
If the issue is the connecting rod.  Same thing.  The rod is captured by the crank webs.  If the big end bearing is worn and the rod big end is worn, then the rod can move side2side on the crank pin.  Some very small movement is normal.  An easy sloppy slapping side2side is not.  Connecting rod, big end bearing wear and burn up is common on 2strokes.  Not so much on 4 strokes.
When the engine was rebuilt, it is possible that excess case sealant has squeezed out in blocking oil system ports, galleries, pump, or screens.
The only way to know and get it fixed up is to pull the engine and take it apart, ensuring to be looking for these things as it is opened up so you can find something.  Often the evidence/cause of the problem is lost when taken apart if not watching for and looking for the possible causes.
For consideration; as not sure from your description which one of the two scenarios it is that you say is moving alot.


Thanks for this reply. It is the connecting rod that is moving sloppy side to side. Everything else looked good taking it apart. No excess case sealant or excess metal from the new clutch. It may have just been a bad used crank that was removed improperly, etc. Ordered a used crank on eBay for $90 and $10 more I get a no questions repair/replace warranty from eBay lol. Thanks for the help and clarifying the oil in that side of the case. Should be running mint next week.

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If you have basic tools with extra bolts and washers and/or big vise ... and some creative innovative thinking you can press the pin out of the crank and replace the connecting rod, the pin, the BE bearing, with new.  A press is nice to have, however it can be done without one.

Glad to have helped, have fun with your repair :)

 

 

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You should have side to side movement on the crank shaft not up and down ... refer to manual for service limits on of crank shaft play ... i would heavily inspect your cylinder and piston which im sure you have already done. I would also take the advice from someone above... double check the crank bearings and everything else to do with the rotating assembly to be sure that everything was correct... if the bearing was not right it can seize and cause the same symptoms . 

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You should have side to side movement on the crank shaft not up and down ... refer to manual for service limits on of crank shaft play ... i would heavily inspect your cylinder and piston which im sure you have already done. I would also take the advice from someone above... double check the crank bearings and everything else to do with the rotating assembly to be sure that everything was correct... if the bearing was not right it can seize and cause the same symptoms . 

I feel pretty good about the crank bearings. They didn't have play and the clearances were all in spec. Got the new crank today feels good. I was just wondering if anyone knew where to get these oil seals for the oil filters. I'm gonna check with auto shops tomorrow too.
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