'00 KX countershaft ejection!

[pace]

My buddy had the countershaft spit out on his '00 KX250 during race practice this weekend. I've never heard of this happening on any bike, and was wondering if this is a known issue on this machine..

Comments?

-Pace

 

[Jaybird]

If it is a circlip held sprocket, then I suspect it was the culprit.
Circlips are very easily damaged if not taken off and placed back on properly. Just one little bit out of flat, or even slightly sprung, can be a problem.

If it's a bolt on, then the bolts worked loose. (preventitive maintenance issue)

 

[pace]

The sprocket didn't come loose. The shaft came out. Far enough that oil started spewing out of the cases.

He said one minute he's riding along just fine, the next.. countershaft departed. There was no crash involved, and my buddy is meticulous regarding maintenance.

I'm guessing this was just a freak mechanical failure, then.

-Pace

 

[kawdude]

I my KX5 the shaft is held in place by the kickstart idler gear and thus a circlip holding that. I can't imagine enough space between the left side bearing and whatever gear is on the inside to let it move. Could be a busted shaft???

 

[pace]

Ok... I guess the countershaft actually moved rearward, not outward. Presumably there was some type of gear wheel failure internally that caused the countershaft to suddenly cease rotating. The torque from the rear wheel then pulled the entire assembly rearward. The left side crankcase is smashed, and who knows what internal damage there is.

Any suggestions on where we could source a salvaged bottom-end and/or complete motor for a 2000 KX250? Any advice is appreciated since he's going to be looking at a pretty expensive repair as it stands.

Is any other MY motor a direct bolt-in fit to the 2000 frame cradle? What about the bottom end - is that interchangeble with any other MY?

-Pace

 

[marcusgunby]

Ive heard of this a few times-its normally dirt gets into the bearing the shaft rides on, that bearing then lets go and allows the shaft to move, sometimes it can be caught early and do little damage, if the bike is ridden just a few more feet it can destroy the bottom end.

 

[VB Racing]

99 to 02 motors should work, you should use the proper headpipe for the year motor though. :cool:

 

[pace]

Thank you, much. I'll pass along the info.

-Pace

 

[Ol'89r]

Ok... I guess the countershaft actually moved rearward, not outward. Presumably there was some type of gear wheel failure internally that caused the countershaft to suddenly cease rotating. The torque from the rear wheel then pulled the entire assembly rearward. The left side crankcase is smashed, and who knows what internal damage there is.

-Pace

Pace.

Have seen this happen when people adjust their chains too tight. Had a YZ426F in the shop a couple months ago that the owner ran the chain too tight on and it destroyed the countershaft bearing. All of the balls from the bearing went inside the gearbox and he did two laps at Glen Helen before shutting the bike down. Had to replace every gear, bearing and shaft in the gearbox except one gear.

From the outside it looked bad but, the cases were ok. All of the shaft movement was due to the bearing.

If the cases are not damaged too badly, a good tig welder may be able to fix them. Where are you located?

 

[pace]

We're in Colorado!

He tells me that left-side case is trashed, but I haven't seen the damage first-hand yet.. The shop is telling him that both case halves have to be replaced together since they need to 'match' from the factory. Is that assertion correct?

-Pace

 

[NO HAND]

...The shop is telling him that both case halves have to be replaced together since they need to 'match' from the factory. Is that assertion correct?...

No, if you order the original part, same part number as the one you replace. It should be identical to the one you replace. Unless Kawasaki has bad consistency and spec wide tolerances.

 

[marcusgunby]

I think kawasaki do reccomend two new halves as they are matched-not sure i believe them but...

 

[Ol'89r]

We're in Colorado!

He tells me that left-side case is trashed, but I haven't seen the damage first-hand yet..

-Pace

Pace.

When you get the case, see if you can post a picture of the damage. There is a good chance it can be repaired for a fraction of the cost of a new case.