125 Pit Bike Oil Leak Repair

[Weldangrind]

My son's 125 developed an oil leak out of the left side, and I presumed it was a shifter seal leak until I started investigating further. I figured that the leak was caused by excessive crankcase pressure, so I added a valve cap vent. That seemed to free up some power, but the leak remained.

The photos below show the removal of the flywheel, stator plate and o-ring. The replacement o-ring, part number 91301035003 was about $7 at the local Honda dealer. No more leaks.

http://i158.photobucket.com/albums/t109/Weldangrind/Pulleron125.jpg

http://i158.photobucket.com/albums/t109/Weldangrind/RemovingStator.jpg\

http://i158.photobucket.com/albums/t109/Weldangrind/StatorRemoved.jpg

[warrior91]

Nice. If all of us can do this once per maintenance item we will have a good tech resource for the novice or the mechanically inclined but forgetful kind.
We should sticky this as soon as you ad honda part# and engine modle...although 125 china horiz. engine says it all

[Weldangrind]

I edited the post to include the part number.

Cheers!

[SpudRider]

I'm sorry I missed this post when you first wrote it, W&G. As usual, your writeup is great, and the photographs are wonderful. :) If I ever get a Honda engine, I am certain I will spend a lot of time reviewing your excellent posts! :D

Spud :)

[Weldangrind]

Thanks Spud. :D

[Jim]

Me too, thanks :) You should add it to the tech stickies.

[FLASHLIGHTBOY]

Is that a tool for removing the pulley?? if so does it work on all the motors???

[Weldangrind]

So far, it has worked on XR200R engines from the early eighties, a GY6 ATV and a 125 pit bike Honda clone.

[Thumper]

My son's 125 developed an oil leak out of the left side, and I presumed it was a shifter seal leak until I started investigating further. I figured that the leak was caused by excessive crankcase pressure, so I added a valve cap vent. That seemed to free up some power, but the leak remained.

The photos below show the removal of the flywheel, stator plate and o-ring. The replacement o-ring, part number 91301035003 was about $7 at the local Honda dealer. No more leaks.


http://i158.photobucket.com/albums/t109/Weldangrind/StatorRemoved.jpg

I guess this is pretty obvious, but does that gear on the crankshaft drive a counterbalancer with that chain?

[dirtbkr188]

No, it doesn't, Thumper, it only drives the oil pump shaft, there is no counterbalancer. At the other end is the cam sprocket