Take a side picture to see what's all involved. It looks like it's just a cover if so it's nothing more than removing some bolts and replacing gasket and torque them back in.

 

I'm assuming that it's the right side engine cover. Really easy fix, just make sure you don't put more than 4-5 lbs of torque on the bolts that hold that cover on. --L*64

 

I'm pretty sure this is the center case gasket...

 

You might be right.

 

It's center case.. Look where the 17mm drain "bolt" is

 

I'd put a dab of silicone over it until the off season, then pull the engine out of the frame and take it to somebody who knows what they're doing when it comes to splitting a set of cases. I was thinking it was just a side cover when I looked at the pic. I guess i'd replace the crank bearings as long as I had it apart... --L*64

 

Thanks guys. Yes it is in the center of the crank case. The thing hasn't been started in two years so I'm think about modding it up while I have the thing apart. Any suggestions? It is bone stock right now.

 

That's the center case gasket all right and it will require removal of the engine, and a complete disassembly. Did the case take an impact? I'm not seeing any skid plate, not even the skimpy factory plastic skid plate or did you remove it to take the picture?

A little advise, the factory kick start gears are a weak spot in the 2003-2005 150F models and are prone to breakage. Some that have experienced kick start gear failure have also suffered case damage. The three kick start gears require splitting the cases to replace them so now is the time to address the issue. If you plan to add any compression these kick start gears are essential, I would suggest replacing them while you are in there regardless of whether or not you increase the compression ratio...call it cheap insurance.

Mikes web site states the mega kick start gears have been discontinued. I would contact him to see if he can still get a set made for you. I know at least one person that needed them and although it took some time he did eventually get a set of the heavy duty kick start gears. I wonder if the heavy duty gears might already be in there and the case gasket is leaking as a result of less than careful assembly. Food for thought...especially if the case did not take an impact. I know Mike sold a lot of those mega kick start gears so anything is possible.


Broken kickstart gears on your 150 yet?? - CRF 150/230 F/L - ThumperTalk

Kick start jammed - CRF 150/230 F/L - ThumperTalk

Motor Performance

Tech23

 

I took the plastic skid plate off to see where the drip is coming from. Thanks for the advice on the gears, I have never heard of this issue before.

I have had this bike for about 4 years and it was and still is completely stock so I doubt the gears were already installed by the previous owner.

Also the only damage that I know of is my wife dropping it on the side. The leak could be coming from the shifter when she dropped it but I didn't notice any trails down the side to the center of the case. It has been like this for about 2 years and it is still full of oil so the leak it very slow.