I have a 2008 cbr 600rr track bike that I rebuilt after it was involved in a crash. It runs and rides great since the rebuild, and I have been racing it. However, I'm still plagued by one small problem: when it was laid down, the right side frame slider caught something and broke off... breaking the motor mount off with it. This left about a 1/2 sq. inch hole in the case (exposing the inners near the cam chain). I had the motor mount welded back on and its solid, and I have no mechanical issues with it. However, even after getting it welded twice, the mount (or the welded area around it) is seeping oil. It isn't bad but its a problem that needs to be taken care of, and I don't know how to fix it.

I have tried putting a coat (or three) of JB Weld over the weld all the way around the mount, but that didn't work- oil still seeped passed it. After cleaning that JB Weld up and attempting to get it welded again, it still seeped oil. I then tried coating the new weld with another epoxy (a two-part fuel tank repair putty) but oil is seeping past that too.

Is there any way to get this oil to stop seeping from that area? Re-welding it is not an option- the welder said he did the best anyone could do given the conditions and the limited space in the area (even though I took the engine out of the bike for the weld). The weld appeared to be a clean, smooth weld, but obviously it wasn't 100% if it still seeps oil.

I need to stop this seeping oil because I cant be wiping down the area after every session on the track (not to mention any oil that may be spewing down the side of the bike and possibly toward the back tire). Can I do anything about this?? Any input would be greatly appreciated. Thank you in advance.

 

Please put up picks so we can help you better.

 

I attached three pics: one of the motor mount when it was broken off, one of the area of the case that the mount broke off from, and one of the completed bike.

 

I say do it right and replace the case. It sounds like you have tried a bunch of band aids that fell off. It might be time to pony up the time and dough to do it right. Just my .02

 

I appreciate your response. Consider my situation though. Its extremely difficult to justify getting a completely different engine and go through all the work to replace it- when this one runs excellent already! Its just such a small little problem- even more of an "inconvenience" than a problem- and I was hoping someone knows some little trick that I could do to "patch" it up quick...

 

I understand this was not the answer you were looking for. I was suggesting that you replace just the case. That is what I would do if I had tried everything else. I hope someone else does know a trick that will help, cause that sounds like a difficult fix. Good luck.

 

The one thing you need to make sure of though is that it is extremely clean. Brake cleaner works pretty good without leaving behind a nasty film, but then use acetone or something to make sure everything is gone. If the paint is still on the case, remove it with some heavy grit sand paper to give the putty something to stick to. there can't be any oil residue at all, or nothing will stick to it.

I'd give these guys a call and tell em what you have. Im sure they have something that will hold up. I've used their durabond stuff before and it is amazing. We used it where I worked and its extremely tough. It really is machinable and bonds extremely well. But Im sure they have something that is even better for your application.

http://www.cotronics.com/vo/cotr/ea_1.htm

Just curious, did you have it TIG welded, or MIG?

 

sorry for the hijack: But - their stainless steel spray paint sounds all kinds of awesome. 1200degree rating - think that would work on headers?

Oh - and to the OP - you might be at the point where you might look to have a machine shop try and fab a new mount with a bigger base that can be welded onto the case over a larger area - as it is, I would think that tab might keep working loose due to NVH - if it were spreading the force out, or gusseted that might help.

JB Weld doesn't like petroleum very well, regardless of what the package might say.

 

If you broke a motor mount then you got two problems. I could go into a 10 page explanation about why it is not a good idea to run a bike with a broken engine mount. Only way to salvage the bike is to weld everything back on that takes either a VERY skilled welder or some really good epoxy product. Please post bigger pics in focus!

 

I'll be the first to suggest something like JB Weld applied liberally after a thorough cleaning with brake cleaner. But in all honesty, when your motor gets to be 300 degrees and the oil starts seeping through the porous welds that are the real problem, you're going to be hard pressed to stop that oil from coming through material in the weld with anything you can apply on top of the metal.