Cracked case? Maybe not??

[ryanschoebel]

Hey all. So as those of you who were at the RPM rally may know, it was said that i may have a cracked case,and that was the source of my oil leaks that I couldn't track down. However, I brought my brother over today, and we dropped the engine out of the frame. After removing too much JB weld, there is no crack in sight. There isnt one on top, down the side, or anywhere around it. Maybe I'm missing something, but i cannot find a crack. The JB weld all came off fairly easily with a flathead screw driver and some small taps from a hammer. Nor do I see anything resembling the triangle that Randy said i was missing. Its just smooth metal, no traces that it was ever there at all?  Either someone took great are to sand or file it smooth, or I'm crazy. I attached a couple pictures, maybe some of you with more knowledge can advise. My leading theory is that the oil may be leaking past the starter?

Much appreciated,

Ryan

[Tuned forks]

This is what my engine looks like.  Does that offer any information?

Joe

[ryanschoebel]

That does look different than mine, but im not sure what that means... I dont have that Yamaha logo stamped into the case.

[red]

Ryan,

Once you get the engine case clean, lightly spray any suspected leak areas with aerosol spray body powder.  That stuff will show you the leak soonest, before the oil can migrate everywhere.

Repeat as necessary.

[ryanschoebel]

Body powder? like, deodorant?

[FJmonkey]

Any spray with a high talc/powder content. The powder sticks where it is sprayed. Then when you run the engine and oil leaks, the lack of white powder residue from oil will show the leaks.

[ryanschoebel]

Then when you run the engine

How would I run the engine? Its not in the bike, and in order to see the leak, i cant have the engine in the frame. Just run a temporary set up for gas to the carbs, and dont hook the exhaust in? Or simply remount, and then take out the engine again to see?

[T Legg]

   since you have the motor out follow up on your starter idea and check the o-ring.did it only leak when it was running?

[FJmonkey]

Yep that might be a problem with the spray powder method.

Considering the size of your oil leak you should be able to find the source. Mine was leaking less than yours and when out of the bike, very easy to see.

[RPM - Robert]

Ryan, clean it is as good as you can especially where the jb weld was located....clean it better...

Once it is cleaned and possibly get the silver paint off as well, I would use a small hand held torch to warm the area. If there is a crack, the oil will rise to the surface showing you the crack.

Here is the example when working on Monkey's cracked case: http://www.fjowners.com/index.php?topic=12794.15

[T Legg]

If the crack can be seen we have an epoxy that is hardened with a torch that we use to repair leaks in aluminum evaporator coils that could bu used without taking anything apart.

[ryanschoebel]

I couldn't actually lift the engine out of the frame, I'm not entirely sure how everyone does that, and i had to have the bike back together by Monday. With the engine lowered out on a jack, it kept hitting frame, and me and my brother couldn't lift the frame off the engine either. So with the engine dropped,and tilted towards me, i cleaned the crap out of everything,and saw no cracks at all. I'm presuming its either on the very back of the engine, or that its leaking from the starter. I went ahead and mounted it back in while he was here again today, and will try and hopefully get it all the way out next time. Its 80% back together now, and while I didn't learn much about the crack, I learned a lot about the bike. Thanks for the link and advice Robert,it was good to see! i know better what to look for and try next time. Travis, What is that epoxy? Do you know if it can take stress at all?

[T Legg]

Its called Red EpoxY  made by highside chemicals . surface preparation of course is critical it is a two part epoxy that you mix and then cure with low heat. you can use a propane torch if your careful to cure it or you can use a hot air heat gun.it cures to a clearish golden color that feels like hard plastic.I wouldnt use it to reattach a motor mount but when applied properly it will hold over 400 psi pressure and is also labeled for automotive use.If your crack is in an area that is flexing open and closed this probably wouldnt work but it should hold up to vibration. they also make solders but they have to get up to six hundred degrees and I think that could warp a case or burn up plastic or rubber peices in your motor.you cant sand it so it's not very cosmetically pleasing.