Well as we all may expect from having read this forum, PG was right yet again. Looks like it was the chain tensioner on the primary. I figure a 38 year old piece of plastic will eventually take a dump on you. SO I have attached a few pics. One of the bike too finally. MY QUESTION NOW... One of the pictures is a of the lower right hand side where you screw in the cover. The chain has taken some substantial pieces of metal out of that part of the case. Cant quite tell if it breaks all the way through to make an exit hole although I can think of a few ways to verify. Not sure how I would resolve that or if it is a problem at all. Sure I'ld like it to be 100% but I assume that will require replacing the case??? Not sure, I need some advice. Replace the tensioner and move on or am I going to have issues from this? So whaddya think? As always, greatly appreciated.

 

What was the indication that this was bad before you took it apart. I was going to check mine out the milage is unkown

 

Good that you found the problem and better yet it did no real damage.
The second pic with the red arrow looks to me like there is a hole worn through to the cover screw.

Hard to tell from the pic, but if it has worn through then this needs to be fixed. Reason to fix it is because it is always going to weep oil (or worse) as long as oil can reach the threaded cover screw.

Question: Is the damage done to the cover or to the crankcase? I am hoping you say the cover.
If it is the cover I would take it to a good Heliarc welder (Tig) and have hime weld up the damage. The problem welding aluminum is getting it clean enough, but a good welder will know what to do there.
Then you can carefully grind away excess weld to clear the chain if needed. Just tell the welder you want to build up the cover to the original size and I believe he can do that with no problem. Cheaper than a new cover I would think.

Now, if there is damage done to the crankcase, the same fix needs to be done but this will be a bit more difficult for the welder because he is dealing with the entire engine. You would want to remove all of the clutch, primary chain and engine sprocket to have the crankcase side of things worked on.

He (or you) will have to get the aluminum super clean to be able to weld on it. After removing all of the oil with lacquer thinner, I would heat the areas requiring welding with a torch (butane is fine) and let the oil bubble out. After wiping it clean several times use a brand new stainless steel brush to really scrub the aluminum clean. You want to use a stainless brush that has never been used on steel, or else you will just add to the dirty-ness of the aluminum............... pg

 

98, I heard it snap. I was shifting gears and heard something snap and then heard something new rattling around. Easy to know something was not right and PG picked it from my simple minded explanation.

PG, thanks as always. Little disappointed to hear Im going to need to find a welder to trust with my bike and do a repair on the case. Unfortunately it is not the aluminum cover. If it were not worn through, would I still need to repair the case? If not worn through, is there a strength issue Im facing if not repaired or can I leave it be? I will shoot some air or water through it to see if it is in fact chewed all the way through but Im curious anyhow. Guess I hoping for the best.

Next question... Anybody know a good welder in Austin that can accomplish this task?

 

Well, it ain't the end of the world. The screws hold on the cover. Most of the screws are going into blind holes. So if there is some metal eaten away, what is going to happen is oil will get thrown into the eaten away opening. Oil always wants to find a patch of ground to fall to for some reason.
I can see the oil traveling towards the head(s) of the cover screws where it will leak out. How much is hard to say.

When you search for a good welder in the Austin area, start looking at some independent bike shops who do custom work. There are several around Houston and there must be some around Austin as well. These guys do a lot of Tig welding and they do it on bikes. So they will know the issues and the best way to deal with it.

Meantime, replace the chain adjuster, install the primary cover and fill with oil.
Then ride the sucker and see how bad the leak is. Maybe you will have no leaks. The only way to find out is to try it.

Let us know the results. If I come across a name in Austin I will let you know. Right now I do not know that many people around Austin....... pg

 

From the pic it looks like the hole is in the middle of the length of the bolt. Since the bolt does not need to be installed at a high torque ...

Put a small o-ring on the bolt to seal it?
Use a thread repait kit to patch the hole? [the type that is like an epoxy steel with a release agent]
Tap the hole deeper and use a longer bolt?
All of the above?

 

might try a shop that rebuilds boat props, I use to work at one and we would repair all kinds of aluminum things.

 

i recomeneded them before to you but in case you forgot. www.budsmotorcycleshop.com i actually talked to them today.good people imo

 

I have the same type of damage to my '72. In the same location. Mine does leak. I just clean up the threads real good and put some gasket sealer on the bolt when I install it. Works just fine. But it is a pain to clean out next time I pull the cover.

I think you have plenty of thread to hold bolt if you don't over tighten it.

Pat

 

Based your pictures, I'd say that slide (that white plastic part ) from your primary chain tensioner is broken..