Topic: Cracked Case ?

[rddcw]

When I purchased this CB 750 K4 last year, I noticed that it weeped a little motor oil under the engine appearing to be coming from underneath the front sprocket cover. I pulled the cover off and examined the case area in front of the sprocket. It looked to be cracked thinking that possibly the chain broke prior in the bike's history of use ?

I read somewhere on this Forum saying that throwing drive chains were common in that era but probably due to the fact how the bike was maintained and ridden ?

The crack is located on the bottom half of the case. I smeared a little RTV in that location which helped a little but still weeps after being ridden when the oil is warmed up well.

So my question is without spitting the cases and repairing the crack correctly, is there another "band-aide" that would work better than the RTV ?

[ekpent]

 Roughing up the area and thoroughly cleaning for good adhesion for some JB Weld to be slathered over the crack.

[dhall57]

How about a pic rd. Not saying you case isn't cracked but the 74's still had the chain oilers and they can be messy causing oil do drip and that could be the issue and that would be great if it was because that can be adjusted or completely turned of. The sandcast and KO's were noted for breaking chains leading to a broke case not so much the later models.

[rddcw]

Sealed the chain oiler with bolt and RTV. No more chain oiler 

[PeWe]

Clean the with degreaser, take a photo and show here, maybe you'll get a good recommendation

[Dunk]

If it's a crack that's weeping and not a gaping hole I'd probably go the clean thoroughly, rough it up, and JB weld route. You can do a proper repair or replace when it's a better time to go through the engine.

[seanbarney41]

+1 on the JB Weld thing, has worked for me in the past, you just have to get the area really clean and, yeah rough it up too

[rddcw]

I appreciate all the "Good" recommendations  and was thinking about JB Weld.  Is there a certain type for aluminum pair ?

[Yamahawk]

There is Marine JB weld also another type Mastercool 90935?? A.C. repair epoxy, both available online if you search for it.
Charlie

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[ekpent]

 I think you will be fine with just the old fashioned regular slow drying two part JB that's been around forever that you can buy at any auto parts, hardware store or Wallyworld for that matter.

[Yamahawk]

Found both those products at WallyWorld online lol...