Air leak sources questions

[FreeWheeler]

I've read some about how to find air leaks and where they occur, but I still have a question. I have seen suggestions that the cap that holds the throttle cable and carb slide in place is a source. I have seen it suggested that some kind of sealant should go on the cap threads.

1. How can this be when it is connected/inline to the same pipe as the air cleaner?

2. Does this blown head cover show signs of running lean from an air leak?

 

[leftywoody]

I've read some about how to find air leaks and where they occur, but I still have a question. I have seen suggestions that the cap that holds the throttle cable and carb slide in place is a source. I have seen it suggested that some kind of sealant should go on the cap threads.

1. How can this be when it is connected/inline to the same pipe as the air cleaner?

2. Does this blown head cover show signs of running lean from an air leak?

That might assist in keeping the cap from loosening , and that would be a something to consider . As for sealing it because it is letting air in even when it is secure , that sounds like overkill . That head shows signs to me of being rich . Is the head itself ruined for some reason or just the gasket ?

 

[Bikeguy Joe]

1.You just wrap the threads with teflon tape. If you are super careful, you can use RTV or other sealant, and do the top of the carb as well.
2.No, that cracked head is from something else.

 

[FreeWheeler]

Thank you both.

The head cracked when I heard a loud pop bang. I ask about lean running because it has a lighter looking area where I guess the flame was hottest. It experienced runaway idle a few times which I thought was an air leak and I couldnt find it by spraying, but when I removed it the bottom of the case was weepy. It smelled like burning rubber when it first ran.

Anyway, I'm waiting on Dax and want to avoid this problem with the replacement if possible.