As the title suggests, has anyone had the mid section of a 305, 307, 309 etc exhaust apart?

The front section is solid the end silencer is a normal wool packed effort. The way the middle section is made it appears to have some sort of internal structure. I was wondering what it is and if anybody has ever tried to clean it out?

Is this link of any relevance to 305/307/309. It's just something I've stumbled across during searches for 300 twin shock info.

 

http://www.classictrial.co.uk/fantic300setup.html

I was hoping somebody had already tried it on one of these exhausts. The Middle section is an S shaped two piece pressed steel part welded along each flange with what look like spot welds holding parts in position inside the exhaust. Due to its shape I’m worried about cutting a big piece out of the back in case it distorts.

If I assume that the manufacturing method is the same on the later bikes as the one in fourex’s link then I should be able to cut a series of smaller holes without the risk of any distortion. I’ll be going to my in-laws soon and he has a small set of slip rolls. I’ll take it up with me and try and make some close fitting patches before I cut the pipe open. 

Thanks for the help. 

I am also interested. does anyone have a photo documentation of the action?

I am also interested. does anyone have a photo documentation of the action?

When I do mine I'll photo what I do and post it on here.

When I do mine I'll photo what I do and post it on here.

 

ooo! great!

That's exactly how I rebuilt the end silencer on the 309. If the mid section was built in the same way I would of already tried it.

It's the fact that it has spot welds at various points along the length that concern me the most. If I cut the whole of the side out in the same way there is no guarantee that it will come away without doing a load of damage.

I'm going to cut windows between the welds and see how I get on.