Flapper Valve Removal (Lessons Learned)

[EEL]

To start, you dont HAVE to do this.

Most people just leave the flapper valve in place. Its designed to spring open when the servo motor is disconnected.

That said, IF you are looking for that clean straight thru pipe, here is the procedure I used & some important items to consider.

1) The flapper butterfly valve is attached to the rotating rod with two screws. These screws are tack welded to the flapper butterfly valve itself. Due to confined quarters. I turned the butterfly valve upside down and drilled out the screws from the backside. Use a 3/16" drill bit and drill out the screws. Due to the heat, the butterfly valve is sometimes fused to the rod. You may need to increase the drill bit size to loosen the butterfly valve completely off the post

2) The rod is installed from the outside in (visible side without the servo brackets) and a cap is welded in place. In order to remove the rod, I just kept expanding one of the already drilled holes with larger and larger drill bit and used a pair of tin snips to cut the remaining sliver pieces until the rod was to pieces.

Once the rod is cut you can pull out both sides from the inside of the exhaust header.

IMPORTANT NOTE:

Ducati uses mineral fiber bushing to seal both ends of the rod assembly and prevent exhaust leakage. They are hard to see due to carbon deposits but you need to remove these now that the rod is no longer in place as they will vibrate out eventually and result in eventual exhaust leakage. Once you take them out you'll notice that you can see light coming thru the tack welded cap on the outside.

The inside bushing (servo bracket side) can just be pushed out with a screwdriver.

For the outside bushing (heat shield side, welded cap) I jammed a large drill bit the size of servo hole and spun it slowly so the fibers catch on the drill bit teeth and back it out.

Take to local exhaust shop and have them weld both the servo bracket side hole and fully weld the tack welded cap to ensure a complete seal.

[oldndumb]

You mean like this?





I think removing everything from both sides and then welding plugs in the holes makes for a cleaner looking installation.

If someone wants to disable it and let it "spring open" keep in mind that it actually rests several degrees from a true neutral position, and that the shaft is relatively large. IMO, better to remove all of it.

Now I wonder how long before someone replies with the torque myth?  

[EEL]

You did a way better job than I will be doing. I agree that looks super clean but I'm on a budget. I'm leaving the bung on the inside and just filling it in. I'm also leaving the heat shield bracket on the outside so I can put the heat shield back on once everything is welded.. Not as clean but if I took it off like you did, it would be way more work.

Right now the exhaust guy is doing it for free so I doubt I'm going to get the same level of quality as you have. I've just asked him to cut the extra servo brackets on the inside.

I agree with you on the amount of restriction but in the grand scheme of things. I doubt it will have any major impact on the over all performance vs the straight thru pipe. The EVO motor power output is probably the most you could possibly go reliably without imparting some NCR magic.