If ya deadset on removing it, it should look like this in the link.
Not sure who put that pic up long ago but i saved it so 'thanks' & credit to 'that man'!!
photos.app.goo.gl/fNp41zCUYuP7S8z58
So if you drive a rod into the center it should break the spot welds on the vane parts if should shake back out or with nosey pliers.
If it pokes a decent hole without breaking the welds then go try it like that.
On the other hand if you can get 'that bit' red hot somehow & then blow your leaf blower or compressor in at it--it might clean it good as new then shake any loose stuff out the front end.
Depending on if that's what's causing this performance issue of course & i tend to get sidetracked down a rabbit hole.

Good question MarkT, if I am remembering right I think you helped me pick them back when I did it. They were off eBay with a red cardboard backing that came with a while set of oil seals for the bike. Curious on if bikebuzzard is a bad route as I ordered some stuff from him for my rt3 that I’m rebuilding. 

RT, I am dead set on getting this bike to rev out and run right so if the spark arrester has to go it has to go! 

The whole reason I started working on the DT3 this week is because I am going up to the cabin this weekend with some buddies to ride gravels. I was planning on just riding the CT3 but the shift shaft that was barely holding on finally bit the dust and is totally stripped. So with that I figured it would be a good time to get the DT3 back up and going.

The only thing leading me to believe it might be something other than the exhaust is that I fitting my rt3 pipe on it last fall and it was still having the issues. 

It may have been Enduronut on the seals. Those NOS sets you described normally have proper dual lip seals... I mentioned Bike Buzzard because he sells single lip seals.

Wild guess but have you changed the spark plug and spark plug cap?  Either can cause a high rpm miss.  Make sure plug gap is 0.020" to 0.024". 

I'm still not clear if it doesn't rev in general or only under load like 5th gear.

Air filter and filer oil can be a problem on this model.  But you said you ran without filter I think. 

P.S.  They run great with spark arrestor and running without one off road can get you in big trouble in the US.  Swapping pipes should have proved it's not the issue. 

It doesnt rev with no load in neutral, or while riding. Spark plug I have changed many times, but I will try that again tonight. The cap on the other hand I have not changed. I could maybe steal one off of my rt3 for testing.

Yes currently I have the air box boot taken off.

What you're describing is likely ignition. Fingers crossed on the plug cap! 

Good to know. I'll start with another new plug today making sure I can find one that is nonresistance then move to the cap. Then maybe try another coil if that isn't it. I am pretty confident my timing is right. Maybe I should give my points a clean anyway though.

Check the gap on the plug too.

Cut 1/4 " off the ignition wire and put the cap back on. No Joy? Pull the kill switch wire and sit on the bike in 2nd gear and see if it revs out. 2nd is to kill the motor by letting the clutch out if it runs away with the kill switch disabled