In process of installing new D and D low cat exhaust on my Slim. Removed the right footboard and the head pipes went on rather easy, left them installed loose. The silencer will not go on to the collector, I can slip it on by hand up to about one inch from where it should be. Tried to tap on with a rubber mallet, will not go past this point.
Started the install last night, same problem...so I slept, then started with a fresh mind this morning. It was 38 degrees in garage so the collector was cold. I heated the silencer in front of my shop heater to the point that gloves were needed to handle it....cold collector and hot silencer, still only goes on to same spot.
Looked for burrs, none on collector. Thought I felt a couple of burrs on inside of silencer so I hit them with dremel, cleaned everything up, heated silencer again...same result. Thought maybe lube would help, used light coat of permatex 598B...same result. Removed head pipe and tried to install silencer on bench, same result.....HELP!

 

By the way, the clamps are loose

 

Nevermind....installed bracket to silencer, placed 4x4 against bracket and drove it on with a 3 lb sledge. Have installed a few slip fits. This was the tightest fit

 

Glad you figured it out. Put my Fat Cats together today and they went together nicely with just some twisting back and forth. Not sure if you have the 2 different muffler clamp fasteners - D&D only gives one torque # of 125-150 in-lbs, but I think that is to high for the small round Allen head fastener - kinda messed mine up a bit but should be easy to replace.

 

The small fastner was for the collector heat shield.

 

Sometimes you feel sooo stupid....