I am looking at putting a dry primary on my bike (2007 FXDSE) can any one give me the pros and cons about it?

 

I have to assume you mean you want to run a primary belt drive.
I started a long diatribe about my experience with belt drives but I had to leave the post briefly and when I came back to it, it was gone. I ain't writing all that again.
So, in a nut shell, and some of this is just my opinion: 1)they are tough on engine and primary/trans. bearings 2) the proprietory BDL clutch that came with my enclosed primary type kit was noisy and loosened up the replaceable shift dogs in the clutch basket (had to tighten them up a few times even while using red locktite) one of which snapped off whilst tooling down a residential street in my neighborhood and got lodged up against the ring gear on the basket making one HELL of a lot of noise (startled the crap outta me)3) the belt flapped up against the inside of the primary when cold 4) the belt got very tight when hot (primary case growth I imagine) 5) ya know how a old style stock Harley clutch is noisy when you disengae it? Well the BDL clutch is noisy then too but its even more noisy when it is engaged 6) chains are stronger and last longer (remember I'm talking about the 1 1/2" belt that fits insidea shovelheadprimary case, not the wider belts that you have to run as an open primary. I believe the enclosed belt drive for your bike would be 1 5/8" or 1 3/4" wide. 7) I negleted to mention the "quiet clutch" that originally came with my kit...it was anything but quiet...it squealed louder than HELL as it engaged but it did engage smoothly, you wouldn't think so with the squeal, but it did.In BDL's defense, I will say they did everything they could think of to help me with that squeal problem but the "quiet clutch" had to go and I switched to their original type clutch which they sent to me at no cost. I had the original clutch in it when the clutch basket dog snapped off. That is one noisy clutch too but I got used to it. When the dog snapped off, I wasdone with that belt drive 8) the other style belt drive I tried recently, and only breifly, used the stock Harley clutch, it would not fully disengage so the bike want to creep at a stop in gear.Everything I tried could not get rid of that dragging clutch(and I'm sure I didn't try everything that COULD have been tried)but at that point, I was DONE with belt drives, period.

Back in the late seventies and early eighties, I had a belt drive that used a gilmer type belt with the square teeth. I had it on a 98" shovelhead. I spun the engine pulley inside the belt. That was due to the tooth design, the parabolic teeth used today are a much better design but I haven't had much luck with these newer ones either...

My opinion is stick with your chain drive if you run an enclosed primary.

Oh, if you do decide to run a primery belt drive in an enclosed primary, make sure you set it up to allow airflow through the primary case, they generate a lot of heat and it will kill itself without cooling airflow. So, you see it isn't quite an enclosed setup...

I cannot speak to open belt drives, Ihave never tried one (I don't like that spinning stuff exposed like that) but they may work great if you like the look...and risk.

Hell, it looks like I blabbed for quite a while anyway...

 

what do you hope to gain from it?

 

I appricate your input and advise megawatt, and i was looking at a 4" wide open belt assembly.and in response to pjb i am tring to make my bike as custom as i can to keep it from looking like ever other bike on the road, besides I think they ( open Primary belt drives ) look cool.

 

4" is pretty wide. If ya don't mind, I'd like to suggest you consider what it may do to you in left turns...especially if there is a crown in the road. It's gonna stick out pretty far.
Whatever you do, I hope it works out for ya.