Got this sled used with 3500 miles, mint condition well taken care of. Got to do some hot laps around the house today for the first time. I was told everything is stock except for 2" handlebar riser. Are these items normal for this sled:
1) Drive clutch has yellow spring with green
2) Roller secondary has no side movement, all my other cat sleds had the secondary move.
3) Sled engages at 3800 rpm and maxes out at about 7800 rpm
4) From a stand still, if you put the throttle to the handle bar it seems a little slow till just before 5000 rpm, then it really pulls hard. I guess I would almost call it doggy from engagement til about 4500 rpm. Messed with the air screws but it didn't fix this. Sled was fogged last spring.

A buddy of mine had the older 440 liq, no roller clutch,(it could have diff clutching ) It did have yellow/green in the front, engaged around 4200-4300, we upped it to 4700 because it was boggy any lower, secondary should have some side movement, topped out about 8100-8200rpm, but I'm not up on that sled, the roller could have changed the clutching.

So what would cause my low engagement? What would cause no side to side movement in the secondary? There are no spacers to take out

Your secondary could be frozen onto the drive shaft. I've seen that happen before. Pull the bolt off and see if the secondary will slide off of the shaft. The low engagement could either be caused by a sacked out primary spring or perhaps they just came from the factory that way. You could replace the spring with a new one and see if that helps. Or you may need a spring with a stiffer preload to get your engagement rpm's up.

Had the secondary off today, not seized. It should have side to side play, right?

Can I see what weights are in the drive clutch without taking it apart? Seems like my two options for the low engagement are wrong weights or bad spring, am I correct? I know the belt is good.

Yes, your secondary should have side to side play. Are there any washers behind the secondary or behind the secondary bolt??? You may need to add washers behind the bolt to get some play. My 600 has 2 washers behind the bolt. Be sure to check your alignment. Can't offer much help on the engagement or peak rpm as I never owend a 440 and don't know how they came stock. But me thinks you need a stiffer primary spring and some heavier weights to eliminate your problem. Or call Goodwin Performance. or ODS, or CPC...they may be able to hep you out with your clutching...

Weights will effect engagment if they were changed, or weak spring, not sure what's going on with your secondary, should be atleast 3 spacers in back of the clutch, should really have all kinds of movement with none, something not right there.

Just take a pry bar and push the clutch open, take a flash light and look down on the side of the weight, most Cat weights are marked on he sides.