Maybe a bit of description will help here?
First, this is a wet clutch. This means that it will always drag (a LOT) until the engine is turning and the plates are unloaded (by pulling in the clutch lifter). At that time, the oil that has pooled up (thru those little holes in the spinning hub) against the metal fingers of the steel plates will swiftly spread between the cork and the steel plates, like in less than 100 mS (0.1 second) and the cork will let go of the steel plates.
So...on a non-running engine, the clutch will never disengage. The plate will simply stick together because the oil can't force its way between the plates.
Next: the spline washer must be there on the mainshaft to hold (space) the clutch basket in position. The rounded side of that washer should be toward you when you put it in, but it will work OK if backward, eventually rounding the other side against the back of the hub (and putting metal grindings thru the oil pump and into the filter, but not a serious problem in terms of performance...).
Others here have mentioned the common errors, which are:
- the spring washer that holds the basket to the mainshaft must have the rounded side domed out toward you so it acts like a spring holding the basket to the mainshaft when you tighten the nut to squish that washer down. Don't forget the little locktab into that fancy nut to prevent it ever coming loose.
-the clutch pack must be set into the splines in order to work: otherwise the pack will not engage (no friction) and you risk breaking the pressure plate from compressing the springs too far when tightening the bolts. It sounds like you figured this part out OK, though.
- the thickness of the clutch plates has become confusing as of late since the non-Honda vendors can mix up the plates in their inventory, or unknowing vendors can sell the wrong ones to unsuspecting customers (!). So, measure the thickness of your cork plates. You can get a cheap-but-good-enough set of calipers at Harbor Freight for under $20 that measures both inch & metric, or just get the inch type with the dial and a calculator if you want metric numbers. The cork plates for the 750 are all in the range of 0.136"-0.140" when new and are (very) worn out if they are less than 0.120". Trouble is: you can get brand-new plates that are 0.109" thick or 0.128" thick that fit just fine - but they won't work. To solve the too-many-too-thin problem on a 750 I just assembled, there ended up being one more cork and steel plate to make the stack "whole" again, because the owner had used the 0.109" plates and it ended up having 8 cork plates instead of 7.
---so, measure the thickness of your cork plates, make sure they are between 0.135"-0.140" and replace if necessary. You can get the right ones at PartsNmore.com, contact me if you need their part numbers.
Last: when all is assembled, the oil gets squished out and the plates bind. Attempting to disengage the wet clutch on a stationary engine will NOT disengage the clutch at all because the oil will not slip between the plates so the tranny's gears can drag slower than the crankshaft speed to break the suction and friction of the cork. This only happens when the engine is actually running and some sort of load (like the mass of the rear wheel) is there to break the grip of the wetted cork from the steel plates. That's why these gearboxes (famously) 'clunk" when shifted: that is their nature.
