1982 550 clutch question

I replaced my clutch yesterday and learned a lot. I screwed up the "special" friction plate placement which took me a while to figure out and is the basis for my question: what is the purpose of the clutch boss spring inside that "special" friction plate and why is it's order in the basket special?

thanks
JRB

 

Hopefully you got the tabs on the plain plates oriented correctly and the dot on the pressure plate aligned with the dot on the hub.

Nobody's really 100% sure what that thing is for. Some of the earlier/Eurospec bikes had two of them spaced within the clutch "pack."

We can only theorize, and the best theory is that it's there to ensure the plates separate when the clutch lever is pulled in. To prevent clutch drag? Dunno. Quite honestly, you could probably do away with it and also run regular round plain plates and never notice any difference in anything. The shaft driven bikes have much simpler clutches and they're pushing more power through them so I can't tell you if it really "does" anything.

You did see this? http://xjbikes.com/Forums/viewtopic/t=29541.html

 

Did I see it? HELL YES! I'd have been screwed without it. I printed it out because the color photos were way better than my Clymer manual. And your write up is what made me realize I put the "special" plate in first. I didn't understand what was meant by bigger ID. My after market clutch kit had a notch taken out of a tooth to identify it as such. That plate has a slightly larger opening to allow the clutch boss spring to nest in it just slightly. I can tell you the space taken up by the boss spring, if not nested correctly, is enough to cause the clutch to not work!! A heartfelt thanks for a great write up.

I'm looking forward to accelerating up a hill today without any slippage!