Hi Beemie, Yes many list one size fits all springs, however, that is not correct. 500,650,750 springs are all different. 500 is weaker, 650 medium, 750 stronger, by a margin. I put in 57-1830 from Rabers. I laid all 3 out on counter to compare visually. I put Hyde clutch 7 plate +1 kit in my bike. I ended up slackening off 650 springs to about 1/2 to 1 turn looser than flush with dome of adjuster. I used stock pressure plate Hyde & Johnitoc suggested no advantage to alum. plate. In fact all the alum plates I looked at were smaller dia. than stock. I would want a larger diag. I flattened the steel press plate with emery cloth. Adjusted to no wobble as normal. The stack height of the Hyde clutch pack is exactly the same as stock clutch was. The extra thickness of the extra plate is compensated for by the friction pads being very thin compared to stock clutch. I mean very thin. While Triumph smooth plates are etched & rough, the Hyde smooth plate is very smooth, no etch whatsoever. They say no need to etch.
Regarding adjustment of springs being too tight I did much experimenting to test that. Depends on the springs, with 750 springs binding sooner, once you get 2 threads of stud protruding from adjuster head you are in danger of spring bind. I do not have & did not test 500 springs. Spring binding puts great strain on the clutch cable as you can imagine. 650 springs gave a dramatic reduction in lever effort in my case with my stock '73 lever assembly. For clutch rod adjustment I'm running 3/4 turn out from touching rod (not plate lift) on my center rod adjuster screw.
Take up point on the clutch lever is not a product of pressure plate spring adjustment, but rather cable adjustment. However rod adjustment must be at least close before cable adjustment.
Amount of lift of the pressure plate is most important. You need at least .110" for good release under all conditions. I found .115-.120" was better. Assuming clutch rod & cable adjustment are correct lift is mostly a product of the lever pull ratio you lever set has. This is dependent on the distance from pivot screw to clutch cable end. So far as I can tell many of the earlier, such as 69-70 levers pull a good 1/8" more cable which translates into a good .025-.035" more lift with lever pulled to handle bar grip. This lever has less leverage however, so effort is greater. But again plate lift is more & works better.
My lever has a shorter pivot/cable distance by 1/8". So far as I can tell the '71-75 levers all have this leverage ratio. It gives a much easier pull, but less cable travel resulting in only .074" plate lift. This is with just a trace of cable free play. Even with Hyde clutch, this was not very good & when very hot plates might drag slightly getting into neutral. But... the lever effort with 650 springs was really good.
To get more plate lift I needed more cable travel. Since I didn't want to change lever assembly I got another lever perch half from Rabers to experiment with. I cut 3/16" off the alum. off perch such that the lever could move closer to the clutch cable. Had to grind out the slot with Dremmel so lever could move further towards cable. Of course now the lever was farther from grip by 1/2-3/4" or so. The reach is farther, but visually you don't see it. While riding bike the extra reach is not an issue because much of the reach is the required free play in cable & the springs are not so hard to compress until lever is closer to grip. With just under 1/8" cold, & a full 1/8" cable free play hot I now get .117" hot. Finally the clutch is perfect & I can get neutral easily even when smoking hot it town. It took me 2 years to get it all right.
This is interesting observation. When I backed off the springs I took the plates out to look at them just for fun. The etched steel plates had no visible wear from the Triumph friction pads. However the Hyde friction pads looked like they were wearing the etched plates slightly, but not the smooth plate. Again I've had no cable/rod adjustment change to speak of so wear is slight. Wear mostly on steel where inside dia. of Hyde pad contacts steel plate. Press plate contact is centered for stock frictions, but biased inwards for Hyde, because Hyde friction has much larger inside diameter. Still clutch works good though. Seems to me smaller dia. alum press plate would be even worse, but again users find them to work good.
I've covered over 2000 miles with this set up now, in both icy & very hot conditions, short & all day rides & I can say it's working perfectly & Hyde clutch has not needed much adjusting. If plates wear the cable free play gets less & rod adjustment gets less as well. So far the adjustments have been holding good. One thing I've noticed on the Hyde clutch is it's just slightly notchy on the take up cold. Not a problem at all & doesn't effect selecting neutral or shifting but with taking off bike starts to move & then the last bit of lever movement the clutch is ever so slightly grabby. After the chill gets off the engine (1-3 min.) or maybe 2 or 3 take offs, the clutch is silky smooth.
Now... Here's an interesting take. My friend John put a full Hyde kit all friction & the smooth steel plates in his '69 Bonnie recently. Hyde suggested to him 500 springs were too weak. They suggested new 650 springs backed off a bit. He got the same Raber's 650 springs I got (SRM). He backed them off as suggested & had clutch slip at times. He then went just slightly looser than flush & no more slip. He has very good release with the Hyde also. He flattened the stock steel pressure plate as I did. His lever effort is similar as before. We both have well lubed Barnett cables. I cannot explain why his clutch had a tendency to slip. He was/is running Type F ATF in primary, I'm running Mobil1 V-Twin 20-50 in primary.
Regarding the Raber's springs, I made a spring tester & found the Raber's new 650 springs were slightly stronger than some old 650 springs I had laying around. My original 750 springs were way stronger. Visually 750 spring wire is much fatter & spring is shorter uncompressed that 650 spring. Even with your fingers 750 spring is much stronger to compress.
That's my experience.
Don