Clutch Pull Questions Model 85 250 Alpina

[bgeacook]

has anyone tried using only 3 springs, or maybe four (which would be slightly out of balance)? like most people I'd like to reduce the heavy clutch pull on this bike. it has the cup/pin retainers BTW. I saw mentioned here of a clutch kit (from BUK?) that consisted of fiber plates and LIGHTER springs. wondering if anyone is familiar w/ the Barnett (usa) kits. they say "heavy duty" springs but not sure what actual rate is compared to stock. I figured if they were heavier then maybe 3, or 4 would hold, especially with the fiber discs?

[markg]

Fibre plates are the way to go. You can then use softer springs as not as much compression is needed to create the drive thru the plates. Heavy duty springs I have found are just that, making the clutch action heavier. I have seen a few set up with 3 springs and fibre plates and this seems to work ok depending on the situation. I think it's important also to set the clutch up so it releases squarely and evenly.

[bondy]

on my 199A the clutch is very light i use the barnet plates but mine as the 6 nuts you can Ajust so can't comment on the pin type. I only use 4 fibre plates also I have softer springs and a longer Arm and the ignition case mode all make for a light clutch.

[bgeacook]

on my 199A the clutch is very light i use the barnet plates but mine as the 6 nuts you can Ajust so can't comment on the pin type. I only use 4 fibre plates also I have softer springs and a longer Arm and the ignition case mode all make for a light clutch.

[bgeacook]

do you happen to know if clutch springs are the same between models (alpina and sherpa, for example) and/or cup/pin type and nut retainers? where did you get the lighter springs?

[bondy]

I have never had a alpine so have no idea but  I should imagine there the same when I say softer springs I mean I just use the old springs not the stiffer Barnet ones.

[nigel dabster]

set the clutch up so it just slips in top gear, by backing off the springs, then back in a bit the springs sre then as soft as can be. A longer arm might not give enough free play, ensure rod is very smooth through motor and very important cable is tangential to pull direction

[feetupfun]

It is much easier to set the clutch up with the perfect amount of preload on the springs if you replace the clutch inner with one that has threaded rods and nuts for the clutch springs instead of the clutch inner that has the pins-through-holes spring retainers.

[motovita]

 Do the fibre plates require more travel to disengage than the steel ones?

 On my Pursangs I used to shorten the actuator arm to prevent drag on the starting line, that was with Barnett plates and springs.

[feetupfun]

The release travel required depends on the sum of the out-of-flatness of all the plates.

The fibre plates (outer plates) I've put in one of my Bultacos (Barnett) were very flat and did not increase the travel required.

The production method of the original Bultaco plates is stamping, which is a method that by its nature introduces some degree of out-of-flatness (depending on the condition of the shearing edges)

It is very common to see high and low spots on used OEM Bultaco plates, which is evidence of their lack of flatness

[feetupfun]

 Do the fibre plates require more travel to disengage than the steel ones?

 On my Pursangs I used to shorten the actuator arm to prevent drag on the starting line, that was with Barnett plates and springs.

 

Did the plates move out parallel? Even with very flat plates, if the springs are not preloaded evenly, the release travel will be long because the pressure plate tilts

[motovita]

Did the plates move out parallel? Even with very flat plates, if the springs are not preloaded evenly, the release travel will be long because the pressure plate tilts

 

 I don't know, I was an MX racer, fine clutch control wasn't a big concern. It wasn't until years later when I started riding Trials that I learned the finer points of dirt bike riding.

Edited December 12, 2016 by motovita