Mouse trap spring ?

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Bikes: 1953 FL
1972 XLCH
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Mouse trap spring ?


Post by panhead1953ohv » Mon Jun 14, 2010 6:28 am

just installed and adjusted a mouse trap on my 53 fl and the clutch lever pull is hard,worse then my 75 fl.the springs in the clutch hub are orange could these be heavy duty springs?the bike was my father in laws and it was foot clutch when i recived it from has taken me over two weeks to get the trap moving like it should.the hub spring spacing is right on at one inch and one click tighter this is how i get the 31/32 the book asks for.the mouse trap cams to full lock,all new bearings and main spring.i am leaning twards replacing the hub springs as a next step.any input please?

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Re: Mouse trap spring ?


Post by beets » Mon Jun 14, 2010 1:51 pm

Normally there is enough adjustment on the trap spring to equal the clutch pressure.
Did you put maximum tension on the trap spring and the lever is still hard to move?

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Re: Mouse trap spring ?


Post by Bosheff » Mon Jun 14, 2010 1:55 pm

I believe foot clutch springs were stiffer than mousetrap springs which in turn were stiffer than 68 and later springs. As far as "Orange" springs I'm guessin you have aftermarket springs and have no idea what they are, but I'm sure someone else out here does. 31/32" is the required spec according to the manual, but is by no means the gospel. It is a good starting point. What this spec does is control the amount of spring pressure on the pressure plate assembly. I set mine up with 3 threads exposed on the 3 stud fingers and that is enough pressure to return the pressure plate without the clutch slipping. Keep in mind the mousetrap is an adjustment of it's own and so is the clutch. Also keep in mind that both adjustments have to work together, so there will be variations in the given specs to get things working in unison....bosheff

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Re: Mouse trap spring ?


Post by RUBONE » Mon Jun 14, 2010 4:28 pm

There are only two types of clutch springs, the -41 spring for hand and foot shift bikes through '67, and the -68 and later springs. When H-D changed the clutch in '68 the operating lever on the transmission was changed to allow the handlebar lever movement to transfer into full release at the clutch, something that the mousetrap accomplished with the earlier long release lever. In order to soften the pull at the hand lever lighter springs with less tension are used. The clutch plates were upgraded and number of plates increased so that less tension operating over more friction surface created a functional clutch. Any -68 clutch can be used in an earlier basket (from '41 up) to allow a lighter clutch pull. If the clutch is adjusted correctly and the mousetrap is adjusted to suit you should have a very light pull. Modern replacement clutch plates tend to have much better friction than original types and will allow the pressure on the springs to be diminished. As Bosheff said in his post, the spring tension adjustment is a starting point and was based on plate material at the time. Any adjustment that prevents slippage is adequate. And make sure the mousetrap cable and clutch handle pivots are well lubricated as well as the mousetrap itself.

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