Mousetrap adjustment

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Mousetrap adjustment


Post by Guest » Sat Dec 30, 2006 5:06 pm

Description: Mousetrap adjustment

I run a '58 Harley Davidson Pan motorcycle with a mousetrap. If you get your clutch setup correctly, the mousetrap is as easy or easier than a 2000 Harley Davidson Softail.

There's a nice section in the old 58-74 Harley Davidson manual on clutch hand booster adjustment, but I'll tell you how I do it. First, if you have anything other than stock Harley Davidson springs (like Barnett), take them out and replace them with the stock -68 springs. Heavy springs don't work with a mousetrap. Then make sure your clutch is tricked out like the article recommends for smooth operation.
Next make sure the adjustment from the edge of the spring retainer to the pressure plate is no less than 1". If your clutch doesn't slip, you might even go a few clicks out. The lighter the spring pressure you can get away with before the clutch slips, the less the mousetrap has to work to counteract it.
Next, put as much slack into the mousetrap cable as you can, loosen the forward stop screw and turn it out a few turns. Loosen up the spring tension hook as well. Unlock the nut on the center of the clutch adjustment screw and turn it out a few turns.
Now everything is nice and baggy, so we can start adjusting. One more thing, grease the pivot on the hand lever and the pin where the cable hooks to the lever.
Run some 3 in 1 oil down the motorcycle cable until it drips out the other end. When everything is juicy, you don't have the "sticktion" that makes the clutch hard initially. Also grease the mousetrap pivot, and the eye clevis that hooks it to the long clutch pull rod, and the hook from the cable to the mousetrap.
Now-turn the center screw motorcycle part on the clutch in slowly until it bottoms out, then back it off about a quarter turn. Lock the locknut. Now set the travel screw on the mousetrap so it goes over center by about 1/8". Be careful or it will bite you, but it should stay locked in the forward position, and snap back over center with just a bit of movement.
You may have to lengthen or shorten the long skinny rod to get just a hair of slack with the mousetrap in the lock forward position. Now take up the slack in the cable until you have 1/16" or so. Now when you pull in the clutch the mousetrap will operate the clutch, but since we loosened the big spring up it will be real hard.
What most folks don't realize is the big spring works in opposition to the clutch springs, so tightening it up makes the clutch easier. Tighten the bottom hook up a half turn at a time until the clutch is much easier. If you go too far, it won't snap forward over center, so go that far and then back off a little at a time until it's easy and still snaps forward and locks over center.
That's it! Just one other thing I can think of and that's if the mousetrap doesn't work freely, or is not positioned correctly on the downtube, it could affect operation. If your clutch slips and you have to tighten the 3 or 5 adjuster nuts a couple of clicks, you need to tighten the big mousetrap spring to compensate.

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Joined: Sat Sep 12, 2009 7:53 am
Bikes: 1958 FLH
Location: Itasca

Re: Mousetrap adjustment


Post by hammerdog » Mon Jul 22, 2013 5:24 am

I will try again tomorrow I have to walk away from the bile right now

Biker bum
Posts: 7
Joined: Mon Jul 21, 2014 1:17 pm
Bikes: 1948 Pan, 1947 Indian, 1948/60 45", 1966 Shovel, 1986 Sporty, 1999 FLSTC
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Re: Mousetrap adjustment


Post by Biker bum » Mon Sep 15, 2014 6:50 pm

Just went thru "Guests" great explanation on setting up a mousetrap, followed his directions to the "t". My 66 shovels mousetrap now works extremely better than I've been able to set up using the factory manual. A copy of his instructions now resides in my factory manual. Many thanks to "guest" for his detailed explanation.

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