Mousetrap adjustment

[JSB55]

Hi, Guys. 65 FLH on which I just had to rebuild the transmission which wouldn't shift into 4th gear. Turned out the 3/4 shifter clutch was installed backwards by whoever was in there last, and had kind of chewed up both 3rd and 4th gear dogs.

Since I had everything apart to rebuild my transmission, I took the opportunity to put the Mousetrap back on, instead of the eliminator. Being my first stab at it, and everything apart, it took a while to get an initial setup to work off of before fine tuning the adjustment per the book. I think I've got it right, but am left with two questions.

1. When the hand lever is released, should the booster spring return only to vertical, or should it go past dead center as it did when setting the bell crank adjustment?

2. This thing is still much harder to pull than my Shovel and Evo clutches, and not much different than I remember it being with the eliminator installed. A mechanic friend had an older Pan in his shop recently, and we were marveling at how the clutch lever could be pulled with one finger, so I know something is not right. To soften it up more, should I be fiddling with the Booster spring tension, or try backing off the nuts on the clutch pressure plate? The book gives the 31/32" setting as a starting point, but also says to employ no more clutch spring pressure than is needed to keep the clutch from slipping. It's still on the lift, so I haven't road tested the setup yet.

Thanks in advance for any expert help!

[Omarttentmaker]

Hi, Guys. 65 FLH on which I just had to rebuild the transmission which wouldn't shift into 4th gear. Turned out the 3/4 shifter clutch was installed backwards by whoever was in there last, and had kind of chewed up both 3rd and 4th gear dogs.

Since I had everything apart to rebuild my transmission, I took the opportunity to put the Mousetrap back on, instead of the eliminator. Being my first stab at it, and everything apart, it took a while to get an initial setup to work off of before fine tuning the adjustment per the book. I think I've got it right, but am left with two questions.

1. When the hand lever is released, should the booster spring return only to vertical, or should it go past dead center as it did when setting the bell crank adjustment?

2. This thing is still much harder to pull than my Shovel and Evo clutches, and not much different than I remember it being with the eliminator installed. A mechanic friend had an older Pan in his shop recently, and we were marveling at how the clutch lever could be pulled with one finger, so I know something is not right. To soften it up more, should I be fiddling with the Booster spring tension, or try backing off the nuts on the clutch pressure plate? The book gives the 31/32" setting as a starting point, but also says to employ no more clutch spring pressure than is needed to keep the clutch from slipping. It's still on the lift, so I haven't road tested the setup yet.

Thanks in advance for any expert help!

I hate being the one that says this, but the panhead manual describes how to adjust a mousetrap, and it works. The only subjective part in the adjustment description is the picture and description of the 1/8" over top dead center that is shown. That's very difficult to determine. Another is the lack of any dimensions that determine where on the front frame leg the mechanism should be clamped. Just from looking at pictures, I try to located the whole assembly so that the rod that goes back to the throw-out arm is relatively parallel to the way the bike sits on two wheels. Good luck and let us know of your progress.....Cheers

[PanheadFred1]

Look on YouTube for a guy called Pacific Mike. He has a video of setting up a mousetrap that is very good.

[Kozy]

Maybe this will help.
Old Harley Davidson Mousetrap (Clutch Booster) adjustment. - YouTube

[JSB55]

I hate being the one that says this, but the panhead manual describes how to adjust a mousetrap, and it works. The only subjective part in the adjustment description is the picture and description of the 1/8" over top dead center that is shown. That's very difficult to determine. Another is the lack of any dimensions that determine where on the front frame leg the mechanism should be clamped. Just from looking at pictures, I try to located the whole assembly so that the rod that goes back to the throw-out arm is relatively parallel to the way the bike sits on two wheels. Good luck and let us know of your progress.....Cheers

Also #Kozy and #PanheadFred

Thanks for the input, guys. Actually, I watched Pacific Mike before tackling it, and then followed the HD manual step by step. And yes, I located the mechanism on the leg so it appears to be a straight line shot from clevis --> clutch rod --> clutch lever, both horizontally and vertically, and is dead on level to the ground. The only thing I overlooked was Pacific Mike's suggestion to lube it up liberally. Guess I'll just have to start over and keep at it.

[JSB55]

SO... After a close look at the diagram in the book, and a freeze frame look at Pacific Mike's video, I noticed my mechanism was mounted a bit lower than theirs. Raised it another 3/4" up the leg, and voila!, it was then able to return past dead center. Next step, remove the new springs and aluminum aftermarket pressure plate, in favor of the OEM plate and springs. Still takes a strong pull, but much less so than before, and I can hold it with one finger. AND, I can now do the adjustment routine in my sleep

[otis71]

It looks like you already figured what I have to say. Most aftermarket springs have more tension than oem springs. Bills Customs has decent replacements for $15.

[Rubone]

A big mistake often made is too much tension on the mousetrap spring. It only needs to "assist" the pull, and should return with very slight pressure from the clutch springs. The factory setting is merely a baseline suggestion. Feel free to experiment.