Board index Flathead Power-Technical Questions, Answers, and Suggestions Pans Throw out/push rod stroke

Throw out/push rod stroke

Post Fri Sep 01, 2006 10:32 am

Posts: 25
Location: Upstate NY
On a 4 speed trans setup, about how far out should the clutch push rod push the pressure plate out for clucth release? I'm looking at about 1/2" now.

Post Fri Sep 01, 2006 7:31 pm

Posts: 646
Location: Detroit
There is no measurement I am aware of. The answer is: until it works meaning it slips and doesn't grab and put any effort into moving your bike forward. With a properly adjusted clutch you can be in gear, have your engine running, sit on the bike, pull in the clutch, and roll the bike backwards with the same effort as if it is in neutral.

To adjust everything do this, and I assume you have a long clutch arm over your trans, not one from a Shovel that works with an eliminator:

IMPORTANT: adjust your pressure plate nuts FIRST so that the inside of the plate under the three adjusting nuts measures 31/32nds from the pressure plate. CHECK ALL THREE NUTS to see that they all have the same measurement. Many clutch problems are related to the adjusting nuts not being adjusted equally so the outer spring plate runs out of plane with the pressure plate. (This does not apply for an eliminator---for that the spec is 1 and 1/32nd I believe.)

1. Loosen the clutch arm adjusting screw nut. This is the one on the threaded adjuster in the center of your pressure plate. Back this nut off maybe 3 full turns. Get a box wrench and a screwdriver for this. You might have to tap the wrench with a hammer to break the nut loose.

2. Loosen the adjusting screw in the center of the pressure plate and back it out maybe 5 -6 full turns, maybe a few more.

3. Look at your clutch arm and push it all the way forward until it touches the back of your trans lid. If it won't move forward that far then back off the adjusting screw enough so that you can accomplish this.

4. Screw in the adjusting screw until the clutch arm goes all the way back AWAY from the trans lid and toward your rear tire. DO NOT overtighten the screw when you do this---enough is when the arm won't go farther back. Back off the adjusting screw maybe 1 to 1 and 1/2 full turns.

5. Tighten your clutch adjusting screw nut. Normally I turn it up against the plate, put a box end wrench on it, hold the adjusting screw with a screwdriver, and smack the wrench moderately with a hammer, but NOT hard, to lock it down. It would be a real pain in the ass to have it come loose at 75 mph half way to nowhere at night.

6. Try to work your clutch. It should pull in far enough so that the arm contacts the back of your trans lid. If it doesn't you might shorten the length of the thin rod that runs from your foot clutch or mousetrap to the clutch arm. Likewise, if this thin rod prevents your clutch arm from going all the way back in step # 4, then lengthen the rod.

7. Don't forget to tighten the lock nut(s) on the thin rod. If you have a chain there in place of the thin rod, good luck.

8. If your clutch slips, you may have worn clutches, grease etc., on them, etc. If the clutches are worn down but otherwise in good shape, tighten up the adjusting nuts EQUALLY a click or two at a time until the clutch grabs. One time I had "weak" clutch springs. Actually they were old as hell knuckle springs and a little rusty, and well used but clean clutches. My steel plates were good. I had to tighten the three adjusting nuts until the back of the outer plate was at 3/4" instead of the spec 31/32nds. Then magically the clutches stopped slipping and everything worked fine.

9. If you have mousetrap problems you need advice from someone other than me since I never ran one, but if you have any type of hand clutch system don't forget to adjust the cable. I still think everyone should run a foot clutch but that is my own preference.

10. Go for a ride but test the clutch at idle or just above FIRST, BEFORE you blast off down the road.

11. If the clutch slips, adjust the three nuts in EQUALLY one click at a time until the clutch grabs properly.
New Knuckleheads? Thank, you, Jesus!!

Post Sat Sep 02, 2006 4:12 am

Posts: 1536
Location: S.Calif.

I don't know if this is about your problem, but you have me questioning myself on (lateral) push rod travel.
The clutch push rod should have a 1/4" of travel. We had a problem with a V-Twin starter cover that had extra material around the casting that held the release finger. It wouldn't let the finger move. The bell of the push rod (throw-out) bearing would also make contact with the inside of the cover, so it took multiple grinds, installs and removals of the cover to get the the finger free and the travel distance to 3/16", but not quite the 1/4" we needed. The second problem we have (or had) may be, that the V-Twin release lever may not have been made at the correct angle. In short, if we need another 1/8" of travel, we'll need to heat the boss of the release lever with a rosebud, where it connects to the finger stud and add (a little bend at the base will translate to alot of extra swing-space at the end of the lever) slightly more bend to the lever (pulling the lever towards the rear wheel), which will give us more release lever swing travel (before the lever hits the backside of the ratchet cover).
I'm glad you mentioned your problem, because I have three 4-speed transmissions to second-check. I believe that two of the trans. will have 1/4" of push rod travel, and the 3rd one 3/16". I'll look and re-measure the push rod travel and post the results. It may not answer your question, but it will answer mine. Thanks for bringing it up.

Post Sat Sep 02, 2006 10:50 am

Posts: 1536
Location: S.Calif.

Yep. 5/16" of travel on this one.
Early starter lever. '74-79 FX top and shifter cam. Shift pattern is forward for first, back for neutral, back for 2nd, 3rd & 4th. (Cometic® main seal is un-installed at present)
Release lever at full forward, clutch would be dis-engaged.
FX top and shifter cam.
Push rod is in the clutch-engaged position.
Push rod is in the clutch-disengaged position. Release lever is fully forward and striking the cover.
Last edited by Plumber on Sat Sep 02, 2006 3:21 pm, edited 10 times in total.

Post Sat Sep 02, 2006 1:53 pm

Posts: 25
Location: Upstate NY
I have rechecked mine and it is moving about 1/4", I had originally stated 1/2" but that was from memory and I should have been looking at the bike. Thanks to everyone for their posts, it has helped immensely

Post Sat Sep 02, 2006 8:32 pm

Posts: 646
Location: Detroit
That measurement doesn't mean much if everything else that goes into making the clutch operational isn't adjusted properly. The various adjustments are there to compensate for wear over time and slight manufacturing variances. HD factory parts normally fit as designed and don't have to be reworked right out of the box. If you have a mix of stock HD and aftermarket parts they might work correctly or they might not. When I built choppers years ago I always wondered why expensive aftermarket parts had to be modified to fit their intended purpose especially since the manufacturers always claimed they were "built by HD riders for HD riders." Right. Today's collary is Twaiwan Wang and Honk Kong Wong repoping as fast as they can.
New Knuckleheads? Thank, you, Jesus!!

Post Sat Sep 02, 2006 8:50 pm

Posts: 1536
Location: S.Calif.

Yes, times have changed for the '41-59 OHV builder without all OEM parts that used to be available (the only years and models I can have an opinion about). A lathe comes in handy for front axle modifications. A Foredom die grinder (with a separate cable fed motor) is good to have.... and a qualified Harley mechanic who has a complete machine shop behind him helps. :lol:
I built a rolling Panhead chassis from a V-Twin frame, with front and back brakes that work, and only used a file and a 7" grinder and die grinder and made it all fit. Some parts like the handlebars are as good as n.o.s. Harley. Parts like with the Glide front brake cover were the biggest challenge and the fork slider leak was hard to figure out, but I had some direction from Mbskeam; and with the crossover shaft reaming, another Mbskeam :idea: idea where he took an socket extension and made a collar out of fiberglass tape that worked like a pilot. But you know, now that I've built one rolling chassis, I could build more and know what to look for immediately.
The frame problems stopped me cold three times. If Don @Corbin hadn't tweaked mine into shape, I'd have been done-in on the project, because we wouldn't have been able to advise a repair. But, I think now all the bad rigid Pan frames are past history. Mine was from '97.
My only regret is that we didn't get to buy a V-Twin replica Knuckle motor and strip it down to the flywheels.
As soon as I can get out to re-paint my frame and fenders, I'm rolling again.
People like the sound of a mufflered Harley. They can speak and be heard as it's idling, and you're not a threat - all which makes a great end to the conversation - Sitting astride the machine, kick it through once*. Say your good-byes, turn open the tank shut off, retard the timer, find the compression stroke, turn the switch ON, and kick-it through completely. It's nice when it starts into a steady lope and speeds up a tiny bit when you pull the timer to full advanced.
It's a rigid Pan or a Knuckle and there is no other comparison. Coolest motorcycles on the planet.
Why the mfgrs. don't make at least every part on Knuckle and Pan to OEM perfection is a question for the scholars. The reasons are manifold, so we deal with the facts and how to adapt.

* This motor was warm, so one prime kick (w/ a Linkert). If the motor doesn't start or mis-fires, you can still hold their rapt attention, if you just leave the key ON, and still standing astride the motorcycle, find the compression stroke again, even if it misfires again while doing so (it will never "kick-back" like a BSA, B-33). And, the amazing part of this polished, fast moving ritual-to-an-onlooker, is that with seeming little effort or "jumping" up and down you've started this huge motor while almost "sitting" down, by about your third steady kick through. So guaranteed to work on a 61 or 74" motor, that you can still talk to them as your kicking it through. It always starts and you've never touched the ignition switch. Awesome is what you'll leave behind. 8)
Fun motorcycles. :!:

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