Big Twin Springer -- Technical Questions

[Rooster]

Hoping someone here can enlighten me - - -
I have a couple sets of OEM rockers for big twin springer forks. Also have a couple sets of studs and bushings, mostly wore out. I have a set of bushings, new, I thought they were OEM, but are not drilled and machined for grease passageway, so don't know what they are, although they are the right size.
I've tried to accurately measure the width of the rockers at the bushing 'boss' area, the length of the bushings, and the length of the studs where the bushings engage them.
I've come up with exactly 1.000" for the bushings, and about 1.012" for the stud. When the 'stud screw' and lockwasher are installed, that would leave .012" end play. Does this seem correct? Anybody got any nice OEM parts they can measure to confirm this for me? What is the width of the rocker itself?... it can't be greater than the bushing, obviously.... right?

[Rooster]

Since no-one on the Antique Motorcycle Club of America technical forum seems to know, I ordered a set of Colony bushings. They claim to be an exact duplicate of the OEM HD originals, and I will use them for my measurements.

[exeric]

Sorry Rooster. I missed your post. I went through this a short time ago. I did an early springer for a friend and made undersize bushings so we could use the genuine worn studs. Of coarse, the studs needed to be turned so we had a nice even dimension and a good surface for the bushings. Way too much work. On the most recent springer I did, I used the Colony kit with new bushings, studs, and lock washers. It's expensive but a much better way to go. Everything looks great and it's nice and tight. I've got 4 big twin springers laying around and that's what I'm going to do for all of them. However, I see your parts are chromed and I can see why you want to save your parts. I have one springer that is all chrome and I'll probably be doing the same thing as you. I can give you a little tip. You can buff the chrome with a sissle buffing pad and white compound in a bench grinder and it will make the chrome look brand new.

[Rooster]

Thanks for the reply, Eric. The set of rockers in the photo is a spare set, I have a nicer set on the bike right now, along with the brand new Colony studs.
Now........, here's the real reason I am asking this stuff---- the bike I am talking about is my old Panhead chopper, I have owned this bike for 35 years. It's a genuine '60s style chopper, unchanged all these years, except for the tanks and seat. Of course, the original wishbone frame has been raked, and the springer that came on it was about 13 or 14 inches over. Real nice extension job done on it, with custom home-made rockers (It was ALL homemade stuff back then!) that corrected the trail and made it handle really nice. Unfortunately, that springer broke about 20 years ago--- twice. I had to retire it and hunt down another nice extended HD springer that I could replace it with. It took about 5 years, but I did end up finding one in the early '90s.
There's more to the story, and I'm sorry to bore you--- in the mid-80's I bought a shovelhead, so the old chopper got pushed aside; it had the 'new' springer on it, but I never really dialed it in. The bike had other issues too.
In the mid-90's, I bought a new Evo Fatboy, so the old chopper got pushed even farther aside.
Two years ago, I started to get the real serious urge to own an original Panhead, or something that I could do my best to make original, and I looked a long time at that old chopper thinking---- should I try to bring this one back? No, there was no way I could mess with that old bike, the one I grew up on, and still am lucky enough to own. So I went out and bought a bitsa-'52, and I'm deep in the middle of that restoration project -- and as you know, won't happen overnight.
Meanwhile--- about a month ago, I couldn't help staring at my old chopper in the corner, wondering why I didn't do all the things I needed to do to "restore" it to it's former 1970's glory. It had a few issues, which over the past 3 weeks I've taken care of, and the thing really runs great! However---- that springer I put on, needs some custom rockers to correct the trail; the rockers off the other springer would not fit due to the way the ends of the fork legs were shaped.
So.......... that's where I am now. I made some mockup rockers out of plywood (yep, plywood!) to see what trail I would end up with, and I'm pleased with my mockup, and now I need to fabricate (or have fabricated) the new rockers. They will place the axle farther forward and farther up than the OEM rockers that I am running on it now. The OEMs give it a rediculous 8-inch trail, and the new ones will bring it right in the middle of the sweet spot, with a 5-inch trail.
Now--- I know this is an "antique motorcycle" club, and I am of course a member. But my roots go back 35 years to this old panhead chopper, and I am perhaps somewhat wiser now than I used to be. How many of us here ever had a chopper before? How many still have that old chopper?
Hey, if you're still with me, sorry to bore you with the lengthy monolog. But I need to figure out the tolerances of the OEM studs and bushings, because I will fabricate the new rockers to accept them. The main thing I need to know now, is what the end play tolerance is on the studs. As I've said, from what I can determine, it is about .012". That seems reasonable to me.

[exeric]

I think that's a noble pursuit Rooster. In addition to being history, it's got to be personally gratifying to have something for that many years. Unfortunately I don't have any new bushings that aren't in a rocker. I was just wondering if a Knucklehead manual would have those tolerances.

[Rooster]

Eric, I will just take apart the rockers that are on the bike right now--- again. They are Colony studs, so I can measure them against the bushings that are on their way to me, and we'll see if my estimate of .012" is close.
I don't know 'noble' the pursuit is, Eric, but I will tell ya-- that old bike is a LOT of fun to ride! I know, this is probably the wrong forum for this photo, but.... well, when someone objects, I'll remove it!

[exeric]

My first H-D sat like your's but it never looked as good as your's. Mine was a '57 in a wishbone frame with an aftermarket springer and a horse saddle for a seat. Whoever did your fork did a nice job with the taper. I've always loved that minimalist, down to business look like your bike has with no useless b.s. Of course the Orange County Chopper boys wouldn't like it because it isn't a theme bike.

[Rooster]

My 'old' springer was even more beautiful--- the guy who did it, cut off the lower tree just inside the fork leg, and ran the extension up past the tree and blended it together at the 'S-curve' portion between the trees. Really clean and sweet. It eventually developed a fatigue fracture just below the lower tree. I had that welded and added a gusset, and a few years later it cracked again, right at the bottom of the gusset. That was the end of that springer. I still have it, thinking some day to find some old radius rods and have the thing redone. But this one here looks okay, too.
Okay--- thanks for indulging my blast-to-the-past. Back to the "antiques"--- I know this isn't a chopper forum-- my apologies.!

[cdndewey]

I measured the rockers I'm getting ready to Parkerize and they came in at 0.995". My other set are assembled but I'll pull them apart in the next week or two and give them a measure and let you know.

[Rooster]

I measured the rockers I'm getting ready to Parkerize and they came in at 0.995". My other set are assembled but I'll pull them apart in the next week or two and give them a measure and let you know.

Wow, now that's some of the info I was after! Thanks very much, Dewey! That number makes perfect sense, with the bushing width at exactly 1.000". I need the length of the bushing surface on the stud itself, and I'll have what I need. I can take my front end apart again and get that. Dewey, don't take your stuff apart just for a few measurements, you don't need to do that.
What I am after is the end play clearance of the bushing on the stud after the stud cap screw is tightened down. This would be it's 'working clearance'. I have come up with .012" by measuring what I have, but I will take the new studs off the motorcycle and measure them when I get the Colony bushings in my hands.
Thanks again, I appreciate it.

[cdndewey]

I measured the bearing surface of the studs and came up with 1.010". Hope that helps a bit.

[Rooster]

I measured the bearing surface of the studs and came up with 1.010". Hope that helps a bit.

Dewey, that helps a lot, and I appreciate your taking the time to do that for me! That's real close to the 1.012" that I got on mine, but the set I measured has been chromed, also. Thanks again, I appreciate the help.