'47 Buddy seat helper spring fender hook

[Snakeoil]

The rear helper spring fender hook on my '47 has three slotted round head screws, with a lockwasher and a nut. The manual shows 2 screws. Those screws are 051 which are 1/2 inch long. Two of mine match that spec and the other is about 1/16" shorter and has a thinner nut.

I know that the fender has 3 holes from the factory as does the hook. Are there 3 holes and two screws to allow for adjustment fore and aft or is the parts manual simply wrong.

The other question on this same part is the manual shows a backing plate for the hook. I assume it goes on the underside of the fender. My bike did not have this plate. My fender is cracked at the forward most hole. I think the backing plate would have prevented this had it been installed. The plate is 13342-38. Did the '47 have that plate? And if it did, did it still use the 051 screws? I ask because I don't think they are long enough if the plate is 1/8 material like the hook. Although the plate may have been much thinner. That would be good to know as well. I'll probably just make the plate while I look for an original.

Thanks,
Rob

[Rubone]

All used three screws, the location wasn't adjustable. The later fenders have a spot welded in place backing plate so it was no longer a separate part.

[Snakeoil]

Thanks. Serial number is 12XXX so about middle of the year I would think. So, probably no spot welded plate. My guess is the seat was purchased as an accessory and the plate did not come with the hook or the owner did not use it. Could be dealer installed the seat and the dealer did not use the plate. Who knows? But at least I know I'll be correct if I install the plate.

Thanks,
Rob

[bobdo]

Rob,
I pieced together a late '47 EL years ago. The research I did at the time was the clip should be the "curl" type, a single thick piece. I had the two piece clip that I replaced. The lower plate was very thin.

[Snakeoil]

My hook is a single 1/8" thick x 1-3/8" wide piece. If bottom plate is thin, this explains the 1/2" screws.

Thanks,
Rob

[Snakeoil]

Can anyone tell me the dimensions of the backing plate? I assume it is the same width as the hook, 1-3/8". But what is the thickness and length?

Thanks,
Rob

[bobdo]

Rob,
I see you haven't gotten a response to your question. I no longer have that type of clip and can only provide an approximation from memory.
My width was the same as the clip, the length was approx. 1/2" longer to protect the paint under the clip. The thickness was much thinner, maybe
1/16" / .06. I don't know the exact gauge steel.

[Snakeoil]

Thanks. I know that the pictures in the part manual are misleading. The manual shows the backing plate and the hook and the parts lists says "thru 47. But in talking to Dan Henke, the 47 used the single hook and no backing plate. My fender is cracked at the forward hole and Dad said that was a common problem and he's seen fenders where the hook actually curled a piece of the fender up like a sardine can opener.

Since my bike is original paint, I cannot weld repair the fender. So, I made a backing plate from a piece of 0.032 sheet steel, formed it to conform to the curve of the fender and will use that to preserve the fender. I might mount it using black 3M 5200 which will give it strength and dampen the effects of vibration. I'll either leave the spring mounted to the buddy seat or loosen the mounting bolts and let the spring pivot so as reduce the tension placed on the hook. My hook was actually bent upward. I suspect that it was because somebody used the spring as a handle to lift the back end of the bike. But I suppose if the spring were left in the hook long enough that over time, with enough vibration it might have bent the hook up a bit.

Thanks,
Rob

[bobdo]

Rob,
With your description that sounds like a good plan to me. I'm assuming your added sheet metal is placed on the underside of the fender. Adding some silicone or something is a good idea for added strength. You shouldn't have any more issues. I'm glad to hear your preserving the paint as best you can. My hook is the same as Dan recommends.
Spring is coming....I'm an optimist.

[55tmm]

I just looked at your thread, I'll try to post some pics of my 47
Mine is early, no plate on under side of my fender.
I believe mine has never been removed.1947 Knucklehead 190.jpg1947 Knucklehead 212.jpg

[Snakeoil]

Sorry for the late reply. Been preoccupied with domestic issues.

That hook looks like the earlier style which is the two piece design. Now I see why there is that extra plate. Mine is a later 5 digit SN and uses the later look which is a one-piece design.

Your color is the same as mine, though. I've never been a blue bike kinda guy. But I have to admit that the color has really grown on me.

regards,
Rob

[Snakeoil]

Well, I'm the first to say that I'm a newbie to Knuckleheads and vintage Harleys in general. But that should not preclude me sharing what I believe to be an accepted misconception about the spring hook. I had an epiphany today as I mounted the aux seat spring to the bike.

The reason that the fenders get damaged from the hook tension is because the hook is improperly located on the fender. And by that I mean it is not located properly for the desired tension on the spring.

The spring comes from the factory with the nuts that establish spring tension all the way to the end of the rod ends. I know this because mine were still sealed in place with original paint from when they were dipped. So, this setting will give you max spring tension and make the rod hoop its longest. Dan Henke had suggested that I adjust the rod to lower the tension and therefore put less stress on the hook and the fender. That is what I ended up doing. It was during that process that I realized what the proper fix was.

The hook has three screw holes. Has anyone ever wondered why? Do you think that two 1/4 inch screws cannot survive the stress put on them when the spring is in the storage position? If not, then how could the sheet metal of the fender possibly be expected to survive. That was the first clue. The second clue was mentioned in my early post where I questioned the number of screws. The parts book says TWO screws. And my 3 screws were two of one size and one a bit shorter. Hmmmm.... The fender without the hook came with 3 filler screws installed. So, if you look at the hook and look at the fender, it is just logical to assume the three holes on both part all line up. And that is where the problem resides.

The hook and fender have three screws so that you can adjust the hook to accommodate the tension setting of the fender. Remember, these bikes were very utilitarian when they were new. So, to provide adjustment that could mean one hole in the hook remains empty is not an issue. So, if you leave the spring adjustment at the factory setting, you should move the hook one bolt hole to the rear. This will then allow you to put the hoop in the storage position, and not put too much stress on the sheetmetal fender.

It would be interesting to see what the original instruction sheet says that came with the buddy seat and aux spring kit, if there was one. There is nothing that I can find in the service manual.

Now some of you may tell me this is common knowledge and that's fine. I said I was newbie. Others might tell me I'm nuts for thinking this, and that's fine, too. We are all entitled to our opinions. But after trying to put that spring into the storage position with the hook mounted using all three screws, and Henke saying he's seen a lot of fenders with the sheetmetal torn upward like a sardine can, I'm pretty confident in this conclusion.

regard,
Rob

[46WL]

Sorry, you would just adjust the 4 large nuts on the spring rod. You wouldn't move the fender clip, because you would have to remove the whole rear wheel assembly to get the nuts/lockwashers on the pre-late47 style fender clip. And if they only wanted you to use 2 screws to mount the clip, they would only put in 2 holes on the clip itself.

[Rubone]

I agree with 46WL, No need to ever move the clip. Most buddy spring assemblies have so little pressure on it that they barely stay clipped. Of the many dozens of original fenders and clips I have observed over the last 40+ years of messing with this junk I have never seen an original fender with the clip in a different location, Big Twin or 45, early or late type. Plenty of cracked fenders though, and more so with the factory spot welded reinforcing plate.

[Snakeoil]

Well, speaking specifically to the '47 with the one piece hook, if you try to use the full range of adjustment on the spring hoop, you will get to a point where you cannot get the hoop over the hook to latch it. I don't disagree that every bike I've seen with a hook has all three bolts in the assembly. But I still believe that if were meant to be in one location only, they would have only used two bolts. Three bolts holes allows you to use the full range of the hoop adjustment threads.

I'm not trying to be right. I know most if not all of you have a lot more experience with these than I do. But if I were needing to have the aux spring provide max support, I would move my hook to put less force on it when in storage or just leave it engaged to the seat, if for no other reason than because my fender is cracked at the forward bolt hole. Fortunately, I can adjust my hoop so that it goes over the hook and does not put a lot of force on it when engaged.

regards,
Rob