Installing exhaust pipes/muffler...

[tomcat1]

Len, I searched Matt O. blog and found pictures of what he posted as 37-45 clamps. They look like yours both (c shape).

http://oldbikesinsd.blogspot.com/search?q=exhaust+clamp

If you have the time to search Matt's blogs, you will find the answer to almost everything.

[bobdo]

All,
I've been through Matt's Blog, the Carl's Cycle photos, my record photography over the years & books, I can't find anything definitive. Most of the images I've found on '47 front header pipes show No clamp! These are highly restored & original paint bikes. Some of them have full slinkys, but most do not. I even found an image of one with a slinkey & the clamp was used under the sidecar loop casting. It was mostly hidden, so I couldn't see the type of clamp. Matt has images of a slinkey that is 5" long being used with a clamp that is the "C" shape stating they were correct for 1937-45, both parts of the clamp have angled tabs. Of the Knucklehead bikes I've seen of various years having front header clamps, they are located just above the casting. I can't make out the type of clamps, "C" or "b" shaped. Since Matt stated 37-45, I'm wondering if the "b" shaped clamps were used from 1946~on? I'm not having my bike judged, but I sure would like to get to the bottom of this.

[bobdo]

I've decided what to do with my '47 EL regarding the front header pipe clamp. Anyone looking for correctness for your own restoration, please don't go by this because its not founded on fact, hopefully someone will still contribute that info. I'm sure it will be appeciated. I had forgotten images I have of 47EL12683 on display at the Harley Davidson museum. ( I understand this may not be accurate, but its in keeping with my image collection showing no clamp above the casting on 47's) My plan is to use a clamp under the sidecar loop casting, this will be mostly hidden. Now that I've made a decision, I'll see if it fits without stressing the head. At this point, I'll put the clamp anywhere. Spring is here, I wanna ride.

[tomcat1]

Bob, this is the best photo's I have of when I was at Matt and Carl's. I was not thinking of exhaust clamps at the time I took them so I didn't get a real good close up at the time. But I don't see any clamps above the sidecar loop casting. You can copy it and try to zoom in and look.

[rustynuts]

c-shaped clamps just above sidecar loop

Here are OEM C-shaped clamps I finally got installed on my 37EL. They wanted to ride up high above the relay, like some of the previous photos. But when I flipped them over, somehow I managed to get them on just above the lug. Definitely not much fun working these. Once the proper tweaks and alignment make up, it's a solid fitment. The tabs on the header clamp had to be twisted in a vice to angle them off center of the clamp. I think you can see the twist in the photo.

[Chris Haynes]

Here is a factory shot of the 1947 UL.

[bobdo]

Thanks everybody. Chris, after alot of searching I discovered a lack of visible front header clamps on excellent restorations & unrestored '47's. That got me thinking maybe they were different than the earlier models. I wish your factory pic was of an EL or FL to put this question to rest, but it sure reinforces my thinking. I found a few pics showing '47 Knuckles with brackets mounted this way. About an equal amount of pics showing them above the casting like earlier models also. Seeing this factory pic really helps. The header clamp is clearly shaped like a "C". The other factory pic you've provided in the past to help with this clamp question, is on an earlier bike with a Teardrop tank badge. It appears to be a Knucklehead. The repop clamps being sold for '47's are "b" shaped. AAOK shows 1936 as the only year for Knuckleheads to have the "C" shaped clamp, but UL's had them through 1948. I wonder why Matt stated 1937 - '45? Maybe after the war they began making the slinkys again & the lower mounting allows for that?

[len dowe]

Bob,
Looked thru my photos and found some of fremont this yr...I will look thru my davenport pics as well and post..The 39 is what Carl, Matt, and Miss Brittney brought for judging...Clearly i have it wrong "again". I have to pull the motor on my el anyway and i'll ceramic the exhaust this time and back to the drawing board i go. I picked up a dead-on best reproduction i have ever seen(besides chip's and he's mia) early muffler from Matt. These muffler's are sweet and after ceramic, I don't see how anybody could tell right from wrong...Hopefully i will get the clamps right this time.. Len.
P.s. Matt is doing another production run of the early mufflers and i highly suggest to eveyone to pick one up. I also picked up one of his rocket muffler's awhile back and if you haven't gotten one yet, i highly suggest that one as well for your 47. They are perfect!!!

[bobdo]

Good lookin' bikes Len.
That '39 is a beauty. The '47 has the clamp above the casting, but its apparent the owner isn't sweating "correctness". It looks like a bike that enjoys alot of miles. I have one of Carl's Rocketfin mufflers, they did a great job. It sounds like your taking good care of your '38. I'm going to just try a high heat paint. I might decide to ceramic coat it later, I dunno. Ya know its funny how we sweat these details. Old timers would think we're nuts, maybe they're right.
Have a great Spring!

[Chris Haynes]

Here is a factory shot of a 1946.

[bobdo]

Thanks Chris,
Ok, so a '46 EL & FL should have the mount above the sidecar loop casting. It appears to me that the pipe clamp is a "C" shape, but not certain. From my research, approximately an equal amount of bikes highly restored & original condition have the clamps above & below the casting on 1947 EL & FL models.
As a Senior Judge, what's your take on this? I'm not having my bike judged, but I't seems to be a detail that varies in placement & type of clamp.
Once again, I appreciate all the help you give. -Bob

[Steve Little]

Here is a factory shot of the 1947 UL.

Chris. It may be my small Ipad screen or lack of reading glasses, can you look at the original picture and let me know you'r definition of what looks to be non original welding just above the sidecar loop.
Maybe this picture is a experimental 1948 U model (taken early in 1947 during the development stage of the new style frames for 1948)
It looks like the sidecar lug has been cut and shut to assimilate the new new angles for the Wishbone frame.
Regards Steve

[Chris Haynes]

All I can tell you is that the photo was entered into the Pholman archives on June 7 1947.

[bobdo]

I'm back on the exhaust installation.
I have a question, what is the typical depth that a header pipe goes into a Knuckle head? I have a matching set of heads. Both header pipes are close to the same diameter. The rear pipe slides in nicely all the way, about 5/8". The front pipe is very tight & only goes in about 5/16". Is that common? Is 5/16" enough? I'd like to know before I trim length.
Also, It's too early to tell because I'm still fitting the front header pipe, but it looks as though I need to attach the clamp above the sidecar loop casting. I have a NOS "C" shaped pipe clamp & a NOS "b" shaped frame clamp that I'm using. (I know that's probably not right for a 47EL) It appears that if I wanted to attach the clamp below the casting I would need both "b" shaped clamps due to the lack of room. -Thanks

[55tmm]

Here is a pic of the clamp on my original 47 FL ,don't think its ever been apart.
Hope it helps