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T140 cafe project, cont. #334366
09/20/10 1:17 am
09/20/10 1:17 am
Joined: Jul 2006
Posts: 1,113
Westminster, MD, USA
J
J. Charles Smith Offline OP
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J

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Posts: 1,113
Westminster, MD, USA
Not sure how many photos I can upload at once, but I guess I will find out! First is a jungle of rear tabs and tubes. [Linked Image] Forgot to list exhaust hanger tabs and fender tabs. Second shot shows the frame sectioning on bottom of primary side downtube and pivot tube bracing. [Linked Image] And finally, your basic bare frame photo. [Linked Image]

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Re: T140 cafe project, cont. [Re: J. Charles Smith] #334530
09/21/10 1:08 pm
09/21/10 1:08 pm
Joined: Jan 2006
Posts: 7,173
Laredo (South) Texas, USA
GrandPaul Offline
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You should do each next post as a reply to the one before it, in the same thread, or this project will have 278 different threads!

What is the scenario here with the non-symetrical bracing and the tab on the primary side with a drilling for something?

Noticed the tab up ahead of the fuel tank, is that for a strap (like for a large cafe racer tank)?


GrandPaul (does not use emoticons)
Author of the book "Old Bikes"
Too many bikes to list, mostly Triumph & Norton, some BSA & European
"The Iron in your blood should be Vintage"
Re: T140 cafe project, cont. [Re: J. Charles Smith] #334581
09/21/10 8:05 pm
09/21/10 8:05 pm
Joined: Jul 2006
Posts: 1,113
Westminster, MD, USA
J
J. Charles Smith Offline OP
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J

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Westminster, MD, USA
Hi GP, I didn't even think of relying to my own post (duh!). Thanks!

Since the braces are meant to box the swingarm pivot area, it seems best to have them as close as possible to the pivot and at right angles with the tubes being supported so there is minimal bending stress. The right bracing tube is in about the ideal position. The left brace tube has to allow for chain clearance, so it is higher than optimal. The asymmetry may look off to some, but it's fine with me. The tab on the left tube is the mid-mount for a frame-mount chainguard. Yes, the tab at the front is for an aluminum hold-down strap. I bought the tank years ago, and so far as I know, it was not made for any particular bike. The clearance at the front, behind the top triple tree, is very tight, but it otherwise fits very well on an OIF. I knocked around the idea of using a stainless-steel hinge at the front, a swivel and pin, and a couple of other ideas, but finally decided to use a simple piece of 1-1/2 wide black leather between frame and alloy strap to allow it to lift up and out of the way. Here is the tank with the rear mount (posted before) before the most recent round of welding. [Linked Image]

Re: T140 cafe project, cont. [Re: J. Charles Smith] #338632
10/17/10 4:22 pm
10/17/10 4:22 pm
Joined: Oct 2008
Posts: 344
Central Illinois
C
charliechan Offline
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Central Illinois
Didn't they use the OIF frame for several years successfully? It isn't my project so it really isn't my concern, but I don't get the idea of adding extra bracing when it isn't really needed. Unless covered up it hurts the lines of the bike. Looks like a fun project and I would love to have that tank.

Last edited by charliechan; 10/17/10 4:23 pm.
Re: T140 cafe project, cont. [Re: J. Charles Smith] #338645
10/17/10 5:20 pm
10/17/10 5:20 pm
Joined: Jul 2006
Posts: 1,113
Westminster, MD, USA
J
J. Charles Smith Offline OP
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J

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Westminster, MD, USA
charliechan, the T140 frame really is an excellent frame. However, the split pivot swingarm design is not the best (the one-piece on the Featherbed is the right way of doing things) and the particular design of the OIF allows for considerable flexing around the pivot area. In fact, even on the street, the pivot tube sometimes breaks away from the 3" main tube, with sometimes catastrophic consequences. Pretty much everyone who races T140s braces the area in somewhat the same way I did. Take a look at some of the bikes at http://www.bigdcycle.com/PHOTO%20GALLERY.html for VERY professionally constructed examples. BTW, I am building a cafe racer, and I am a pretty sickly 61-year old, so almost everything I am doing is more for the sake of seeing what I can create than anything else. But that is what a cafe racer is all about; it's basically a chopper in road race disguise. I rather like the extra tubes, and even their asymmetry, but to each their own - that's what customs are all about.

Re: T140 cafe project, cont. [Re: J. Charles Smith] #338657
10/17/10 6:29 pm
10/17/10 6:29 pm
Joined: Oct 2008
Posts: 344
Central Illinois
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charliechan Offline
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Central Illinois
J, I have only owned one OIF and it was a T25 so I am not that familiar with the OIF's. I always assumed that it was a beefy frame with little problem. I was more curious than anything. Thanks for expanding what you are doing and keep posting your results.

CC

Re: T140 cafe project, cont. [Re: J. Charles Smith] #342727
11/11/10 4:41 pm
11/11/10 4:41 pm
Joined: Jul 2006
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Westminster, MD, USA
J
J. Charles Smith Offline OP
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J

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Westminster, MD, USA
Got my black powdercoated parts back from Westminster Powder Coating in Westminster, MD. about 3 weeks ago. Just had a chance to take a photo. I was very pleased with everything - the quality, the price, and the service. I decided to polish the front disc carrier, so it's not in the "after" photo. [Linked Image] [Linked Image] For those who are curious, I am using a DR350 Suzuki rear hub and an XS650 Yamaha front hub. The headlight rim is from a GT380 Suzuki and the (to be painted) headlight shell is from a GT250 Suzuki.

Re: T140 cafe project, cont. [Re: J. Charles Smith] #362692
03/13/11 12:53 am
03/13/11 12:53 am
Joined: Jul 2006
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Westminster, MD, USA
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J. Charles Smith Offline OP
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Westminster, MD, USA
Had a long lull, but back to fiddling with the project. This is a shot of the front tank mount I am working on. Nothing finished in any way, but you can get the idea. As I think I've mentioned, the paint job will be an old-style 3" racing stripe in a blue as close to my blue-anodized PM calipers' blue as I can find. It will be pinstriped in bright red and the tank itself will be a dark, charcoal gray. I will epoxy (JB Weld?) the leather strap to the polished tank hold-down strap, so 3 of the 6 alloy screws are probably redundant. Consider them my homage to the Rockers' studded black leather jackets. Does anyone know what these screw-together alloy things are called? There is a sample screw and rivet-like nut sitting behind the strap. I have had them in a box for decades.

[Linked Image]

Re: T140 cafe project, cont. [Re: J. Charles Smith] #362700
03/13/11 2:02 am
03/13/11 2:02 am
Joined: Feb 2007
Posts: 303
nashville, TN
t.read Offline
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nashville, TN
Originally Posted by J. Charles Smith

The right bracing tube is in about the ideal position. The left brace tube has to allow for chain clearance, so it is higher than optimal.


Why not just put the right one at the same as the left one? That's how the Big D bikes, mine, and others are. You still have room for battery box and it's still doing the bracing needed. And I agree about the pivot getting weak without. My frame cracked around the right side of the pivot along the factory weld causing a bad leak. Could have been from a crash during racing, didn't start noticing the leak until after. But I had those braces at the time anyway so tough to tell.


Tony Read
AHRMA 176
'73 T140V
Re: T140 cafe project, cont. [Re: t.read] #362727
03/13/11 4:02 am
03/13/11 4:02 am
Joined: Jul 2006
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Westminster, MD, USA
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J. Charles Smith Offline OP
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Westminster, MD, USA
t.read, I have seen a lot of variety in the placement and O.D. of the bracing tubes. I could have made mine like Big D's, or yours, or others, but why would I? Cafe racers, like all customs, should be unique. Besides, I believe I am correct that the right brace on mine is close to ideally located (though it may not really matter). If so, raising it away from the swingarm bolt to match the left side would make it weaker just for the sake of symmetry. While I'm not trying to be unconventional, I'm certainly not afraid of doing something a bit differently so long as it makes structural sense. You must have really been pushing your race bike to crack its braced frame! If Triumph had followed through on the Trackmaster design, and poked the pivot tube through the backbone instead of sticking it to its backside, we wouldn't be talking about braces at all.

Re: T140 cafe project, cont. [Re: J. Charles Smith] #362781
03/13/11 4:07 pm
03/13/11 4:07 pm
Joined: Feb 2007
Posts: 303
nashville, TN
t.read Offline
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True, it is your bike and you can do what you want. I just figured them both being welded in the same spot would increase strength. I'm not an expert on this design by any means, but I was under the impression that we were trying to triangulate that entire rear section. Have to ask someone who knows more about this frame geometry. But I would hazard a guess that this is the reason structural bracing is symmetric. Just going on my experience working with aluminum box trussing to hang production lights and sound in my regular job.

I would like to add gusseting to the swingarm pivot on my next frame after all this mess to avoid cracking in the future. Again, not sure if the pinholes in the weld were there before the wreck, exacerbated during racing and made worse with the wreck. Or, if they occurred after racing a braced frame and opened up after the wreck.

Cool project though, I like the tank. I'm probably going to get my pivot fixed and put the frame back on the street since I have the title to it. Use another untitled frame for racing.


Tony Read
AHRMA 176
'73 T140V
Re: T140 cafe project, cont. [Re: BikeVice] #363212
03/15/11 7:06 pm
03/15/11 7:06 pm
Joined: Dec 2007
Posts: 128
fowler , ohio
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oleblu72 Offline
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fowler , ohio
I have a 73 that has an ugly looking weld at the bottom of the main tube (oil tank) look's like it was arc welded.

Mark

Re: T140 cafe project, cont. [Re: t.read] #363252
03/15/11 9:40 pm
03/15/11 9:40 pm
Joined: Jul 2006
Posts: 1,113
Westminster, MD, USA
J
J. Charles Smith Offline OP
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J

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Westminster, MD, USA
t.read, so far as I know, what needs bracing is the swingarm pivot, not the seat tubes, so getting as close as possible to the swingarm bolt should be best. (Tom Sharp mentioned once that it did help to put a crosstube underneath the seat to prevent cracking up there, but only for racing, and only for the very fastest guys - not me even in my heyday!) I would certainly be interested in other people's thoughts on this.

Re: T140 cafe project, cont. [Re: J. Charles Smith] #363280
03/15/11 11:27 pm
03/15/11 11:27 pm
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Posts: 47
hendersonville NC
speedfiend Offline
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hendersonville NC
Great looking progect, J. Charles

Hey, sorry to hijack your thread, but while we're on the subject of cracking OIF's; Do the oily frame BSA suffer from the same issue? I've had personal expierance with the Triumphs cracking, but haven't heard of it on the BSA's. Is this b/c of the slight diffrences of the frame or just the lower production numbers?

Should I think about bracing my 71 T-bolt before it becomes a problem?

Re: T140 cafe project, cont. [Re: speedfiend] #363288
03/15/11 11:55 pm
03/15/11 11:55 pm
Joined: Jul 2006
Posts: 1,113
Westminster, MD, USA
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J. Charles Smith Offline OP
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Westminster, MD, USA
If you are anything like your screen name, Speedfiend, you should brace your BSA! My understanding is the the Triumphs have almost no swingarm pivot problems compared to the BSA OIFs. I think it has to do with the outboard engine-to-frame plates that the swingarm bolt goes through. I have no personal experience with this, though.

Re: T140 cafe project, cont. [Re: J. Charles Smith] #363305
03/16/11 1:16 am
03/16/11 1:16 am
Joined: Dec 2010
Posts: 47
hendersonville NC
speedfiend Offline
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Well shucks! I knew that was coming. Of course I would discover these concerns only AFTER I just had my frame powdercoated. Oh well,I was looking for a reason to tear it down. Its smoking a bit on one side and I have a set of alloy hoops to lace up. Here I go again...

Re: T140 cafe project, cont. [Re: J. Charles Smith] #368665
04/18/11 12:03 am
04/18/11 12:03 am
Joined: Jul 2006
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Westminster, MD, USA
J
J. Charles Smith Offline OP
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Westminster, MD, USA
My machinist/engineer friend, Paul Martinson (http://www.street-unique.com/), has finished the swingarm and rear brake mount for my T140 cafe project. This is everything dummied up (using his stock Suzuki rear hub and rim). The swingarm was made from two GR650 Suzuki arms welded to stock Triumph front pivots. The alloy pivot "bushings" are just for set-up purposes. I bought the little Performance Machine caliper 20 years ago for this bike - yes, I am a procrastinator! [Linked Image]

Re: T140 cafe project, cont. [Re: J. Charles Smith] #368670
04/18/11 12:33 am
04/18/11 12:33 am
Joined: Feb 2007
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nashville, TN
t.read Offline
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That's pretty slick. I like that caliper. Need something that small and lightweight for my race bike. Still got the iron one on.


Tony Read
AHRMA 176
'73 T140V
Re: T140 cafe project, cont. [Re: speedfiend] #368674
04/18/11 1:03 am
04/18/11 1:03 am
Joined: Mar 2006
Posts: 3,769
gastonia nc
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raf940 Offline
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gastonia nc
re: cracking BSA OIFs...the 72 A65T in my garage has a bad crack where the rear motor mount bolts to the frame...was 'fixed' once and has cracked again same spot...i think this is common


1972 Triumph T120
1968 BSA A65
1968 MGB Roadster
1979 Chevrolet Camaro Berlinetta
1969 Honda Mini Trail
1939 farmall f30 tractor
2004 Honda Shadow Aero
1972 BSA Thunderbolt
1975 yamaha xs650b
1972 Norton commando
Re: T140 cafe project, cont. [Re: t.read] #369066
04/19/11 11:58 pm
04/19/11 11:58 pm
Joined: Jul 2006
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Westminster, MD, USA
J
J. Charles Smith Offline OP
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J

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Westminster, MD, USA
Fed-Ex delivered the swingarm, etc. today, and it looks great. I was surprised how light the SA felt, so I went back to some weights I had measured in September '06 and posted on this forum (unfortunately, I couldn't find the old post in a search; got a message saying "We encountered a problem. The reason reported was Database error only visible to forum administrators. Please click back to return to the previous page."). At the time, I had stood on our digital bathroom scale and subtracted my weight to get the weights of the stock 1973 T140 frame and swingarm, plus the weights of my early Trackmaster frame and its swingarm. Here is how they compare to the modified frame and the custom SA. The scale measures to the nearest 1/2 lb.

Stock T140 frame - 36.5 lb
Stock T140 Swingarm - 6 lb
Trackmaster frame - 27 lb
Trackmaster SA - 8 lb
modified frame - 35 lb
custom SA - 6.5 lb

So the modified frame & SA is actually a pound lighter than stock, and only 6.5 lb heavier than the rather spindly, chrome-moly Trackmaster frame!

Here's a photo of the two stuck together: [Linked Image]

Re: T140 cafe project, cont. [Re: J. Charles Smith] #369164
04/20/11 2:33 pm
04/20/11 2:33 pm
Joined: Jan 2006
Posts: 7,173
Laredo (South) Texas, USA
GrandPaul Offline
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Any good reason why you didn't mount the caliper OVERslung?


GrandPaul (does not use emoticons)
Author of the book "Old Bikes"
Too many bikes to list, mostly Triumph & Norton, some BSA & European
"The Iron in your blood should be Vintage"
Re: T140 cafe project, cont. [Re: GrandPaul] #369178
04/20/11 3:47 pm
04/20/11 3:47 pm
Joined: Jul 2006
Posts: 1,113
Westminster, MD, USA
J
J. Charles Smith Offline OP
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Westminster, MD, USA
Hi GrandPaul. The caliper is somewhat more exposed to water and dirt below the swingarm, but in that position, the caliper will pull on the brake rod, essentially trying to straighten it out. (The alloy caliper mount has almost no load on it; it just locates the caliper properly, while all the braking force is transmitted to the arm though the brake rod.) Mounting the caliper above the swingarm would put the brake rod in compression, so any misalignment would basically tend to bend the rod. At the least, I think I would need a beefier rod if it were mounted above. (I think the rod would also interfere with the shock a bit if it was overslung.) Besides that, I prefer the look of the underslung caliper. Incidentally, on the front, I prefer the looks of the caliper behind the fork leg, as is common practice these days. Unfortunately, because my Cerianis are the standard, single fender/brake lug type, I think I will end up mounting my 4-piston PM caliper ahead of the fork legs, where it will also be in self-aligning tension, rather than compression.

Re: T140 cafe project, cont. [Re: J. Charles Smith] #369308
04/21/11 1:05 pm
04/21/11 1:05 pm
Joined: Jan 2006
Posts: 7,173
Laredo (South) Texas, USA
GrandPaul Offline
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Well, that certainly makes sense.

Looks like a fun project either way!


GrandPaul (does not use emoticons)
Author of the book "Old Bikes"
Too many bikes to list, mostly Triumph & Norton, some BSA & European
"The Iron in your blood should be Vintage"
Re: T140 cafe project, cont. [Re: GrandPaul] #369346
04/21/11 6:21 pm
04/21/11 6:21 pm
Joined: Jul 2006
Posts: 1,113
Westminster, MD, USA
J
J. Charles Smith Offline OP
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J

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Westminster, MD, USA
It IS a fun project. But it really shouldn't take me decades to build a bike, especially when I used to finish one in a year or two. But that was when I was younger and didn't have my own business, so I had more time and money!

Re: T140 cafe project, cont. [Re: J. Charles Smith] #430155
04/17/12 12:54 am
04/17/12 12:54 am
Joined: Jul 2006
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Westminster, MD, USA
J
J. Charles Smith Offline OP
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J

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Westminster, MD, USA
Well, it's been another year of (almost) no progress. However, I finally did get my frame, swingarm, and Sun rims powder coated. Ken at Westminster (MD) Powder Coating did a great job for a great price. (The gray looks very light in the photo on my computer screen.) I am looking forward to bolting parts together for a change.
[Linked Image]

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