Need some assistance/guidance on Triumph frame chop

This section is for all posts concerning frame design and construction.
Bjorn218
NewB
Posts: 7
Joined: Thu Apr 16, 2015 9:01 pm
SELF INTRODUCTION: I am currently planning my first build based off a Triumph T120R. I am hoping to learn from you guys as this seems to be the only real deal, no BS, no ego, building forum on the internet. I don't have an extensive fabrication background, but know how to stick weld and how to turn a wrench. I figure that between those two skills, my own intuition, and knowing when to ask for guidance or help, my first build will be something I will be proud of.

Need some assistance/guidance on Triumph frame chop

Post by Bjorn218 »

Hello all, Bjorn here. I didn't find an introduction thread, so I am introducing myself here. I am working on my first build which is based off a 1971 T120R motor and a 1978 T140 front loop. I do have a few questions regarding my build, but the topic of this thread pertains to my best bud's Trumpet build. I've been off motorcycles for over 20 years riding motorcross previously and this guy gave me the bug again and I chose a Trumpet as it will not be a "Me too" bike once done. Nothing against Harleys, but I am one that seeks to walk paths less tread by others. The Bonneville's power/weight ratio is more than enough for me. Plus they just look damn cool. Anyways I am rambling.

My bud Kelly has a T120R frame that was poorly hardtailed. The PO used a bolt on which they proceeded to try and weld on to smooth out the lines. They also used about 20lbs of bondo to try and hide totally disgusting looking welds. We are amazed at all the crap that was used as we are stripping his frame down. The top of the tail was bolted then welded where the weld actually sheared the nut off te bolt and the only thing holding it together was weld slag. Once we discovered this, I told him we have to take it all the way down, clean everything off that the PO did then start from scratch to attach it again. At least we will know it's put together safely.

Aside from his hard tail we have to re work, he is wanting to add some stretch and change the rake of the neck. We were wondering if it is possible to still utilize the stock neck gusset? My thoughts on this are if we cut the backbone a few inches rear of the neck gusset AND below the bend at the backbone/seat post, use a new piece of tubing adding the length and altering the radius of the seat post bend (increasing the radius will raise the neck as well as change its angle for rake he wants(35-36 deg vs. 28deg stock). At the same time remove some tubing below the down tube portion of the neck gusset, adding longer tube and utilize a slight bend which will allow it to properly fit into the tubing in the stock gusset.

His train of thought is to cut the neck off, trim back the backbone until it allows him to get the take he wants, re weld, continue to march forward. My concern about that way is that you risk damaging the stamped ID numbers off the frame which we need here in Texas to get our titles for the bikes.

How would you guys approach this?

Thanks for any suggestions and guidance on this. I truly appreciate it.

Bjorn218
User avatar
curt
Long in the Tooth
Posts: 1068
Joined: Tue Oct 25, 2011 11:36 am
SELF INTRODUCTION: hi everyone its me from the old bord hopeing to see everyone come here and all the newcomers . lets make this as good as the old one or even better . lookin foreward to seeing everyones projects continue and ill be continueing mine too
Location: utica new york

Re: Need some assistance/guidance on Triumph frame chop

Post by curt »

most of the guys I seen try and save the numbers by cutting below the casting by 3 or four inches on both the lower and upper so they can slug the tube and not damage the numbers . shouldn't hurt at all to raise the top tube to change the rake a little . love those brit bikes myself post pics
ever notice when you hit somethin or someone with a hammer you feel instantly better
User avatar
railroad bob
Contributor
Posts: 939
Joined: Fri Nov 04, 2011 10:07 pm
SELF INTRODUCTION: Hi Dan, thanks for your time and energy spent on this new board. I hope you will give me a waiver on the email account, I have used gmail so long I don't have a clue what my service provider account is.
I just returned home from a 2 week trip in New Mexico, have a few good pix, can't wait to share my off-highway traveling. Got to put 1400 miles on the scoot.

Best, Bob Davidson
Location: Alaska

Re: Need some assistance/guidance on Triumph frame chop

Post by railroad bob »

great description.
Alaska - Land of the Individual and Other Endangered Species
An Armed Society is a Polite Society,...
Politicians Prefer Unarmed Peasants
TANSTAAFL
User avatar
railroad bob
Contributor
Posts: 939
Joined: Fri Nov 04, 2011 10:07 pm
SELF INTRODUCTION: Hi Dan, thanks for your time and energy spent on this new board. I hope you will give me a waiver on the email account, I have used gmail so long I don't have a clue what my service provider account is.
I just returned home from a 2 week trip in New Mexico, have a few good pix, can't wait to share my off-highway traveling. Got to put 1400 miles on the scoot.

Best, Bob Davidson
Location: Alaska

Re: Need some assistance/guidance on Triumph frame chop

Post by railroad bob »

and welcome to the sire, and please post progress of both builds.
A lot of us like the brit bikes.
Alaska - Land of the Individual and Other Endangered Species
An Armed Society is a Polite Society,...
Politicians Prefer Unarmed Peasants
TANSTAAFL
hansgoudzwaard
Contributor
Posts: 804
Joined: Wed Oct 26, 2011 10:43 pm
SELF INTRODUCTION: I was on the last board as bonustoolkit. I have changed that to my given name.
I started a project build there " File and Fit." I paln to continue that when I go back home in Dec. 2011. I first joined the board when Gary W had it in the year 2005. That was the time I really gained an interest in building chops. I have a long way to go, compared to some here.

Re: Need some assistance/guidance on Triumph frame chop

Post by hansgoudzwaard »

My older brother owned Triumphs in the 50's and 60's.Great bikes. It sounds as if you have planned it well. I will be watching this.
Bjorn218
NewB
Posts: 7
Joined: Thu Apr 16, 2015 9:01 pm
SELF INTRODUCTION: I am currently planning my first build based off a Triumph T120R. I am hoping to learn from you guys as this seems to be the only real deal, no BS, no ego, building forum on the internet. I don't have an extensive fabrication background, but know how to stick weld and how to turn a wrench. I figure that between those two skills, my own intuition, and knowing when to ask for guidance or help, my first build will be something I will be proud of.

Re: Need some assistance/guidance on Triumph frame chop

Post by Bjorn218 »

Sorry for the pause in responding to my own thread. Thanks all of you for advice/compliments. I appreciate it.

Update on these two builds:

First for my Bro's build. He started stripping the paint off of it so we could really get into the meat and potatoes of what was up with this frame he bought. I swear whoever did this welding a bolt on hard tail used at a minimum a gallon of Bondo to cover uber poor welds, create smooth lines where welding some sheet metal to create what they were looking for would have been easier, faster, and less expensive. Example, where the upper wishbone attaches to the seat post, they installed a seat pan. Nothing out of the ordinary on certain frames. Until paint was stripped. We find that pan was only tack welded in like 4 places, and bondo was used to fill all the non-welded areas. The underside was filled with Bondo and with paint, the whole thing looked like a thick piece of plate was welded to the wishbone. Every single weld was bondo'ed until it was smooth. Quite hilarious in hind site. We ended up stopping using paint stripper, and picked up one of those nylon stripping wheels from Harbor Freight. Faster and less caustic of a mess. The welds around the lower wishbone bolt areas were welded over rust. Tapping with a small hammer and cold chisel where bead met tube, I knocked off three entire bead runs which came off in one piece.

The only bad item about this adventure with his frame is that it looks like someone either repaired a bad frame, or screwed up a tubing cut and welded over said cut, obscuring the T12 of T120R(two letter date code, 4 numerical sequence, making his frame era 1964 due to last 4 numbers). The last he worked on his build was about a week after my initial post of this thread. He's been dealing with other issues in his life.


On to my project. My mistake on the age of my frame. Comes from a '76. I have been a little more active on my build, as I have a bit more parts to tinker with. Just picked up the frame last Thursday. I had been polishing case covers, repairing the dents and bumps in a Bonneville fuel tank I had, cleaning other parts, etc.... The fuel tank is a bum deal as it is a really nice Bonneville tank and only had dents from what appeared to be triple tree smacks. Heat gun and compressed air in a can trick got them about 95% gone. I stripped the 5-6 layers of disgusting colored paints until I hit the hideous Triumph greenish gold. Stripped it down to bare metal, cleaned all the thick rust from inside the tank with Dawn, hot water, and 1-5/8" coarse thread sheetrock nails, while aerobicizing to death metal, and hard core punk with a diabolical motorcycle version of a shake weight. Rinsed the tank out with water, then acetone, and poured in Evaporust til it was full and left it alone for a couple weeks. Waiting for a Caswell set to show up in post. fast forward to last Thursday. Tank is not for OIF. :doh: Oh well My Bro needs a tank. Il Caswell treat it, paint it with primer and sell it to him, to cover some cost to obtain a proper T140 tank. Man I really really dug that Triumph spine ridge on that tank. I haven't seen a T140 stock tank in person, hope they are similar. Aside from that dopey bolt hole through the top of the tank.

I do have a few questions for you Curt. Seeing how your thread on a Triumph hard frame fabrication had my attention until it just, well stopped....

Question #1, Do you have any idea what the wall thickness of the OIF backbone/seatpost/oil tank tubing is? I need to purchase some sheet to form the patch that will replace where the swing arm is. Hopefully it will also work in the areas around the base of the seat post/tank once I weld in the lower wishbone to the lower rails.

I am also planning on raking the neck out a bit as well and I am so glad these later frames are a lot easier to work with. Once I remove the gusset plates, and steering neck, I should only have to cut back a little of the upper portion of the backbone/tank to get the rake I want, and not have to add any length to the down tubes. At the current moment I will be trying to still use the Frame for my oil tank barring any leaks that cannot be repaired. I cleaned the frame filter tonight and some from the lower portion inside the frame and what was there was more like roofing cement than old oil. I am up to date on where I am at on this project. I will be making a blog that will act as my build log, as well as my other luthiery projects. I'll link back pictures as I upload them. I will put that thread in its appropriate place on the forum.

Question #2: Curt, did you ever finish those frame drawings you were going to post in the downloads section? I didn't see them last I looked. I would like to use them for base dimensions to figure out my rear frame proportioning if you don't mind. I think you were designing a hard tail frame based on roughly stock measurements IIRC.
User avatar
Customize IT
Contributor
Posts: 992
Joined: Thu Sep 19, 2013 7:54 am
SELF INTRODUCTION: I am a young punk kid that needs some help building himself a chopper!!

I am sorry I only have a hotmail account???

Tell me what I need to do I need help with my girder!!!

PLESE HELP????


[url=http://imgur.com/8saXkqN][img]http://i.imgur.com/8saXkqNl.jpg[/img][/url]








[url=http://imgur.com/pXJZqQ0][img]http://i.imgur.com/pXJZqQ0l.jpg[/img][/url]









[url=http://imgur.com/T3Q4Ev4][img]http://i.imgur.com/T3Q4Ev4l.jpg[/img][/url]









[url=http://imgur.com/fsXGYQw][img]http://i.imgur.com/fsXGYQwl.jpg[/img][/url]
Location: Ohio, USA

Re: Need some assistance/guidance on Triumph frame chop

Post by Customize IT »

I need to get back to the drawings sorry curt.

Got everything saved from curts end to start the top view and front.
User avatar
curt
Long in the Tooth
Posts: 1068
Joined: Tue Oct 25, 2011 11:36 am
SELF INTRODUCTION: hi everyone its me from the old bord hopeing to see everyone come here and all the newcomers . lets make this as good as the old one or even better . lookin foreward to seeing everyones projects continue and ill be continueing mine too
Location: utica new york

Re: Need some assistance/guidance on Triumph frame chop

Post by curt »

its cool ive seen u been busy
ever notice when you hit somethin or someone with a hammer you feel instantly better
User avatar
curt
Long in the Tooth
Posts: 1068
Joined: Tue Oct 25, 2011 11:36 am
SELF INTRODUCTION: hi everyone its me from the old bord hopeing to see everyone come here and all the newcomers . lets make this as good as the old one or even better . lookin foreward to seeing everyones projects continue and ill be continueing mine too
Location: utica new york

Re: Need some assistance/guidance on Triumph frame chop

Post by curt »

the dims I am working on with custom are for a non oif but I do have an oif in storage id be willing to dig out and measure the wall thickness for you and we don't have the dims done yet buy if you send me a pic of what your looking for id measure and send em to ya
ever notice when you hit somethin or someone with a hammer you feel instantly better
Bjorn218
NewB
Posts: 7
Joined: Thu Apr 16, 2015 9:01 pm
SELF INTRODUCTION: I am currently planning my first build based off a Triumph T120R. I am hoping to learn from you guys as this seems to be the only real deal, no BS, no ego, building forum on the internet. I don't have an extensive fabrication background, but know how to stick weld and how to turn a wrench. I figure that between those two skills, my own intuition, and knowing when to ask for guidance or help, my first build will be something I will be proud of.

Re: Need some assistance/guidance on Triumph frame chop

Post by Bjorn218 »

Curt, thanks for the offer. Much appreciated. The area I am looking at is cutting the swing arm bracket off the seatpost. If the whole tube that makes up the tank/backbone/seat post is the same dimension wall thickness, I can get the measurement off of it by using a manual internal caliper then take a reading with my micrometer. I just asked in case you had already known the wall thickness.

I'm planning on chopping the frame similar to how Jim Strang from Chopperz in Scotland did his in his video on YouTube. His channel is Chopperz. Basically cutting off the seat loop support above the engine mount. Seat loop etc. and building the hard tail into that area. Instead of capping off the top of that to their out was actually thinking about incorporating the passenger foot rests on the end of that tube.
User avatar
curt
Long in the Tooth
Posts: 1068
Joined: Tue Oct 25, 2011 11:36 am
SELF INTRODUCTION: hi everyone its me from the old bord hopeing to see everyone come here and all the newcomers . lets make this as good as the old one or even better . lookin foreward to seeing everyones projects continue and ill be continueing mine too
Location: utica new york

Re: Need some assistance/guidance on Triumph frame chop

Post by curt »

I have seen hardtails on ebay for oif I think they look cool all done but I will check out your link and ya it should be the same thickness the whole length of the tube
ever notice when you hit somethin or someone with a hammer you feel instantly better
Bjorn218
NewB
Posts: 7
Joined: Thu Apr 16, 2015 9:01 pm
SELF INTRODUCTION: I am currently planning my first build based off a Triumph T120R. I am hoping to learn from you guys as this seems to be the only real deal, no BS, no ego, building forum on the internet. I don't have an extensive fabrication background, but know how to stick weld and how to turn a wrench. I figure that between those two skills, my own intuition, and knowing when to ask for guidance or help, my first build will be something I will be proud of.

Re: Need some assistance/guidance on Triumph frame chop

Post by Bjorn218 »

To Curt, or Customize IT, I am trying to get a base stock dimension of the swing arm in relation to bottom of lower rails as well as full rearward extension of the swingarm itself.

I came up with approximate numbers for both, just wanted to bounce them of either of you, or both.

On swing arm, from center of pivot bolt hole to full end of arm itself I get approx 18-5/8"

Setting the swing arm 90* to the rear portion of the seat post, using centerline of swing arm horzontal line to bottom of frame rail is approximately 6-3/8". If you have more accurate numbers, please add them in a reply. I was using tape measure and speed square to line up the swing arm. I was after just a crude better than ball park figure so I could start to draw this on paper.
User avatar
curt
Long in the Tooth
Posts: 1068
Joined: Tue Oct 25, 2011 11:36 am
SELF INTRODUCTION: hi everyone its me from the old bord hopeing to see everyone come here and all the newcomers . lets make this as good as the old one or even better . lookin foreward to seeing everyones projects continue and ill be continueing mine too
Location: utica new york

Re: Need some assistance/guidance on Triumph frame chop

Post by curt »

the drawings we are working on are for a 69 Bonneville non oif with a hardtail I do have a 73 oif swingarm I could dig out and get some measurements from for you they are very different
ever notice when you hit somethin or someone with a hammer you feel instantly better
Bjorn218
NewB
Posts: 7
Joined: Thu Apr 16, 2015 9:01 pm
SELF INTRODUCTION: I am currently planning my first build based off a Triumph T120R. I am hoping to learn from you guys as this seems to be the only real deal, no BS, no ego, building forum on the internet. I don't have an extensive fabrication background, but know how to stick weld and how to turn a wrench. I figure that between those two skills, my own intuition, and knowing when to ask for guidance or help, my first build will be something I will be proud of.

Re: Need some assistance/guidance on Triumph frame chop

Post by Bjorn218 »

Ah, ok. Gotcha. I was under the assumption the measurements were taken off the oif frame from your other thread. Yes, the non-OIF vs. OIF are indeed different. Aside from the obvious, the tubing for the down tubes, lower rails, seat loop, swing arm are larger than the largest tube on the older models. The frame in general appears geometrically larger without pulling out measuring devices.

As for pulling out your OIF, if it's a hassle Curt, don't sweat it at all. I met another Triumph rider on a job we both were working on for a mutual friend. He is taking me up to a Triumph Greybeard mechanic in the next town over who has all sorts of running and non running Brit bikes at his shop, I can get the measurements from him.

If it's easily accessible and you have time, and remember,, by all means have a go. If nothing else, it will help others that may look for the same info that is missing out of the shop manual. The reason the frame dimensions are in there is for frame repair for the shops back then, as they were in the OIF manuals, but why no information for the swing arm in those later bikes is beyond me, but hey run with what you got right?

Anyways man thank you for the words of support as well as the rest of you, and especially Mr. Gary for providing the sites. Love this place. Everyone helps each other. No cliques, no elitism that permeate other build sites.
Bjorn218
NewB
Posts: 7
Joined: Thu Apr 16, 2015 9:01 pm
SELF INTRODUCTION: I am currently planning my first build based off a Triumph T120R. I am hoping to learn from you guys as this seems to be the only real deal, no BS, no ego, building forum on the internet. I don't have an extensive fabrication background, but know how to stick weld and how to turn a wrench. I figure that between those two skills, my own intuition, and knowing when to ask for guidance or help, my first build will be something I will be proud of.

Re: Need some assistance/guidance on Triumph frame chop

Post by Bjorn218 »

Update: haven't done much except cut off the seat loop and loop support about 3-1/2" above the motor mount plates, and removed the gusset plate from around the steering neck.

I don't have rims/wheels yet so kind of in a holding pattern on trying to design the rest. Does anyone know of a formula to figure out what the full diameter of a wheel with tire on? I found something on a sport bike site but think that formula is geared more towards those type of bikes and unsure of their math. I would just like to have something to take to paper, this way I won't be blind without reference.

URL for that wheel formula: http://www.rbracing-rsr.com/tirediamcalc.html

I have also decided against building springer forks for the time being. Going to start off with stock triple tree and buy some extended fork tubes from a guy up in Austin. I also was introduced to a builder in New Braunfels who has an amazing shop. More Brit bikes then I have seen in my life up there in various states of repair. I also found that my barrel I bought is not applicable for my build. It was advertised as coming off an early 70s T120 but it is late 60s and does not have same oil channels so won't mate up to the case properly. At least the head I bought will work with both so that's another expense I won't have to worry about.

No updates on my buddy's build as he hasn't been able to do anything due to time constraints
Post Reply

Return to “Frame Fabrication”