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Discussion Starter · #1 ·
Hey guys,

I'm looking for someone to chop my 1973 CL350K5 subframe and weld on a new loop. Does anyone do that kind of work or know a person/shop who does in Minnesota? I live in Rochester, but can take the frame anywhere around the twin cities, too.

Thanks in advance!
Mike
 

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I'll say this, they have a nice website with some of the more believable and interesting info (and properly-written, no typos), along with a decent looking shop
 

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Discussion Starter · #4 ·
I've heard this shop mentioned over on Sohc4 a few times, might be worth an email.

Blue Cat Motorcycle
Thanks for the reply. These guys have terrible reviews on Yelp sadly. Tons of complaints about zero communication, keeping people’s bikes for months, and returning them in worse shape than they got them. I don’t think I want to take the risk.


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Thanks for the reply. These guys have terrible reviews on Yelp sadly. Tons of complaints about zero communication, keeping people’s bikes for months, and returning them in worse shape than they got them. I don’t think I want to take the risk.
Wow, just shows the "can't judge a book by its cover" adage is true... they say the right things, look the part, but apparently aren't. I guess the red flag is that they claim to work on everything - and we here know that it's hard to know enough about everything to be good at all of it
 

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Discussion Starter · #6 ·
If anyone else knows a shop and wants to chime in, I’d be grateful. I haven’t had any luck with the Google. Or if you live in the area and have the skills to help, I can pay in good company and beer
 

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A small fab and welding shop would be a good option but they might not want to mess with it if you don't know what you want walking in the door. This probably won't be high dollar work for them. So having the frame remove, mark the cut lines, and have a drawing with dimensions of the new modifications would make a big difference when they're trying to figure out how much labor it will take. You'll need to ask if they have a tube bender for the hoop.
 

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Discussion Starter · #10 ·
Just buy the standard cafe/brat loop from any online store with the word "moto" in the name.
TOOLS
TOOLS, you were right on the money...TWICE. I was just at Home Depot scouting out some fasteners and the guy who worked there has restored two 350 twins. He suggested a place called Muffler Center in town that apparently has experience building race cars.

And I've been planning on getting the frame loop from Cognito MOTO. :p

Assuming I found a shop to do the work, can you guys help me plan it out? Do you cut just behind the shocks? Is there anything to keep in mind like tabs for wiring or something? Other details I'm not thinking of?

Thanks again.
 

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Discussion Starter · #11 ·
Here’s what I’m working with. It’s this stamped-type frame that is more squared-off than tubular.

Any help on how to chop it and weld a hoop on?






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The only thing I know about the cafe/brat hoop is that they make good suspension stops when the rear tire hits them or the skateboard being used as a seat. This one guy I know did solve that problem by putting a box under the seat for his electrics, the tire hit it before it hit the seat.
TOOLS
 

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Yeah it's a slippery slope with these modifications. Where do you stop? At a certain point it seems like the stock bike is just being used as a starting point for the invention of a new motorcycle entirely. Guess it depends on how far down the rabbit hole you want to go down.

Tools- your friend just didn't give it enough clearance for the electrical box. Usually the electronics are moved under the seat, but I've never heard of the tire hitting it. Perhaps he was trying to fit a battery that was too large under there.

IMG_2509.JPG
 

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Discussion Starter · #15 ·
Perhaps something like this?

View attachment 265746

The overall dimensions depend on the seat your fitting it to. Do you have a seat or are you re-purposing the old one?

I found it was hard to get this exact and pretty much ended up custom making a seat to fit the modified frame hoop.
Yes, something like that! Sounds like you’re the guy I need to talk to in order to learn what exactly I should be doing.

I called the muffler shop today and they agreed to at least look at it if I bring the frame and hoop in, so like you said, I’m sure they want me knowing exactly what to do —— which I don’t.

SEAT: I am planning on having a custom seat made, or buying one of those cookie-cutter brat seats you find around on Dime City and stuff. I do know a local shop that does custom seats. Do I need the seat first and then work out frame dimensions? Vice versa?

I’d love the crash course on this if you got time.

This is my inspiration for frame fab and seat



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So my advice is to define what you want. I say that because many shops have dealt with customers and projects that keep evolving and multiplying in scope. While the customer thinks it should cost one thing and the shop another. This leads to disagreements on pricing and can be a mess for everyone. Perhaps that won't happen but it's not uncommon. That's why it's important to either know what you want walking in the door or be up front with the shop about the development and collaborative design effort this project will require. Some shops will say no or just charge an hourly rate which could cost several hundred dollars, while others would be open to the project. Depends a lot on the shop. Do you know what the max you want to spend is?

What comes first the seat or the frame? Again you have to define what your doing. You can do it either way. The picture of inspiration shows a different frame then the 1981 400 you have and a big design problem for a cafe style seat. The frame dips down just behind the gas tank and makes it really difficult to get that straight flat style seat without some significant frame fabrication. Are you installing pod air filters? Are you relocating electronics/ battery? Generally speaking you would think about this when modifying the frame because you need to design mounting points for all this. You could cut the frame to make it look more like your photo but know that your opening a problem with the rear shocks. Either redesigning the entire shock mounting points or buy entirely new longer shock to fit the new frame design. I'm a pretty experienced fabricator and really didn't want to do either because of the effort and resources involved.

Not sure how mechanical you are, but I would start by measuring your frame, making some sketches, and deciding on a seat. Once you have an idea, you can cutout mock ups with cardboard to get a sense of how things will look and fit. You'll probably need to make several revisions over a period of time until your happy with it. Then once you have a decent mock up, most fab shops could recreate and weld it all together.

You could get a good idea of the process by looking through my build log where I took a lot of pictures on doing all this. Link is in my signature. Let me know if you have more question. I've put many hours and thought into the best way to tackle this design on these motorcycles.
 

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Discussion Starter · #17 ·
Thank you so much for your thoughtful response. I will absolutely be checking out your build thread for information on how to do this. Its also a great idea to do mock-ups with cardboard until I'm happy with a design.

A few points/answers regarding your post:

The picture of inspiration shows a different frame then the 1981 400 you have and a big design problem for a cafe style seat.
My bike is actually a 1973 CL350, which has a flat frame after the gas tank and is quite similar to the CL125 frame in the photo, I believe.

Are you installing pod air filters? Are you relocating electronics/ battery? Generally speaking you would think about this when modifying the frame because you need to design mounting points for all this.
Yes. I believe I'm going with UNI foam filters. I'm also going to grab the bolt-on electronics tray from Cognito Moto for under the seat. I haven't worked out what all goes in there yet, but I think Li-Ion battery, reg/rec, and M-unit. I figured I would have to think about this before cutting the frame, but I don't really know where to start as far as proper planning for tabs/mounts, etc.

You could cut the frame to make it look more like your photo but know that your opening a problem with the rear shocks.
What problem??

Not sure how mechanical you are
Not very...yet! I have never built a bike before and would appreciate all the help I can get on this aspect of the project.
 

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Discussion Starter · #19 ·
Hey guys, I called the muffler shop and they seemed apprehensive about it. Sounds like they'll do it, but I'd have to tell them exactly what to do because they don't have motorcycle frame expertise.

Luckily, I found another option! The shop is about an hour away from me, but it's probably worth it to get the work done right. What do you guys think of this shop?

Welding Machining | Albert Lea, MN - Interstate Junction

The end product I'm after is basically exactly what fellow forum user ants.mcfarlane achieved on his CB350. Lots of guys want to know how he did it on his thread, but the answer is that he sent it out to the pros. Link to his thread below.

https://www.hondatwins.net/forums/1-project-logs/30712-cb350-brat-scrambler-build-2.html

Lastly, what are the major things to consider before I start lopping things off, aside from what Brian has already mentioned? What are the major mounting points, tabs, etc. to keep in mind? Seems like it should be pretty minimal since I'm only cutting from behind the shock bosses, but it's my first time doing this so I don't really know.
 

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Well, now that I know what bike you have, I don't think it's going to be such a big deal to complete this modification. Looks like your going for the skate board style seat with the rear hoop bent upwards slightly. You'll probably just need to decide how many inches beyond the shock mount you want the hoop to be. I would guess somewhere between 6" to 8" inches from the center of shock mounting. Check the reviews on the motorcycle shop you found! A impressive website doesn't mean that much these days. It looks like they could handle the frame welding fine but again it's up to you to define.

Consideration for frame mods should be battery and electronics mounting. Probably just under the seat you'll want a tray or plate to hold these items. It's good to measure the fuse box and other electronic components and put the same hole pattern in the tray for easy mounting. I also made sure there was holes cut to run my main electrical harness into the tray and to the rear lights. Consider how you'll zip tie or strap the wires secure in a safe and hidden way. Make something you can easily access as you may need to maintenance or troubleshoot electronic items in the future. Batteries are the biggest thing and usually more challenging to completely hide if you don't have the cafe back hump. Besides that you should be good. Make sure your not welding a tab that interferes with something else and that your new modifications have plenty of clearance away from you rear tire, chain, etc. That would suck bad.

Most of this would be obvious to a skilled motorcycle fabricator. Good luck!
 
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