Butchered Margay New Breed Sprint, prepare to cringe!

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Stuart Thomas
Posts: 15
Joined: Fri Sep 07, 2018 8:13 pm
Vintage Karting items owned: Margay New Breed
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Location: Indianapolis, IN

Re: Butchered Margay New Breed Sprint, prepare to cringe!

Post by Stuart Thomas » Sun Sep 09, 2018 10:22 am

Thanks for the advise good sir! Any suggestions on low spots that already exist? I was thinking about using j.b. weld putty as a filler for a couple of small notches and regular old body filler for the spots they hit with a grinder.

While we are talking about the frame, I noticed last night that the main frame rails have a bit of a bow to them. Is this something i should concern myself with? I have the ability to straighten them if needed.

Thanks again.

Rob Voska
Posts: 1393
Joined: Fri Jun 15, 2007 9:04 am

Re: Butchered Margay New Breed Sprint, prepare to cringe!

Post by Rob Voska » Mon Sep 10, 2018 9:44 pm

You mean a sway back like an old horse.......... Don't want to dampen your enthusiasm but that is a BIG negative for me.......
Bending it back will make it straight....... until you run it and it will go right back or worse.......
Also he kart will probably not handle that well. Old tubing, welded on by who knows, grinder gouges, thin spots........

Stuart Thomas
Posts: 15
Joined: Fri Sep 07, 2018 8:13 pm
Vintage Karting items owned: Margay New Breed
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Location: Indianapolis, IN

Re: Butchered Margay New Breed Sprint, prepare to cringe!

Post by Stuart Thomas » Tue Sep 11, 2018 8:00 am

I hear you loud and clear! I'm not quite ready to call it's time of death just yet but if it does come to that, i wont be out any money and I have already learned a lot. No matter what the outcome, I'll have no regrets.

The frame does have a bit of sag but the good news is that all the grinder marks and low spots I thought it had were actually in the paint. So far I have identified two shades of yellow at the base, a metal flake orange, lime green, black, pink, blue, silver, two shades of red and one of the heaviest coats of primer I have ever seen! Lol

I'm going to see how things look after all of the paint is off. I'll keep you guys posted.

ted johnson
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Joined: Fri Jun 15, 2007 7:59 am

Re: Butchered Margay New Breed Sprint, prepare to cringe!

Post by ted johnson » Tue Sep 11, 2018 8:23 am

Two simple choices. One, find another straight base frame and use all the bolt-on parts from the old. Two, CAREFULLY cut the various pieces from the old frame and replace your main rails with new chrome moly rails from someone like Aircraft Spruce. Since your front axle is buggered up, option one may be your easiest way out. The only reason I even mention option two is that the Margay has straight rails, so replacement is relatively easy. A simple weld jig of either 3/4" plywood or heavy particle board is a simple one to make. Pruit Ginsberg and I did the new scratch-built Photon frames on 3/4" ply with glued and screwed on wood blocks to hold things in position, a surround and crossmember frame underneath and conduit clamps to secure the tubing. I show this pic because, like the Margay, the Photon frame has no off-plane bends. I used a large holesaw to cut out places for Ben Herr to reach from underneath and weld places he couldn't reach from above. Ted
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Stuart Thomas
Posts: 15
Joined: Fri Sep 07, 2018 8:13 pm
Vintage Karting items owned: Margay New Breed
User Agreement: Yes
Location: Indianapolis, IN

Re: Butchered Margay New Breed Sprint, prepare to cringe!

Post by Stuart Thomas » Tue Sep 11, 2018 7:43 pm

Thanks for the suggestion! I agree replacing the rails would be fairly straightforward given the simplicity of the frames design. I had actually given this idea some thought prior to your post, in part, but I hadn't considered changing the whole rail. I noticed that the the frame is perfect until just after where the steering wheel hoop attaches. My thought was to replace just the back where it is actually bent. These karts came from the factory with pipe inserts that run from the back of the frame forward about a foot. I was thinking I could do the same thing only running the new pipe inserts further up to reinforce this weak area. I'm sure this would effect how the kart handles since the frame would effectively be stiffer but would it be a negative effect? I could run the next size down tube all the way to the front but I figured this would be overkill or have a negative impact. What are your thoughts on this? Thanks again!

Stuart Thomas
Posts: 15
Joined: Fri Sep 07, 2018 8:13 pm
Vintage Karting items owned: Margay New Breed
User Agreement: Yes
Location: Indianapolis, IN

Re: Butchered Margay New Breed Sprint, prepare to cringe!

Post by Stuart Thomas » Tue Sep 11, 2018 8:03 pm

Got it down to the original yellow paint! Thank goodness for poor paint prep. I was able to remove all the layers with my commercial pressure washer.
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ted johnson
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Re: Butchered Margay New Breed Sprint, prepare to cringe!

Post by ted johnson » Tue Sep 11, 2018 10:11 pm

If you insert either a piece of tubing or a solid spud, leave a gap of about 3/32" between the end of the two full diameter tubes, Insert your spuds at least 1-1/2" into each tube, chamfer the ends of the original tubes and drill a 1/4" diameter hole in the two ends of the original tubing for plug welds. Now, when you weld, you're doing a groove weld instead of a butt weld, The plug welds into the spuds through the 1/4" holes will help a lot. With a groove weld that not only penetrates the main tubes, but also penetrates through the 3/32" gap into your spuds, once you grind the welds flush, you'll still have full strength in the rails. Ted

Stuart Thomas
Posts: 15
Joined: Fri Sep 07, 2018 8:13 pm
Vintage Karting items owned: Margay New Breed
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Location: Indianapolis, IN

Re: Butchered Margay New Breed Sprint, prepare to cringe!

Post by Stuart Thomas » Tue Sep 11, 2018 10:31 pm

Wow, it sounds like you've done this a time or two. Thank you! Is there a preference on the type of welding? I am fortunate to have a neighbor who welds for a living. He is highly skilled in rod welding, mig and heli-arc/tig. Im sure he will know exactly what to do when I pass on this information.

Stuart Thomas
Posts: 15
Joined: Fri Sep 07, 2018 8:13 pm
Vintage Karting items owned: Margay New Breed
User Agreement: Yes
Location: Indianapolis, IN

Re: Butchered Margay New Breed Sprint, prepare to cringe!

Post by Stuart Thomas » Wed Sep 12, 2018 12:49 am

99% stripped. Now to decide on what to do....
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ted johnson
Posts: 1393
Joined: Fri Jun 15, 2007 7:59 am

Re: Butchered Margay New Breed Sprint, prepare to cringe!

Post by ted johnson » Wed Sep 12, 2018 7:50 am

Stuart, I'm not versed on the materials Margay used on frames. If it's chrome moly, then TIG by all means. If it's mild steel, then someone else will need to chime in. We built two LMC Swoopsters, my Nike "standoff" replica, and the two Photon chassis all from 4130 chrome moly. All these frames have tubes joined by the above process, and it has worked well. My friend, Ron Cubel, has restored several karts, using the same process. It's a good setup, as you can insert the spud the required distance and spot plug weld it through one of the holes. This ensures that the spud won't slip into the tube when you slide the other tube over the spud. That gap between the two tube ends ensures full penetration, and the bevel at the end of both tubes, forming a groove when the two tubes are on the spud is standard industry process for welding high pressure tubing or pipe. I worked in high pressure stainless steel gas/fluid tubing and pipe systems design at Kennedy Space Center and Cape Canaveral in Florida for over twenty years. A consumable ring in industry takes the place of the spud, but the principle is the same. In the pic, you can see the vee groove and just see the plug weld holes where the rear bumper joins the main rails. The shaft collars locate the cross tubes for tack welding. Ted
Attachments
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