Dr. Shop Teacher's Tonic le Moto--Broncco T-XL

#83
Been a few days, but things are moving. I got the welds ground down on Sunday and started finish sanding the frame today. There is a lot of light pitting and I decided to smooth the welds as much as possible. I used an orbital sander and 60 grit, pad sander with 50 grit and a "triangle" finish sander for the tight stuff. The dremel came in handy too. The frame is a little under half done in the photos.
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#87
Finally all sanded. After 3 days, it's about ready for coating. All the welds were ground and smoothed. Need to fill the inner spring caps and drill for the kick stand.
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I also made a spacer for the caliper mount.
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And finally, I never had a Craftsman tool do this....split wide open.
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#89
Robert, I probably don't wear one enough--when I do (always with aluminum), I use a heavy duty tight fitting paper mask.
We use 3M half masks and cartridges.
M7502 mask
Paint respirator supply kit: 6022PA1
3M6001 cartridges
P95 Particulate prefilter: 5P71PB1
You should be able to source them pretty easy. It’s a very cool mask to wear, meaning cool air temps upon exhaling.
Once you use one, you’ll never be without it.
 
#90
On the downhill side:
Intake manifold--so a bunch of stops and starts on this little project. Making flanges is not exactly the easiest task in the process. I started with a step drill matched to the existing intake port on the block.
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Then I was able to locate one hole for the bolts, and measure off to locate the second bolt hole location.
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From that, I was able to rough cut the flange shape providing clearance for the head and the exhaust pipe--all trial and error.
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Then I pulled the intake and carb off of the Quas-Animal that I did a few years ago make the flange for the carburetor.
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I found myself making things too difficult and I realized I still had a section of 1" Gilson handle bar that I could use to make the curve to pull the carb away from the header. I made a cut in the center of the curve and realized the metal was pinched. To fix that, I heated the pipe and used an old wheel spacer to drive in the tube center to bring it back to round.
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Once that was done, it was matching the length to the edge of the shroud ensuring clearance to the exhaust port. After about 6 hours, here's what we've got.
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After final sanding and alignment, and'll be ready to be welded up. The joys of figuring and cutting by hand....:)
 
#92
Kickstand and Blower Housing:
I ordered a close facsimile of the original kickstand off of e-Bay, and proceeded to fight it all morning. The kickstand is held in place with a spring and I had to figure out the geometry to make it stay in place. It is a little big, but it is the correct length. I'll reduce the width with the angle grinder.
The actual U-bracket is 1/4" wide, so I made a 1/8" shim with a stop for the kick stand in its extended position.
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I picked up a spring at the hardware store and used a c-clamp to locate the spring upper pivot.
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Once I located it, I drilled an 1/8" pilot and then drilled to tap both the shim and the mounting tab on the frame.
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I used a 1/4-20 bolt temporarily to locate the pivot point. This will be replaced with a threaded pin and Loctited in place. The bolt will be replaced with a cap screw. You can see the stop/shim in this photo. The new foot pegs fit perfectly but I will reduce the size of the kickstand arm and foot.

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Next up was surgery on the blower housing. The top of the shroud had a 1/2" deep dent that came across the front lip (no pic). I decided to rescue it, rather than replace it. I used a torch to heat the tin, and a variety of makeshift tools to bring it back to shape. A little angle grinding and it's pretty much smooth. I then filled the rivet holes on the front of housing and ground them down....little more work to do on them.
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The last small parts are ready for welding and I discovered a few places on the frame that still need some loving before we're ready for powder.
 
#94
Finally back at it: Wheels. Got a call last Monday that my mom had fallen Sunday and was found 9 hours later by her cleaning lady, so I cancelled class and was up in Winchester, VA through Thursday. I am exhausted but found the energy to strip the wheels. The tires had never been off, so I paid the local motorsports shop to pop the Pirellis off the rims. Lots of corrosion--one half is steel, the other aluminum. Over 3.5 hrs per wheel, so I did one Saturday and one Sunday. I have new metric bearings and axles (from a pit bike).
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#96
Inching closer....Final welding of Tank Shroud and Clutch Cover. Finally got shop time to get the aluminum welded. The manifold, caliper mount and Gilson-style chain tensioner were also welded up. Much easier welds to clean up than the booger welds on last year's build-off bike!
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#97
Grading papers and running up and down the road....
So, things have slowed down a bit on this build. The frame is still at the powder coater, the engine has not been put together yet and the tank shroud and clutch guard needed work. I tackled the last two over the past couple of days when I had time. I ended up buying aluminum brazing rods to fill a couple of spots as I ground the welds down. Took a little getting used to, but stick welding aluminum with a MAPP torch is actually pretty simple.
IMG_0418.jpg I used a N95 mask as I ground aluminum down.
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Rough finish with 60 grit on the angle grinder.
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I filled a few pin holes with aluminum brazing rod and sanded with 60 grit in the orbital sander followed by 50 grit in the pad sander. I won't do much more until the tank filler hole is cut and the bracket for the clutch guard is made. All the edges are rounded, btw.
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#98
Fork bolt and tensioning knob. I know there are couple for sale on e-Bay, but I decided to fix the chunk missing out of the tensioning knob with epoxy. I wet sanded the knob first to remove the 40 yrs of crud and wire brushed the damaged section. I used an angle grinder to rough shape and then judicious use of the Dremel. To get the shape right, I made a paper template and traced it onto the epoxy. Several coats of black, and it's drying (by far the quickest job I've done on this beast!).
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