Meanwhile back in the basement - Central Plains

Discussion in 'Some Assembly Required' started by Tanshanomi, Oct 23, 2019.

  1. Tanshanomi

    Tanshanomi Your Favorite Uncle Supporter

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    You know that whole part about swapping the engine in without cutting the frame?

    boris-didntwork.gif

    No matter how I reoriented the engine and torque converter, something ended up bumping into the frame somewhere: the flywheel, the cylinder head, the starter motor. At one point, I was willing to lose the electric start if that would have allow things to go into the frame, but ultimately that wasn't a magic bullet.

    So, after a bit of measuring and a long time staring at the frame and trying to think things through, I bit the bullet and whacked the down tubes off. With that done, I could prop the engine up on wooden blocks to figure out where it had to go, in order to figure out where the frame could go.

    IMG_2614.jpg
    This view gives you an idea of the tubes' original path. Even without the starter, the flywheel and torque converter would have been in the way.

    IMG_2616.jpg

    It took a lot of jockeying around, but once the engine was sitting properly, I got out the angle cube and did some measuring.

    measurements.jpg
    The engine was inclined at 10.9° forward, nicely within the normally accepted 0° – 15° "safe" range for a GX clone/Pedator engine. As the bike sits, the lower frame tubes of the SST frame are –9.1° from level. The forward seat tube is 36.05°, and the top of the cylinder head is "eyeball close" to parallel. I know the GX/clone engines have the cylinder inclined 25° from horizontal, so my numbers all check out:

    GX200_DD.jpg

    So, my next step is to make an engine mount with an included angle of 20°, and get everything bolted up with the torque converter sprocket properly aligned.

    After that, I will have to figure out how to configure replacement frame tubes. For this, I'll be using the Ridgid #368 bender (3/4" OD x 3.75" radius) that I bought to modify Bultakenstein's frame. I got a cheap score on a few 3-foot remnants of 0.75 OD, .065 wall, unspecified "carbon steel" tubing. The existing frame tubes are 7/8" OD x 0.95" wall, so these are thinner and the smaller OD will be a visible mis-match, but so be it. For what a different mandrel bender would cost, I am super okay sticking with the OD that matches my tool. Even the tools for this project are whatever I have lying around. And even though my bender is rated for up to .120 wall, the 0.65 will be just fine for this application (and as a bonus, super easy to bend!).

    IMG_2615.jpg

    Stay tuned!
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  2. Tanshanomi

    Tanshanomi Your Favorite Uncle Supporter

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    It took me three tries to get the proper bends. Fortunately the very first test bend was with cheap conduit.

    Now I need to duplicate it for the other side and turn some slugs for the joints.

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  3. Tanshanomi

    Tanshanomi Your Favorite Uncle Supporter

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    I’ve ordered some lengths of .109 wall 1026 DOM off EBay. I figure, I'm only going to modify this frame once. If I'm going to go through the effort, there's no reason to use flimsy mystery metal.
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  4. Tanshanomi

    Tanshanomi Your Favorite Uncle Supporter

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    I had to take a break from the workshop for the usual homeowner tasks, a couple of family gatherings, plus some travel. I'm the guy behind the annual Smackdab Summer Solstice Run, and my wife and I did the ride on our Can-Am Spyders again this year.

    Last night I was finally able to get back to The Bride's fame mods. My Ridgid ratchet bender coped with the thicker .109 wall tubing just fine, though judging the springback was a bit of a wild guess. I had taken the initiative to throw some math at the problem ahead of time, and I was pleased that I was able to replicate my pattern pretty accurately.

    It will need to be trimmed to fit, obviously.

    I only had time to get the first one bent. I'll give the other side a go sometime in the next week or two.

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  5. Tanshanomi

    Tanshanomi Your Favorite Uncle Supporter

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    In other news, it's official: I'm an irrational parts hoarder. I picked up yet another frame that I don't have room for. I've had a hankering for a long while to create a lightweight retro-bobber-cruiser-sorta-thing, something with a sprung saddle and a swingarm-mounted rear fender. To this end, I've been on the lookout for a swingarm frame that had rear shock mounts low and forward enough to emulate the look of a hardtail or plunger frame, or perhaps old BMW /2s. Naturally, I was looking mostly at cruiser frames, but then I found this '79-'80 KTM 250 GS80 frame with a cracked rear frame section. Lop the rear off and I've got a dandy basis for a lightweight bobber. It was too cheap to pass up: $79, delivered.

    Once I unwrapped it, I had to hang some stuff from my cache of extra parts on it to visualize how it might look. None of this stuff is necessarily what I'd actually use (I'm still wanting a Yamaha Blaster powered street bike). However, seeing it, I'm kind of digging the chunky look of the Venture 1200 wheels. The mess of upper frame tubes will complicate fuel tank choice, but all this is waaaaay down the line. The parts will get squirreled away in the corners of my shop again, and the frame will get hung in the rafters for the foreseeable future. I just wanted to demonstrate the ease with which a fool can part ways with his hard-earned money.

    [Excuse the cluttered basement; it's time to make another trip to to the recycling center.]

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  6. TUCKERS

    TUCKERS the famous james

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    This inspiration is killing me, the only way out is more beer
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  7. sruss67

    sruss67 Been here awhile Supporter

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    Great thinking, very cool idea.
  8. TUCKERS

    TUCKERS the famous james

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    image.jpg
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  9. 3legs

    3legs Real men ride sidecars Supporter

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    Please don't tell me that's beer. Looks more like a piss sample :lol3
  10. TUCKERS

    TUCKERS the famous james

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    Miller Lite 35c a glass
  11. Tanshanomi

    Tanshanomi Your Favorite Uncle Supporter

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    I sent that photo to my podcast co-hosts. Eric sent me back this:

    3B6BFE69-6885-44E2-8177-4CBC23E4470D.jpeg
    DesmoDog, Honda-50, Scoozi and 7 others like this.
  12. Richarde1605

    Richarde1605 Long timer

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    Gold, sums many things perfectly :-)

    Imma steal that for introspection and taking the piss out of others that are also afflicted with that genetic marker.

    Peace
  13. Tanshanomi

    Tanshanomi Your Favorite Uncle Supporter

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    This is me being disciplined, sticking to my prioritized task list, and NOT getting distracted by the newest trinket I bought. Actually, I told myself that I needed to go ahead and cut the rear section off the KTM frame because I had nowhere to store it as it was, which was probably the truth.

    B1DAF972-D09C-4F92-88E2-ABA2B9252243.jpeg

    The rear section was not held on by much: two funky little saddles at the front attached to the frame with just two tack welds per side. At the bottom, there was just one tube to cut — one of the lower seat supports was already split in two. Zip, zip with the angle grinder and about 90 seconds later, my frame was a Manx cat lookalike.

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    The tubes were caked with dirt under the saddles, so I sanded the frame and shot a bit of primer. The rear section had little rubber tube plugs that I was, surprisingly, able to extract after 41 years. Voila, finished!

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    I also discovered the rear axle from an old Bultaco Pursang threads into the funky KTM swing arm pivot. Bit long, though, so not a perfect fit.

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    No, that won’t be in my way. Not at all.

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  14. Tanshanomi

    Tanshanomi Your Favorite Uncle Supporter

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    Back to work on "The Bride," my torque-converter bike.

    I have successfully bent both of the downtubes to fit.
    But how do I go about inserting a slug into both ends of the tube simultaneously?

    In the past, I have typically left a sizable gap between the tubes I was joining. That way, I could insert an extra-long slug into one tube, slide it partially into the other, and weld the slug separately to each tube. Unfortunately, that ends up with a skinnier section in the middle that looks pretty cobbly. Since I already have two different tube diameters here, I really didn't want to do that this time.

    So, there may be more straightforward ways to do it, but here's what I came up with:

    First, I turned a couple of slugs that are the ID of the frame tubing on one side, and the smaller ID of my new tube on the other. Note that one of them has a little lip or collar in the middle, and one does not.

    IMG_2884.jpg

    I bored a big hole in the bottom of the one without the retaining collar and soldered a length of 16 ga. automotive wire to it.

    IMG_2885.jpg

    I drilled a small hole at the bend of the new tube, and threaded the wire through it. I also drilled a hole at the very end to create a notch for the wire.

    IMG_2890.jpg

    On the bike, I fitted the slug and tube to the bottom frame tube first. The lip keeps the slug centered at the junction point.

    IMG_2891.jpg

    At the other end, I slid the slug fully into the downtube, moved the tube into position, and then pulled on the wire. The difference in inside diameters prevents the slug from coming too far, and my little alignment marks show when it is fully seated. Gravity will help it stay in position until it gets welded.

    IMG_2893.jpg

    And now it's locked in place and ready for welding. Once I do the same operation on the other side, I will drill a couple of additional holes in the frame tubes and plug-weld each of the slugs through the holes on both sides of the joint.

    IMG_2896.jpg

    Below, you can see my little, blue, 85-amp Clarke spoolgun welder on the right. I have a big bottle of 100% argon hooked up to it, which is great for welding aluminum and MIG brazing, but no bueno for MIG welding steel. Under it on my welding cart (hidden by the trash can) there's also a H-F Titanium 125 gassless flux-core welder. I'm undecided whether to: A) try my hand at silcon-bronze MIG brazing around the diameter of the joints; B) flux-core weld the whole thing with the Titanium 125; C) spend the money for a bottle of 25/75 MIG gas; or, D) take the whole thing to my friendly neighborhood welding shop.

    IMG_2898.jpg
  15. TUCKERS

    TUCKERS the famous james

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    Fantastic stuff!
  16. sruss67

    sruss67 Been here awhile Supporter

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    Ingenious solution you came up with for fitting the slugs.
    And a nice look at your project collection sitting patiently :-)
    Tanshanomi likes this.
  17. Richarde1605

    Richarde1605 Long timer

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    I'd give the brazing a go knowing that any welding would be void after that.
    But a smooth braze is a thing :-)
  18. Tanshanomi

    Tanshanomi Your Favorite Uncle Supporter

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    Work continues...

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  19. TUCKERS

    TUCKERS the famous james

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    Tidy!
  20. VX Rider

    VX Rider Long timer

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    Nice work