Meanwhile back in the basement - Central Plains

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

  1. TUCKERS

    TUCKERS the famous james

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    It fits he cried
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  2. Tanshanomi

    Tanshanomi Your Favorite Uncle Supporter

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    Trying to find a space for my carb that won't be occupied by my right leg. I'm not sure how successful this arrangement is. And yes, I know that silicone hose downstream of the carb is a no-no. I'm just temporarily jiggering this for now. The hose actually has hard contact with the frame, so this is no bueno on that count, too.

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    I am considering making up a 180-degree intake pipe, similar to what Mike Festiva did on his XR100 build:

    Screen Shot 2021-09-08 at 10.24.36 AM.png
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  3. TUCKERS

    TUCKERS the famous james

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    Shoulda put the engine in assbackards like those funny BMW 310's
  4. Tanshanomi

    Tanshanomi Your Favorite Uncle Supporter

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  5. Tanshanomi

    Tanshanomi Your Favorite Uncle Supporter

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    Since the engine mount only bolts to the frame towards the rear of the base plate, It'd be wise to distribute some of the stress to additional points on the frame. I am adding these link rods between two extra mounting bosses on the front of the crankcase and the original downtube gussets below the steering head. It's not the most robust point on the frame, but that's not the point. I just want to prevent the mount and lower parts of the frame from fatiguing. I am also optimistically hoping this will help damp vibrations. Obviously, I need to cut and thread steel rods to replace the wooden dowels in the photo.

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  6. Kai Ju

    Kai Ju Long timer Supporter

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    I think the wooden dowels would be better for vibration damping than aluminum or steel...
    But I would suggest a nice hardwood.
















    :hide
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  7. Tanshanomi

    Tanshanomi Your Favorite Uncle Supporter

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    thats-not-how-the-force-works.png
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  8. Kai Ju

    Kai Ju Long timer Supporter

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    Depends whether it's under tension or compression.

    But in all seriousness, if you were to make a 'shallow' U shaped bracket instead of that solid aluminum bar you could build in some vibration absorption.
    I'm actually thinking of two thin brackets nested together. Think horn brackets, too thick and it can't vibrate.
    Hope that makes sense.
  9. Tanshanomi

    Tanshanomi Your Favorite Uncle Supporter

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    I was thinking more in terms of quelling side-to-side movement of the engine. The whole engine is cantilevered pretty far above and in front of the lower mounting points. Without any other constraints, that's a pretty big lever. These are not turnbuckles (right-hand thread at both ends), so they won't be highly tensioned. However, since they're angled inward on each side they should limit gross lateral deflection.
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  10. Kai Ju

    Kai Ju Long timer Supporter

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    to quote rosanne rosanna danna: Never mind...
  11. Tanshanomi

    Tanshanomi Your Favorite Uncle Supporter

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    I squeezed in a brief workshop session before work. Just trying stay intentional and keep on doing a little bit whenever I can.
    One side down, one to go.

    IMG_3050.jpg
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  12. TUCKERS

    TUCKERS the famous james

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    Tidy!
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  13. Tanshanomi

    Tanshanomi Your Favorite Uncle Supporter

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    I rolled the whole monstrosity outside to take a few "in-progress" photos. Seeing how far it has come, overall, helps keep me motivated. Next on the punch list: carb intake, shock mounting, steering stops. I have all the parts to rebuild the front brake, so maybe that, too.

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  14. Tanshanomi

    Tanshanomi Your Favorite Uncle Supporter

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    I'm working on the intake, and it's taking more effort than I expected.
    I did find a commercially-available plug-and-play option, but it puts the carb so far outboard that I would have to run the cable outside of the tank, and I want to route the throttle cable through the tank tunnel in the conventional manner.

    Honda_GX200_Mikuni_Carb_1.JPG

    I tried a straight u-bend, but putting the carb close to the center of the frame also put the float bowl pretty close to the cylinder fins — really not ideal.

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    I slapped the 45° hose bend I had tried previously, and it moved the carb forward into a good position.

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    I verified that I will be able to get to the choke with the tank on.

    IMG_3106_web.jpg

    So, there: desired configuration settled. But there's still a long way to go. The hose section will need to be replaced by an additional metal section; that silicone hose isn't fuel resistant, and even though it's molded, it allows the carb to sag a bit. But that's okay; I need to start fabrication again from scratch anyway. First of all, I was overconfident about my welding skills. After taking a great deal of time to fabricate a flange and fit it to the U-bend, I totally gobbed the welding. Totally — as in, I'm too embarrassed to show any close-ups.

    Secondly, one of the mounting screws for the exhaust is right behind a frame tube. Installing and torquing it properly requires un-bolting the engine. It would be better to have the intake tract mounting bolts more accessible. The engine's intake is an odd D-shape, so an adapter flange is needed to smoothly transition it to round (the red anodized plate visible in the photos). I'm going to make my own version of this adapter, similar to one that I made for my Honda CL125S:

    cl125-nibbi-adapter.jpg
    • It will be thicker than the anodized one on there now (1/2" alloy) so the transition in shape of the interior hole will be less abrupt.
    • It will have countersunk holes to mount to the intake, like above, and a second set of studs clocked to resolve the frame interference issue.
    • The intake pipe mounting studs I'm adding will be slightly farther between centers. One of my problems welding was that there was very little clearance between the 1.25" tube and the bolt holes in the flange plate. The new studs will also be centered on the intake tube. The existing holes are offset slightly.
    • The design is shaped so that I have three equidistant points at 120 degrees, so I can mount in my 3-jaw chuck to cut the taper in the center hole.
    Bride Intake Adapter Plate.jpg
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  15. sruss67

    sruss67 Been here awhile Supporter

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    Love the stance of the bike in the photo taken outside, it looks really good.
    The final location of the carb you had above looks like it will work well, and I am sure you will have it sorted soon enough.
    Keep up the great work, oh, and the welding will come to you. Do you have pieces of the same thickness material you can practise with to get the amps etc right?
  16. Tanshanomi

    Tanshanomi Your Favorite Uncle Supporter

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    Well, that was the problem — I do okay on 3/16" plate. Trying to weld 3/16" plate to 18 ga. tube, however, is a bit more tricky.
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  17. sruss67

    sruss67 Been here awhile Supporter

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    That's where it can be handy to have both types as pieces to practise on before you weld your keeper.
    I have started TIG welding this year and did plenty of test pieces before welding anything I wanted to use.
    I have cut pieces for a welding table and left it that long that I will need to practise on similar material again prior to tacking and welding the table up.
    Blowing holes in scrap is better for me than in the table I want to finish nicely. :lol3
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  18. Tanshanomi

    Tanshanomi Your Favorite Uncle Supporter

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    Getting better gradually? Actually taking time to practice?

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  19. sruss67

    sruss67 Been here awhile Supporter

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    Getting better gradually? Actually taking time to practice?

    A bit of both!
    With more TIG practise or revision I recall what was taught in the course I attended 2 years ago.
    Any offcuts of steel are kept to use for welding practise.
    By playing around with amperage on the welder for different gauge steel I look for the puddle of molten metal to flow from both parts and then add my tig filler rod.
    Then once I have the amperage and speed sorted I am happy to weld my project.
    I am new to welding but do enjoy the process very much when the time is there to do it.

    I hear you when you say "I want it now" haha, it can be frustrating at times.
  20. DesmoDog

    DesmoDog Desmo was my dog. RIP big guy.

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    I learned to weld with an oxy/acetylene set up. At one point when working on a traditional old school hot rod I had a lot of welding to do and discovered it was almost like meditation once I was "in the groove" as it were. Had to remain relaxed and calm to get it right.

    A couple years ago I finally purchased a MIG set up for the aforementoned hot rod project. So much faster. But not the same feel when doing it. I do practice welds with that in new situations but still manage to screw up when I move from test to real deal!

    I've been threatening to buy a TIG set up for years, but think that window may have closed at this point, I'm not sure I have enough projects left to make it worth the cost. I guess I just need to buy the right project that "requires" TIG welding to have an excuse!