3D Printing an Intake Boot

Discussion in 'The Garage' started by TravisK, Mar 31, 2019.

  1. TravisK

    TravisK Adventurer

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    Hey everyone,

    I'm working on a '76 Yamaha DT400 (ignore the tank). I didn't have an intake boot from the airbox to the carb.

    [​IMG]

    [​IMG]

    You can find them on eBay, but a good one will go for upwards of USD$100 + shipping. A real janky one will cost $50 or so. And at the end of the day, its 40 year old rubber.

    My wife gave me the idea of 3D printing one. Luckily I have a few friends who are into 3D printing, and they agreed to help. I didn't have an original part, so I measured up the gap on the bike to design one. I didn't know flexible filament was a thing - but it sure is. We used TPU filament, and the end result is something I assume is similar to the flexibility of the original, based on other intake boots I have handled.

    A roll of 800 grams of TPU filament was roughly USD$30, and the part used approximately 68 grams, meaning it was only 1 or 2 dollars in material cost. The print went overnight (something like 13 hours), because you have to print at slow speeds with TPU.

    TPU is resistant to oil and apparently quite durable. I will keep a close eye on this part over time and report back if anything goes wrong.

    Here is the part being printed, shortly before its finished.
    [​IMG]

    And here is the part on the bike, before we added the hose clamps.
    [​IMG]

    All in all, we are very pleased with how this first attempt turned out. I think it opens up a bunch of possibilities for me in the garage, not just with intake boots (though I need a few of those), but also with other rubber parts like grommets, stoppers, and the like.

    For me, this was possible because I am familiar with CAD software, and I have close friends who are willing to spend their time helping me out. It is definitely not a plug and play type thing, there is a learning curve involved with 3D printing. I can elaborate more on the printer and settings of this particular job, if anyone is interested in knowing more.
    #1
  2. bmwroadsterca

    bmwroadsterca RadioFlyer

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    Well done. Consider putting the file on Thingiverse.
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  3. sasho

    sasho Dual Personality

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    Very cool, thanks for sharing!!
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  4. TravisK

    TravisK Adventurer

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    Thanks! Yes, I probably will. It'd be nice to get stuff like this modeled and online with the associated part number so that down the line, when 3D printing is even more ubiquitous, we can try this method to avoid getting hosed on eBay.

    And just for a visual, here is an example of the flexibility of this TPU filament.
    [​IMG]
    #4
  5. CA_Strom

    CA_Strom Cunning Linguist Supporter

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    That is very cool! I've restored a few classic Honda CT's, and the OEM rubber boot for a 1965 CT200 runs well over $200 if you can even find one!
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  6. ajpjive

    ajpjive Adventurer Supporter

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    Definitely interested what printer and settings you're using. I haven't had much luck printing with TPU in my Prusa, but then again, I haven't spent much time troubleshooting why.
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  7. lkraus

    lkraus Long timer

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    So, how much needs to be invested in equipment and software to produce a $100 part from $2 worth of material?

    How much time to create the CAD file?
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  8. TravisK

    TravisK Adventurer

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    Yea, it isn't easy justifying that much for some ancient rubber! We already have plans to create a new boot for my CT90, since I put the Lifan in it with the Mikuni carb, we have had to run pod filters. We're hoping to create a boot to hook it up to the stock airbox.

    The printer is an Anycubic I3 Mega, so a Prusa-based design. My friend will get back to me later today with the settings he used, so I can forward those on. It should hopefully give you a good jumping off point.

    The printer used is approximately $400 Canadian from Amazon prime. It didn't take long for me to design the model in CAD, maybe 10 minutes. I think there was probably a couple of hours of dialing in the settings and test prints too, because this was the first time my friend was printing with TPU. And then a 13 hour print, so I think there is some element of deciding what your time is worth, of course.

    If we have to make another part out of TPU, I expect maybe about another 10-20 minutes to CAD the part, and then the job can be printed straight away without the fiddling. Assuming nothing goes wrong in the printing process (it can happen), then there would be fairly little work required. It is mostly just waiting for the print to finish.

    For me, personally, working on multiple vintage bikes, I could see myself recouping the cost, if I had to buy a printer. I own 4 DT400s, and none of them have boots for the airbox to carb. Not to mention the parts we will probably be printing for my Trail 90. Also, I've seen many grommets, isolating gaskets, etc. that are cracking and disintegrating, and now this opens up a way of getting those for cents in material cost.
    #8
  9. andynj

    andynj Been here awhile

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    If you are handy with a CAD type package or know someone who is you can just have it estimated and made on something like Shapeways, once you have done it you can take a cut of anyone that uses your design to pay shapways to make it. Thats what a member on here did for some GS parts which I ended up buying.
    #9
  10. CA_Strom

    CA_Strom Cunning Linguist Supporter

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    I hear you! I had a couple of stock CT200 boots I sold off after I Lifan'd my Ct200. Here it is with a make-do universal fit boot sold by Dr. ATV, but something more custom would have looked better! The DrATV piece is basically a curved piece of auto Rad hose:
    IMG_2014 (2).jpg
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  11. ohgood

    ohgood Just givver tha berries !!!

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    so many vintage bikes will benefit from this !
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  12. fast1075

    fast1075 Not a Lemming Supporter

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    Being an old fart, I scoffed at 3D printer "toys". Then When I wanted to upgrade my 2013 PCX-150 to LED lights, no one made them. I found on Thingiverse, a 3D modeled adapter that I used to install H4 LED bulbs. Win!
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  13. anonny

    anonny What could go wrong?

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    That’s brilliant! Do you have to babysit the printer for the entire time it’s printing?
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  14. bwringer

    bwringer Gimpy, Yet Alacritous

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    I'll be very interested to see how this material holds up to gas vapor and heat.

    There are loooooooooooots of vintage bikes out there needing intake boots. There are a few companies molding a few popular parts, but for many there's no solution.
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  15. TravisK

    TravisK Adventurer

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    We are curious too. We were initially worried about the vacuum pressure but I believe this part to be stiff enough. One of the recommended applications for this TPU filament is automotive, because it is resistant to oil and greases apparently. Not so sure about gas vapors though. How the heat and moisture affects it - we will have to see, too. I will keep reporting back here as the bike gets running, and it gets more miles.

    That's part of the reason I thought I'd post it here! I hope this "experiment" works out for the best and others can make this process work for them.

    I used to joke that 3D printers were only good for replacing lost knobs on home appliances. We're a bit farther from that now!

    Once the settings are dialed in on some test prints for the material, you can leave it be for the prints (thankfully!). My friend printed this overnight, so it was largely unmonitored.
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  16. TravisK

    TravisK Adventurer

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    Love your bike! Your posts in the Lifan engine thread back in 2016 were instrumental in me going with the Lifan swap on my 90. If you need another boot done, let me know! Maybe we can whip something up.
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  17. CA_Strom

    CA_Strom Cunning Linguist Supporter

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    Thanks for the offer. In a moment of weakness I sold off my 1965 CT with the Lifan.
    #17
  18. MrBob

    MrBob Long timer Supporter

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    3D printing custom order dildos didn’t occur to anyone else
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  19. greasyfatman

    greasyfatman Long timer

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    I would be interested in this as a service. Could I pay for a BW80 boot? 20190322_232908.jpg I have some as take offs to be modeled

    I used clear tubing molded with a heat gun and it causes cavitation do to the mismatch in ID.

    If you could make the cad file and get a prototype I would pay gladly. Then turn the file over to the bw80 community. Looks like there are some print for hire services out there.
    #19
  20. SHEP_5

    SHEP_5 Been here awhile

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    I use Grabcad for my part i have designed
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