A BTR Build in Progress: Lets reach 100mph

Discussion in 'Board Trackers and Vintage Motorized Bicycles' started by projectstarter2012, Jun 22, 2012.

  1. projectstarter2012

    projectstarter2012 New Member

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    So it begins. A quest to build a BTR.

    The Motivation: Don't own a Car, Quick & Efficient Transportation, the awesome history these bikes have, and a drive to build something that has speed and style!

    The Inspiration: A Passion for Engineering, the satisfaction of setting out to build something and then looking at the finished product when completed, and the feeling of going 100mph on a Motorcycle (Yes, I am shooting for a top end of 100mph)

    The Budget: $2000.00

    My Resources: My College Apartment (the workshop), Internet, Adobe & Autodesk Software, AutoCAD Lab, 3D Printer, and a 44" Plotter.

    Experience: No Motorcycle Experience, Jr. in undergraduate Engineering Degree, No Fabricating Experience.

    Where I currently sit in my journey to the BTR.....

    The physical inspiration for my build comes from two BTRs and a Flat Track racer. The first is the Flying Merkel from Joseph Merkel's 'Merkel-Light Motorcycle Company'. The key elements I wanted to take from this bike was the style and rigidity of the front end along with the interesting contour of the gas tank with a sharp angle in the center of it. The second bike is the Rudge 'Bitsa' Bike built by french artist Jean-Claude Barrois. The bike is a take off a french brand called Soyer from the 1920s. The 'Bitsa' bike has smooth lines on the upper half of the frame and seems to transition well from the frame to the wheels. I really wanted to take the seemingly proportional frame-wheel figure the 'Bitsa' bike had to keep the bike on the smaller side. In other words, I wanted a bike that would sit very low and racer like. The third bike is actually a bike that user: Lurker: built called the Cobra Cycles Flat Track Racer. I really liked the way he built his bike in terms of how tight everything seemed to be from the front fork through the engine and rear wheel.

    So after figuring where my inspiration was coming from I printed out as many different pictures as I could of these bikes and stuck them all over my apartment. Whenever I was home I stared at the features that I like the most in these bikes and thought of a way to incorporate them into one bike. I then began putting things together.

    After about 2.5 months I had my final 2D drawing finished in illustrator. I scaled everything up using a wheelbase of 52" and a Wheel size of 28" and printed it on a plotter to-scale. I pasted that on my wall.

    Where I am now: I am almost done with a 3D render of my bike using Autodesk 3Ds Max Design Software. I am currently stuck on making the seat...I had to teach myself the software and its getting harder to find videos on youtube. However, once I am done I hope to mask all the pieces together and take advantage of one of the 3D printers that is open to the public on campus an print my bike in 3D to observe proportionality and precision thus far in my design.

    I have also begun to develop a parts list for my bike and even purchased the first part for my build! A Puch Peugeot Rear Hub w/sealed bearings 36H. The ETB(Estimated time of Build) is July 2013, so between now and then I hope to acquire parts here and there.

    Engine: I want to use a modded GX200 (or Clone) package from NR racing. I calculated the theoretical top-speed and energy lost to friction and found that if I tune the engine to around 18+ HP (Roughly 7500 RPM output) I could reach 100mph, sacrificing torque a little bit. I am still hoping to find an original V-Twin though...barn find? Long shot...

    Wheels: This is were I need some input. I am definitely going with Coker Firestone Tires 28 OD x 2.5 Cross Section (Speed Rated), and I know I am going to take a hit on price, thats why I'm considering a Unicycle Double Walled 42mm x 622 mm Rim...(still contemplating speed factors : ) ) which are roughly $75.00...I have done a lot of the tire size-wheel calculations and it might work...just wondering about speed.......

    I will post as much information as I go along, I will probably be making a blog to cover the build as well, once I actually begin to obtain a lot more parts/go into fabrication.
     
    #1 projectstarter2012, Jun 22, 2012
    Last edited: Jun 22, 2012
  2. truckd

    truckd Active Member

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    You might want to go to Dan at Taylar Motor Bikes for a little advice and or certain componants for your build like forks & frames,Dan was building Custom motorcycles long before he got into custom BTR M/B's, you can see some of Dans work on various threads through out this forum and most recently mine at "Blood Thursty"
    Here are some pic's of a couple of bikes Dan did and one called a Comet
    (1912) similar to a Flying Merkel,I have tried doing research on the Comet but find next to nothing on it ,the Comet bike might be a good build for you, the Harley has a Honda GC 160 with a cruising spd of 55 MPH without sweet. Good luck keep us all posted
     

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  3. Rebuilder

    Rebuilder New Member

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    Here's a link to my build. It's pretty much exactly what you're talking about only at more of a motorcycle scale with a Yamaha XT500 motor. In my research I found to stay away from the Coker tires mainly because they're "clincher" style and if they lose pressure they fall off the rim. If you're going for 100mph I would look into motorcycle tires and rims. 21" are very common but you could also go 23" which came on some older Honda Dual Sports. I went 21" because the tire selection is better. My wheelbase is 56" and it scaled up pretty well. If you have any questions, I'd be happy to help.

    http://www.advrider.com/forums/showthread.php?t=619303
     
    #3 Rebuilder, Jun 25, 2012
    Last edited: Jun 25, 2012
  4. Velodrome

    Velodrome Well-Known Member

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    HO LEEE CRAP!!! Rebuilder. Welcome aboard ( Everybody click on his link ) EDIT: Well. Aparently his post was taken down for some reason. Nevermind...EDIT OF THE EDIT! Post is back ( getting confused.)
     
    #4 Velodrome, Jun 25, 2012
    Last edited: Jun 25, 2012
  5. Rebuilder

    Rebuilder New Member

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    Thanks. Glad to be here. Maybe I'll start a thread with some pics and a link to my build. I think it'll fit right in.

    ...... or maybe not!!!

    Link http://www.advrider.com/forums/showthread.php?t=619303
     
    #5 Rebuilder, Jun 25, 2012
    Last edited: Jun 25, 2012
  6. Rebuilder

    Rebuilder New Member

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    Thanks Velodrome. Guess I can't link to another site. Or maybe it's because it's a "motorcycle" and not a "motorbicycle". Just thought it was relevant to the OP's project. Oh well.

    Can I link a photo?
    [​IMG]
     
    #6 Rebuilder, Jun 25, 2012
    Last edited: Jun 25, 2012
  7. Rebuilder

    Rebuilder New Member

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    Can I post a picture of it?

    [​IMG]

    or two...

    [​IMG]
     
  8. harry76

    harry76 New Member

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    Oops double post
     
    #8 harry76, Jun 25, 2012
    Last edited: Jun 25, 2012
  9. harry76

    harry76 New Member

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    What was it? And why is it gone?..... now youve sparked my interest :-||

    .................................................................................

    Also i think $2000 for 100mph is probably out of reach, but if you prove me wrong i hope you share your secrets :) Good luck
     
  10. truckd

    truckd Active Member

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    DAMMNNN!!!! it's a Merkel, Harry or ? oh well whatever it is is ? its cool! How'd you like to have that in your Garage Harry? Ya 'all can see the build on youtube, even see a vid of the guy ride'n it and it sounds like the beast it looks like, I do beleive it needs a rear fender I couldn't imagine hitting a dump in the road , comming off that seat and getting a new one ripped, you know where.
     
    #10 truckd, Jun 25, 2012
    Last edited: Jun 25, 2012
  11. harry76

    harry76 New Member

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    The pictures are now back up on this page.... they were missing earlier.

    Ive read the thread of this bike over on 'ADVRIDER'. What an absolutely awesome build, truly one of the best and rebuilder was nice enough to share a lot of his secrets. OUTSTANDING!!!!!!!

    Hey Rebuilder have you thought anymore about casting an engine cover for the right side of your bike like you suggested in the other thread? That would put this bike over the top.
     
  12. projectstarter2012

    projectstarter2012 New Member

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    Rebuilder,

    That is an awesome bike! I was actually checking out your ride on ADVrider a while back and messaged you about some design advice. I am the same name on ADVrider: projectstarter2012. Thanks again for the advice. The only reason I really want to go with the 28" wheels is because I feel they really fit my design better. I am really trying to make the frame kind of flow right into the wheel without trimming the height of the bike to much. I'll have to figure out how to post a picture....

    Thanks for the heads up on the clincher tires. Do you think if I had a rim with a steeper sidewall the issue of the tire falling off will be risky also, with low pressures?
     
  13. projectstarter2012

    projectstarter2012 New Member

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    Here are a few images of my 2D Drawing and my 3D Render (A work in progress, currently a clown bike)......

    [​IMG]
    [​IMG]
    [​IMG]
     
  14. Rebuilder

    Rebuilder New Member

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    Oh yeah. I remember for sure. Small internet world.

    One thing to remember is motorcycle and bicycles use a different measuring system for wheels. Motorcycle uses rim size and bikes use tire O.D. My 21" rims hold a 28" O.D. tire. If I recall, the Coker tires are 28" OD as well. Granted the Cokers look more authentic but they're just not safe for higher speeds. I happen to have a Honda in my garage with a 23" front wheel and the O.D. of that is almost 30". Tires are limited thoogh as I stated in my other post. Speaking of other posts.... sorry about bombarding your thread. My posts kept getting deleted so I just posted again and then they all just reappeared.
     
  15. projectstarter2012

    projectstarter2012 New Member

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    No worries about the posts, your bike looks awesome! Glad you posted some pics on the thread.

    In terms of the Motorcycle versus Bike Tire dimensions I understand what you mean. The Unicycle Wheel I was considering was for a 29er Bicycle (29" O.D.), The Unicycle Wheel I was going to use consists of two important measurements, the ERD (Effective Rim Diameter:595mm: Approx. 23.4"), which is the length from the bottom of the spoke nipple (inside the rim) on one side-to the bottom of the spoke nipple (inside the rim) on the other-side: think of it as a Inner diameter. Then the ISO measurement (O.D. of the rim) is 622mm. approx 24.4". So the sidewall of the rim is approx. 1" thick. Also, the rim thickness is 42mm (approx. 1.64"), plenty for a Coker tire with a 2.25" Cross section. (There might be just enough play to squeeze a 23.5" or 24" (Recommended Rim Size) Clincher onto this rim and have an extra bite on the rim.

    The contact surface distance between the bottom edges of the tire and the top edge of the sidewall of the rim would be roughly 14.5/16", this seems to be a lot more than the clincher rims that are offered from Coker and might provide more bite on the beaded wire with the combined appropriate pressure....then again a unicycle has never gone 100 MPH.

    If I go with the 21" or 23" motorcycle rim, with the added increased tire cross section of approx. 3-4" or so, I will need to increase the torque on the engine and may not be able to reach such a high top end because of the added weight + friction using the GX200 Mod.............

    How hard was it to integrate mounts/fittings for the larger engine such, Yamaha XT500....?
     
  16. truckd

    truckd Active Member

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    I'm no engineer and my question is just outta curiosity but why are the upper and lower rear frame stays so long? will you be putting a rear fender on as well? otherwise very nice design
     
  17. projectstarter2012

    projectstarter2012 New Member

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    That is still something that I might change. I thought about possibly making them shorter by increasing the length of the top tube and bulging it out more and then increasing the length of the lower engine loop also...I wanted to keep everything tight in the engine area, but keep the base length at 52", that is how they wound up so long. I will be putting a rear fender on.

    You bring up a good point though, for stability purposes I may need to shorten those......
     
  18. truckd

    truckd Active Member

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    Have you ever watched a drag bike go down the strip? longer frame creates instability thats just what I've learned from an old motor head (my Dad) but do try to keep the design and if you rounded the center bar it would be reminisante of the first Merkels but with a bad ass atitude.
     
  19. projectstarter2012

    projectstarter2012 New Member

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    Yeah you got a good point. By the way, I took your advice and contacted Dan at Taylar Bikes, I sent him a link to the forum. I would like to hear what he says about the length of the upper and lower rear frame stays also. I think I will definitely have to shorten them up a bit. Shortening the bike might not be that bad now that I'm thinking about it, it would cut weight also.....
     
  20. truckd

    truckd Active Member

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    Dan is the Man!! and if he likes it I do!
     

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