A Mixte framed motorised bicycle for a lady.

Discussion in 'Motorized Bicycle General Discussion' started by Intrepid Wheelwoman, Nov 1, 2011.

  1. Intrepid Wheelwoman

    Intrepid Wheelwoman New Member

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    Almost two years ago now I purchased a new 66cc manual clutch Chinese engine. At the time I was told it was an 80cc engine, but I now understand there is no such thing as an 80cc Chinese bicycle engine and that they are in fact only 66cc in capacity. I made a number of attempts to fit this engine to a variety of English made bicycles, only none of the bicycles were really ideal for my purpose. You see I wear long skirts for religious reasons and none of the classic English ladies frames I was trying to build a motorised bicycle around had space for both an engine and a long skirted rider.

    Then a picture of a Mixte frame conversion came to light and at once I saw that this was what I was looking for.
    From what I could see this conversion was everything I could want. The frame was a modern Mixte, but the wheels, mudguards, forks & etc were all classic 3 speed English bicycle parts. As you can see it's a tight fit to get a Chinese engine into a Mixte frame and it involves quite a bit of lifting and rotating the engine as well as holding one's mouth right to get it into place to can tell you.
    The red Mixte frame in the picture has a wider spacing between the twin frame tubes where they cross the seat tube than the frames commonly available here in New Zealand. Because of this I found it almost impossible to get the carb to fit between the twin frame tubes. Perhaps I could have made a custom intake manifold, only I didn't want to do this. I wanted my carb to fit between the tubes using the standard intake manifold.
    The blue frame isn't the actual frame I'm using, - the picture is intended to show you what I'm having to do in order to get the carb if fit. After cutting through the crosstube between the twin tubes I was then able to spread the tubes sufficiently to allow the carb to fit between them. Once I know exactly how far to spread the tubes to obtain a good working fit, a new longer crosstube will be made up and welded in place.

    To complete the conversion and make it a proper rolling bicycle I have a set of Rudge forks, chainwheel, chainguard and 26 inch wheels with 'Westrick' rims, BSA coaster hub as well as Raleigh pattern mudguards and a classic brand new 'Middlemore' sprung bicycle seat. I'm sure I can find a nice period Miller lighting set to finish it off nicely as well.
    If it can be neatly done I will fit a Rudge head badge to the Mixte headstock which should set the purists a-scratching their heads.

    Colour? Black with white mudguards, - what else? ;) Black mudguards might be more classic, but white mudguards are more visible in traffic. If I get really keen I might even attempt a little pinstriping in red and gold on the frame.
     

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  2. BarelyAWake

    BarelyAWake New Member

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    We've had a number of step-through bikes converted, but I can't recall any quite like your Mixte frame, which is resulting in both a very tidy looking & strong build - I can't wait to see it completed!

    As you're familiar with the "classic English ladies frames" I'm sure you've seen the skirt/coat guards that some, particularly the vintage ones came equipped with. As you're planning to ride in a full dress at the greater speeds of motorized bicycling, have you considered fitting the Mixte with them?

    They come in a wide variety of styles, from vintage steel to modern netting & as I'm particularly fond of greatcoats, I've considered them myself :)

    [​IMG] [​IMG] [​IMG] [​IMG]
     
  3. Intrepid Wheelwoman

    Intrepid Wheelwoman New Member

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    Thankyou so much for the reminder! I've been so busy with getting the engine to fit that I hadn't thought ahead to fitting a skirt guard. Amongst all my vintage treasures I did at one time have a rear mudguard that had been drilled to fit a skirt guard, but unfortunately it had been 'bobbed' by some horrid little vandal so I couldn't use it.

    Trust me to be attempting to break new ground with this conversion, but as you say it should result in a strong and tidy motorised bicycle once I have it completed. I do own a digital camera so once I have the frame properly sorted out I will take some pictures.

    [​IMG]
     
  4. Intrepid Wheelwoman

    Intrepid Wheelwoman New Member

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  5. Ibedayank

    Ibedayank New Member

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    make sure the Exhaust Pipe can not touch your skirt
     
  6. Intrepid Wheelwoman

    Intrepid Wheelwoman New Member

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    Oh yes! - another very good reminder that I shall indeed take notice of. Thankyou :)
     
  7. MEASURE TWICE

    MEASURE TWICE Active Member

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    .bt.I welded a platform for a 3hp 4 stoke engine on an old 1960's era JC Penny Foremost steel frame. I am getting to try and finish it now with winter about to start and only outdoors to do most of the work. I'll work around the storms as best I can in California.

    I think that you have as a 2 stroke as I see the intake and about half way down the cylinder so you probably have quite a bit of power and not to worry.

    I can remember for a while using a street motorcycle Kawasaki 350 with 3 cylinder two stoke, was a bit worn out as it was then 3rd hand. I once reached down to grab something on the ground under the headers by the front fork and smelled plastic burning. It was the poplin shell of my down jacket. I did not get burned, but as I saw a large hole melted on the sleeve, I also saw feathers stuck to the pipe.

    Covers on moving parts around chain a belt drives also I have made for the motor bike I am making.

    I eventually am to make a modification to have my motor bike when it is done. It is so it can run a crawling speeds and to look like a sea creature to bring to the next Burning Man event for 2012 in Nevada.

    Measure Twice
     
    #7 MEASURE TWICE, Nov 3, 2011
    Last edited: Nov 3, 2011
  8. harry76

    harry76 New Member

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    Welcome Intrepid Wheelwoman, i am currently building a bike for my girlfriend and know how tricky it can be to do a ladies frame build while still being friendly to ride.

    I also have a "mixtie" bike and considered using it but i didnt think a chinagirl engine would fit, nice work getting it to fit in there. I really really like it. I dont know how much work you are willing to do to it, but it would look absolutely awesome if you could make (or get one made for you) an inframe tank to sit above the engine.

    I look forward to seeing what you come up with....

    For my girlfriends bike i ended up using a Briggs and ladies mountainbike frame and modified it a bit..... heres where im at

    Before:

    [​IMG]

    Where im up to:

    [​IMG]
     
  9. Intrepid Wheelwoman

    Intrepid Wheelwoman New Member

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    Hello Harry, - I must say that's a nice job you have done with adapting a B&S engine into that mountainbike frame. I was looking at your Villiers powered bicycle last night and was very much impressed with it. Plainly you have a nack for building very interesting motored bicycles :)

    Yes a Chinagirl can go into a Mixte frame, but it's a tight fit to do it. The final result is worth it though and to my mind the engine looks like it belongs in the frame. With the frame tubes so close around the carb and the cylinder barrel there is also a measure of protection for these components as well.
    I haven't made up my mind about a gas tank as yet and may just use the standard tank to begin with until I find something more suitable. Ultimately I would like to make this bicycle as good looking as I can make it, but with a subtle patina of age about it to match the Rudge cycle parts I'm using.
     
  10. Intrepid Wheelwoman

    Intrepid Wheelwoman New Member

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    Well it was pouring with rain so I couldn't move anything around in the garage or the carport so I could take a decent picture, but this is my Gen II 66cc Chinagirl try fitted into the Mixte frame I'm using. This frame was much more of a tight fit for a Chinagirl than the nice red frame in the photo that first caught my interest, but I think it will do and by the time I'm finished the liberties I took with the frame won't be all that visible anyway.

    The Rudge rear wheel fits into the Mixte frame just fine and there's plenty of room for a sprocket. That front fork, handlebars & etc are all going and will be replaced by a Rudge fork and front wheel. I have a slightly shabby 'Oryx' pre-war leather seat with a rearward facing type seatpost that I've been saving and I think I'll use it on this bike. As for the gas tank I'm considering using a cylindrical tank which is presently being mocked up by that scrap gas cylinder. I need to do a little cardboard aided design in order to devise various skirt and chainguards that will look the part as I'm aiming for a sort of British motored bicycle appearance with my Mixte project.
     

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  11. silverbear

    silverbear The Boy Who Never Grew Up

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    Nice project. My favorite skirt or coat guards have an art deco look to them and were made for 1930's to 1941 Elgin step through models. The first one is a 1939 I built a couple of years ago with my first stab at a sidecar utilizing a modified kiddie trailer. The second one is in progress and is a 1934 model with a Tomos moped fork, 66cc engine, expansion exhaust and will have a 3 speed SBP shift kit when leaves appear on the money tree. The guards are like poetry, suggesting movement and speed. This model was made for almost ten years and was very popular. There are still a number of them around in the USA and come up on ebay now and then.
    SB
     

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  12. Intrepid Wheelwoman

    Intrepid Wheelwoman New Member

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    Oh my! - those bicycles are beautiful works of art. You are right, the Art Deco skirt guards are pure poetry. I love the carrier mounted gas tank and the chrome flexipipe on the exhaust. For many years I owned sidecar outfits and I loved piloting them at speed; - my health isn't up to it now and I really do miss them. A little Watsonian copy sidecar could be a good project though, - we shall see.
    My Mixte will be more styled after British Utilitarianism than anything too artistic. All that black enamel and 'Rudge Whitworth' transfers/decals will be about sitting up straight and thinking of England rather than giving into hedonistic impulses ;)
     
  13. silverbear

    silverbear The Boy Who Never Grew Up

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    Thank you for your kind words. Elgin had a wonderful designer in the early years. This model step through and the boys models on general were exceptional. The boys Bluebird and Robin are the most beautiful bikes ever made, in my opinion. Google "Elgin Bluebird" and you may agree. In the end, utility wins the day, however.
    I got interested in step through bikes due to a partial paralysis from nerve damage initiated by being stuck by lightning some years ago which led to a disease called Guillane Barre Syndrome which is similar to polio. The short of it is that I was more crippled some years back and had difficulty swinging my leg over the seat to mount a bike. I also needed motor assist due to weakness in my lower legs. The good part of all this is that it is what led me into motor assisted bicycles and eventually building bikes and some wonderful friendships here with remarkable people. Step through is good for geezers and my interest in sidecars and three wheeled bikes is for when mounting and balancing is more difficult than it is right now, should the disease takes a downward turn. I'd like to keep riding one way or another for a long time yet. Feeling the wind in my face is good medicine. If I ever need a wheelchair I want the wheels to be in front and a gas engine driving the rear wheel. Ha! Vroom...
    SB
     
  14. Intrepid Wheelwoman

    Intrepid Wheelwoman New Member

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    Living with a disabilty of my own I can completely understand your need for a nice step through frame and a little motor assistance to help things along. Bicycles are a great hobby for anybody who needs to maintain a level of exercise to maintain their good health. Once I moved away from the city to the country and could safely ride a bicycle again my health improved no end and I needed a lot less medical interventions than before. Bicycles are gooood, I need to use a stick when walking, but once on a bike I feel free to go wherever I want.

    This afternoon I made some final adjustments to the Mixte frame with the 'Adjustatron' (2x3 inch length of timber) to get the Chinagirl fitting nicely without the headfins rubbing on the twin diagonal frame tubes. It all looks nice and neat now and I managed to get all the bends smooth and even so the frame doesn't look like it's been levered about with a baulk of timber (which it was!).
    Next thing to do is to completely strip down the frame and do a spot of welding to properly brace up the 'adjustments' I've made. After that I should do a trial assembly of all the Rudge parts onto the Mixte frame to make sure everything fits properly. I will have the trusty BSA coaster brake hub on the back wheel and as to the rest of the brakes I'm not entirely sure as yet. Rod brakes would be absolutely ideal, but I'm all out of rod brake spares at the moment and I'm certainly not going to rob them from any of my other bikes.
     
  15. diceman2004

    diceman2004 New Member

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    The bottle tank looks awsome .. do the tank like that . it will look SO cool when its done .
    That motor looks perfect in there . Its so tight , its like the frame was built around the motor .
     
  16. silverbear

    silverbear The Boy Who Never Grew Up

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    Wheelwoman,
    I agree that your engine fits the frame so nicely with your alteration. Looks like it was made that way as a commercial motor bicycle. A cylindrical tank would be just right. Looking forward to the finished bike, as I'm sure you are as well...
    For the skirt guards you could drill holes along the edge of the fenders for lacing cord or maybe there is a way to use spokes from a spare wheel. At the hub you could have a disc shape the cord gets laced to or the spokes fit in and which is held in place by the axle nut. That piece could be kind of like a washer... maybe the end section of a tin can with the lid in place and a lip of the can perhaps an inch or so with holes drilled into the lip. At the center of the lid (still attached), it could be drilled out to fit over the axle. Just a thought.
    SB
     
  17. Intrepid Wheelwoman

    Intrepid Wheelwoman New Member

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    SB, that sounds a lot like the skirt guards I've seen on a few older English made bicycles and I think I'll be doing something very similar to that. The spokes instead of cord idea is a good one and I'll have a look at that because it's no more work than stringing cord and it would be a lot stronger.
     
  18. MEASURE TWICE

    MEASURE TWICE Active Member

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    I saw that picture at the beginning of this thread of that red colored bike. The chain guard had reminded me of what I had started out with when I saved it at the dumpster where it would have been taken by the scrap metal guy or into landfill.

    What I saw on the web of what it may have looked like.

    OldRoads.com

    Technical Resources Tab - then Picture Database for Sears Foremost

    oldroads.com - Vintage Bicycle Picture Database

    You might get some ideas of the fake but very stylish gas tanks / head lights from the way they were originally made on these old time bicycles.

    It is not what I am doing as I am when done with my motor bike build; I want it versatile to be moded to be an art motor bike. In the future when time allows I should like to keep the look close to what they were back then, just motorized.

    Measure Twice

    PS

    The picture at my albums page shows the steel frame paint removed

    http://motorbicycling.com/members/measure-twice-albums.html

    I updated my post possible side car today

    http://motorbicycling.com/f36/motor-bike-diyer-build-add-side-29678.html
    reddd
     

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  19. Intrepid Wheelwoman

    Intrepid Wheelwoman New Member

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    The link to your albums page isn't working unfortunately Measure Twice :(

    I purchased a carb for a pocket bike to see if it will fit into the Mixte frame better than the original Gen II Chinagirl carby. It certainly is a physically smaller carb which is good and the fuel tap is on the carb body itself which could make life easier too.

    There is something else that I'm wondering about, - there is no heat spacer block on the Chinagirl intake manifold. Is this normal? - looks like it could be a source of problems to me with the carb getting too hot and vapour locking.
     

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  20. Markknorr

    Markknorr New Member

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    I completed my mixte frame motor bike in 2013 for my wife. She didn't take to it, but I was very pleased with the bike. I did have to come up with an alternative design for the chain tensioner, intake manifold and cheesy foam and chrome throttle grips, but a worthwhile project. I had bolted up kits before, but I really thought this one out.
     

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