Build Problems

Discussion in 'Frame Mounted Engines' started by upshifter, Jan 18, 2009.

  1. upshifter

    upshifter Member

    Yesterday I purchased a new 26'' Roadmaster mountain bike from Wal Mart for $50.00. It was marked down from $77.00 because it had some little thing wrong with it and had been repaired by their bicycle guy. It looked suitable for a new build; and I like the front forks with suspension. I thought it would work out. It won't.

    The frame tubes are oval shaped, not round, and that keeps the engine from fitting by about an inch or so. Bah! I had my mind set on it.

    I might get it to work if I remove the engine mount studs and replace them with longer ones. Also, it's such a tight fit that I'll have to slide it into the frame without one of the front engine studs, and then install the stud to the engine after it's in. That is, if it can be made to fit at all.

    That Roadmaster isn't even close to as well made as the American made Roadmasters of several years ago. It's a Chinese bike with "Roadmaster" in name only.

    Okay, what should I do? Take it back to Wal Mart and have them return my $50.00?

    Keep it for parts because the tires and tubes alone are worth about 30 dollars or more? (The wheels, and other parts are fairly standard and would work on older more suitable frames.)

    Get a friend of mine to weld the frame so the engine will fit? (It would ruin a beautiful paint job and decals.)

    Advertise it in the paper to see if someone would swap me another bike for it; preferably a used Cruiser?

    What do think would be the best thing I can do with it?

  2. fetor56

    fetor56 Guest

    Replace any necessary studs.
    Last edited by a moderator: Jan 19, 2009
  3. wheelbender6

    wheelbender6 Well-Known Member

    Don't cut up your frame. Vendors on this site sell engine mounts for oversized tubing. Many on this site have solved this problem, so search on engine mounting posts. Cheers
  4. upshifter

    upshifter Member

    Thank you for the good advice.
  5. You can drill and bolt right through the frame instead of bracketing around it. A lot of people get nervous about drilling holes through the frame but not me. Cheap steele frames are cheap because they are heavy...not weak
  6. waylow

    waylow Member

    If you were to ask me, I would say bring the roadmaster back. I am stuck with one bicycle that I bought from the internet. I thought it would work for what I had in mind. I liked the bike when I got it. but after riding it for a few weeks, all of its weaknesses started to show. and it is cr4p. get your 50 bux back, and put it toward good tires: MAXXIS Hookworm Tires 26" x 2.50"


    I have the 2.5" wide set on my Diamondback Response Comp. and I absolutely LOVE them. They are absolutely with out a doubt, the best road tires period.

    I am really disappointed that they do not make a 29" version of the tire. I just got a Diamondback Overdrive Comp. that I absolutely love as well. it has big chunky offroad tires on it now... which is what it is made for really. those big a55 wheels roll right over the biggest roots and rocks with ease. But I still wish that I had an on-road set of wheels that I could throw on it.... speaking of which. lol Now I want to put my 26" hookworms, on my 29'er. they both have the same disc brakes, the Response just has one less gear in the back.

    Speaking of which, GET DISC BRAKES!!!!!! coff up the money for a decent bike with disc's they make all the difference in the world. I HIGHLY recommend the Diamondback Response Sport. It is the best/most bicycle for the money: best bicycle value for the money that I have ever seen.
    I hope this doesn't come off as arrogant, but, I have been riding 800/1500 dollar bikes for a long time now... and let me tell you, it makes a WORLD of difference over a walmart bicycle.

    This right here: This bicycle rides like an 800 dollar bicycle.
    above is a link to the DB Response Sport that I speak of. it costs about 430/450. Comes with great components, they're not the best shocks in the world, but 500 times better than any shock on any walmart bike. the trigger shifters on it are totally amazing. this thing can shift gears in a fraction of a second, and snaps perfectly into place.

    This is how much I like and recommend this bike for your project: my neighbor bought the DB response sport, I rode it once; Then ordered my own Response Comp and Overdrive Pro at the same time. The Overdrive is the 29'er, and my play-around/off-road bike. it rides like a gigantic bmx. different geometry than a regular 26" wheeled mountain bike. Also, I am 6'4" and have XL sized frames, so my bikes are enormous. But back to my point. I bought the Response to put my engine on. the Strong-Boxed frame is SUPER strong. and not to mention, I can seriously ride wheelies on this thing for about 200 feet. I am still working on getting my engine mounted and everything together. but I have a GP460 engine, and I am going to do a rack mount over the rear wheel. ... talk about a moneypit lol this thing better be fun as 5hit to ride when I get it done. and after break-in, I have got to do some highspeed runs with the GPS, to see how fast it will go.

    The 29'er I don't think would make a very good motored bike, but is a great ride. I can't do wheelies on it... which is probably a good thing. lol. I hope that I can keep myself from trying to ride super long wheelies with the engine powering me lol. ... /me flirts with danger far too much.

    I hope my ramblings have helped with some good advice. I know that I am talking some big numbers; but, I started out just like you, and every single thing that I bought in the beginning... has since been replaced with something better. before ever even getting any motored bike together. the longer I had each piece, the more it was not up to my personal standards of quality. I don't even want to think about how much money I have dropped on stuff for this project. It has been almost a year since I started this venture, I have the bike and engine and LOTS of parts, but not quite everything. I have some designing to do yet. but it will get done one day :)

    Best of luck on your project. get that thing together and on the road!
    Last edited: Feb 17, 2009
  7. upshifter

    upshifter Member

    Waylow, I did finally take that Chinese Roadmaster back, and it was cr4p. I took the 50 dollars and bought 3 other bikes with the money. One was a nearly new Moon Dog, but green, with broken plastic cr4p pedals, and a broken bracket in the seat; but really nice for the 30 dollars I paid for it. It Looks new. I bought 2 other mountain bikes with the remaining 20 dollars; they're not too rough, but I'm still going to use them for parts.

    Waylow, I appreciate your good advice and wisdom about these bikes. You're right; those cheap bikes are pieces of cr4p, and dangerous with or without a motor. People buy them because they look good in the store, but after several weeks, especially used by novices, they self destruct.

    I climbed on that Chinese Roadmaster and started to ride it around to see how it felt. It was the worst, most unstable, new bike I ever rode. My old Giant Iguana mountain bike makes you want to throw rocks at that Chinese Roadmaster. I once had an American made AMF Roadmaster mountain bike. It was strong, and functional, but it was a lead sled and would work you to death.

    (By the way, I've never had a better shifting bike than the Iguana. It has two levers for both the front and back. When I shift down it winds a spring as it shifts. When I shift up with the second lever, the spring power upshifts the speeds automatically with only slight pressure, and shifts perfectly every time.)

    Thanks again for your good advice, and good luck to you on your projects and builds.