Chainsaws,weedwhackers,snow blowers...oh my!

Discussion in 'Rack Mounted Engines' started by Guest, Apr 14, 2007.

Tags: Add Tags
  1. srdavo

    srdavo Active Member

  2. happycheapskate

    happycheapskate Active Member

    I saw a bike with a snow blower engine on youtube, that used a chain turned by motor, idler pulley with spring tensioner, and a bmx wheel mated to a 26" wheel by little tabs, like the old 1900's motorcycles. If you put rubber tool coating on the inside of the bmx rim, or mated 2 narrow BMX rims with rivets, you could have almost 1/1 "cog" size. Cheap bmx chains should run a long time on it without stretching being a problem.
  3. happycheapskate

    happycheapskate Active Member

    Wow, that is just awesome.

  4. Jeco

    Jeco Member

    I am glad I've found this thread, I am planning to put a weed whacker or chainsaw on a foldable bike I have here.
  5. 5-7HEAVEN

    5-7HEAVEN Guest

    Hey Jeco. Be careful how much power you install onto your folder. My first MB was 1.6hp Subaru engine w/friction drive. Perfect, w/top speed 27mph. The bike went much faster w/2.2hp Mitsubishi engine and Staton chain drive. HOWEVER, it became too unstable and squirrelly. i removed the engine and gave away the bike.:bowdown:

    Be careful in your choice of engine/bike combination.
  6. Jeco

    Jeco Member

    Thanks for the advise 5-7Heaven!

    I am not sure how much power on the 26cc homelite weed trimmer or on the 25cc Ozito chainsaw I am eyeing on.

    Some more queries 5-7heaven...

    Will these engine do? Which one has better torque?
    Will this be good on friction or chain drive setup? I might use a sprocket from an HT or a bicycle chainring if applicable.

    I will make sure the bike is good enough to motorize.

    Thanks again!
  7. 5-7HEAVEN

    5-7HEAVEN Guest

    I wouldn't know about these engines, but modt weedwhackers end up on friction drive, bump start. Chain drive with clutch would be nice.

    Contact deacon on the other forum. He is most knowledgeable on DIY-weedwhackers.:idea:
  8. happycheapskate

    happycheapskate Active Member

    Most weedeaters are designed to be cheap, lightweight implements that can turn a 6" string hard enough to beat down weeds in the fence corners. Anything under 50cc is probably going to suck, but may be able to hold 20mph if you pedal first.
  9. Jeco

    Jeco Member

    thanks happy,

    a chainsaw motor will be better you think?
  10. happycheapskate

    happycheapskate Active Member

    Depends on the make, I guess. I expect a chainsaw will generally have higher compression, higher RPM range, and probably gobs of torque. The problem will be how to fit it to a bicycle. Its been done, a variety of ways, so I would guess that is where I'd start if I wanted to use such a motor.

    Chainsaws generally have a small notched wheel running directly on the crankshaft, attached by a flatted, threaded shaft, with a locknut. You will have to use something else to either turn a standard bicycle chain, or mount some type of roller for use as a friction drive.

    I have seen Youtube videos where users have welded a modified bicycle cassette sprocket to the clutch, and used the chainsaw, mounted on a cheap bicycle rack, to turn either a Happytime sprocket, or the front crankset. Dangerous territory there!

    This video shows a chainsaw motor driving the tire with the actual clutch!

    If you can order a Bike Motor Parts rack drive, you can use dozens of standard auger, 2 cycle air pump/water pump engines, pocketbike engines, etc, but I haven't heard of a chainsaw engine that has the same mount holes and clutch.
    Home made friction drive from junkyard chainsaw. Looks like the standard BMX axle peg for a roller. This would work well, but eventually wear the bearings, and if the nut on the peg loosens, the axle peg can be thrown violently. "Check your nuts!"
    Last edited: Dec 27, 2010
  11. motorbikele_man

    motorbikele_man New Member

    I tried the same idea with a chopper bike, and busted out the plasma cutter after the triple gear reductions and all three chains failed to bring my ratio to under a ten mph IDLE!!! Twas a blast all the way through, but i would never attempt such a complicated mess again... I think that thing could have succesfully turned back into a toothless chainsaw on my inner thigh, was WAY too dangerous. The bike will see another motor someday... anyways... nice work, be carefull, and invest in chain guards! lol
  12. 5-7HEAVEN

    5-7HEAVEN Active Member

    With chains and sprockets, you definitely need a clutch. If not, the engine will not disengage and run the bike to 10 mph in idle.....just like yours does.:detective:
  13. happycheapskate

    happycheapskate Active Member

    Here is a successful chainsaw bike (40-45mph!) It is a friction drive using a little tire to turn the bicycle tire.
    It has a really weird looking expansion pipe, but look at this dude go!
  14. 5-7HEAVEN

    5-7HEAVEN Active Member

    This guy lives on the east side of Honolulu, about 20 miles from me. I travel that way once every 6 months. The highway there has excellent pavement, long stretches and heavy traffic going 35mph-45mph.

    That youtube was shot two miles above Waikiki. One way traffic is mild, 20-35 mph speeds, okay roads. If I rode there, I'd be in the second lane from either curb.

    If we were to race, I would beat him. He has to pedal furiously from a stop to start his engine. By the time it kicks in, I'd be long gone.

    And I ALWAYS stop accelerating @ 5mph above the speed limit. By the time Mr. Chainsaw catches up, I be cruising.:devilish:
  15. happycheapskate

    happycheapskate Active Member

    Why does he have to rotate it so fast to start? Is it the jetting on the carb, or the freaky looking expansion pipe? It looks like it is just high-geared, so that it is actually firing and running weakly as he pedals, but hits an rpm range it likes and accelerates more rapidly (not lugging).

    Is it true the police confiscate bikes at the Critical Mass rides (in Hawaii, like some of the commenters on the ytb video suggest), even for non offending riders (polite traffic)? If so, that would be crazy to ride the MB there. He would stand out so surely would catch more scrutiny or harrassment.
    Last edited: Aug 9, 2011
  16. 5-7HEAVEN

    5-7HEAVEN Active Member

    The MB rider was not heading towards a Critical Mass gathering. He was meeting a friend he'd just called on his cell phone.

    The street he's on passes the Honolulu Police Dept.'s main station two miles away. I doubt he rides there.(I "phantom pedal" when I pass there on rare occasions). :whistling:

    If I bump into him, I'll ask him about his bike's operation.

    As the poster's mentioned, he's asking for trouble with no protective gear and rubber slippers.:ack2:
  17. jander6442

    jander6442 New Member

    What would happen if the MB rider hit a wet patch or, Heaven forbid, a oil patch? Where I'm at there everywhere.

    I live in FL... in the summer time I notice that the police have much sympathy for anyone braving a bike motor or not in these temps of late. Still I like the simplicity of his set up and can see a hint of experience with how he is riding it minus his safety virtues
  18. 5-7HEAVEN

    5-7HEAVEN Active Member

    I just rode on that street two hours ago and eyeballed it.:detective:

    The road is fair, with LONNNG patches in the lane he was riding in. It is a 25 mph zone, so he was WAY past the speed limit.

    Wet roads does seem a problem for me, but I ride slower when roads are wet. Haven't had problems with an oil patch yet. HOWEVER, it's those wet steel plates, manhole covers and plastic "reminders" I watch out for.
  19. happycheapskate

    happycheapskate Active Member

    Does anyone know if you can mount a conventional v-belt type pulley on a chainsaw, such as if you have stripped the housing off and the bar? If you can mount a long piece of square tubing to the place where the bar conventionally goes (the two large bolts), I think it might be easier than I thought to make a chainsaw bike, and gear it closer to 30 than 50!

    Small world, when someone can post a bike video and someone says "Hey I know that guy" (or recognize him). I guess maybe when you live on an Island it's like that even more.

    I'm a fan of the staton-drive type, but as far as I know, they aren't compatible with chainsaw engines. If anyone knows different, please redirect me to the proper thread.
    Otherwise I just plan to get a roller drive kit and some standard engine. I've been holding out a really long time for a BmP, but if I get $300 to spend on MB before they resume sales, I'll probably get something else.
    Last edited: Aug 11, 2011
  20. 5-7HEAVEN

    5-7HEAVEN Active Member

    I don't KNOW the guy, but he looks and acts familiar to me.

    Bump start MB's must be a pain to run on busy streets, especially in gridlock. Methinks a lever to raise and lower the engine onto the tire would make this bike more enjoyable.:idea: