Overall...When these are running properly..are they as safe.

Discussion in 'General Questions' started by kamikazi_kostka, Jan 10, 2007.

  1. As say...a moped for riding in the city traffic?

    I want something that I can do 35 mph on, I AM willing to wait for break-in, but I want something that can do 35 mph safely on.

    Will this bike work for it? Will I need to get the 36 tooth Sprocket?

    How safe will my bike be? I have a V-brakes, are they safe enough to stop me from higher speeds? Or not.. The thing is, there are roads here labeled 35 mph, and I would like to keep up.

    Thanks for your info. I already have the kit and I am assembling it currently. I use to have it on another bike, but it would take forever to start, and throttle went in and out as it pleased. I want something reliable, and granted I changed the positiion of the carborator and stuff.

    I have a small motor mechanic who repairs cycles, mopeds, snowmobiles, dirt bikes, and atv's that is willing to look at it and fine tune it. Would you trust it to be safe if I keep it in good condition?

    Can I get it to idle properly?

    I am still confused about how idling works on this motor. If I peddle it up to speed, and pop the clutch, and the motor starts, then if I approach a stop sign, should I just leave the clutch out and motor engaged? Should it stay idling, and then I can just twist throttle and go? or do I need to pull the clutch lever back in, (usually when I did this, engine just turned off...didn't idle), and then peddle back up to speed and pop clutch again?

    I don't know what I am looking to do.

    Any comments would be greatly appreciated, and btw...my kit is on a Schwinn High Sierra 26" Mountain Bike.

  2. gone_fishin

    gone_fishin Guest

    these things are very much like motorcycles, some mc experience is alway helpful but not necessary.

    the clutch is either "engaged" ie the torque is being applied from the engine to the rear wheel, or "disengaged" ie the engine is idling but not driving the back wheel. let out the clutch-lever to engage, pull the clutch-lever to disengage.

    to start the bike: disengage the clutch, start pedaling up to speed, pop the clutch (rapidly engage it), the torque from the rear wheel will turn the engine over and start it running.

    to take off under power: start pedaling, increase the throttle while slowly engaging the clutch. this WILL get easier to do with experience.

    to stop or slow down: decrease the throttle, disengage the clutch and lock it, use your brakes to slow down or stop.

    to idle in place: disengage the clutch and release the throttle, lock the clutch lever for extended stops.

    now, another thing about a motorized bicycle being like a motorcycle is USE YOUR HEAD: be safe, don't go faster than your brakes can safely stop you, always assume you'll need to stop NOW. in traffic, that's the only way to be...save the wilding for open roads.

    TIP: disengage the clutch while slowing or stopping. only an experienced rider should use the engine as a braking force, these 2-strokers easily stall under hard braking and will stop you on a dime. guess what, then? hint: an aerial view of your handlebars usually means you just flew over them, get ready for an owie :eek:

    hope that was helpful, if i missed anything, someone else will surely fill you in 8)
  3. Thanks for the insight.

    The issue I had is that my engine would never idle.

    When I would pull the clutch lever in, it would just totally kill engine, so I would have to take off from a dead stop.

    I am just curious, if it is idling with clutch disengaged (pulled in) at a stop sign, can you just then put out the clutch and accelerate, or do you need to pedal? If the engine is already running, can you start from stand-still, or do you need to peddle up to 5 miles an hour again, and pop clutch?

    I mean I know if you peddle, much faster acceleration, but it is required to start moving?

  4. Yes it does idle at a stop with the clutch disengaged. Since there is no real transmission with gears you do want to pedal up to about 5 MPH and the let out the clutch even when taking off from an idle.
  5. bird

    bird Guest

    you can get up to about 30 with a stock 55cc, maybe 35. i have a completely stock 80cc kit on one of my bikes and it goes about 30 to 35 easy. i ride in traffic almost at a daily basis on my other bike with a 36t sproket and can get up to 40 to 45, i beat cars accross town or most of the way there, rush hour there isant a chance to keep up with me.
  6. gone_fishin

    gone_fishin Guest

    as i recall, the idling problem was about having the carb sideways, correct?

    well, when built right, they will idle very nicely, screw the idle screw all the way in, then back off about 4 turns, that'll get ya started, then tune the idle for your conditions.

    when stopped and idling, simply start to pedal & as you gain speed you can slowly (or quickly, hehe) hit the throttle & release (engage) the clutch.
  7. ok well maybe this is why I'm having my engine locking problems because sometimes I stop at a light or stop sign, pull in the clutch, then just pop the clutch and revv up the throttle to get going again - I don't always peddle to get started again...
  8. gone_fishin

    gone_fishin Guest

    that's a real possibility, 'sideswipe, your feet have to be 1st & 2nd gear 8)
  9. Do they make left-side derailers?

    Cause if so..that would be the most kick ass motor bike ever.

    Flip a bicycle tire around, rather than have the 44 tooth sprocket, and then just have a shifter. It would have 5 gears, that would kick ass. No pedaling required then. :)
  10. there has to be a way to rig up a left side gear but it doesn't seem safe to me now that I think about it - my bike gears slip out all the time but at 5 or 6 mph not at 30 mph...
  11. psuggmog

    psuggmog Guest

    There is a type of hub currently used on some fixed gear(no freewheel, no coasting, cranks always turning when the bike is moving)bikes. This is the way the very old and current track bicycles work. Some freaks like me ride these kind of bikes around on the road too. The track bikes have no brakes except the resistance of your legs against the inertia of the bike moving when you want to slow down. I posted a picture of one of my fixies in my bike&bikehaulers post. Some people install a front brake for road riding. This type of hub is threaded for mounting a sprocket on both sides of the hub. Some hubs are threaded for fixed gears on both side and some are threaded for a free wheel on one side and a fixed gear on the other. To change gears you stop the bike, remove the rear wheel and turn it over and reinstall with the different sized cog now engaged. I thought about using one of these hubs on my motobike. Mount the motor cog on the left side.(the fixed gear threads onto the hub and is kept for unscrewing during legbraking with a reverse threaded lockring). A conventional freewheel single or multigear threaded on the right side. I tried a grubee supplied 44 tooth gear on one of my flipflop hubs. The hole in the center of the chainring is a larger diameter than the threaded gear mount on the hub so an adapter would have to be made. You could use the regular rubber spoke-grab system, but there would be no point in wasting a flipflop hub that way. Here is picture of a 1940s-50s flipflop hub on one of my fixed gear bikes. The two cogs have a different number of teeth. Change gear by flipping the wheel. These hubs work best on bikes with slotted rear dropouts so that the chain can be tensioned properly for both sized gears. Some hubs have giant wingnuts on the axles.



    Some people who have single speed fixed gear bikes reverse the bottom bracket spindle and put their chainring and crank on the left side. If you hooked to motor drive chain to a freewheel on a rear hub you wouldn't be able to compression start the motor because the rear wheel would just coast without turning the hub gear.
    Last edited by a moderator: Jul 14, 2008
  12. psuggmog

    psuggmog Guest

    left side gear more thoughts

    If you want to use a freewheel on the left side of a bike the ratchet would have to be the opposite of a regular freewheel, otherwise it would work for pedalling backward and freewheel going forward. There are leftside freewheels for BMX applications, but I think they are single speed.
  13. Wheels

    Wheels Guest

    Why not mill a strong what ever size sprocket you desire out of a BMX front sprocket for the motor drive side of the hub? some designs are very close to a motorized style.


    Last edited by a moderator: Jul 14, 2008
  14. psuggmog

    psuggmog Guest

    bmx chainwheel

    I thought about doing just that. I will probablly use a disc brake rear hub instead of a flipflop hub. I was thinking of drilling slightly oversize holes in the sprocket to match the disc mounting holes on the hubflange. then line the oversize holes with rubber grommets or pieces cut from rubber tubing with the I.D to match the mounting bolt size and the O.D. to match the sprocket mounting hole. This would allow a little give and decrease the shock load on the mounting bolts. I have a nice heavy duty hub with sealed insert bearings I plan to use.
  15. jlebh1

    jlebh1 Member

    My old 80cc kit got past 60kmp/h which I think is 40mp/h?