Breaking in a new motor- how do you keep the speed low?

Discussion in 'General Questions' started by B.K. Hosken, Aug 17, 2008.

  1. B.K. Hosken

    B.K. Hosken Member

    I have only had my Dax 70cc for a week, but as instructed, I have kept the speed mostly under 2/3 throttle or so. My question is, how do you DO that!? I find my hand twisting the throttle more and more....I NEED to go faster...18-20mph at 2/3 throttle is KILLING me!! How do you others handle this?! I've only gone about 15 miles, and I really don't see how I can stand another 100 miles of this without freaking out.

    Also, this little engine seems to be underpowered. Does it get more power as you break it in? I don't think this thing will go more than 24-26mph and it's mounted on a skinny-tire 27" bike. I weigh 220, is that what's limiting my speed?
    Last edited: Aug 17, 2008

  2. stude13

    stude13 Active Member

    hi bk; you are doing right. go all out every so often. it will get faster. check all fateners and chain. just do that 15mi. run six more times.
  3. JemmaUK

    JemmaUK Guest

    As stude says - to run in a motor properly you need to run it in by varying the speeds slowly running up the time you use the engine at high or full power.

    The trick is to run in the motor at all speeds since they move differently at all speeds and the wear is therefore different at different speeds.

    You will get more speed as it runs in - its also possible to get different sprokets for better speed - however - more speed equals less torque so you really need to know what sort of roads and routes you'll be using and fit the according sprocket..

    good luck with the bike

    Jemma xx
  4. Skyliner70cc

    Skyliner70cc Active Member

    Just ride the darn thing. Odds are your happy time won't last 3,000 miles anyway.
  5. B.K. Hosken

    B.K. Hosken Member

    Well, I would be happy with 3-4K miles. If I have to replace it I will buy a Robin-Subaru or Honda in a higher quality kit. I just wanted to try one, and see if I use it enough to justify having it.
  6. Pablo

    Pablo Motored Bikes Sponsor

    There is more than one school of thought for ICE break-in.

    Babied too much at constant speed and you glaze the cylinders....and the risk at full throttle is? Hanging on ports? Seizure world?

    The reason for the heavier oil in the fuel at first is to deal with the asperites (basically high spots) on the metal wear surfaces. Anything too nasty from the factory machining will either get welded (seized) right away or get worn down rapidly. With the 16:1-25:1 ratios for break-in, after the first tank, excursions to full throttle for short bursts will no absolutely no harm.

    I have been reading these sites for a year+ now (yeah young timer) and I don't remember too many earlier seizures. I'm sure **** happens, but I wouldn't sweat it.

    Now get out there and ride the thing! Hard - like you stole it. :cool:
  7. Mountainman

    Mountainman Active Member

    It's hard - but - try your best at holding back a little. Kind of wondering about your top speed - sounds like it is going to be low for a 70cc - but - I don't know much about your engine. I have a Subaru - quality engine - but - it doesn't sound like you would be happy with my top speed of 22.5 mph with a 1" friction drive. For now - Ride That Thing - Mountainman
  8. SirJakesus

    SirJakesus Guest

    Hey look at it this way without the motor you'd have to get a very expensive and light road bike and pedal your buns off to keep around 18-20mph. So enjoy the speed and power right now and take the opportunity to enjoy the bike and scenery. Generally as far as federal regs go anyways anything that is motored is not supposed to exceed 20mph without being a motor vehicle and subject to a whole list of legalities. Just remember that once your engine is broken in and you can top out around 30.
  9. Warner

    Warner Member

    The more times I ride my bike to work, the more I realize that if my bike were only able to do 20 mph it wouldn't really be feasible to take it 20 miles each way. I'm averaging about 28 mph on my commute (when I'm moving) and the entire trip takes me between 45 and 50 minutes. Totally feasible for a commute. If it started taking over and hour (and especially if it took me an hour and a half), I probably wouldn't do it anymore. I'm cruising between 32-35 mph on my ride in. 20 just wouldn't cut it.

  10. B.K. Hosken

    B.K. Hosken Member

    Well, it must be breaking in, because now that I have 25miles on it, it's got more power, running smoother, and top end is 30mph, (may be a little higher, but I'm limiting anything over 20mph to 30 seconds or less). I think this little engine will be GREAT fun, and I may actually use it practically. I really need to get a beach cruiser or something like that, and put a rack or a basket on it. Not cool, but if it can't carry at least a bag of groceries, it's a toy. Right now it's on a skinny tire ten speed (only thing I had). The advantage is the gears are on the headset/gooseneck so I didn't have to remove or modify them, but I don't use them anyway so a beach cruiser is on my list. More comfortable upright riding position.
  11. computergod2001

    computergod2001 New Member

    handle bars

    put some bmx handle bars on your bike then your sitting up i have them on mine very comfortable i would never use any other handle bar
  12. webbee

    webbee New Member

    I couldn't agree more. I've done BMX bars on mountain bikes for city crusing. Should work just great on a motorbike.
  13. Warner

    Warner Member

    You could make a rack and mount some panniers (saddlebags) like I did...and keep the skinny tire ten speed. I was using 1.25" tires and it was fine. Here's some photos of my bike with the panniers....engine essentially hidden:

  14. happycheapskate

    happycheapskate Active Member has awesome riser/cruiser bars for $15. I have them on a pro mountainbike with a 50mm stem, and I love it. They are a little higher than the seat now. I used to have flat bars but got tired of sore back and muscle aches from off road maneuvering. Now I feel like i have more control.

    My MB has generic bmx bar on it at the same height. Nice to switch between the two now.

  15. professor

    professor Active Member

    Thanks for bringing up this older post. Cool how that engine is hidden on the road bike!
    I find the mountain bike position hard on my back, so I made some that come up and back.
  16. happycheapskate

    happycheapskate Active Member

    Thats great. If you want to hide the battery, there are those famous little $15 roll bags, or cheap motorcycle handle bar bags, or even "men's travel bags", like you would put a shaving kit in. I'm going to use a lunchbox for now. I tried a tool bag, but it would rub on the front tire.

    Dollar stores have little zip bags that is the perfect size for a 7AH 12v battery.

  17. AussieSteve

    AussieSteve Active Member

    Back on the subject of running in. I think that everyone is right.
    I'm generally an advocate of following the manufacturers instructions, then you can't go wrong, (most of the time).
    Having said that, an engine will do most of the important running in a very short time. As mentioned by Pablo and Jemma, running the engine at WOT for short bursts won't hurt anything. It beats running it constantly at low RPM under low load and allows the parts to settle in under normal operating conditions.
    The run-in follows an exponential curve, with a rapid change initially and the rate gradually slowing.
    Be a bit careful for the first tank or two.
    I pulled my top-end down a couple of weeks ago after 280km and the top ring was beginning to bed in, but the bottom ring looked new, so they take a while to settle. Everything else would be pretty right by now.
    330km, (206 miles), so far and counting.

    To keep your speed low, just ride up steeper hills.

    ... Steve
    Last edited: Dec 7, 2009
  18. flashstar

    flashstar Member

    It's tempting to fly down roads with a slight down-slope at 26+ mph, but I too have only 100 miles on my engine now so I try to keep it to a 22 mph cruise speed and 17 mph uphill speed.

    I try not to worry about keeping the engine under a certain speed at all times. Rather, I just vary the engine speed constantly. Even while going up hills, I vary the speed from full throttle to ~1/2 throttle.

    Although I don't know if this is true, try to blip the throttle when going downhill with the clutch out.
  19. Al.Fisherman

    Al.Fisherman Active Member

    Not to be funny, but don't twist the throttle full open. Take many short slow trips and enjoy the ride. I'm surprised at 220# that a stock set up goes 24-26 MPH. I don't want speed but I can get 27 out of mine if I'm so inclined and I'm 200# and not fully stock...boost bottle, and a thin head gasket.
  20. happycheapskate

    happycheapskate Active Member

    How do you know when its "broken in"? I don't like puttering. I want to run this sucker like a chainsaw and get somewhere!