Engine size

Discussion in 'Performance Mods' started by raceryan, Feb 27, 2008.

  1. raceryan

    raceryan New Member

    What is the biggest engines and horsepower that some of you all have attached to your bikes. I was looking at some small engines online, and began to wonder... There are so many engine choices out there.

  2. graucho

    graucho Active Member

    Your going to hear a lot of varied comments on this. On a bicycle, mine was a liflan 150cc 4 speed. (approx 5hp) I chickened out at 50mph in 3rd gear. Remember bigger isnt better on a piece of machinery designed to go 20-40 mph max.
    Pick an engine thats easy to get parts, and you can work on it yourself. Have fun.
  3. JemmaUK

    JemmaUK Guest

    Theoretically the sky is the limit - I have seen 50-60cc model V8s that would fit a modified bike frame and put out 6 and a bit horsepower at the crank...

    Then again you could get a tuned single cylinder engine of around 40cc that puts out between 4 & 6 horsepower.

    We havent even discussed 2-stroke vs 4-stroke yet - and then there are the semi-diesels... :D

    The balance is basically durability and reliability against power and sensitivity. The more tuned the engine the less reliable it will be compared to the base engine.

    The largest engine I have had is the 32cc tanaka - and to be honest if I was going to upgrade I would be more likely to go the tuning and fettling route than the cost of building something completely new..

    Jemma xx
  4. kerf

    kerf Guest

    I'm running a 46cc @ a little over 4 hp. It's high reving giving a top end over 40 but I just run between 25 and 30. Save the motor and some of my old hide as well.
  5. weez

    weez Member

    My homebuilt recumbent has a Honda G100, 97cc 4-stroke sidevalve, rated 2.5hp @3600rpm. Will run 55-60km/h (35-40mph) on the flat.


    I've had it up to 74km/h (46mph) on a slight downhill grade.

    I'd never consider going such speeds on a typical upright bike. The steering head angle on an upright (particularly MTBs) is steep so the steering response is rapid for slow speed manoevering. The rapid steering response is a bad thing at twice the design speed- can contribute to speed wobblies.

    My bike has V-brakes, which as rim caliper brakes go, are pretty good. They'd stop my bike from 55-60km/h all day long, but when I was riding it every day, it would eat a set of pads every 2 weeks and require frequent brake cable adjustment to compensate for wear. Rim heating after stopping from high speed was pretty scary. Ran my front tyre at about 85% max pressure, just in case, as it did most of my braking.
    Last edited: Mar 1, 2008