I want more acceleration - not top end - ideas??

Discussion in 'General Questions' started by CARROT-The DESTROYER, Oct 25, 2008.

  1. Hi,

    All the threads I come across seem to talk about top speed.

    I want to get up to average speed faster.
    I'm getting bored w/ the slow acceleration of my bike. - which is actually pretty good for a stock bike - no hesitation at all - but want more.

    I want your ideas.

    I live on a steep hill, so smaller sprocket is not an option.

    Looking for the cool mods that worked that you want to share

    Changing the air filter - pointed to the front for a ram air system?
    read about beer can conversions - but didn't really cover what the changes did to the bike that much.

    Best ideas for a muffler that helps acceleration w/out damage to a 2 stroke.
    creating a glass pack type muffler - that has straight through exhaust but still has sufficient back pressure?
    heard stories about packing the pipe w/ steel wool- but can't find it now.

    Best idle pin location on the notches that may increase acceleration w/out over-leaning the motor? - mine is at 2nd to the top.

    Read about the "bottle" - but never found any conclusive evidence that it actually works.

    I know there are many individual threads that talk about different performance enhancements, but I have not been able to locate a complete -
    step by step:
    "how to increase your overall off the line performance" manual that covers all areas of performance enhancements.
    A manual like this would let a builder know how well the different performance mods work when integrated together to create "one" - complete performance package.
    That would be cool.

    So throw out your best, and see if we can make one complete thread for this topic.

    Thanks,

    Troy Fitz.
     

  2. spunout

    spunout Member

    actually, you said you dont want a "smaller sprocket" .....a smaller sprocket will give you more top-end, but will actually slow your acceleration.
    what are you using now? if you're running a 44-tooth, switch out to a 48-tooth. you'll get up-to-speed quicker, and that'd be better for hill climbs.
    the downside, is that your flat-out-wide-open top speed will drop a little.

    i pulled the baffle out of the exhaust, my intake port was dremmeled, and my friend jay handmade an intake to fit a carb from an XR80. i gained a ton of acceleration with that combo. i have MAD power, and i'm running a 36-tooth

    EDIT: what about a tuned pipe? look for andyinchville in the members list. they make them. he could give you a better idea about the performance benefits.
     
    Last edited: Oct 26, 2008
  3. Mountainman

    Mountainman Active Member

    gearing change -- starting point ?

    carrot -- this was my first thought also
    gearing down a little -- will get you to speed much faster
    but - as you know - to be taken into account
    you will lose a little of your top end speed

    before making or thinking about a lot of other changes
    this for me anyway -- would be my starting point

    ride that MB thing
     
  4. Hi,

    Shave the head to raise compression....this is a nearly free way (if you have the materials to do it with) or low cost method to raise power....A tuned pipe will help also but it is more expensive....

    Hope this helps.

    Andrew
     
  5. hill climber

    hill climber Member

    take about .040" off the head.
     
  6. Great idea about shaving the head!

    Don't know why I didn't think of that. I had the heads resurfaced on my REX, So it should work the same way on the bike.

    I assume any machine shop should be able to do this.
    Any changes in the octane? - since basically it's raising the compression.
    I had read that higher octane is a waste of money for a stock 2 stroke.
    I have been running 85 octane - think I should increase that?

    What about the spark plug? - It would run hotter, so is a shorter plug in order now? - or not enough to really make a difference?

    Yeah, got the gearing a little mixed up -

    top speed - smaller 36

    acceleration - larger - 48

    got it.

    I am working on a side mounted air cleaner that would get direct air.
    Pretty excited about how it will work - and look. I am using an extra chrome breather cap I had that didn't work on my 5.0 engine.
    I'll show pic's when closer to the completion.

    "spunout"

    "i pulled the baffle out of the exhaust, my intake port was dremmeled, and my friend jay handmade an intake to fit a carb from an XR80. i gained a ton of acceleration with that combo. i have MAD power, and i'm running a 36-tooth"

    Wow! - I am intrigued! - questions.
    OK - so did you basically just do a match port to the intake tube and head?
    I noticed they were very different. I would think getting better air flow w/out all that turbulence would make a huge difference.

    Regarding the custom intake - that is exactly what I was looking at, but I was not sure if it was too long it would negatively effect the performance gain i was looking for.
    I wanted to have it bend at a 45 degree angle to create more of a side draft set up - direct air. Which to me would equate to providing more air mass, less heat, and greater power - if done right.

    When pulling out the baffle, I have heard bad things can occur. The motor needs the back pressure to operate w/out eventually burning up. Have you taken any precautions, or have you not had any problems with it?
    That's why I was looking for the thread on the steel wool muffler.

    Any pic's would be appreciated.

    thanks for the feedback so far.

    Have some good ideas, but wanna see what else is out there.

    Troy Fitz.
     
  7. BoltsMissing

    BoltsMissing Active Member

    Before you go to "major surgery", shaving heads etc, try these first,

    1. Electrics
    Change copper plug lead with a better quality copper lead.
    Change Spark plug, NGK B6HS, Gap .025" as a base starting point
    Plug Cap, NGK has a better qulaity plug cap

    My personal bike does not have kill switches, I simply stall the bike or use the choke, but that's a personal choice.
    Change Magneto to CDI wire crimps with quality crimps and use solder.
    My persoanl bike has no crimps, soldered all in 1, personal choice.
    -----
    2. Exhaust.
    Make exhaust gasket the same shape as the engine's exhaust port.
    ----
    3. Carby.
    Same, make the gaskets the same shape as the inlet port where the "manifold" joins onto the inlet port.
    Seal the carby where the clamp goes on, with oil resistant plumbers thread tape, seal the thread tape with hard setting gasket stuff, and place the clamp back on after it has set. This limits the air leak due to the way it's made.
    ----
    4. Fuel
    95 octane....., we have here 92,95,98.
    ----
    5a. Oil mix.
    ??? your choice, but use hight quality 2-stroke oil. It's trial by trial.
    5b. ratios
    20:1, 25:1, 30:1, 32:1
     
    Last edited: Oct 26, 2008
  8. Mountainman

    Mountainman Active Member

    to - CARROT THE DESTROYER
    I was just checking back to see all of the comments to your thread
    man -- good stuff comes in very fast on this site

    so as not to get -- far ahead of yourself -- I would

    take into account BOLT'S recommendations first -------- #1
    why spin your gears -- if you know what I mean
    I believe what BOLT'S trying to do here is
    help you with the basic known (weak points) known to your set up -- engine

    once we get the basics down -- then we may move on
    ya - easy for me to tell you all about it - but - admitted - not my strong point
    but - one day at a time - working on it - as I

    ride that MB thing
     
  9. hill climber

    hill climber Member

    when milling the head that much it is going to up the compresion quit a bit.possibly causing detination or a ping. higher octane fuel is in order as well as a cooler spark plug. 85 octane go to 91, ngk b5hs go to ngk b7hs.
     
  10. srdavo

    srdavo Active Member

    I had a head milled .030

    the results were NOT good.

    granted, it ran much stronger......but the added power also added more vibration. On the 1st & only ride, crazy things vibrated loose.....engine studs....the small gear on the crankshaft (right side), mangling the key & the keyway slot on the crankshaft.
    IMO.....you can't really beef up these chinese engines.
    they are, what they are.
    stick with larger sprockets for lower gearing & you'll be okay.

    my $0.02
     
  11. hill climber

    hill climber Member

    i cant agree with that. i have 500+ miles since, milled .040" from head, .015 thiner head gasket, .015 thiner cylinder base gasket. total removed .070". there is a noticable differance with less vibration, smoother idle, more power all the way up from idle. i also opened up the intake and exhaust ports on the cylinder. i love it and will never do another install of an ht without first doing all the mods i have done to this motor. by the way its a powerkingshop 80cc roller bearing kit off ebay.
     
  12. ok -
    first:
    "1. Electrics
    Change copper plug lead with a better quality copper lead.
    Change Spark plug, NGK B6HS, Gap .025" as a base starting point
    Plug Cap, NGK has a better qulaity plug cap"

    I have seen this upgrade many times, but when looking at my CDI, it's basically a sealed unit - I have not been able to figure out how to open it "knowing" I won't damage it. All the posts state to change it out, which I can definitely see the advantage of doing, but can someone explain "how to" open the CDI - feelin like a noob, but want to know.

    "Exhaust.
    Make exhaust gasket the same shape as the engine's exhaust port."

    Already done for the most part - the original leaked the first few rides. Made my own out of automotive gasket material.

    "Seal the carby where the clamp goes on, with oil resistant plumbers thread tape, seal the thread tape with hard setting gasket stuff, and place the clamp back on after it has set. This limits the air leak due to the way it's made."

    I noticed the importance of this when my bike started bogging when going up my steep hill. When I got home, I went through the motor trying to figure out what changed. And that was it. The carb clamp was not loose, but not tight either. As soon as I re-tightened it, the bike goes up the hill no problem again. Simple vacuum leak - makes sense, and great suggestion to seal it up. I used electrical tape to do mine, but didn't think of the gasket sealer to make sure it's leak proof.

    I am currently using a 20:1 ratio, but when hit 400 miles, I was going to switch to 32:1 - a very comprehensive article I read stated that was the best all around ratio. That should increase the power slightly I'm sure.

    SRDAVO - thanks for the heads up. - no pun intended:grin: - that is something to keep in mind for sure.
    Anytime you upgrade one part, pretty much have to do everything else so you don't have that weak link show up.

    HILL CLIMBER
    when milling the head that much it is going to up the compresion quit a bit.possibly causing detination or a ping. higher octane fuel is in order as well as a cooler spark plug. 85 octane go to 91, ngk b5hs go to ngk b7hs.

    Have you already machined your head and talking from experience? - or is this useful advice you have read about elsewhere?
    I like dealing w/ people talking from first hand experience on these kinds of matters.
    If you have already done this process, what did you have to do to strengthen the motor to handle the additional horsepower gains?
    Did you go .30 or .40 on the head?

    Still curious on the muffler mods. If I create more air mass into the engine - I need to have a muffler to exhaust it as quickly.
    If anyone has the steel wool thread - I would appreciate a link to it.

    Again, thanks for the input, this is the kind of stuff I want to hear about.

    Other ideas?

    Troy Fitz.
     
  13. spunout

    spunout Member

    OK! actually, the porting wasnt 'matched' perfectly, per se. just made the port bigger and rounded. sorry for the blurry photo. if you notice, the intake doesnt have that sharp bend (thats a good thing)...its pretty straightforward (straight is good....bends decrease flow) all the way down to the jug, and its not any longer than stock.

    some people SAY that taking the baffle out is bad. in the 5years ive been doing this, i've taken the baffles out of all my personal bikes, and have gained mondo power, with zero negative effects.
    two of my bikes have over 12,000 and 14,000 miles on the motors. never had problems worse than replacing gaskets, which brings me to another thing: i tear out the paper gaskets between the jug and base, and replace it with a thin bead of silicone...that increases compression, also.

    perhaps, what i do goes against many mechanically correct (or thought to be correct) ways of doing things. i'm just telling you what works for me. :evil::evil::evil:
     

    Attached Files:

    Last edited: Oct 26, 2008
  14. hill climber

    hill climber Member

    im speaking from experiance. the motor is currently on the diy chopper that i ride to work 130 miles a week. i took .040 off the head and used a .015 thinner head gasket. i did nothing to the motor to handle the increased power, what can you do to the ht? i also ported this cylinder, opened up the intake and exhaust, well lower the intake and raise the exhaust but didnt mess with the transfer ports.have a #79 jet in the carb but i think it needs a #78 and a home made/rolled expansion chamber, way better than stock exhaust. runs a bit warmer than stock but havent noticed any ill effects after about 500 miles since mods and over 1000 miles on the motor.a month ago i was riding in 100+ degree temps and one hill is 1 1/2 miles at 6%, at least the sign says so.
     
  15. BoltsMissing

    BoltsMissing Active Member

    I
    No need to "open up the CDI", trust me on that one !
    To remove the plug lead, it simply unscrews. You will notice the copper is soft. The right plug leads have a diferent grade of copper and carry the voltage far more efficiantly with less resistance. Same goes with plug cap and all other electrical wiring that has anything to do with ingnition side of things.
     
  16. Tinker1980

    Tinker1980 Guest

    There might be some confusion here... over here in the states, we use the (R+M)/2 rating for fuel. It's an average of the RON (Research Octane Number) and MON (Motor Octane Number - used in aviation, tested under load) and as a result, there is a lower number for the same grade gasoline. 92,95, and 98 octane, in Australia and most of the world is the same as the 87,89, and 92 that we have in the US and Canada.

    Why is it that way? dunno. Americans are weird. We never can decide what measurement system to use. Distances are measured in miles, buildings are designed, built and measured in feet, Soda is sold in 1 liter, 2 liter, and 20 oz bottles while milk is sold in quarts and gallons, and I could show you a very well built pickup truck that needs both S.A.E. and Metric sockets when changing the clutch.

    Whew.

    -Mark
     
  17. BoltsMissing

    BoltsMissing Active Member

    Well, I dunno either, but we also have color codes at the pumps.
    I know the one I use is yellow, at the BP pumps for 95, I think.
    What are your color codes at the pumps ?
     
  18. Mountainman

    Mountainman Active Member

    a known fact that people DO NOT like change

    reason - we just have never complectly made the change over
    from American (S.A.E.) to Metric sizes
    it's been an expensive, hassle of an endeavor
    change over first decided on in the 1950s ???

    looks like it may take another 50 years to finish the change over

    it's really not true what we hear on tv
    it's a known fact that people DO NOT like change
    just one reason why it has taken so long to switch to Metric
    and never to forget - the cost has been out of this world...

    ride that MB thing
     
    Last edited: Oct 27, 2008
  19. Tinker1980

    Tinker1980 Guest

    The pumps here are (usually, not always) blue for 87, silver for 89, and gold for 91-93. Green for diesel, and yellow for E-85.

    Back to the original question... sorry bout that...

    I wouldn't waste time trying to hot-rod these little engines, unless you want to buy more little engines. For more acceleration, look no farther than a 48-50 tooth gear, as a few others have said. If you get another back wheel, you can put your larger gear on it and keep the old one for an easy swap. If you want to get REALLY fancy, spread your front fork, and put your other back wheel up front - keep 2 chains appropriate for the differing size gears, and you can swap ratios in minutes.

    -Mark
     
  20. PatrickW

    PatrickW Staff Member

    More Speed......


    ************************

    I am glad I wandered in...frankly Pal, I woul throw away all of the fancy carbs, boost bottles, and J.C Whitney type HP boosters. Polish and port the engine with your dremel; put an a good quality, open muffler w/insertible baffles for town; and, let 'er RIP"! If you can, find someone 'really good' to port out and polish the carb (they are few and far between now days, except on The Left Coast),..otherwize, leave it alone...don't fuss with the jets unless ya know exactly what you are doing!. You should have a Top-Notch set-up at a very reasonable cost. Do anything else with drive geara. They are actualy cheap, and quite easy to swap, at least in my case. Questions? Just ask again.
     
    Last edited: May 8, 2010
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