Not getting the full potential from modifications

Discussion in 'Performance Mods' started by Ibkukin, Jun 3, 2015.

  1. Ibkukin

    Ibkukin New Member

    This is the third bike I've built and I feel like I have a pretty solid set up. It's very smooth with considerably less vibration than my previous builds. However, I feel like I should be getting a little more top end than I'm getting. Here's the list of what I've got:

    -New Micargi Rover GT
    -Standard issue Chinese engine kit, 80cc
    -Aftermarket expansion chamber with matching exhaust port gasket
    -upgraded chain tensioner
    -Billet rear sprocket and mount, 32 tooth
    -Upgraded performance carb
    -CNC aluminum intake manifold matching the port and gasket
    -Boost bottle
    -CNC Aluminum front motor mount
    -NGK cooler range plug

    Here's the problem. At higher RPMs the motor almost sounds like it's hitting an electronic rev limiter and just runs flat when it should be reaching the top end of the power band. It's relatively flat where I live so there are no hills, which is why I have the small rear sprocket. I feel like I should be turning more RPMs than it's getting. My other stock motor seemed to rev higher. I feel like with the tall gearing I should be able to easily hit 30MPH but it isn't happening.

    What is the next step in performance mods? Can this carb be jetted differently? Is the upgraded CDI worth the money? Should I buy a ported and polished cylinder and high compression head?

    What are the next logical upgrades to get me to the next level?

    20150603_173658.jpg 20150603_173708.jpg

  2. Ryusei139

    Ryusei139 New Member

    Is your carb properly jetted. I have same bike with special expansion chamber, hd lightning cdi, rt carb, dax high comp head (puch clone), 36 tooth, mild porting. I have a top speed of 41.4 GPS verified.

    Attached Files:

    Last edited: Jun 3, 2015
  3. jaguar

    jaguar Well-Known Member

    nice looking pipe (1st photo) but horrible design. throw it away.
    put your stock pipe on till you get the bike set up for the speed you want and then you can try different pipes. (that is because the header length has to be varied till you can feel that the pipe powerband matches the rpm range you want)
    play with different jet sizes till it runs really good.
    get a good aftermarket CDI.
  4. Ibkukin

    Ibkukin New Member

    Good advice on the pipe, I can't say that I really noticed any difference over stock. Is there any particular brand of CDI that you recommend? Also, where should I start with the jetting?
  5. butre

    butre Well-Known Member

    the jaguar cdi and the hd lightning are both great, the lightning has more advanced timing for race motors or motors with lower compression while the jaguar is a bit more streetable. I believe they're both based off the same design.

    what's your elevation? in my experience most motors want a 66 or 68 jet
  6. Ibkukin

    Ibkukin New Member

    I'm in New Orleans so basically at sea level. The cylinder and bottom end are both stock. The carb is one of those eBay performance carbs, not sure the type/brand. I also have a boost bottle on it.

    This one had good reviews. Looks like something he's putting together from other parts.
  7. butre

    butre Well-Known Member

    I'm just up the road then, I live in Biloxi, MS, also a sea level city. a #66 or 68 will probably be right for you, depending on the particulars of your engine
  8. HeadSmess

    HeadSmess Well-Known Member

    getting plenty of answers to steer you in the right direction, but the question was answered in the first reply...

    those four teeth make a difference. i wouldnt use less than 36 on 26" wheels...

    28-33 was good on 20"...
  9. butre

    butre Well-Known Member

    yeah 32 tooth should be reserved for 24 inch and smaller in my opinion.
  10. Ibkukin

    Ibkukin New Member

    I stand corrected. I do have a 36 tooth sprocket. I put the new CDI on yesterday and no improvement whatsoever. Also, my carb came without extra jets and no one will sell me jets alone without buying a carb.
  11. desertsteve60

    desertsteve60 New Member

    The jets in those carbs are standard 5mm(DelOrto) you can find on ebay or you can go to, do a search for delorto jets and they will sell you any size you like. either in groups or individually. I think thatsdax sells them also.
  12. Slogger

    Slogger Member

    SBP has them, too. $2.50 a piece but the shipping adds up, buy several at once to save some money.
    You could also get a set of numbered drills and a soldering pencil and do it yourself.