NRG WONT REV UP!!

Discussion in 'The Workshop' started by Jay_Jay, Nov 15, 2011.

  1. Jack mallett

    Jack mallett Member

    Messages:
    46
    Hi, got a nrg 2006 liquid cooled, brought it as a little project.it has a sport exhaust on and should be fully de restricted but still having trouble getting it to stay between 7000-9000rpm which is what I need. It gets to 30mph then stops revving as high and goes down to 5000-7000 rpm which won't give enough power to give me the speed I want. Has any one got any idea what the problem could be, I've already adjusted jet to 60 and rollers to a 6.3g!!
     
  2. Tamiyacowboy

    Tamiyacowboy Pippa's Owner

    Messages:
    1,850
    Rides:
    Piaggio Skipper
    Cdi restriction kicking in ?

    most modern bikes are restricted in the cdi to stop it going over a certain rpm value, when the bike reaches the value the cdi starts to pulse the spark charge so the rpm falls back, when it hits a acceptable range the cdi stops limiting the spark pulse.
     
  3. Jack mallett

    Jack mallett Member

    Messages:
    46
    It's a 2006 plate would the cdi still be restricted? I've had new spark plugs but as soon as it gets to 30mph even tho it is still deestricted in the exhaust and has been upjetted it's still lowers the revs and goes back down to 28mph unless I'm on a hill it keeps the revs high and I can push 46moh out of it!?
     
  4. Tamiyacowboy

    Tamiyacowboy Pippa's Owner

    Messages:
    1,850
    Rides:
    Piaggio Skipper
    still possible the cdi , BUT if your going down hill and the rpms are getting higher it says its not the cdi but something else.
    what weight rollers were in it before you changed out ?
    have you adjusted the midrange needle setting ? (1/4 throttle to 3/4 throttle is not the main jet but the needle setting inside the throttle slide , move down one notch to richen that midrange a little see if that helps, if not reset it back to its original setting before you adjusted it )
     
  5. scubabiker

    scubabiker NITROJUNKIE

    Messages:
    7,321
    Are you sure the variator ring has been taken out? Sounds like its restricted to me.
     
  6. Jack mallett

    Jack mallett Member

    Messages:
    46
    Variator ring has been taken out, I've been pushing 46mph max and I'm quite heavy, i will try changing the needle setting and get back to you cheers
     
  7. Tamiyacowboy

    Tamiyacowboy Pippa's Owner

    Messages:
    1,850
    Rides:
    Piaggio Skipper
    yes but this is 46mph down a hill , you should be atleast getting 40'ish on a flat .

    most folks think you stuff a bigger jet in and everything is plug and play, your bike then gets more fuel and its all eggs and bacon, this is NOT true, with an upjet you have to also remember the main jet only comes into play when the throttle is fully wide open, so the slide needle may need adjusting to make sure your not running lean between 1/4 throttle and 3/4 throttle ranges.

    you may also find with an upjet your idle goes out of whack and again this needs to be reset/adjusted to. so i also advise you do this adjust the idle so when your not on the throttle you have a stable idle without throttle.

    when you twang the throttle you dont want it to hesitate before it picks up rpm ie a pause then the rpm gains , you want smooth transition from idle to rpm gain without a pause / bogging / spluttering
     
  8. scubabiker

    scubabiker NITROJUNKIE

    Messages:
    7,321
    But on the flat its 30
     
  9. Tamiyacowboy

    Tamiyacowboy Pippa's Owner

    Messages:
    1,850
    Rides:
    Piaggio Skipper
    yeah scuba's , hes pushing 46 down hill in over rev but its barley pulling 30 on a flat , he running 6.3g rollers and upjetted to a 60.
    im thinking its a mid range issue the needle slide a bit lean so its holding back , but on a hill he's pushing past the lean on a wide open throttle and the mainjets coming into play.

    its either to small an upjet - a poor midrange needle setting , and a slight misjudgement on roller weight
     
  10. scubabiker

    scubabiker NITROJUNKIE

    Messages:
    7,321
    Thats a restriction. Stevep will agree. 28mph on flat ground is what restricted bikes do....
    Downhill doesnt count as they cant test that on a dyno when restricting a bike in a factory...
    Unless it was doing more before?
     
  11. Jack mallett

    Jack mallett Member

    Messages:
    46
    On flat ground it ranges from 28-43 but it just can't seem to rev high enough sometimes to get the speed but sometimes it keeps the revs high and gets higher speeds so I don't think it would be a restriction unless it was in the cdi. I will try adjusting the needle and see if that effects it
     
  12. Tamiyacowboy

    Tamiyacowboy Pippa's Owner

    Messages:
    1,850
    Rides:
    Piaggio Skipper

    hold on a min , what rollers were installed before you swapped out to the 6.3g ?
    also what pipe is installed on this bike ?

    to heavy rollers will manifest as a fairly high top end speed but takes years to get there, or a stall out at a certain speed, as the pipes unable to release its power before the variator is fully closed.

    PIPES: exhaust pipes have a powerband spread, this is where the power from the pipe kicks in , some pipes have a somewhat larger spread from say 8000rpm to 9600rpm , where others like a leo vince tt has a powerspread from 8600 to 9000 and thats a very short area wher ethe powers delivered and that also means a newbie tuning mistake with to heavy rollers will not release that power from the exhaust, because the rollers are not closing the variator in time and not allowing the variator/motor to reach a high rpm value.
     
  13. Jack mallett

    Jack mallett Member

    Messages:
    46
    The rollers before were much heavier I don't know the exact weight but it would barely budge, it has a technigas qtre exhaust I don't know when the power band kicks. I'm finding it hard to describe the problems I'm having.

    Basically it will pull away quite slow and after easing on the the throttle it will pick up and rev at around 7000-7500rpm then I give it full out throttle and it will splutter and juder along until it finally kicks in and produces just over 7000rpm.when I give it full throttle it completely cuts out the acceleration until the revs pick up?!

    I had my friend give it a ride and he said that it is dodgey and he can't think of why it does not give a nice smooth acceleration like it does between 1/4 throttle and 3/4 throttle. He said it may have been the cdi and the spark not giving eveough spark or something but I have had a new spark plug fitted in the last 3 months
     
  14. scubabiker

    scubabiker NITROJUNKIE

    Messages:
    7,321
    Hows the top end? By witch i mean when were the rings last done?
     
  15. Jack mallett

    Jack mallett Member

    Messages:
    46
    Have no idea I havnt looked and I've had the bike almost 6 months now
     
  16. scubabiker

    scubabiker NITROJUNKIE

    Messages:
    7,321
  17. Jack mallett

    Jack mallett Member

    Messages:
    46
    Ordering a derestricted cdi this week will get back to you all when it's fitted and I'll see if there's still problems, I appreciate the help guys I would have been buggered if not for all these ideas
     
  18. gilly_runner

    gilly_runner Member

    Messages:
    180
    Rides:
    Gilera runner
    Jack your rollers are too heavy you should have around 5g rollers 6.3g is way too heavy. It should go fine with lighter rollers it may want upsetting to 62, If the bronze plate has been removed from the mouth of the carb it will need a even bigger main jet roughly in the 68 to 72 range.

    A standard cdi is not restricted by revs I've had a standard cdi reving to 13,500rpm with my Yasuni c21! All these generic replies it's sad to see how bad this form has got anyone with any history with these engines should know 6.3g is too heavy for just a sports exhaust and that the cdi is not rev limited.
     
    Last edited: Feb 20, 2017
  19. Tamiyacowboy

    Tamiyacowboy Pippa's Owner

    Messages:
    1,850
    Rides:
    Piaggio Skipper
    i did say he has maybe to heavy rollers in, and im not that in with the nrg models, jack has been vauge with what the problem specificly is he makes its sound like roller weight to heavy but then goes between that and sluggish on throttle ie a jetting problem
     
  20. Jack mallett

    Jack mallett Member

    Messages:
    46
    I will try lighter rollers if I am still having problems I will ask for more help in the forum thanks
     

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