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UNable to go past 80kmh

Discussion in 'Technical and Troubleshooting Torque' started by Prime, Jul 20, 2006.

  1. my CBX250 wont go past 80kph, upto 80 is no prob, once i get into 4th gear it just dies on its ass, no power, now its done nearly 70000 so I sorta figure maybe its a tired engine, but ive never had any other problems.

    I purchased it about 2 or so months ago and the only thing the bike shop has done to see if we can increase the speed is put a new sprocket on the front, they said next thjing they will check is the carby and see if its ok, im a noob for technical crap but im really disappointed that my first ever bike is a dud, im quite sad about it.

    I get scared if I have to go on the freeway so I try to avoid it where possible, any suggestions :?:

  2. Did they check if the air is getting into the motor (air filter) and if it's getting back out again (exhaust pipe)??? If either one of these is blocked, the engine will be 'strangled'........
  3. Is the problem that you can't get to 80kph or that you can't get to a certain rpm? (I'm thinking that mabe you might only get to a certain rpm when you get to 80kph). IF the prob. is that you can't get to a certain rpm, then to my limited knowledge it sounds to me like there is could be a problem with your carburator jets (I'm assuming the bike even has a carburator, or even two!). A carb. has several jets that are used to deliver fuel at different throttle positions. mabe the jet that is used to deliver fuel at the higher rpm is blocked? Just my 2 cents worth! For all my motorcycle fix it knowledge I use this web site, http://www.dansmc.com/MC_repaircourse.htm
  4. With that sort of mileage it might also be worth getting the compression checked - if the compression ratio is low then the power output will be too.
  5. Try these two tricks. when it hits the wall, choke it. Goes faster = not getting enough fuel.
    If that doesn't work, temporarily take the air filter assembly out.
    If that doeesn't work, it's spark or compression, and I can't help you.

    Regards, Andrew.
  6. I had a CBX250, and it was capable of "Wayyyy" more than 80Kph...... but, hitting a hill at 120Kph would see it at about 80 by the top of the hill .....

    I'd say a full service will see a few more KPH . . . . .
  7. Hey man,

    Yeh I feel ya. I bought my rgv250 for $3500. little 2 my knowledge it was a home rebuild off a smashed bike! I had numerious electrical problems. such as:

    1. Wouldnt start
    2. Head light & indicators were low
    3. Would stall in between traffic and at lights.

    etc, etc.

    It gets really scary when ur a Leaner and u have problems on ur bike. Esspecially when you dont know anyone who rides.

    Take my advice..
    Roll with the flow, find a decent motorcycle mechanic. Not just Jim up the road or uncle bob who has a 'played' with engines, but someone knowledgeable and trust worthy. Get there advice on what to do exactly and fix the problem(s).

    Then either a: keep it till ur off ur L's & P's or b: sell it asap.

    Hope that helped.

  8. Maybe its been resrticted by a jumpy mum or dad at some point in its life..??
  9. OK scenario, im travelling along the freeeway I get upto about 80kph in third gear, i change to 4th and no matter how far around the throttle goes I dont get any engine response, 1st 2nd 3rd gears are great no probs, in third gear at 80k im doin about 7000rpms, then i change to 4th it drops to around 5000 - 5500rpms. and the engine pretty much holds at that but i cant get any pickup...

    when I got the bike I replaced the oil and filter plus I replaced the Air filter. but thats about it so far.
  10. Hmm with my CBX250 I rev it out way out to 8-9K!! b4 I change gears... At about 5K it has a flat spot out of which at 80Km/h it will not pull out but that is in 6th...

    (I'll have to check that... I have not readen the bike for a while)
  11. Really? it redlines at 9k...
  12. LOL yep I redline it every gear change... right up to the speed I want to ride at... poor little 250...
  13. That sounds like the problem. If the bike is performing close to it's max speed, and you don't let it rev out, the revs will drop so much when you change up that it won't have the guts to go faster. Rev it out in third and it will keep pulling in fourth.

    (edited to remove reference to mythical fifth gear)
  14. Ring the bloody kneck of the thing.
    I had same issue with my first bike. VT250c cruiser.
    It didnt have a rev couter so i was short shifting without knowing.
    When I asked some advice i was told the Ring its kneck in all gears before shifting up.....

    That got me to 150kmph at some stages and had no worries after that.
    But I got bored with it and bought a Hornet... OOooo the joy
  15. lol,

    thats poor bike... I can tell it's going to take awhile to get used to riding a tupperwear bike.

    I'm interested, did you have any luck ringing it's neck prime?
  16. I have gotten it to about 8k so far, then change gear but I still dont get much out of it, i think maybe fuels not getting thru or who knows hehe, will be riding it decently over the next 2 days ill try ringing the beejeebus out o fit and see what happens heh.