dirtbike question

Discussion in 'OT Driven' started by φ, Jun 11, 2005.

  1. φ

    φ Eugenics is the self-direction of human evolution.

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    So I pulled my old dirtbike out of the garage the other day and it started up on the first try, but it wasnt running right.
    The bike wouldnt run on its own without the choke on so i rode it a little with the choke on just so it could get warmed up you know, but from second gear up after a second of giving it gas the engine would act like it wasnt getting any gas and it wouldnt acceletate any more--its like i was taking away the gas feed when increased the throttle. Not only that but it wont even run without the choke, even giving it gas. After a few seconds the engine would do the same as above with increasingthe throttle.
    i dont know what the hell is going on. i put a new spark plug in the thing but that didnt have any effect. I'm not a mechanic and i dont knowthe first thing about any kind of engine so i guess I'll just have to take it to a real mechanic unless you all know anything about what the problem could be.
     
  2. Frequency

    Frequency New Member

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    sounds like the carbs are gunked up you could try running a cleaner through, but you may have to have them re-built
     
  3. Ivy Mike

    Ivy Mike New Member

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    The carb on a dirtbike is probably pretty simple. You can take it apart and clean it out a bit.

    They really aren't that tough or complicated. I used to be able to pull the one out of my old CR250 in about 5 minutes. I could tear it down clean and reassemble in about 25.
     
  4. Clingman

    Clingman Clingman runs Bartertown.

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    Drain your fuel and mix some fresh. If that doesn't clean it up, then your jets are clogged with old, nasty, gooey fuel. Since no fuel can flow through them, you are having to use the choke, which actually opens up another passage which allows more fuel into the carburetor.

    You need to remove the float bowl to get to the jets. Remember to turn the fuel off and disconnect the fuel line first. The float bowl makes up the bottom of the carb, usually held on by four screws, one at each corner. There will be some fuel in it. Set the bowl aside.

    With the bowl off, look at the bottom of the carb. The main jet will probably be gold colored, with a hex shape. It will be right in the middle of the bottom of the carb. Take it out (it threads in) and carefully run a needle through the hole and then blast it with carb cleaner until there's no more crud visible inside it. The pilot jet will be down inside a recess next to the main jet. It'll have a slot in it for a flathead screwdriver. Take it out and clean it too. Then put everything back together and go run the hell out of it!
     
  5. φ

    φ Eugenics is the self-direction of human evolution.

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    well i didnt understand any of that, but thanks.
    I'll just try it, got nothing to lose anyway, i could always just get another to replace that one
     
  6. Ivy Mike

    Ivy Mike New Member

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    The fuel bowl is usually a square or rectangular 5 sided box (the tope is open as it forms the botttom of the carb)

    You take it off and you'll see the jets he was talking about. It isn't that hard. Just be careful with the jets. Don't scratch or nick them. They won't flow right if you do.

    Rethread them carefully and you'll be fine.
     
  7. XR250rdr

    XR250rdr OT Supporter

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    Get a service manual for the bike. It will explain the carb rebuild and list any base adjustments.
     
  8. Clingman

    Clingman Clingman runs Bartertown.

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    What kind of bike is it?
     
  9. φ

    φ Eugenics is the self-direction of human evolution.

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    Update:
    i put a bottle of some of that fuel cleaner stuff (STP) in today and I ran the fuck out of it for about an hour straight and it is running a little cleaner so i guess I'll just keep doing that for another day or two, and if that doesn't get it running properly, i will just break down and clean the damn carb. I haven't done this yet beacause i dont really know what a carb looks like, so i have been trying to avoid doing that. thanks for the help
     
  10. Clingman

    Clingman Clingman runs Bartertown.

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    .
     
  11. φ

    φ Eugenics is the self-direction of human evolution.

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    I can't remember. It's a Yamaha, and it's been sitting in the garage for about two years now so it's not a newer model. And i cant tell the difference between the types of bikes, except for those that climb on rocks and stuff, those are pretty cool looking.
     
  12. XR250rdr

    XR250rdr OT Supporter

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  13. Infrastructure

    Infrastructure New Member

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    how old is the bike? Probably doesnt look anything like either of these two bad machines :cool:






    [​IMG]
     
  14. φ

    φ Eugenics is the self-direction of human evolution.

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    I don't race.

    thanks for the carb info.

    Another q: Is it easy/pratcical for an amateur like myself to change tires on bike? And I'm talking about just changing the rubber, not the entire rims with it.Will i need to take the rim/tire to a mechanic and get them to put the tire on the rim or could I just do that myself with a crowbar or something?
     
  15. Clingman

    Clingman Clingman runs Bartertown.

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    It's a total pain in the ass, and you'll never get it without a special set of tire irons and an hour of hell. Most motorcycle shops will install the tire for a small charge if you bought the tire there. Last time I bought a michelin from cycle gear the guy installed it for 5 bucks.
     
  16. Infrastructure

    Infrastructure New Member

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    :werd: If you buy the tire from a shop most times you can just toss $5 to the mechanic and they will put the new tire on
     
  17. φ

    φ Eugenics is the self-direction of human evolution.

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    I'm tired of this old bike. I was looking on the Honda website at the XR250s and they look like exactly what I want just for trails riding and stuff, no racing. Then i looked at a CRF230 and they seem very similar to me but i dont really know, except they are about 2k less. I was going to pick up a pair of either XRs or CRFs. What are your thoughts on the two? Why is one so much less?
     
  18. XR250rdr

    XR250rdr OT Supporter

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    The CRF is heavier and much less performance oriented than the XR. It is a good play bike, but much less capable than the XR. The suspension on the CRF is softer, has less travel, and has less adjustment than the XR. The CRF makes less power

    The XR has been discontinued though, so the only option is to buy used. But buying a lightly ridden year or two old XR250 will just save you some money over buying new and they run forever.
     
  19. φ

    φ Eugenics is the self-direction of human evolution.

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    are they coming out with another trail bike to replace the xr
     
  20. Infrastructure

    Infrastructure New Member

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    where did you get this ignorance from? The CRF is less performance oriented than the XR? Really now, then tell my why the CRF line is built for motocross and the XR line was built for trail riding if the CRF is much less performance oriented? Motocross is very much a performance oriented sport, as opposed to trail riding. Also the suspension on a CRF does not have less travel than an XR and is much more adjustable and you can dial it in more than the suspension on an XR.
     
  21. Clingman

    Clingman Clingman runs Bartertown.

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    Easy dude... I think he was talking about the CRF150F and CRF230F. The Honda play bikes, not the MX bikes.
     
  22. Infrastructure

    Infrastructure New Member

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    :doh:
     
  23. XR250rdr

    XR250rdr OT Supporter

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    Yea I guess you missed him saying 'CRF230'. :p And besides only 2 CRFs are made for MX. The other 8 CRFs are made for off road use. ;)

    Honda has 'replaced' the XR250 with the CRF250X. I dont feel its a very good replacement though. While the 250X is more powerful and better suspended it demands a rigorous maintenence schedule and lacks the bulletproof nature of the XR.
     

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