Using a different carb during break in

Discussion in 'Motorized Bicycle General Discussion' started by fischer550, May 6, 2014.

  1. fischer550

    fischer550 Member

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  2. crassius

    crassius Well-Known Member

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    shouldn't make a diff, but remember that as the engine runs in, it will usually get leaner
     
  3. TakeiT

    TakeiT New Member

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    should be fine
     
  4. mapbike

    mapbike Active Member

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    That is what most refer to on here as either the RT carb or Dellorto 15mm SHA Clone carb which is what it is, nice running carbs, but like all of them must be jetted correctly for your engines set up, normally comes with a #70 jet in my experience, that jet size has worked good on my engines that are modified with port work and good flowing exhaust set up.

    Map
    .wee.
     
  5. SuperDave

    SuperDave New Member

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    Ebay listing shows it comes with extra jets & a longer throttle cable. Under 40 bucks, that's a good deal.
     
  6. jesse

    jesse New Member

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    I just bought the exact same carb from that same person. It just came in but i have no idea how to install it. I dont know how to i stall the throttle cable on cause im afraid i wont put it back together right. And i dont know where to put the jets! Please help.thanks!
     
  7. SuperDave

    SuperDave New Member

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    Jesse, did you buy the bike complete with the motor or just a kit you installed? My kit required some assembly, including mounting the carb. If yours did too, its not rocket surgery to install an upgraded carb. But if you are over your head & lack ANY practical mechanical know how, take it into a motorcycle shop, or even a small engine shop that services lawn equipment & pay them to mount & dial it in.

    If you're not mechanically inclined, maybe a ChinaGirl isn't right for you.
     
  8. maniac57

    maniac57 Old, Fat, and still faster than you

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    If you have no idea how to swap the carbs, why bother in the first place? The stock NT carbs work fine.
    You may notice a difference, but that new carb will not make much power on a new stock engine. Once it's fully broken in, you can worry about carb tuning.
     
  9. jesse

    jesse New Member

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    Dont have to be rude or make me feel stupid guys. Ive had the bike for a year and made sure all nuts have been fastened. But the stock carb started leaking gas really bad from the prime button. And a man had helped me put the carb on. Everything else i was able to install. I just need to put a jet in and put the throttle cable on and tune it. I thought there could be a video on how to do it but had no luck.
     
  10. Henshooter

    Henshooter New Member

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    I have to agree with Maniac the stock "speed" nt carbys work a treat and are easy to tune , I purchased a racing carby and the thing was a pain in the arse to tune , there's no way to tune it without replacing jets and there's no pin adjust , I went back to the speed NT , IMHO the racing carby slide is much more prone to seizing with dirt and a pain to fit the cable correctly

    Yeah the air filter looks cool but it's not worth the potential issues you can have with the racing carbys in my oppinion

    Regards Hens
     
  11. Henshooter

    Henshooter New Member

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    Sounds like either the pin that holds the float tank has popped out one side or your carby float is buggered ,easy fix mate , no one here is trying to be rude or make you look stupid at all ,simply trying to help and save you potential frustration in the future

    Regards Hen
     
  12. maniac57

    maniac57 Old, Fat, and still faster than you

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    Not trying to be rude or make you feel bad. Just wondering why you want to change it?
     
  13. jesse

    jesse New Member

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    Well me being still a newbie, i figured its just the stock carb thats probably no good anymore and might as well buy a performance one.
     
  14. mapbike

    mapbike Active Member

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    If fuel started leaking out of tickler button most likely you have some trash in the needle and seat valve.

    Are you running an inline fuel filter between tank and carb?

    The carb you bought is a good replacement for someone who has the no how to set it up right, one thing I will say is that in my experience the throttle cables that come with these carbs dont work without a slight mod done to them, the end that goes into the carb has the small cylindrical nub on it and in all of them I have seen that nub is to long and needs to be ground down to about half its length, these Dellorto clone flat slide carbs work great but are a little tricky getting together after cable is installed if you dont pay close attention to how things go back in.

    The main jet can be seen once the fuel bowl is removed, it screws into a brass tube that extends down through center of the float.

    Map
     
  15. fischer550

    fischer550 Member

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    I just want to know your thoughts for running this performance carb with a BRAND NEW motor, I don't want to mess-up the break-in. drn2
     
  16. Theon

    Theon New Member

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    There is no problem with running a different carb during break in, as long as it is tuned right.
    I have tried the RT on several motors and never got it to run as well as a speed carb, Others seem to have had better 'luck' with them than I have.
    Seems they don't like hot weather?
    There is no needle adjustment only main jet.
    I found my motors 4 stroked too much through the mid with the RT, and there is no way to adjust the mid.
    I wont use one on a china girl.
    They seem to work OK on a pocket bike, and this is what they are for.
     
  17. 2door

    2door Moderator
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    If you plan to stay with that RT, clone carb you need to know how the choke works. It is spring loaded to the open position but isn't adjustable like the one on your original carburetor. It is either wide open or closed. Once you close it, it stays closed until you twist the throttle to wide open. That is a feature I don't like. I don't use the chokes on my engines as a rule but if I do I like to run about 1/2 choke to start on a cold day. Also if your cable adjustment isn't right the choke won't release (open).

    Actually I've never really seen any performance improvement with that carb. I prefer the venerable NT or NT Speed. They're easier to tune, provide all the fuel that a stock engine can handle and are essentially troublefree as long as you give them clean, filtered fuel and air.

    Your leaking problem is almost certainly caused by a blocked needle valve or a cracked float that has sunk in the bowl. Both take minutes to repair. There isn't actually anything to wear out or go bad with the NT carburetor except the plastic float.

    Tom
     
    #17 2door, May 7, 2014
    Last edited: May 7, 2014
  18. mapbike

    mapbike Active Member

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    I have had good luck with both carbs but the NT speed is probably my favorite overall, it has nothing on the standard NT accept I like being able to use 1/4" fuel line and having the extra shut off valve.

    No performance gains overall with RT above the NT other than maybe a little better on the low end, but not enough to matter much and I have got 45+ mph with both carbs, I run some RT carbs and have two brand new ones but its hard to justify spending as much on one RT as you can get two NT Speed carbs for.

    Map
    .wee.
     

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