Trying to figure this carb out, Dellorto SHA type, has adjustable fuel jet

Discussion in 'Performance Mods' started by JVROOM, Oct 21, 2012.

  1. JVROOM

    JVROOM Member

    I have a clone carburetor,Dellorto SHA type, with an adjustable fuel jet. You can see the exact carburetor on pedalchopper/carburetor solutions. Haven't found the parts breakdown on it, and I do not see any replaceable jets. When I first got it I had a fuel leak, and thought the adjustable jet was leaking, and tightened it in a bit. Obviously that messed up the setting. It starts fast and idles great, but I'm leaning out. I don't completely understand if this adjustable jet is part of the low-end idle circuit or if it's really a main jet. Anyone know about these and how to adjust them? Thank you for your thoughts, John. On afterthought when I had this thing apart, I found the gaskets are very touchy and the leak is actually where the fuel inlet cup screws on to the side. Also found rocksolid as the Gasket parts that I need. :ack2:
     

  2. Fabian

    Fabian Well-Known Member

    If your Delorto SHA clone has an adjustable jet, it's one of a kind. Sounds more like your Delorto SHA clone has an adjustable fuel leak.
     
  3. JVROOM

    JVROOM Member

    look at the web site as noted
     
  4. JVROOM

    JVROOM Member

    The leak is not the fault of the carburetor but mine, already fixed it and have jets on order looks like a strong contender suggest you check it out.
     
  5. BigBlue

    BigBlue Active Member

  6. jaguar

    jaguar Well-Known Member

    You can adjust the idle speed by the slide stop screw on the side. The fuel mixture is "adjustable" only by changing the main jet which is in the middle of the fuel bowl. I found mine was too lean when the main jet was just right for top speed and so I drill another orifice in the fuel outlet column. See the picture on my site by clicking on my signature link.
     
  7. JVROOM

    JVROOM Member

    Sorry, I thought it posted we could see a picture of this carburetor

    dellorto carburetor with adjustable fuel circuit. You can see the exact item I'm referring to on pedalchopper.com, under carburetor solutions there's a picture of it. Thank you, John
     
  8. jatgm1

    jatgm1 Member

    this might be the carb i was looking for on another thread. does the adjustment screw actually adjust the mixture as a whole or just the idle?
     
  9. jaguar

    jaguar Well-Known Member

    just the idle
     
  10. jatgm1

    jatgm1 Member

    it seems like it would be pointless to have two idle adjustments.
     
  11. jaguar

    jaguar Well-Known Member

    all good carbs allow you to adjust the volume and the ratio at idle
     
  12. Vapourtrail

    Vapourtrail New Member

    it adjusts the mixture from idle up to 1/4 throttle

    if its set too lean it will ping from idle up to 1/4 thottle
     
  13. Fabian

    Fabian Well-Known Member

    I have messed around with a number of float style carburettors for the Chinese 2-stroke motorised bicycle engine, and have found that the standard NT carburettor works as well as any of the other carburettors when jetted correctly.

    That said, i wouldn't waste time messing around with a float style carburettor when you can install a diaphragm type carburettor (similar to a walbro) as fitted to chainsaws - no mess, easy to adjust the air/fuel ratio and it "just works" all day, every day.





     
  14. Frankfort MB's

    Frankfort MB's Well-Known Member

    I've seen all of your videos and never realized they were all yours:D

    I'm a fan! Most people don't go into depth why and how they work.....

    If I could afford to convert a carb to a walboro it would happen


    Not to run off topic but I'm a groupie to your videos;)
     
    Fabian likes this.
  15. Fabian

    Fabian Well-Known Member

    Thank you for the compliment Frankfort MB's
    I will get my backside into gear and start making some more videos, in particular, some more of the bicycle trailer train in action; working hard, hauling payload.
     
    Dustmonkey likes this.
  16. jatgm1

    jatgm1 Member

    i was going to get a walbro, but the kit i saw online didnt have an "isolation spacer", i dont know where to get it, and my bike works well. im probably just going to use the new exhaust and jaguar cdi i ordered, and call it a day. speaking of, thanks to jaguar, fantastic cdi's.
     
  17. jatgm1

    jatgm1 Member

    not to mention the kit was 100$
     
  18. Fabian

    Fabian Well-Known Member

    The reed valve kit boosts low and midrange rpm torque. It will not give your engine any more peak power.
    For the same venturi size as an NT carburettor, a Walbro style diaphragm carburettor will not give your engine any more peak power, but offer far greater flexibility to tune your engine on the fly.
    I have found that the Jaguar CDI does not increase peak engine power, but significantly improves the big end connecting rod bearing life, which in turn gives vastly improved engine reliability.
    The shift kit will not make your bike go any faster than the engine could otherwise provide, but it allows you to use your bike as a viable means of everyday transport, regardless of the steepness of hills or terrain, as it improves drive-train usability and reliability.

    All of the above mentioned accessories add an important element : usability and reliability.
    If you only want to be the neighbourhood nuisance; setting up your bike for maximum speed; ripping up and down the street as fast as possible, and as noisily as possible, with complete disregard for others around you, there is no need for any of the above mentioned accessories.
     
  19. jatgm1

    jatgm1 Member

    i assume compared to a dellorto knock off a walbro will allow you better performance due to the ability to tune it.
     
  20. jatgm1

    jatgm1 Member

    hey while im here fabian, would you know where to get the thermal isolation spacer?
     
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