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Thread: CRF 70 carb issues.

  1. #1
    Senior Member mick's Avatar
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    CRF 70 carb issues.

    Anyone know of common probs with these bikes??? Looking at two and both are at mechanics one waiting for new carb. One getting carb cleaned. Been told the carbs are sealed up inside at hard to clean???
    74AŚ3. 78J1. 79R. 82R. 83R. 99R. 74MR50. 75XR75. 98XR70 Crf70. Crf230. Crf450. KLX140.

  2. #2
    Forum Founder Classic Honda 50's's Avatar
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    I have been running the XR/CRF70 carbs on my Z50 stockers as a stage 1 carb upgrade for over 10 years without an issue and still have 2 bikes running that carburettor set-up.

    - Current XR/CRF70 carburettor set-up on my XR50:
    Dsc02687 S.jpg


    - Old XR/CRF70 carburettor set-up on my Z50J1:
    DSC01355.jpg


    - When you look at the fiche diagram they pull apart just like any other carb:
    CRF70 Carb Fiche.jpg


    I haven't pulled apart a CRF70 carb from one of the last few models to see if they have changed them, if the carbs have been left to dry out with fuel in them they can be a bugger to clean the brown treacle like crap that is left behind as all the holes and jet passages are so small.

    Cheers

    Jaimie
    Classic Honda 50's Australia - Visit our online store at -Hidden Content

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  3. #3
    Senior Member Tinman's Avatar
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    I have a Honda carb where the main jet is held in by the carb casting being rolled around it so to speak
    I had to break the casting to remove the main jet perhaps thats what the mechanic is referring to

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  5. #4
    Senior Member mick's Avatar
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    Advice anyone? So the crf70 had a few issues today. Didn't start as easy as it should have and seemed flooded at first. When running, it was pissing fuel out the drain hose. Pulled the carb apart and cleaned the best we could. Definitely had water in it! Put back together and got it going. Ok at first, then started leaking again. Got home. Washed bikes. Gave them a run. No leaking!!! The floats are not adjustable on these so not sure what to do next! Pulled apart atm. Drained the tank to find this20170820_181726.jpg
    I have a china carb where the tube in the bowl is slightly longer. May be worth a try.20170820_181754.jpg
    74AŚ3. 78J1. 79R. 82R. 83R. 99R. 74MR50. 75XR75. 98XR70 Crf70. Crf230. Crf450. KLX140.

  6. #5
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    add 1 cap full of metho to a full tank of fuel will clean up any excessive water left behind in fuel system, my lad has a crf70 no carby issues with this one starts and runs well hot or cold

  7. #6
    Moderator dex's Avatar
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    Worn or sticking needle and seat ,,,
    " rubber tipped needle ,?"
    its engine oil madge ,,,
    Your soaking in it ,,!!

  8. #7
    Senior Member mick's Avatar
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    After a real good clean, it seems to be ok again.
    74AŚ3. 78J1. 79R. 82R. 83R. 99R. 74MR50. 75XR75. 98XR70 Crf70. Crf230. Crf450. KLX140.

  9. #8
    Senior Member mick's Avatar
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    Should I have put $89 for 4 litre synthetic oil in this bike? Please say yes!
    74AŚ3. 78J1. 79R. 82R. 83R. 99R. 74MR50. 75XR75. 98XR70 Crf70. Crf230. Crf450. KLX140.

  10. #9
    Moderator dex's Avatar
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    In a semi auto clutch motor ,,,


    No
    its engine oil madge ,,,
    Your soaking in it ,,!!

  11. #10
    Senior Member mick's Avatar
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    Oh poo!
    74AŚ3. 78J1. 79R. 82R. 83R. 99R. 74MR50. 75XR75. 98XR70 Crf70. Crf230. Crf450. KLX140.

  12. #11
    Senior Member mick's Avatar
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    Still leaking!!! Question : should the float needle have a spring loaded button? 15037949255251929705801.jpg15037949255251929705801.jpg
    74AŚ3. 78J1. 79R. 82R. 83R. 99R. 74MR50. 75XR75. 98XR70 Crf70. Crf230. Crf450. KLX140.

  13. #12
    Life Member z nut's Avatar
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    yes....
    You have two parts of brain, 'left' and 'right'. In the left side, there's nothing right. In the right side, there's nothing left.

  14. #13
    Senior Member mick's Avatar
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    New needle. Old one not springing! No leaks yet.
    74AŚ3. 78J1. 79R. 82R. 83R. 99R. 74MR50. 75XR75. 98XR70 Crf70. Crf230. Crf450. KLX140.

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  16. #14
    Senior Member mick's Avatar
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    20180212_195155.jpg
    The 70 failed me again!!! Found this in the carb again. Drained tank to find a small amount of sludge. Must be remainder of water. Will give the tank another flush and try the metho trick. A Zd failed also. Wouldn't start. Couple of pops out exhaust. Normally starts easy. Not a fun camp at all!!!!!
    74AŚ3. 78J1. 79R. 82R. 83R. 99R. 74MR50. 75XR75. 98XR70 Crf70. Crf230. Crf450. KLX140.

  17. #15
    Moderator MattyP's Avatar
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    Keep at it. It’s going to feel so great when you finally get it sorted.
    Life is too short for cheap carbs...

  18. #16
    Senior Member mick's Avatar
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    Cheers Matty. Lucky a mate had a little kdx 50 there so my girl didn't miss out.
    74AŚ3. 78J1. 79R. 82R. 83R. 99R. 74MR50. 75XR75. 98XR70 Crf70. Crf230. Crf450. KLX140.

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