Idle Problem

Discussion in '2-Stroke Engines' started by JimKamenidis, Jul 14, 2010.

  1. JimKamenidis

    JimKamenidis Member

    guys please help, my motor runs very well and I like it very much etc.
    But from the first day I have a very frustrating but particular problem, when I stop with the clutch disengaged the motor can't stay alive unless i rev it slightly!
    Can you please tell me what can my problem be rather than the idle screw?(because I think I have tested that solution!) :cool:
     

  2. ezdzd

    ezdzd Member

    @Jim
    On top of your carb where the throttle cable comes out there should be a long nut that when turned will pull on the slide in the carb. you can also adjust the nut where the cable goes into the housing on the twist grip housing. Keep in mind a little goes along way. If none of this does the trick you may want to try,(this happened to me out of the box)with the motor off, giving it full throttle and twist the idle screw all the way in. Then let off the throttle and back out the idle screw to an appropriate position. Bon chance!
     
  3. professor

    professor Active Member

    Regardless of the engine type, that normally comes from a vacuum leak if the fuel mixer is not buggered up. So take off the carb and manifold to check the gaskets and seal everything. If the carb slips on to a spigot and doesn't have an "O" ring, you can put some blue silicone on it.
     
  4. JimKamenidis

    JimKamenidis Member

    Thanks for the replies !
    And what position should the choke be at?
     
  5. Al.Fisherman

    Al.Fisherman Active Member

    Every engine is different, everyone lives in a different climate. I only use 1/2 choke on first start of the day (I purge air out of the carburetor, about 5 pumps). Choke handle up in center. After engine warms up enough (a few minutes or about 500' of riding), I take all choke off. Handle down.
     
  6. AussieSteve

    AussieSteve Active Member

    Jim, first up. ignore any advice to adjust your idle by tightening the cable. Not good. If you do that, the idle will vary as you turn the bars from side-to-side.
    Adjust the cable to allow about 2-3mm slack. (Just enough so that moving the bars side-to-side doesn't quite move the carb slide.)
    Then adjust your idle by screwing in the idle screw on the LHS of the carb.
    (You should have mentioned what sort of engine you have - I'm assuming a Chinese HT 2-stroke with an NT carb.)

    An air leak would cause your engine to idle high, not low, so you can rule that out for the moment.

    As Ron said, you'll have to sort out the choke for what works best for you. I use full choke for one attempt, then an attempt with no choke and it fires right up.
     
  7. JimKamenidis

    JimKamenidis Member

    thanks, I just screwed the Idle alot
    (I always confused clockwise and anti-clockwise :p)
     
  8. AussieSteve

    AussieSteve Active Member

    Did it fix it?
     
  9. ezdzd

    ezdzd Member

    aussie i don't know your setup but, on mine if you adjust the cable your doing so at two fixed points. If the cable, ie idle moves when you turn the bars you've got some weird unsafe issues going on. The length of the cable remains stagnant regardless of where the cable housing is. By adjusting the nuts on the cable housing your simply applying pressure to the return spring inside the carby, thus pulling the slide up and adjusting the idle.
    If it makes you feel any better jim, I had your exact problem when i first built mine. Problem solved and many miles of happy riding. Good luck to ya!!
     
    Last edited: Jul 16, 2010
  10. AussieSteve

    AussieSteve Active Member

    No, a cable inner will always pull slightly when the casing is bent.
    I'm not making this up, do a test - it's a fact. I'm speaking from long years of experience riding motorcycles.


    Not true - see above. I'll correct this. Of course the length of the inner cable stays the same, but because it's being bent around a circumference it's shorter relative to the outer casing.

    As I said earlier, do a test. Don't just try to think out the logic. Believe me, I'm right.

    Further to what I just said, I have a question - what is the purpose of the idle speed screw?
     
    Last edited: Jul 16, 2010
  11. ezdzd

    ezdzd Member

    Yeah steve if the cable inner always pulls when the casing is bent, you have a problem. what your trying to say is completely irrelevant to the fact that a cable housing adjustment will affect the idle speed of the motor. It's shorter relative to the outer casing? If the cable is being bent the housing is being bent as well. Relative to each other the are the same. My statement saying that the length of the cable remains the same is meant to be viewed as follows: Hold a cable straight horizontally. Now slide the housing that is shorter than the cable along that cable. The cable itself does not shorten. Bent or not bent a cable in a housing occupies the same space and takes up the same volume relative to each other. They both move, bending something doesn't change it's molecular makeup. I'm not trying to call you out or anything but it is what it is. Perhaps during your years of motorcylcle riding you had improperly positioned throttle cables. mu hahaha. I believe the idle screw's purpose is to regulate the electrical current output from the magneto to the seat. I was trying to be helpful, but I've got better things to do with my time. oh yeah im right, why cause i said so trust me.
     
  12. Stan4d

    Stan4d Banned

    Sorry but I think you are on the losing end of the disscussion. Working on LP forklifts I have found that bending the accell cable I could vary the engine RPMs. Nothing changes, simply you have two things of equal length when you bend them their relational position changes.....if you really want to see it in action, take 2 equal lengths of fuel line. Hold them side by side....both ends are even. Bend them into a 180 degree bend. The outer one will appreat to be shorter. My daughter taught me that trick....she learned it in preschool. Just sayin.
    One other thought, are you sure that the attitude is neccesary?
     
  13. AussieSteve

    AussieSteve Active Member

    Thanks for the support, Daryl, you explained it well.

    I was going to suggest grabbing a cable and casing by both ends, clamping the cable to the casing between finger and thumb, then bending the casing. The inner cable will be pulled between your fingers.


    Regarding this:- "oh yeah im right, why cause i said so trust me."

    No, not because I said so. I suggested that you test the theory, as I have, but you prefer to argue.
     
    Last edited: Jul 16, 2010
  14. Stan4d

    Stan4d Banned

    I found an easy way to overcome the pedal govenors at the gokart track using this theory....the pedal had a screw stop for the govenor, by bending the cable I was able to go faster than my brother, not much but when we were both at wide open I had the advantage.
     
  15. JimKamenidis

    JimKamenidis Member

    help!
    I am using the stock two metal brackets to mount the engine and one of the little metals, on the back vertical tube, snaped only on the one side where the bolts go through because I over tightened them, but the bracket is still on and pretty tight too..
    And the engine is still pretty solid, do you think I am in trouble?? :(
     
  16. Stan4d

    Stan4d Banned

    Are you able to post a pic of the problem....I have extra brackets and I could mail you a replacement if it is the one I am thinking of.
     
  17. ezdzd

    ezdzd Member

    kinda missed my point. wasn't tryin to be a ****. The cable shouldn't be positioned in a manner that provides an opportunity for the idle to change when the handle bars are turned. "Yeah steve if the cable inner always pulls when the casing is bent, you have a problem. what your trying to say is completely irrelevant to the fact that a cable housing adjustment will affect the idle speed of the motor." "My statement saying that the length of the cable remains the same is meant to be viewed as follows: Hold a cable straight horizontally. Now slide the housing that is shorter than the cable along that cable. The cable itself does not shorten." I suppose assuming that one would not route a cable that would move when you turned was a mistake.
     
    Last edited: Jul 17, 2010
  18. ezdzd

    ezdzd Member

    Here's an idea for your mount. The original rear mount broke within the first week. Keep in mind this is a pic of the front mount, but my rear mount has pretty much the same concept. It would probably be a good idea to read up on what to replace out of the box. I think there are a few threads with lists. Personally would suggest new mounting bolts, chain, and throw out the tensioner. Half the fun of owning one of these things is working out the kinks at the start.
     

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  19. JimKamenidis

    JimKamenidis Member

    I have changed all the mounting bolts because some failed really early..
    As a matter of fact I have seen this mounting method in SBP but does it also fit the back vertical tube that I had a problem with?
    Also without a chain tensioner how will the chain fit correctly, because either it was too slack and then after I got rid of a pair of chain-links it was too tight and even wouldn't come together!
     
  20. ezdzd

    ezdzd Member

    You'll have to make it yourself, just some steel, proper size u-bolt, and a good dose of locktite. If you take a close look at SBP's shift kit where mounts under/around by the jackshaft I think it's kinda similiar. I'll try to sneak a picture in tomorrow, mine's burried between two chain guards and a battery case. I haven't had and problems with mine so far... If your still using the stock chain you can use metal shims inbetween the engine and and the rear mount to eliminate the tensioner. I havent' tried this but i've seen it done. If your dead set on the stock chain I think its a #35? chain, you can get half links for it, Lowes, Home depot, maybe even saw them at SBP. I've switched to a #41 chain. Was going to go with a 415 HD, but you've got to buy 2 to make it fit. So $10 for a #41 from a farm supply store vs. $50 from the bike shop, easy economics. You can also make a spring loaded tensioner. Do a search, I think i remember seeing a parts list for it. I've put just at 2200 miles on the chain and had little to no stretch and more importantly, it hasn't broken! Don't sweat the small stuff!
     
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