Bogging Engine?

Discussion in 'Motorized Bicycle General Discussion' started by psprat496, Apr 15, 2010.

  1. psprat496

    psprat496 New Member

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    Ok I know there are a lot of threads on here about tuning your carburettor and maintaining everything, but I haven't seen one that addresses this specific problem so here it goes. I hit the 350 mile mark on my bike a few days ago and have noticed something weird.

    I'll be riding at about 3/4 throttle and if I keep the throttle there for more than 10 seconds the bike will sound like it's "bogging." Not sure if anyone is familiar with what I'm talking about but it the engine runs, and then brrrrrrrrr then it runs smooth again but it goes back to brrrrrrrrr. It's weird and really annoying. Does this mean I have an air leak or something? Maybe the carbs dirty and needs some carb cleaner?

    Any ideas?
     
  2. captainrichhill

    captainrichhill New Member

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    Maybe just a tad rich. If I'm running under load it runs smooth, If I'm just at a constant speed then it 4 strokes just a tad bit.
     
  3. noco

    noco New Member

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    sounds like 4 stroking....check the cap on the carb(above the slide) if this comes loose it will 4 stroke.....there is a sticky thread in the clasic instructions all about this....the new speed carbs are supposed to help eliminate this by providing a larger slide....


    http://motorbicycling.com/f30/4-cycling-mystery-solved-12102.html


    hope this helps
     
  4. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    If the cap comes loose, it will suck air and burn the engine up.
    Four stroking is from too rich of a mixture.
    Four stroking at cruise is normal, and in fact it SHOULD break back and forth between a two and four stroke at a no-load cruise.

    When is the last time you checked your plug?
     
  5. vwine

    vwine New Member

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    I am not a professional at these things like alot of guys here, but Mine was bogging running smooth then bogging again like urs. And I did 2 things that I was advised to do from this site... The first one was to apply silicone on the tip of the intake manifold and the carb.. to seal that area because of a crappy connection to prevent airleak, the second thing i did, was instead of turnining the fuel valve on the tank petcock fully open, I only opened it half way, and BAM all bogging was gone... it was like unlimited power riding after being so use to the bogging killin ur speed... The fuel valve thing is frowned on by some here.. So whether its bad for ur engine, I dunno. But it worked for me. Hope it helps, and if im wrong I applogize.. VWbrnot
     
  6. BarelyAWake

    BarelyAWake New Member

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    The reason "regulating" your fuel with the petcock is "frowned on" is pretty simple, far from a precision instrument - there's no way to be sure you're not starving your engine for fuel, more importantly the oil that's in it - it's pretty random the amount of flow you'll get with that method.

    Running lean can cause serious damage to to your engine, it's easy enough to adjust your fuel/air mix properly by examining your spark plug's coloration and adjusting the carb needle's clip appropriately.

    You should always warm the engine up completely by riding it around normally for at least 15 minutes and let the engine cool down thoroughly before attempting to remove the plug. This way you'll get an accurate reading and letting it cool will help prevent stripped threads when removing the plug.

    Your plug should look like this (or a lil darker if yer paranoid/new engine);
    [​IMG]

    If it's black - move the clip up one notch, if it's white - move it down (towards the pointy end) one notch.

    [​IMG] [​IMG]




    Anything else is dangerous guesswork. If yer four-stroking a little from time to time - that's pretty normal, if you try and "fix" it w/o even looking at your plug odds are yer gonna run it lean.
     
  7. vwine

    vwine New Member

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    Hey, There you go... I was waiting on someone to correct me on the matter. I was doing that for a while, and it ran great, but my motor mount recently broke, so I guess I didnt stick around long enough to see the long/short term effect.. Thanks.. Thanks Barelyawake for the input. VW
     
    #7 vwine, Apr 16, 2010
    Last edited by a moderator: Apr 16, 2010
  8. mapbike

    mapbike Active Member

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    Yes..... checking the plug is a must, so no matter what you do be sure to use the plug as your guide so you dont lean it out to much and cook your engine.

    I have three of these carbs. and in all of them the main jet size was to large, I could put a #71 wire gauge drill bit through each of them, which was allowing my engines to run just a little rich, ( a little rich is a lot on these little motors I found out) so anyway I just soldered my jets up and redrilled them with a #73 wire gauge bit and SHAZAM.....! problem solved, they will still 4stroke a small amount when running with no load on them which like it was said earlier in this thread is normal, but when I crank the throttle my engines come alive and just take off, my bikes run WOT in the 36-37 MPH range and cruise real nice in the 28-30MPH range with a 41T sprocket, I've made some 50+ mile trips without a single snagg, they just squall, whine & Buzz...along like they should, so......... I said all this just to make the point that you may have over size jet in carb. that could be reduced just a little which may solve the to much 4stroking problem, it sounds like you were having. Just my experience and 2 cents, I fought my carbs for about 2 weeks before I did this and solved all my issues with them. Good luck, and get that mount fixed quick..... Fun is just waist-in away....!

    .shft.
     
  9. psprat496

    psprat496 New Member

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    Wow didn't think I would get so may replies. Ok we'll I'll go check my plug and see how it is but I'm still running a 24:1 gas ratio so that may be the problem. I'll see if it looks a plain brown and if it does I guess I'll move the slide up a notch and decrease the oil in my mixtures.
     
  10. BarelyAWake

    BarelyAWake New Member

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    Try only one of these at a time and be sure to examine the plug between such experiments, while it may be both - if it isn't you could mess up one thing while yer fixing the other and you'll not know which was responsible for what ;)

    I do that alla time and confuse the heck outa myself :p
     
  11. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    If it's "plain brown" leave it alone.
     
  12. Retmachinist

    Retmachinist New Member

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    I would certainly do away with the 24:1 mix, especially since you have 350 miles on the bike. I don't run that much oil even when they are new, since all it really does is drip oil out the exhaust.
    That being said, I am the original idiot that started the opti 2 100:1 thread. Several thousand miles later, and I am still running it.

    John
     
  13. psprat496

    psprat496 New Member

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    Yeah I actually did notice that. I get A LOT of oil just dripping from everywhere but I was told this is normal. I'm still gonna move my ratio up though since I do have close to 400 miles already.
     

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