No Power

Discussion in '2-Stroke Engines' started by dancycle, Jun 5, 2009.

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  1. dancycle

    dancycle Guest

    I've read up and down the posts and threads and found lots of helpful information but nothing so far that has helped me figure out the problem with my bike.

    I first built her in the summer of 2007. At this time, it ran very well and I had broken it in a bit- probably around 150 miles on it.

    One day I stupidly mixed a bad batch of gas- whether it was too lean or just plain too old of gasoline I'm not sure, but the gas must have not been making the engine happy, as it proceeded to loose power quickly on the first ride with the new gas in it and was barely puttering along by the time I finished riding. I did not restart it for over a month.

    The next time I tried to start it, I was unable to get any power. By this I mean that when I let out the clutch, the engine turns over but I am unable to feel any evidence of power or the engine actualy firing. It makes the bogogog sound as far as I ride it with the engine engaged but has no sign of life.This has gone on until now and I'm getting desperate to find a solution.

    I have checked all the potential problems I have found listed on the the stickys and elsewhere in the tech forum to the best of my knowledge but I'm just not having any luck getting this thing alive again. The both of my sparkplugs I have tried pass the wheel spin test with healthy looking sparks, The carb is full of fuel when I check, there is nothing blocking the fuel line or inside the carb as I have checked, the fuel is fresh and 20:1 mixed. I removed the kill switch contact from the bike in case that was the problem.

    One last note- last summer when I tried to get it going again, after pedaling for some time- probably a half mile- the engine started bucking and lurching intermittently as if it was trying to kick to life every so often but never really got any where.What can I do? Please, any help is appreciated.



  2. srdavo

    srdavo Active Member

    a couple things to check......

    after attempting to pedal start, have to pulled the spark plug to check if it is wet or dry?
    If the plug is dry.... your carb jet is probably clogged.

    If the plug is wet:
    Have you tried starting it, with the choke lever in different positions?
    Lever up (full choke) may not allow enough air in.... try it with the lever 1/2 way down.

    good luck
  3. solitus3989

    solitus3989 Member

    Try this:

    First, try riding the bike with the clutch in (lock it into position) and while holding the throttle with your right hand, learn where the choke is with your left hand. It involves a little awkward movement, but is not too hard once you get it down.

    Next, pedal quite fast - you need enough time to try adjusting.

    Drop the clutch. With your right hand, go about half throttle. don't just go WOT.

    with your left hand, slowly raise and lower the choke, and look for signs of life.

    If there is absolutlely nothing, then you have bigger problems than just being rich or lean.
  4. 2stroketech

    2stroketech New Member

    You fried your engine. The piston is melted down and you will need to rebuild the engine.

    If the cylinder is not scored you can hone it out using a ball hone and a cordless drill. You will need a new piston and rings. If when you hone the cylinder out and you are unable to get the scratches if any out then you will need to pick up a new cylinder as well.

    If this is not some thing that you want to invest in the tooling for then a new piston and cylinder set is the way to go.
  5. dancycle

    dancycle Guest

    I don't think it a problem of being rich lean, as I have tried just about every choke and throttle adjustment that I can of think under the sun. This bike isn't firing at all. It seems that the engine is turning over only on the momentum I have from pedaling up to the point where I engage the drive. Also, I keep pedaling for a while after I engage the drive and I'm almost certain that then engine only keeps turning because I am pedaling the bike forward. When I pull the clutch lever in, the engine IMMEDIATELY stops turning over. If the weather it good today, and I know this sounds really stupid, I will try dropping a little bit of fuel through the plug hole to see if it is really just a fuel supply problem. I'm guessing I'll get some kind of kick, at least initially, that I haven't been seeing.

    P.S. I tore down the cylinder sometime back when I had this problem, and nothing appeared amiss with the piston or cylinder
    Last edited by a moderator: Jun 5, 2009
  6. 2stroketech

    2stroketech New Member

    Did you check your rings? Your piston and cylinder might be fine but you might have wore the ring out. (unlikely but I have seen this before in other two stroke engines) Have you checked your compression?

    Did you just pull the head or did you pull the entire cylinder? Look through your exhaust port and double check your psiton skirt and pay close attention to the ring. If you see striation markes ont he rings then pull your entire jug and measure you rings inside the jug to make sure that they are not out of tollerance.
  7. dancycle

    dancycle Guest

    I pulled the entire cylinder. I forgot to mention that when I pulled it I did replace the rings since I accidently broke one of the original two while trying to reinsert the piston into the cylinder. What would a striation mark look like?
  8. 2stroketech

    2stroketech New Member

    They will be deep vertical marks on the rings them selves. they can look like a bunch of flat marks. When you put your new rings in did you measure them first to make sre that they had proper gap? No tighter than about .002" and no wider than half the thickness of the psiton stop pin.
  9. dancycle

    dancycle Guest

    Tested compression with thumb, seemed like it was creating plenty. The piston rings appear fine. I have confirmed that there is compression, the sparkplug sparks, there are no air leaks I have detected. I guess all I can do now is try adding a bit of fuel through the top and see if it changes anything.

    Thanks guys for the help
  10. dancycle

    dancycle Guest

    Uh oh. So I put about a tablespoon of gas in through the spark plug slot and the bike definitely showed more signs of life. The engine had intermittent hiccups or bucks as if it was firing, but weakly, only ever other second or so. Now I'm really not sure what to do. Upon returning home, I looked under the bike to see that there was very dark(oil looking) that had oozed out of the crack on the very bottom between the bottom side of the magneto cover and the main engine gasket. Also, there a slow drip of what I'm asuming was very oily gas dripping from the exhaust pipe.
  11. dancycle

    dancycle Guest

    Update: I took the head off and everything looked good. I inspected the magneto and it seemed to be ok. I then increased the spark plug gap with a gap checker to .04 and it sparked just fine when I turned the back wheel. So I don't think that the spark is the problem. What should I try?
  12. boogerballs

    boogerballs Member

    I just fixed a problem on my HT with somewhat similar symptoms. I have been riding for about 8 months and have put on about 750-900 miles. It started to lose power so I thought it was a plug fouling. Nope. I had tried just about everything without disassembling the cylinder. No power, felt almost like a fouled plug, good spark, getting fuel. Just couldn’t figure it out. I also had some black oily mess oozing out of the small hole on the muffler.
    I removed the muffler and started it up. Wow! It ran great! So I shut it down since I didn’t want to ruin anything running it without a muffler at all. I had a real hard time getting the muffler apart until I put a solid rod inside the stinger end and clamped that in a vice. Tapped and pulled until I was able to remove the baffle. While there was a bunch of oily, oozy grease-like stuff in there, there was also caked on hardened black deposits. I run Castor oil mix and was told after the fact that it tend to leave more exhaust deposits than regular 2-stroke oil. The baffle was just a length of pipe the size of the little stinger that sticks out the end, with one-eighth inch holes near each end and crimped in the middle. There was also a disc of steel welded on to keep the end that sticks inside the muffler housing centered.
    Well all those little holes were almost completely clogged. The half inch pipe with those holes in it was probably a bit smaller than one-quarter inch i.d., clogged with hard black deposits. Once I cleared everything out and reinstalled the baffle into the muffler and the muffler back on the bike, I started it up and it runs better than it ever has.