Engine temporarily locked down but piston and cylinder are fine?

Discussion in 'Motorized Bicycle General Discussion' started by mapbike, Apr 22, 2010.

  1. mapbike

    mapbike Active Member

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    I got my new bike going today and took it for a little road trip, I had run the engine on it before on another bike so it was not the first time it had ran but it only had maybe 30-40 miles on it.

    Ok.... now to my problem, I was going along fine and then I ran it at WOT for about 200-300 yards going up hill and down and then back up another hill, when I got leveled off again I backed off the throttle to a comfortable slower speed, after about an 1/8th mile or so the engine started choking down but not like 4stroking or anything like that, it was more like it was seizing up, so I back off the gas and pulled in the clutch and tried to rev it up a little but it would just barely rev and then it died on me, I stopped and let it sit for a minute and then it started back up and I got going again and then after about 1/8th mile or so it started seizing again and this time it was for keeps.

    I had to peddle the darn thing back home up all those hills about 7 miles, woo wee I aint in shape for that....! but I made it home just the same.

    I pulled the engine off the bike earlier and took the head off to look at the cylinder & piston, it all looks fine no scoring and the spark plug was a good dark brown color too, this engine has a pull start so I pulled it and wala, it just spun over just like it should, but I could hear a squeaking noise in the bottom end of the engine like it was dry, I checked everything I could see or try to wiggle and all seems good and tight, I pulled all side covers off and checked everything and seems good , I then turned the engine over until I could see the intake gap below the piston through the intake port, I sprayed a little silicone spray into the engine and spun it over again and the squeaking stopped and it spun very easy with no noise, I cant help but think that it leaned out real bad for a short time causing the lower end to dry out.... but, I have not run into this problem before so I'm unsure what to think about it, I'm gonna put the engine back on the bike in the morning and see what it will do now, I am also gonna mix my fuel with more oil instaed of the 70:1 full synthetic I'm running in my other engine and maybe go with about 32-40:1.

    Anyone else ever had this happen?

    Was I running to lean and is this the cause of the problem?

    Sorry this is so long but I wanted to get all the details in here.

    Shan
     
  2. Venice Motor Bikes

    Venice Motor Bikes Custom Builder / Dealer/Los Angeles

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    What ratio did you mix your oil??

    Maybe a bad main bearing???
     
  3. mapbike

    mapbike Active Member

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    I was running about 70:1 Full Synthetic Schaeffer 7000 which is what I run in my other engine and it runs great on it, Maybe I just should have put 2-3 tanks of a richer oil mix through it before putting the 70:1....???? Shrug....!

    I will find out tomorrow when I run it again if it is cooked on the lower end I guess!

    Yes you are right it very well could be a bad main bearing.
     
  4. Ted

    Ted New Member

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    70 to 1 runs good in the other engine because it's broke in, 16 to 1 is the brake in ratio, sounds like you got lucky and just had a mild seizure.
     
  5. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    16:1 is not really the break in ratio....UNLESS YOU READ THE TERRIBLE INSTRUCTIONS THAT CAME WITH YOUR KIT.

    If something is squeaking, it WILL RETURN.

    Time to find out what "made the noise".
     
  6. mapbike

    mapbike Active Member

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    Well guys I put the engine on the bench and have not done anything with it yet, I decided to just run the engine I have on my other bike, so I put the entire suspension front end off the new schwinn onto my old MT Bike and the suspension seat post as well and then I put handle bars off an old BMX bike I had, I also put fenders on the bike and now I have a bike built out of three different bikes that rides like a dream and looks pretty good for and old mountain bike that spends most of it's time on dirt roads, it aint fancy but it runs like a top with a 41T sprocket and this will be my 32 mile a day round trip to work and back when the weather is good, I just got a band brake set up in today that I plan to put on the back of it too, the old caliper brake on the back is not really good enough I go through brake shoes like crazy.

    Thanks for all the comments everyone and I will be tearing the other engine down before I try to run it anymore, I afraid I my cook it good if I dont find out what was locking it up.
     
  7. Ted

    Ted New Member

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    Would you share some info on the band brake.
     
  8. mapbike

    mapbike Active Member

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    Found on ebay, search bicycle band brake, there are 2-3 people selling them from $9 - $17
     
  9. Ted

    Ted New Member

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    I guess I should have been more to the point, how does one install it, are they good in the rain, what's the longevity of the band, is there another cable involved to make it work or is there another way.
     
  10. mapbike

    mapbike Active Member

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    It installs on the left side of the back wheel, they work in any weather, they will last many many many times longer than the standard caliper brake shoes that are typically on bikes, and yes it is cable operated.

    I can not give you any more details than this becuase I do not have it on my bike yet.

    Do a search on e-bay under bicycle band brake or just bicycle brake and you can take a look at the set up and see how it will work.

    usflg
     

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