Wheel, Gear Spin freely with clutch engaged or disengaged

Discussion in 'Frame Mounted Engines' started by ola, Oct 21, 2014.

  1. ola

    ola New Member

    Please forgive me if this is answered somewhere else. I tried searching first but didnt find post on this.

    Here is my problem I have an 80cc engine installed on my road bike. Here is the engine I bought and installed: <http://www.ebay.com/itm/80CC-BICYCLE-MOTOR-KIT-COMPLETE-MOTORIZED-BIKE-KIT-BLACK-PEARL-ENGINE-2-CYCLE-/371137070183?pt=Motorcycles_Parts_Accessories&hash=item56697e4467&vxp=mtr>

    Got everything working on Sunday and it worked well Sunday afternoon and for a quick 15min ride Monday night and then something happened where the engine still ran but it acted as if the clutch was disengaged allowing the wheel to spin freely. So no the wheel spins regardless of the clutch. I thought that maybe the pressure plate wasn't being released or that there was something going on with the clutch cable so i checked the cable and all ok. Then i removed the cover to expose the pressure plate and see that the plate is being pushed and released fine. When the clutch is squeezed the outer gear around the plate spins freely when the wheel it spun. When the plate is seated then everything spins when the wheel is spun. Seems that something inside the engine is not doing what is supposed to do. Has something broken or been sheared off?

    If the engine is off and the wheel is spun there is very little resistance and the piston does not move.

    Any help would be greatly appreciated. I can post videos or pictures or anything requested to help with the resolution.
    Thanks for any assistance you can provide.

    Ola
     
    Last edited: Oct 21, 2014

  2. butre

    butre Well-Known Member

    if it doesn't spin freely with weight on it, that's fairly normal. you might benefit from adjusting the cable tension a bit but my experience says that it's nothing to worry about
     
  3. piecepatrol99

    piecepatrol99 Member

    I had a similiar issue when my clutch cable frayed and jammed inside the sleeve. If you've already checked that, next in line is the 'flower nut' on the clutch it self.
    I've also heard mention of where the clutch arm pivot actuates the clutch shaft wearing down and limiting travel. But if this is a new purchase/set up, that shouldn't be it.
    The last bad news is, is it possible your clutch shaft snapped in half? You would still see movement on the clutch plate when working the lever. But it needs to spin to move you. If its broken, going no where fast...
     
  4. dougsr.874

    dougsr.874 Active Member

    Sounds like the small drive on the end of the crankshaft is either broken or key shearded. if this gear is turning but piston is not moving then thats what it is.
     
    piecepatrol99 likes this.
  5. ola

    ola New Member

    Is there any picture or "how to" on confirming that this is what is going on and then fixing this?
    Thanks!
     
  6. ola

    ola New Member

    So it was the Woodruff Key. Don't know what happened but seems it didn't even have one on under the gear. I bought a wooddruff key assortment kit from HF but none fit so i had to use my angle grinder to shrink one down to size. Seems things are spinning like they should be now. Any idea where to get the right size key from so i can buy spares?
     
  7. piecepatrol99

    piecepatrol99 Member

    Kingsmotoredbikes should have what you're looking for. Just in case I spelled that wrong, try pistonbikes.com or thatsdax.com

    Hope you get rolling soon...
     
  8. ola

    ola New Member

    So thanks for the replies... I got everything back together and now hear the pistons moving like it should but try as I might I can not get the bike to start. I read another string on troubleshooting bike not starting and did everything including removing the kill switch and replacing spark plug. (even though had strong spark with stock plug). Is it possible for timing on this little engine to get off. Maybe when i was turning the shaft and trying to troubleshoot the woodruff key problem? I have checked the carb and verified its full of fuel and appears to be working. After alot of none starts oily black fuel is dripping from exhaust. I'm at the end of my options and have no idea what to try next.
     
  9. dougsr.874

    dougsr.874 Active Member

    As far as I know the timing can not be screwed up on these engines....if you have a bright blue, or white spark at the plug itself then that's not it....however , under compression some plugs can fail I had an NGK plug that did that....Too much oil in the gas or a stopped up muffler. I assume you have compression ....(break a ring when reassembling)
     
  10. ola

    ola New Member

    Guess I can pull the head off again and verify that the piston is good. dont think i messed up a ring though rings were already not full circles. There are breaks in them around piston where the two dots are. But pretty sure this is normal. Will circle back after I pull the piston and check that everyhting there is fine. How can the muffler get clogged? Also how do i check that and if needed clean it? It is a pretty new engine with less than 30min ride time on it.
     
  11. piecepatrol99

    piecepatrol99 Member

    Is it possible the carb is running too rich? Flooding the cylinder before the motor can fire...
    If its stock thn that would be last place to look.

    Is it possible you spun the rings? The gap in the rings (for installation) need to be in a specific position to one another to prevent too much blow by. Could be another source of low compression.

    I've changed the jet in my carb and opened the exhaust to match the dual boost bottle kit I installed. I'm running great except...
    After long run times, (I use my bike to commute) the exess unburned fuel carmelizes and coats the plug. After I've ridden 14 miles, what ever stop I make has to be quick. Gotta get the motor fired again before it cools off or its a fight to start.
    I've yet to add a piece of sand paper and a 3/4" socket to my tool bag, so fight it is until I get the jet changed to a smaller one.
     
  12. ola

    ola New Member

    What does this mean and how do i Fix it? How do I know if it is running to rich and also the oil/gas mix was 8oz:1gallon as suggested for break in period. Looking to find out any options to resolve this and get it started again.
     
  13. ola

    ola New Member

    Oh. forgot to add that I looked at the piston and the rings appear to be fine. Also torqued the head bolts at 12ft/lb per another post. And checked the muffler. Even went so far as to remove it all together. Very loud pops occurred without it. Still no start. Seems black fuel is dripping from the pipe and/or pipe hole so thinking fuel must be getting to the cylinder. getting puddles of black fuel.
     
  14. piecepatrol99

    piecepatrol99 Member

    Could be the break in mixture is too much oil for the plug to burn. That would explain the black...

    I haven't had my 2 stroke apart yet. I'm going what I know about 4 stroke engines. There can be as many as 4 rings on a piston to keep the compression/combustion in the cylinder and not blow by in to the crank case. (4 rings is a really high compression engine) the gaps in the rings (if there is more than one) are usually 180 degrees from one another. So what ever gets past the top ring, very litle gets past the next. If the ring gaps are less than 90 degrees from each other, that can ge a source of low compression.

    Also if you search youtube for "how to diagnose magneto loop" you'll find the specs for the ohm resistance ratings you should get from the loop and coil. You can confirm or deny an electrical failure as failure to start cause.

    You got carb, compression, and electrical to look at. These engines are not to complicated but tend to act like a computerized paper wieght when trying to diagnose them...only other thing I can think of is a broken or loose wire...
     
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