Engine Trouble Engine wont start? TROUBLESHOOTING GUIDE

i have a piston question if anyone can answer it.
I have the head off the engine.
are u suppose to be able to see the manifold hole when your piston is all the way down? mine wont show but i can see the exhaust. (i had to swap out the top half and maybe this is my problem to my engine not wanting to start.)

ps it ran for about a minute at 5 miles and hour. never started again.:eek:

No you should NOT be able to see the intake port when the piston is all the way down in the cylinder.
You should only be able to see 3 ports.
1. Exhaust port.
2 AND 3. Left and right transfer ports.
 
Hi ; I bought all new electrical components before I read this. The addition of new CDI and Magneto did nothing to help my bike not starting.. went through the included guide Not the problem; still will not fire. I did pull the head and finally the body only to find a broken piston ring; no compression, no fire I guess?? Anyway, will order new rings tomorrow. I managed to break one ring then another, and then the third. Awful brittle lil gems!!!

I am sure there is an easier way to load the rings and get them back into the cylinder. I tried just squeezing them but found it very difficult. A friend said he uses hose clamps. If you know an easier way, please let me know. Also, if anyone can tell me where , other than off the internet, i.e. bike shop, moped shop, etc. that might sell what I need, it would be appreciated.

Thanks for the advice!

Gary

An engine needs 4 things to run (some folks say only 3 but that's only 3/4 of the whole pie.

1. Fuel
2. Air mixed with the fuel at the correct ratio (14.7 to 1)
3. Compression
4. Ignition

If you are missing any of these it will not run.

As for compressing the piston rings, I have always used my fingers when working on small displacement engines.
Some auto parts stores sell piston ring compressors for use on small engines, or you can use the hose clamp method too.

The trick to installing piston rings on 2-stroke engines is ensuring that the ring is both installed right side up and also that the end gap is centered over the locating pin in the piston's ring groove.

The locating pin is usually not installed dead center of the groove, but rather off center to either the top or bottom of the grove.
The piston ring ends will have an angle or a "rounded notch" on them to sort of hug around the locating pin. If the ring is installed up-side-down the pointy side of the ring end will hit the locating pin rather than allow the angle or "rounded notch" to properly hug the pin.
 
When the piston travels up in the cylinder it pushes the intake charge (gas and air mixture) into the combustion chamber (the dome in the cylinder head). This action is forcing the physical volume of the intake charge into a much smaller area thusly compressing it. If you have poorly sealing piston rings or a leaking head gasket the intake charge will escape past them reducing the compression and lessening the available charge in the combustion chamber. An engine may still be able to ignite the remaining intake charge and run but it will have very little power output and typically be hard to start.
 
My bike just broke down and I can't figure this one out. What if y can't kick start it to see if there us a spark? Normally if my clutch isn't engagedthe back tire is hard to rotate but will click as if trying to start but my bike won't click. I pedal and get speed going and pop the clutch out and all that happens is the back tire slowly locked up and makes a squealing noise. Can some one please help me.
 
Another bike wont start

I have a blue spark
the bowl has gas
the clutch engages the engine
but my readings on the multimeter=
Here are the specifications for the mag and CDI. You'l need a multimeter(under $5.00 @ harbor freight)
To check the mag set mutimeter @ 200 ohm (scale with pic of the upside down horse shoe on multimeter) use either lead red or black it doesen't matter for this test and touch the black wire with one lead and the white wire with the other, your reading should be around 2 ohm mine 2.5. Next using your lead wires from multimeter check the blue wire to the white wire, should read around 300 to 400ohm's.mine 348
To check the CDI set the multimeter @ 200k same scale as above. POS. lead (red one) to blue wire neg. lead (black one) to black wire, should be no activity on multimeter mine o l (infinite) reading. Next POS lead on black wire and Neg. on blue wire should read about 130 to 150 k ohm's mine 7.8. Next POS. lead on Spark Plug wire and Neg. on blue, should read about 135 and 155 k ohm's mine 7.8. Next POS. lead on plug wire and Neg. on black wire. should read 2.5-2.7 mine 2.3
 
Is your gas on, or do you have a clogged fuel line??? Clogged filter? Gas tank filter plugged??
 
gas is on and its also in the carb bowl so to that point I dont think it's a gas problem to that point of course. I really want to know what the strange multimeter readings are that should be 130-150 and read 7.8 on miy cdi every other electrical checks to tolerance and I have insulated the wires from each other and eliminated the the kill switch
from the equation
 
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Remember you can destroy your CDI by pulling off the spark plug with the engine running or even juct cranking the engine with the spark plug lead open circuit

Kay so today i was riding and the part that connects the wire and the CDI to the spark plug has been loose and finicky scince i baught the bike. Sometimes when im going WOT / going over bumps at a fast pace the connecting peice comes undone and my engine dies. I sometimes get scared thinking something bad happend and soon realized that its the peice that rests on the spark plug that connects it to the CDI. Today though, ever scince that peice came loose my bike hasn't been the same. It was running weird then when i shut the engine off and tried to start it again it wouldn't start. Now the only way i can start it is to find a nice sized hill and peddle my *** off down the hill and crank the throttle. It putt putts and gets going WOT. Then as soon as i let the throttle go even a little bit or have to slow down it Putt Putt dies. I have been checking all sorts of things and nothing seems logical. Theres fuel getting in (probly flooded it plenty trying to make it work) the spark seems okay(im about to test it for a spark) and yeah. Does anyone else think it could be the CDI? / Does it sound like the CDI is dead?
 
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