80cc engine will not start...

GoldenMotor.com

Tim Ford

New Member
Mar 17, 2009
6
0
0
68
Cambs, England
My 50cc was running great but after 500km it seemed like it was running out of fuel even though the tank was full. With lots of good advice from the forum, I did everything. Mike Jones from Tigertooth sent me a new CDI and I got a spark but alas no go. Got fuel and compression and spark, then as an old formula mech, it twigged. The left handed strangulated thurgle rod nurdler was jamming the bubble stick causing the waste gate and pop off valve to malfunction, one quick blow with a mallet and back to 500 hp. Do you think I would make a good politician? My engine still wont go but it seems to want to, even an occasional missfire. Sounds just like it used to but wont run but I think with choke I am getting a bit of assistance. No b/ shi1i, I was a Formula and Group C mech but this beastie has got me
 

Dave31

Active Member
Mar 1, 2008
11,199
47
38
Aztlán, Arizona
If you got fuel, comp, and spark. And you are sure there is no major vacuum leak. I would look into ignition timing.

Have you tried as new plug? Maybe it's fouled.
 

Tim Ford

New Member
Mar 17, 2009
6
0
0
68
Cambs, England
Most of you guys seem to know about starting the beasties but I cant work out why mine stopped, it just peterred out and that was it. I had done loads of miles and some pretty hard, appart from the usual gremlins, the beastie has run. Had everything to bits exept the main lump and I am now worried that I may be on the road of Biker Joe's theme song.
 

Tim Ford

New Member
Mar 17, 2009
6
0
0
68
Cambs, England
Hi Fairracing, checked stator and rotor. all fixings tight and nothing seemed to have moved. Will have to stick to my ATB for the rough. Had intake manifold off, gasket good but broke on splitting, no signs of leaks, replaced. No sign of h/gasket probs but next check. Know everything about 4 stroke but 2 stroke is pure witchcraft to me and I am a Druid.
 

Tim Ford

New Member
Mar 17, 2009
6
0
0
68
Cambs, England
Hi Fairracing, typed this once but it seemed to have vanished. I have checked the stator and rotor and all seems tight. No movement seems to have occured and all wiring looks ok. Had intake manifold off, broke gasket in doing so but no signs of leaks, replaced. Checked exhaust for blocks, none. Going to check the lump out next but there is no sign of head leaks ect. Nothing seems to be wrong with it but it stopped.
 

Norman

LORD VADER Moderator
Jan 16, 2008
2,605
6
38
71
pampa texas
check for spark you might have the kill switch shorted out if you have spark your wood ruff key might of sheared and the only way to know is to take the mag rotor off and take a look. the wires to the mags coil the part under the cover can break or unsolder one is very hard to see very fine wire that is the wire from all the coils winding if it breaks or is loose you will need to re solder it back on.
If you leave your bike out in the weather moisture can raise h3ll with the wiring water droplets will short it out you could have something as simple as a foweled spark plug systemmatically work through the systems one at a time you should be able to find the gremlin or gremlins.
something else is make sure you find the sweet spot on the fuel valve where it will flow the most fuel. The fuel valve on most have a screen inside the tank and they will gob off due to the BS inside the tank. You can pressure up the tank with your lungs as long as the tank is not too full for some reason the fuel filters will cause a stoppage a little pressure into the tank and away it will go the main jet can plug off and so can the float needle the choke is known to get onery at time and vibrate to the on position at times. A quick check with a compression guage will let you know if the cylinder is in good shape about 90 to 100 psig with the throttle closed should be in the good range.
The air filter will gob off with fuel/oil and over a short time it can cause a very rich condition wash it out with warm soap and water wring it out and install it dry as it will soon be oily by itself(no need to oil it unless you really want to)
Just some ideas to get you to think what is thecause of your problems these are dirt simple engines take your time and enjoy the little booger.
.duh.
Norman
 
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Tim Ford

New Member
Mar 17, 2009
6
0
0
68
Cambs, England
Thanks Norman, I have done everything except comp check. Investigating the rotor is todays project. The tank and carb and internal filter have all been thoroughly flushed, I have changed the fuel to eliminate that. I always filter my fuel through 7 micron mesh (because I have lots) so thats clean. If the timing has slipped it cant be much as the head and exhaust feel warm after 100 yds peddling and it does seem to offer a bit of assistance to the peddling but no run if the clutch pulled in. Thanks to all who have offered assistance. UK.bld.