Post by scooter on Jul 1, 2015 18:35:17 GMT -5
lain tvnacman crawford steve toddmaples EDIT:PLEASE SEE UPDATES IN RED. (Then green, then blue.)
2013 Bintelli Sprint 50cc 4 stroke won't start in spite of having spark, fuel, and compression.
EDIT:COMPRESSION GAUGE SAYS
PSI MAX.
I watched the spark plug make spark, I cleaned the carb and got fuel on my hand when cranking by covering the intake with my hand as a test for fuel flow,
(However, after several attempts at cranking the engine, the spark plug was not wet, not fouled or burnt either.)
the gas cap is vented, the vacuum lines appear to be working, activating the fuel petcock and letting fuel flow out the line, I adjusted the intake and exhaust valves properly, and compression feels good by the"stick your thumb on the hole" method. EDIT: COMPRESSION TEST SAYS PSI MAX.
On cranking, there is no sign of popping or attempting to start, in spite of having spark and probably good fuel flow. I also tested it with a used but working cdi and coil with no result. I think the gas should be okay and it smells pretty much like gas and the filter looks good. I sprayed some "extremely flammable" carb cleaner into the intake manifold and still no combustion. EDIT: ALSO TRIED STARTING FLUIDI'm thinking maybe weak spark? The battery is strong, indicating the battery and charging system are working properly. EDIT: ALSO MIGHT INDICATE ENGINE IS TOO EASY TO TURN OVER AND THAT'S WHY THE BATTERY IS HOLDING UP SO WELL TO SO MUCH CRANKING. I TURNED THE FAN BY HAND AND THE MOTOR DOESN'T FEEL LIKE IT'S VERY HARD TO TURN OVER AT ALL.
EDIT:ALSO THE DIPSTICK READ NO OIL, ALTHOUGH THERE APPARENTLY WAS AT LEAST SOME OIL IN IT.
ALSO, I PUT A LITTLE OIL IN THE SPARK PLUG HOLE. THIS WAS SUPPOSED TO TEST FOR COMPRESSION LEAKS IN THE RINGS. I BROKE THE COMPRESSION TOOL SO I DIDN'T GET TO RETEST COMPRESSION, BUT SOMETHING ELSE HAPPENED. I WAS ABLE TO GET IT TO CRANK UP FOR A FEW SECONDS WITH SOME BURNING WHITE SMOKE AS WOULD BE EXPECTED WITH THE OIL IN THERE. SO, I ASSUME MAYBE THE RINGS ARE LEAKY AND THE OIL HELPED THEM SEAL ENOUGH TO START THE ENGINE BY INCREASING COMPRESSION?
NEXT EDIT:
A leak down test showed some leaking, but putting air into the cylinder only made a hissing noise just before and after TDC with the valves still not touching the rocker arms. I think the cylinder may be damaged, or the rings, or the valves.
Another compression tester registered only 70psi.
I put oil in the cylinder and redid the test. The compression went up to around 120. I am suspecting the rings or cylinder or both.
Okay. Got a new head and cylinder on it, compression reads 125 with the kick starter. Scooter cranked up like a champ, but has a little smoke. I am told this might be the rings seating, and I sure hope so. If not.... I'll have to do it again. The bike also got a new variator, belt, fuel filter, valves adjusted, etc. It's running great. The owner is breaking it in, and I'm putting a new clutch on it this weekend. So far so good!
lain tvnacman crawford steve toddmaples geh3333
Final update:
Smoking has stopped and all is well. Done.
2013 Bintelli Sprint 50cc 4 stroke won't start in spite of having spark, fuel, and compression.
EDIT:COMPRESSION GAUGE SAYS
PSI MAX.I watched the spark plug make spark, I cleaned the carb and got fuel on my hand when cranking by covering the intake with my hand as a test for fuel flow,
(However, after several attempts at cranking the engine, the spark plug was not wet, not fouled or burnt either.)
the gas cap is vented, the vacuum lines appear to be working, activating the fuel petcock and letting fuel flow out the line, I adjusted the intake and exhaust valves properly, and compression feels good by the"stick your thumb on the hole" method. EDIT: COMPRESSION TEST SAYS
PSI MAX.On cranking, there is no sign of popping or attempting to start, in spite of having spark and probably good fuel flow. I also tested it with a used but working cdi and coil with no result. I think the gas should be okay and it smells pretty much like gas and the filter looks good. I sprayed some "extremely flammable" carb cleaner into the intake manifold and still no combustion. EDIT: ALSO TRIED STARTING FLUID
EDIT:ALSO THE DIPSTICK READ NO OIL, ALTHOUGH THERE APPARENTLY WAS AT LEAST SOME OIL IN IT.
ALSO, I PUT A LITTLE OIL IN THE SPARK PLUG HOLE. THIS WAS SUPPOSED TO TEST FOR COMPRESSION LEAKS IN THE RINGS. I BROKE THE COMPRESSION TOOL SO I DIDN'T GET TO RETEST COMPRESSION, BUT SOMETHING ELSE HAPPENED. I WAS ABLE TO GET IT TO CRANK UP FOR A FEW SECONDS WITH SOME BURNING WHITE SMOKE AS WOULD BE EXPECTED WITH THE OIL IN THERE. SO, I ASSUME MAYBE THE RINGS ARE LEAKY AND THE OIL HELPED THEM SEAL ENOUGH TO START THE ENGINE BY INCREASING COMPRESSION?
NEXT EDIT:
A leak down test showed some leaking, but putting air into the cylinder only made a hissing noise just before and after TDC with the valves still not touching the rocker arms. I think the cylinder may be damaged, or the rings, or the valves.
Another compression tester registered only 70psi.
I put oil in the cylinder and redid the test. The compression went up to around 120. I am suspecting the rings or cylinder or both.
Okay. Got a new head and cylinder on it, compression reads 125 with the kick starter. Scooter cranked up like a champ, but has a little smoke. I am told this might be the rings seating, and I sure hope so. If not.... I'll have to do it again. The bike also got a new variator, belt, fuel filter, valves adjusted, etc. It's running great. The owner is breaking it in, and I'm putting a new clutch on it this weekend. So far so good!
lain tvnacman crawford steve toddmaples geh3333Final update:
Smoking has stopped and all is well. Done.
