Post by austin on Aug 6, 2015 21:36:25 GMT -5
Hey there,
I am new to the forums to please excuse me if I ask already answered questions. I have ran into some problems with my scooter. It is a 49.5cc Dykon JK50QT-A. The problems started when I was having starting issues. It would take a bit longer to start than new, which I figured was just the normal course of events with the battery. It finally got to where it would bog out and cut off after first starting the engine and riding a short distance. It would be fine one it warmed up.
Alright, so that was annoying enough. Near the end of the problems it begin to not start for like 20-30 minutes of kickstarting, which I knew wasn't normal. I checked the valves (scooter at around 1900-2000 km or miles as I'm not sure what it measures in since the speed it measured in km/h with mi/h in small font) and found the exhaust valve had almost no gap at all. I couldn't even fit a .002 inch guage in it and the intake valve was at .004, which I read is normal for it.
I readjusted the exhaust valve back to .004 inch and installed a new spark plug. The scooter started right up and I took it to the corner stop sign for a short road test. It ran fine and I thought the problems were gone as it no longer cutoff whenever I stopped after just starting the engine like I mentioned earlier. I dediced to take it for a about a 7 mile trip to a friends house to get my battery charged. Halfway through the trip - the scooter started slowing down and had no acceleration until it finally cut off.
I thought it was odd because I felt what seemed like an engine seize, but I wasn't sure as the gas wasn't exactly new. The scooter would not start back up for around 20 minutes. I got it started and continued my journey to no avail as the scooter cut off again a short distance down the road. This repeated one more time and then the engine wouldn't start at all or would cut off as soon as I tried to accelerate.
I pushed it to my friends house and let it set over night. I tried to start it in the morning to no avail and I was never able to get it to crank up again. I checked for spark, which is a good blue. I checked that it was getting gas, which it was to both the carb and cyclinder as the spark plug would be wet with gas. I rechecked the valves and tried the other recommended settings I could find, which proved futile.
I finally found a compression gauge and checked it. The highest reading I could get was around 65 psi. I took the valve cover, head, and cylinder off to check those next. I noticed little wear on the rings or cylinder in a visual inspection and by running my finger across them; however, I know this isn't exactly the recommened way to inspect them. I put those back together and checked the valves for leaks next. I looked up a way to checked them by pouting a solvent such as gas or alcohol into them.
I took the head completely off, so I assumed that both valves should be sealed shut. I poured the solvent into the intake valve an it didn't leak out of the other side; however, when I did it with the exhaust valve - it leaked a good amount. I purchased a new head w/ valve assembly to fix this along with new gaskets. I reinstalled all of them and put the engine back together along with the cooling shroud.
I tried starting the engine, but it still wouldn't crank at all. The engine would turn over seemingly fine and the timing was correct. I no longer had access to the compression guage, but I could feel a little more compression from the exhaust compared to the old head assembly. I believe I could have worn rings now or potentially a worn cylinder/piston. Does this sound plausible or am I completely off on my judgement?
Thank you and I appreciate any help you can give!
I am new to the forums to please excuse me if I ask already answered questions. I have ran into some problems with my scooter. It is a 49.5cc Dykon JK50QT-A. The problems started when I was having starting issues. It would take a bit longer to start than new, which I figured was just the normal course of events with the battery. It finally got to where it would bog out and cut off after first starting the engine and riding a short distance. It would be fine one it warmed up.
Alright, so that was annoying enough. Near the end of the problems it begin to not start for like 20-30 minutes of kickstarting, which I knew wasn't normal. I checked the valves (scooter at around 1900-2000 km or miles as I'm not sure what it measures in since the speed it measured in km/h with mi/h in small font) and found the exhaust valve had almost no gap at all. I couldn't even fit a .002 inch guage in it and the intake valve was at .004, which I read is normal for it.
I readjusted the exhaust valve back to .004 inch and installed a new spark plug. The scooter started right up and I took it to the corner stop sign for a short road test. It ran fine and I thought the problems were gone as it no longer cutoff whenever I stopped after just starting the engine like I mentioned earlier. I dediced to take it for a about a 7 mile trip to a friends house to get my battery charged. Halfway through the trip - the scooter started slowing down and had no acceleration until it finally cut off.
I thought it was odd because I felt what seemed like an engine seize, but I wasn't sure as the gas wasn't exactly new. The scooter would not start back up for around 20 minutes. I got it started and continued my journey to no avail as the scooter cut off again a short distance down the road. This repeated one more time and then the engine wouldn't start at all or would cut off as soon as I tried to accelerate.
I pushed it to my friends house and let it set over night. I tried to start it in the morning to no avail and I was never able to get it to crank up again. I checked for spark, which is a good blue. I checked that it was getting gas, which it was to both the carb and cyclinder as the spark plug would be wet with gas. I rechecked the valves and tried the other recommended settings I could find, which proved futile.
I finally found a compression gauge and checked it. The highest reading I could get was around 65 psi. I took the valve cover, head, and cylinder off to check those next. I noticed little wear on the rings or cylinder in a visual inspection and by running my finger across them; however, I know this isn't exactly the recommened way to inspect them. I put those back together and checked the valves for leaks next. I looked up a way to checked them by pouting a solvent such as gas or alcohol into them.
I took the head completely off, so I assumed that both valves should be sealed shut. I poured the solvent into the intake valve an it didn't leak out of the other side; however, when I did it with the exhaust valve - it leaked a good amount. I purchased a new head w/ valve assembly to fix this along with new gaskets. I reinstalled all of them and put the engine back together along with the cooling shroud.
I tried starting the engine, but it still wouldn't crank at all. The engine would turn over seemingly fine and the timing was correct. I no longer had access to the compression guage, but I could feel a little more compression from the exhaust compared to the old head assembly. I believe I could have worn rings now or potentially a worn cylinder/piston. Does this sound plausible or am I completely off on my judgement?
Thank you and I appreciate any help you can give!
for that?