Kymco agility 50 4stroke

[mekascoot1]

Hi guys .
I have a special problem with a kymco 4stroke.
I've been working on it for about 2 weeks and still no succes in finding the problem.
At first the bike was brought to me for hard start and no power to climb hills and a maximum top speed of 50 km/h per hour.
The bike had been poorly stored for winter so i proceded to remove and clean the carburator.
Replaced the fuel in the tank and tested the fuel valve and installed a brand new gas filter.
I put back the carb on the bike and started it ..and proceded to adjust the air/fuel mixture....
But then i noticed that as soon as i would put the engine under load like a w.o.throthle the bike would flood itself..and loose all power..and if you insist the bike could eventually stall...
I took the carb apart a second time cleaned it again...inspected the intake and spacer...
Reinstalled the carb...but still no results...
Thinking i might have caused the problem i ordered a new carb just to make sure.
Installed it and bang trouble was still there.
I procede to check the ignition system...
Found a number6 plug (hotter)instead of a 7 anyway i replaced it with a new one.
I had a brand new coil in stock..installed it..
I had also ordered a unrestricted c.d.i from naraku...tried it on..no results..
Tested the resistance of the pick up coil...the results where in tolerance...
Tested the voltage found it was a bit low..i adjusted the pick up to .010 mil.
Tested all the electrical connections and wires one by one...everything is ok.
The battery is also brand new.
Charging system at 14.2v..
Checked the compression pressure tested at 120.
Checked the valves for leaks and nothing found..
Piston and cylinder in good shape..
Checked valve timing everything ok.
Checked ignition timing and good at idle but my timing light acts funny at higher rpms so i cant really be sure if i have full advance .
The plug turns black and bike still flooding even with needle in the carb set to the leanest position and main jet installed was 80..went as low as 60 and still the engine dies under load and the plug comes black.
My next step is replacing the pick up coil...
I can only think of a bad ignition timing or a bad spark at this point.
Any of you stumbled on that problem before?
I was hoping to be able to talk to the God of scoots.for any advice...
Thanks guys

[tocoo]

50 km/h is the usual speed for restricted scooters. Do you manage to make it idle for a like 15 minutes or more?

[diynuke]

Jun 19, 2018 3:36:05 GMT -5 mekascoot1 said:

Hi guys .
I have a special problem with a kymco 4stroke.
I've been working on it for about 2 weeks and still no succes in finding the problem.
At first the bike was brought to me for hard start and no power to climb hills and a maximum top speed of 50 km/h per hour.
The bike had been poorly stored for winter so i proceded to remove and clean the carburator.
Replaced the fuel in the tank and tested the fuel valve and installed a brand new gas filter.
I put back the carb on the bike and started it ..and proceded to adjust the air/fuel mixture....
But then i noticed that as soon as i would put the engine under load like a w.o.throthle the bike would flood itself..and loose all power..and if you insist the bike could eventually stall...
I took the carb apart a second time cleaned it again...inspected the intake and spacer...
Reinstalled the carb...but still no results...
Thinking i might have caused the problem i ordered a new carb just to make sure.
Installed it and bang trouble was still there.
I procede to check the ignition system...
Found a number6 plug (hotter)instead of a 7 anyway i replaced it with a new one.
I had a brand new coil in stock..installed it..
I had also ordered a unrestricted c.d.i from naraku...tried it on..no results..
Tested the resistance of the pick up coil...the results where in tolerance...
Tested the voltage found it was a bit low..i adjusted the pick up to .010 mil.
Tested all the electrical connections and wires one by one...everything is ok.
The battery is also brand new.
Charging system at 14.2v..
Checked the compression pressure tested at 120.
Checked the valves for leaks and nothing found..
Piston and cylinder in good shape..
Checked valve timing everything ok.
Checked ignition timing and good at idle but my timing light acts funny at higher rpms so i cant really be sure if i have full advance .
The plug turns black and bike still flooding even with needle in the carb set to the leanest position and main jet installed was 80..went as low as 60 and still the engine dies under load and the plug comes black.
My next step is replacing the pick up coil...
I can only think of a bad ignition timing or a bad spark at this point.
Any of you stumbled on that problem before?
I was hoping to be able to talk to the God of scoots.for any advice...
Thanks guys

You said the pickup wasn't really good so that could be a little thing.
valve timing should be ok then (as you said you checked)
And if everything is stock main jet 80 should be good.
but if you give throthle and it bogs down it sounds like a vacuum leak then. or a fuel issue. 
So i guess its air in your fuel hose's  and its normal for a scooter to bog down when you had your carb apart. because there is almost no fuel in the carb yet 


I Would say make a video, Remember a video say's a million words. and check for vacuum leaks with some brake cleaner

And with wide open throthle you say it bogs down. I almost would think its an clogged exhaust then.
so you could give it a try to loosen the exhaust studs and see what happens with that. if it can't get rid of its exhaust gasses it also won't have power. same effect as blocking the inlet 

[GrumpyUnk]

I have not read that the air filter was checked for dirt, crumbs, leaves, grass or small critters. If the filter is clogged, the engine will flow fuel at higher speed, but not enough air to match the fuel. Result is a rich or over-fueled condition. Take a look, it can't hurt. Be ready for nesting critters to attempt to make their escape.
tom

[pinkscoot]

Are you sure you seated the diaphragm when you put the carb back together. Here are videos on how to test that.

[mekascoot1]

Ok this scoot is unrestricted. And yess it idles like a charm...i can even make it run a 600rpm's if i want it to...it's juste that it cannot accept more than a 1/4 to half throtle without dyingor misfire..the plug becomes black.

Jun 19, 2018 5:35:07 GMT -5 tocoo said:

50 km/h is the usual speed for restricted scooters. Do you manage to make it idle for a like 15 minutes or more?

[mekascoot1]

Jun 19, 2018 10:02:02 GMT -5 GrumpyUnk said:

I have not read that the air filter was checked for dirt, crumbs, leaves, grass or small critters. If the filter is clogged, the engine will flow fuel at higher speed, but not enough air to match the fuel. Result is a rich or over-fueled condition. Take a look, it can't hurt. Be ready for nesting critters to attempt to make their escape.
tom

Sorry forgot to mention the air filter is like new...the scoot as 2408 km/h only it's a 2013

[mekascoot1]

And also no restrictions what so ever..

Jun 19, 2018 11:49:02 GMT -5 mekascoot1 said:

Jun 19, 2018 10:02:02 GMT -5 GrumpyUnk said:

I have not read that the air filter was checked for dirt, crumbs, leaves, grass or small critters. If the filter is clogged, the engine will flow fuel at higher speed, but not enough air to match the fuel. Result is a rich or over-fueled condition. Take a look, it can't hurt. Be ready for nesting critters to attempt to make their escape.
tom

Sorry forgot to mention the air filter is like new...the scoot as 2408 km/h only it's a 2013

[mekascoot1]

Jun 19, 2018 6:54:09 GMT -5 diynuke said:

Jun 19, 2018 3:36:05 GMT -5 mekascoot1 said:

Hi guys .
I have a special problem with a kymco 4stroke.
I've been working on it for about 2 weeks and still no succes in finding the problem.
At first the bike was brought to me for hard start and no power to climb hills and a maximum top speed of 50 km/h per hour.
The bike had been poorly stored for winter so i proceded to remove and clean the carburator.
Replaced the fuel in the tank and tested the fuel valve and installed a brand new gas filter.
I put back the carb on the bike and started it ..and proceded to adjust the air/fuel mixture....
But then i noticed that as soon as i would put the engine under load like a w.o.throthle the bike would flood itself..and loose all power..and if you insist the bike could eventually stall...
I took the carb apart a second time cleaned it again...inspected the intake and spacer...
Reinstalled the carb...but still no results...
Thinking i might have caused the problem i ordered a new carb just to make sure.
Installed it and bang trouble was still there.
I procede to check the ignition system...
Found a number6 plug (hotter)instead of a 7 anyway i replaced it with a new one.
I had a brand new coil in stock..installed it..
I had also ordered a unrestricted c.d.i from naraku...tried it on..no results..
Tested the resistance of the pick up coil...the results where in tolerance...
Tested the voltage found it was a bit low..i adjusted the pick up to .010 mil.
Tested all the electrical connections and wires one by one...everything is ok.
The battery is also brand new.
Charging system at 14.2v..
Checked the compression pressure tested at 120.
Checked the valves for leaks and nothing found..
Piston and cylinder in good shape..
Checked valve timing everything ok.
Checked ignition timing and good at idle but my timing light acts funny at higher rpms so i cant really be sure if i have full advance .
The plug turns black and bike still flooding even with needle in the carb set to the leanest position and main jet installed was 80..went as low as 60 and still the engine dies under load and the plug comes black.
My next step is replacing the pick up coil...
I can only think of a bad ignition timing or a bad spark at this point.
Any of you stumbled on that problem before?
I was hoping to be able to talk to the God of scoots.for any advice...
Thanks guys

You said the pickup wasn't really good so that could be a little thing.
valve timing should be ok then (as you said you checked)
And if everything is stock main jet 80 should be good.
but if you give throthle and it bogs down it sounds like a vacuum leak then. or a fuel issue. 
So i guess its air in your fuel hose's  and its normal for a scooter to bog down when you had your carb apart. because there is almost no fuel in the carb yet 


I Would say make a video, Remember a video say's a million words. and check for vacuum leaks with some brake cleaner

And with wide open throthle you say it bogs down. I almost would think its an clogged exhaust then.
so you could give it a try to loosen the exhaust studs and see what happens with that. if it can't get rid of its exhaust gasses it also won't have power. same effect as blocking the inlet 

Removed the exhaust also and still present...and yess there is enough fuel...i tried a new pick up coil this morning but no results...
I have a video just dont know how to post it yet

[mekascoot1]

Jun 19, 2018 10:22:18 GMT -5 pinkscoot said:

Are you sure you seated the diaphragm when you put the carb back together. Here are videos on how to test that.

Yes diaphragm seated and also installed a brand new carb...same condition

[mekascoot1]

Jun 19, 2018 6:54:09 GMT -5 diynuke said:

Jun 19, 2018 3:36:05 GMT -5 mekascoot1 said:

Hi guys .
I have a special problem with a kymco 4stroke.
I've been working on it for about 2 weeks and still no succes in finding the problem.
At first the bike was brought to me for hard start and no power to climb hills and a maximum top speed of 50 km/h per hour.
The bike had been poorly stored for winter so i proceded to remove and clean the carburator.
Replaced the fuel in the tank and tested the fuel valve and installed a brand new gas filter.
I put back the carb on the bike and started it ..and proceded to adjust the air/fuel mixture....
But then i noticed that as soon as i would put the engine under load like a w.o.throthle the bike would flood itself..and loose all power..and if you insist the bike could eventually stall...
I took the carb apart a second time cleaned it again...inspected the intake and spacer...
Reinstalled the carb...but still no results...
Thinking i might have caused the problem i ordered a new carb just to make sure.
Installed it and bang trouble was still there.
I procede to check the ignition system...
Found a number6 plug (hotter)instead of a 7 anyway i replaced it with a new one.
I had a brand new coil in stock..installed it..
I had also ordered a unrestricted c.d.i from naraku...tried it on..no results..
Tested the resistance of the pick up coil...the results where in tolerance...
Tested the voltage found it was a bit low..i adjusted the pick up to .010 mil.
Tested all the electrical connections and wires one by one...everything is ok.
The battery is also brand new.
Charging system at 14.2v..
Checked the compression pressure tested at 120.
Checked the valves for leaks and nothing found..
Piston and cylinder in good shape..
Checked valve timing everything ok.
Checked ignition timing and good at idle but my timing light acts funny at higher rpms so i cant really be sure if i have full advance .
The plug turns black and bike still flooding even with needle in the carb set to the leanest position and main jet installed was 80..went as low as 60 and still the engine dies under load and the plug comes black.
My next step is replacing the pick up coil...
I can only think of a bad ignition timing or a bad spark at this point.
Any of you stumbled on that problem before?
I was hoping to be able to talk to the God of scoots.for any advice...
Thanks guys

You said the pickup wasn't really good so that could be a little thing.
valve timing should be ok then (as you said you checked)
And if everything is stock main jet 80 should be good.
but if you give throthle and it bogs down it sounds like a vacuum leak then. or a fuel issue. 
So i guess its air in your fuel hose's  and its normal for a scooter to bog down when you had your carb apart. because there is almost no fuel in the carb yet 


I Would say make a video, Remember a video say's a million words. and check for vacuum leaks with some brake cleaner

And with wide open throthle you say it bogs down. I almost would think its an clogged exhaust then.
so you could give it a try to loosen the exhaust studs and see what happens with that. if it can't get rid of its exhaust gasses it also won't have power. same effect as blocking the inlet 

How do you post your videos ..i have one i'd like to share

[diynuke]

Jun 19, 2018 12:06:02 GMT -5 mekascoot1 said:

Jun 19, 2018 6:54:09 GMT -5 diynuke said:

You said the pickup wasn't really good so that could be a little thing.
valve timing should be ok then (as you said you checked)
And if everything is stock main jet 80 should be good.
but if you give throthle and it bogs down it sounds like a vacuum leak then. or a fuel issue. 
So i guess its air in your fuel hose's  and its normal for a scooter to bog down when you had your carb apart. because there is almost no fuel in the carb yet 


I Would say make a video, Remember a video say's a million words. and check for vacuum leaks with some brake cleaner

And with wide open throthle you say it bogs down. I almost would think its an clogged exhaust then.
so you could give it a try to loosen the exhaust studs and see what happens with that. if it can't get rid of its exhaust gasses it also won't have power. same effect as blocking the inlet 

How do you post your videos ..i have one i'd like to share

I use Youtube so just upload it on youtube as an unlisted video and share the url here then only the people here on the forum can see it