|
|
Post by lavendje on Aug 21, 2008 7:49:17 GMT -5
I have a MC-05-50 Roketa. The day I got it on July 3rd, 2008 it fired right up so I took it to the road and it when 2 miles and shut off. I waited 20 seconds and it fired up again. I drove it home. I took it out the next day and it went 2.5 miles then shut off. I waited 20 seconds and it fired up again. I drove it home. After driving it for a few days without any problems I took it on a longer trip, 25 miles to work. At about 23 miles it shut off. I waited 20 seconds and it fired back up. I finished the trip to work. On the return trip home I went about 20 miles and it shut off. I waited 20 seconds and it fired back up. I drove it home. The next day I drove it to the store which is about 3 miles and returned. Pulling into the drive way it shut off. I waited 20 seconds and it would not start. I kept at it for several hours taking the carb off and checking the fuel flow, the CDI, the coil and spark plug wire, and the spark plug, replacing them all. Still nothing, it would just turn the crank and when I turned the throttle it would spin faster but not start. I put it all back together and I tried it several days till one day it started to spin faster and faster. Then it started. I went for a month without any problems then once again It stopped and will not start. I pulled the stator and magneto which are good. I have checked all the connections and they are good. Fuel flow and air intake is good. One thing that is in the back of my mind is the Auto choke. I don't know how to test it, and the voltage regulator. I thought that was part of the CDI, but if not I need to check it. Anyone have any other Ideas? I pulled the carburetor and checked the float. It is totally clean. It works properly. The injectors are not clogged. From my avionics days I feel it is an electrical problem. It started when the bike got warmed up. It was like an electrical component was getting hot had failing and I think that is why it would start after 20 seconds. Now it has gone completely and I am stuck finding the culprit. There is one component that I have not checked and need to locate. The rectifier is some were. I am about to strip the bike down so I can see very thing. Maybe it is in some obscure location. Oh it also can be the Stator. I took it apart and did not find any lose wires or connections but that does not mean it is putting out like it should.  Thanks in advance. Jeff |
|
|
|
Post by kkyolpep on Aug 21, 2008 9:28:39 GMT -5
I believe the rectifier is in front of the handle bars under the front plastic just above the horn. If your 50 Rok is like my 50 Rok that is.
When you say the scooter stops, are you meaning it stops when driving or after you have come to a stop it dies?
|
|
|
|
Post by Karl on Aug 21, 2008 9:37:24 GMT -5
Jeff, check for an open ground. A lot of people have had problems with the ground wires mounted over a painted surface.
I had a similar problem and my fuel filter, although it looked perfectly clean, was restrictive. I bypassed the fuel valve (vacuum petcock) and it still was restricted. Same thing with me. I'd wait about 20 seconds, the carb bowl would fill up and I'd be on my way. This happened to me when I was a WOT for about a mile.
Keep us posted.
|
|
|
|
Post by lavendje on Aug 21, 2008 10:02:07 GMT -5
When I say it stops I mean the engine would slow and then shut off. Now it just doesn't run. I have cleaned the carb even though it was not gummed up. The fuel flow is good. It puts out what it should. I just don't think it is getting enough spark. I have replaced the plug, wire, coil, and CDI and still nothing. It just sounds like it wants to start when I put a little more throttle. If I put to much it slows again. I had this problem before and it took a while but started again after a few days. I pulled the gas cap off and it is not vapor locked. So now I'm left with the Stator, Rectifier, and the Auto electric Choke.
|
|
|
|
Post by tortoise on Aug 21, 2008 10:23:33 GMT -5
I feel it is an electrical problem. It started when the bike got warmed up. It was like an electrical component was getting hot had failing and I think that is why it would start after 20 seconds. Related thread. |
|
|
|
Post by kkyolpep on Aug 21, 2008 11:08:30 GMT -5
I know you say that it is getting fuel, but it sure sounds like it isn't getting enough. When you say that it slows down and stops I would replace the fuel lines and filter. It is only a few dollars to do and it couldn't hurt. Just an easy thing to try before going after the electrical.  |
|
|
|
Post by lavendje on Aug 21, 2008 15:20:25 GMT -5
That had a good thread to it. I will be checking my stator as soon as I can.
Thanks
|
|
|
|
Post by lavendje on Aug 21, 2008 16:46:37 GMT -5
Ok I checked the stator. It has 517 ohms which is good. Although the instructions that were on the other thread had 3 wires going into the multi connection. Mine only had 2, a yellow and a white. The Yellow on the other connector is tide directly to grown so I check the yellow wire to the red an black wire.
I ohmed out the Auto Electric Choke. It has 8 ohms. I don't know if this is the correct ohms for the device. I then ohmed out the other end of the Auto Electric Choke connection. It has low ohms. I turned the ignition on and there was 40 mv going to the plug. I pulled the Auto Choke and it does nothing. I doesn't move in or out. Unless I push it, but not by its self.
|
|
|
|
Post by Karl on Aug 21, 2008 19:23:26 GMT -5
Easier to change the auto choke than the stator and cheaper too.
The auto choke rod will take about 20-30 seconds to protrude (or retract, I forget it's exact operation) once power is on. It's very slow moving. Measure it before switching key on and then again after about a minute. If it measures the same then obviously, it's failed.
I've never taken one apart but maybe it's an obvious problem. See if you can fix it before you have to buy one.
|
|
|
|
Post by lavendje on Aug 22, 2008 9:30:07 GMT -5
I measured it prior to turning it on and then during the entire time I had the left brake handle activated like I was going to crank it and it did not move any. Is 40mv enough to get this thing to move? I put down 40v but it was actually 40mv.
|
|
|
|
Post by indy50 on Aug 22, 2008 17:02:55 GMT -5
Are you sure you arent having a fuel delivery problem. ( Vacuum controlled petcock )
|
|
|
|
Post by indy50 on Aug 22, 2008 17:09:00 GMT -5
I measured it prior to turning it on and then during the entire time I had the left brake handle activated like I was going to crank it and it did not move any. Is 40mv enough to get this thing to move? I put down 40v but it was actually 40mv. To check your enricher, remove it from the carb and apply 12v dc to it. The needle should extend about 1/4" or so in a few minutes time. It really doesnt sound like a choke prob though. Is the bike just shutting down at once or does it kinda starve/stall out? |
|
|
|
Post by lavendje on Aug 22, 2008 21:23:19 GMT -5
It slows and then stalls out like it lost fuel or was flooded. So are you saying that 40mv is not enough to get this thing to move and it should be 12v?
The fuel system up to the carb is working as it should. Fuel is getting into the carb and the float tank is filling. If I tilt it to the left I can get fuel to come out.
I'm going to order the Auto Choke and the Regulator. I will replace one at a time and try it. I will let you know if one or both fix the problem.
|
|
|
|
Post by Karl on Aug 22, 2008 22:45:01 GMT -5
The cutting out when running makes me suspect of a coil/cdi.
|
|
|
|
Post by lavendje on Aug 23, 2008 6:12:34 GMT -5
Lets go over what I've already done.
1. Replaced CDI, Coil, and Spark plug. I get a spark. Is it hot enough, I don't know.
2. Checked fuel flow from the tank to the engine. Gas comes out. I did the test thats described in my Owners Manuel. First I pulled the hose off the carb and then, using the manual crank, pushed it down and let returned it to the start position. Fuel came out when I got closer to the bottom of the stroke. Showing that the vacuum lines are working properly.
3. Checked the vacuum lines, even though I'm getting gas to the carb. They are not kinked or crimped.
4. Replaced the fuel.
5. Replaced oil.
6. Pulled apart Carburetor. It was clean but I cleaned it again. Checked the Main and the Pilot. Both are spotless. I can see light through both. I did not use anything metal to clean it out. Returned the air-screw to its original 1.5 turns counter clockwise.
7. I have pulled the stator and flywheel. Checked connections on the Stator. They are good. Resistance on the Stator is 517 ohms. This is good. Put it back together. Checked the clearance on the from the flywheel to the Magneto .013. It is perfect.
8. I checked the timing. The flywheel has a marks on it that have a "T", "F", and two other marks. The "T" lines up with the mark on the engine and with the head cover off I can see the cam has the large hole at the top in the middle with the two smaller holes splitting the case on either side.
9. While the head cover was off I checked the Valve clearance, .004 on both.
10. Checked the resistance of the Auto Choke, 8 ohms. Unsure if that is what the Ohms should be.
11. Checked Voltage to the Auto Choke, 40mv. Unsure if that is what the voltage should be.
Has anyone checked the voltage going to their Auto Choke?
12. Checked the Ground wires on the chassis. Perfect.
13. Pulled the Air filter. Clean and not clogged.
14. Charged the Battery to full capacity.
15. Removed the Kill Switch from the circuit to rule out shorting.
So now what are we left with?
1. Rectifier.
2. Auto Choke, if the readings are wrong.
Is there anything else?
|
|
|
|
Post by Karl on Aug 23, 2008 10:36:07 GMT -5
Sounds like you have it covered and have almost solved it.
My wife works Saturdays and I have my 2 year old to watch, so I can't go out into the garage just yet. I'll go when he takes a nap....which will be in a few hours.....and measure the Ohms and volts of my scoot's auto enricher.
Nice writeup, Jeff!
Karl
|
|
|
|
Post by tortoise on Aug 23, 2008 11:00:26 GMT -5
The auto choke is really just one element of the carb low speed circuit . . nice to have but not absolutely essential during warm weather start-ups. If you have not already done so, pull the vacuum line off the intake manifold and squirt a few cc's of gas into the port, then re-attach the line. If it momentarily starts, that would indicate a fuel or vacuum related issue (possible cracked manifold). If still no joy, your electrical gremlin suspicions are probably correct. While troubleshooting, if the new coil was energized when not connected to a spark plug, the air-gap spike may have damaged it.
|
|
|
|
Post by lavendje on Aug 23, 2008 11:26:39 GMT -5
Sounds like you have it covered and have almost solved it. My wife works Saturdays and I have my 2 year old to watch, so I can't go out into the garage just yet. I'll go when he takes a nap....which will be in a few hours.....and measure the Ohms and volts of my scoot's auto enricher. Nice writeup, Jeff! Karl You sound like me. I have a 2 month old to watch during the week while my wife works. I'm on FMLA leave till the 1st. So I've been going to my shop while the baby is sleeping. I appreciate the help. |
|
|
|
Post by lavendje on Aug 23, 2008 11:34:44 GMT -5
The auto choke is really just one element of the carb low speed circuit . . nice to have but not absolutely essential during warm weather start-ups. If you have not already done so, pull the vacuum line off the intake manifold and squirt a few cc's of gas into the port, then re-attach the line. If it momentarily starts, that would indicate a fuel or vacuum related issue (possible cracked manifold). If still no joy, your electrical gremlin suspicions are probably correct. While troubleshooting, if the new coil was energized when not connected to a spark plug, the air-gap spike may have damaged it. I'll pull the vacuum line and try the gas trick as soon as I get some food in me. I don't think it's a cracked head. The scooter was brand new on the 3rd of July and I have been having problems with the shutting down issue for the entire time. It has just changed from starting after 20 sec to not starting for days and now not starting at all. |
|
|
|
Post by Karl on Aug 23, 2008 11:57:03 GMT -5
The auto choke is really just one element of the carb low speed circuit . . nice to have but not absolutely essential during warm weather start-ups. If you have not already done so, pull the vacuum line off the intake manifold and squirt a few cc's of gas into the port, then re-attach the line. If it momentarily starts, that would indicate a fuel or vacuum related issue (possible cracked manifold). If still no joy, your electrical gremlin suspicions are probably correct. While troubleshooting, if the new coil was energized when not connected to a spark plug, the air-gap spike may have damaged it. Tort, Will a scoot run with the auto-enricher removed or will it present an air leak? The choke's electrode tip seals a gap when at operating temperature, right? |
|
|
|
Post by Karl on Aug 23, 2008 12:00:50 GMT -5
Sounds like you have it covered and have almost solved it. My wife works Saturdays and I have my 2 year old to watch, so I can't go out into the garage just yet. I'll go when he takes a nap....which will be in a few hours.....and measure the Ohms and volts of my scoot's auto enricher. Nice writeup, Jeff! Karl You sound like me. I have a 2 month old to watch during the week while my wife works. I'm on FMLA leave till the 1st. So I've been going to my shop while the baby is sleeping. I appreciate the help. LOL, yes, as soon as my little one goes down for a nap, I'm going to undo my 70cc top end and put the stock 50cc one back on. I ordered a larger carb for the kit but it could be weeks before it gets here. With my current carb I need to rejet and ordered a few jets but they haven't arrived. Once I get all my parts in, I'll tackle it again. It's a 2stroke so it's only about an hour's worth of work. |
|
|
|
Post by tortoise on Aug 23, 2008 15:14:04 GMT -5
Will a scoot run with the auto-enricher removed or will it present an air leak? Never tried to run mine without the enricher installed. My guess would be that running the engine with the enricher removed would allow more air to enter the carb low-speed circuit, leaning out air-fuel mixture. The engine should start in warm weather even if a non-functioning enricher needle is stuck in the extended position (no enrichment jet fuel flow). |
|
|
|
Post by Karl on Aug 23, 2008 16:18:31 GMT -5
Well, I measure the Ohms of resistance on my auto enricher and I have to tell you beforehand....I'm very green when it comes to electronics.
The reading I got on my meaurement was about 30.
I ran my scoot with the enricher in place but unplugged. When I came to a stop, the scoot stalled. It did start up but not as easily as it normally does.
Hope that helps you some, Jeff.
Karl
|
|
|
|
Post by lavendje on Aug 23, 2008 16:24:12 GMT -5
Thanks. Could you tell me the voltage to the plug that it plugs into. You just put the black lead on one side and the red on the other. The auto chock does not have to be plugged in. You just have to squeeze the break to activate. If it is + or - 40mv then the input is fine on mine if not the I have a voltage rectifier problem.
|
|
|
|
Post by Karl on Aug 23, 2008 21:38:57 GMT -5
OK, I'll run out and check.....
Well, my voltmeter measures 1v-1000v.
However the minus sign blinked while I was testing the plug for the auto choke.
|
|
|
|
Post by lavendje on Aug 24, 2008 9:49:05 GMT -5
OK, I'll run out and check..... Well, my voltmeter measures 1v-1000v. However the minus sign blinked while I was testing the plug for the auto choke. That just means you have a volt meter that does not reverse the polarity. Just revers the plug and it should show 1v if it is less than a volt and don't forget to go through the normal start mod except for hitting the starter switch. |
|
|
|
Post by lavendje on Aug 26, 2008 7:06:06 GMT -5
The auto choke is really just one element of the carb low speed circuit . . nice to have but not absolutely essential during warm weather start-ups. If you have not already done so, pull the vacuum line off the intake manifold and squirt a few cc's of gas into the port, then re-attach the line. If it momentarily starts, that would indicate a fuel or vacuum related issue (possible cracked manifold). If still no joy, your electrical gremlin suspicions are probably correct. While troubleshooting, if the new coil was energized when not connected to a spark plug, the air-gap spike may have damaged it. I put a few cc's of fuel in and still no go. It didn't change anything. It sounded the same with or without the extra fuel. |
|
|
|
Post by leo on Aug 28, 2008 22:40:18 GMT -5
|
|
|
|
Post by allengrota on Aug 30, 2008 11:49:50 GMT -5
I think you have a loose electrical connector somewhere. It is not the enricher. The stator should be ohmed hot right after it stalls if you want to rule that out...There have been cases where they cut out hot and run ok cold, but you, my friend, have a loose wire somewhere. You need to check the back of the coil and every pin connector. Use a pick and tighten all pin and socket connections, then zip tie them together so they can't pull apart.
|
|
