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Curtis Underwood

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Curtis Underwood last won the day on June 16 2022

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  1. To start with on the fuel pump, it should have three hose connections. One is the out to carburetor, one is from fuel tank, and one is a vacuum from the crankcase. The pump has diaphragm that the vacuum from the crank case pulls back and forth to pump the fuel if these lines are not on the correct places, it will not pump correctly but can give some fuel depending on the way it is connected. After market fuel pumps may look the same but hook up different and also, they can be bad from the factory. I had one I bought on eBay that would pump with line to carb off and not pump with line on. I replaced it with another one and solved the problem. The carb that runs good with just main lining to the card is probably a good carb and the others are probably even if one is an OEM carb. Most carbs are made in China even OEM ones. My advice is to check to make sure the hook ups to the fuel pump is correct and if it is, replace the pump because that is where your problem most likely is with the carb you have mainlined, and it ran well. I have heard aftermarket stuff is junk well I have used a lot of both OEM and after market and have had problems with both. I bought a new OEM carb for a Yamaha and had nothing but problems with it so I ordered an aftermarket. When it came in it was the exact same carb with exactly the same markings as the OEM and it worked, cost less and ran well.
  2. For some reason it posted before i finishe the comment and would not allow me to edit. So here is the finished comment. Those 4 wheelers all have issues with the carb needle valves which shut of the fuel to the carburetor when the carburetor bowl is full. Since you stated it was leaking from the carburetor overflow then the needle valve is not cutting it completely off. This can and does cause more problems then just fuel leaking out on the floor. It can flow back into the engine and into the oil through the rings. If this happens it will cause damage to the cylinders, main bearing and valve seals( you need to check oil and smell of it to see if oil has fuel in it). The vibration of running motor will usually cause the needle to close this is the reason they don't usually leak while running. But if you see them leaking while engine is running then the carb has to be cleaned or rebuilt. Mine leaks by the needle but I trun the pitcock valve to the off position as soon as I kill it. This prevents the overflow which in most cases only happens when you stop the engine. Those pitcok valve have orings in them that do go bad and will allow fuel to pass the pitcock. To check to see if your pitcock valve is working correctly turn it to off position and disconect fuel line to carburetor. If fuel continuously runs out, the pitcock valve is bad so you need to replace it. I have replaced carburetors on several machines because of this issue. The problem is those Chinese carburetors which is sold online and sold by OEMs are not very good. You might get one out of 3 that does not start leaking by the needle either as soon as it is put on or with in a week. Cleaning them some times will stop issue for a month or two.
  3. Those 4 wheelers all have issues with the carb needle valves which shut of the fuel to the carb when the carb bowl is full. Since you stated it was leaking from the carb overflow then the needle valve is not cutting it completely off. This can and does cause more problems then just fuel leaking out on the floor. It can floof back into the engine and into the oil through the rings. If this happens it will cause damage to the cylinders, main bearing and valve seals. Mine leaks by the needle but I trun the pitcock valve to the off position as soon as I kill it. This prevents the overflow which in most cases only happens when you stop the engine. Those pitcok valve have
  4. Does the engine have more than the 6 wires coming from it? The engine stator usually has three wires that goes to the rectifier/regulator, one or two wires from the ignition sensor (depending on if the sensor used ground or not), and a ground wire. The neutral switch is usually only one wire unless it has a shift indicator system, that gives which gear it is in then it might have a 6 wire connector. Then on most engines you have a coil with two wires running back to the CDI. Engines usually have either 9 wires to 13 wires coming from the engine going to the atv body. Engines on early model machines have: 1. 2 coil wires one that leads from the coil to the ignition/stop switches and the other to the CDI. 2. 1 neutral safety wire that prevents the starter engaging unless the switch is closed. 3. 3 stator wires that got to the rectifier. 4. 1 ground wire from stator to body ground on atv. 5. 2 sensor wires that got to the CDI unit. Engines on later model machines depends on the type electronic display if it has any certian wire: 1. 2 coil wires one that leads from the coil to the ignition/stop switches and the other to the CDI. 2. 1 neutral safety wire that prevents the starter engaging 3. 3 stator wires that got to the rectifier. 4. 1 ground wire from stator to body ground on atv. 5. 2 sensor wires that go to the CDI unit. 6. 6 wires from the shift switch (which includes neutral safety) 7. 1 wire from the oil pressure switch (optional) 8. 1 wire from the engine temperature switch (optional) So you see how complex it can get. If you can not get a print that is color coded for your engine and one for you ATV wiring harness then you will need to trace each wire on the engine and on the ATV harness to see what it goes to then hook it up to the corrosponding wire on the ATV. There is no easy solution without the prints.
  5. Frst and foremost. You will need the wiring diagrams for 250cc Zongshen engine and the 2002 Yamaha Blaster. Wiring on the engine itself has: 1. The stator/altenator wires that will connect to the your regulator/rectifier on your ATV. 2. The engine may also have a neutral safety switch wires, oil pressure switch wires and or temperature switch wires. It depends on the engine to what wiring it has. So unless you are good at identifying which wire does what. You will have to have the engine and ATV wiring diagrams. Then you if you are not real familar with electrical wiring, you should have someone that is do the connections.
  6. Well first thing first 😂. Lets start with standard troubleshooting. 1. Make sure battery is fully charged. 2. Drain the fuel and put new fuel in since it has been a year since you worked on it. Drain the carburetor. Fill with new fuel. 3. Check to see if it is firing by removing plug and turning it over. If it is not firing goto step 11 and if it is firing goto step 4. 4. Remove air filter and use 1 sec burst of starting fluid while turning over. If it ran for few seconds you have carburetor issues goto step 5. 5. Remove fuel line from carb use a cup to catch fuel and turn engine over to see if fuel is flowing (most artic cats have fuel pumps). If fuel is flowing goto step 9 6. Remove input line from fuel filter and turn engine over if you have fuel flow replace filter. 7. Remove fuel line that runs from tank to fuel pump. Lay the fuel hose lower than tank or use a hand pump to see if you have fuel flowing from tank(if you do it is a problem with the fuel pump). 8. The fuel pump on most of these use crankcase pressure changes to pump, if fuel pump hose to crank case is good and you turn the engine over with the tank line hooked up and no fuel flow out of the carb line then either one of two things is wrong you have a bad crankcase pressure leak or the fuel pump is bad. Replace pump and recheck. 9. Clean carburetor by removing caburetor, remove bowl, remove jets (use torch tip cleaners to clean jets out), Spray all ports and tubes with cleaner(Best to use a tank cleaner and let soak then use water to wash carb and blow out with air). 10. Put carb back together and try if it runs great but if not replace carburetor. 11. Not firing. This area get complex due to the CDI module has a lot of inputs and outputs that have to have the correct voltage for it to run. Below is a wiring diagram for a 400 Artic cat. Item 11 is the CDI module that controls the firing, Item 16 is the magneto and firing sensor, item 10 is the coil. As you can see it is complex. I could not find a decent diagram without purchasing the manual. But below is a diagram but not very readable. So if it is not firing we will have to work you throught it.
  7. Congrats. Getting any machine to run is an accomplishment and a learning curve. On your other machine you know now how to go about finding the problem. Trouble shooting for starting problems is the same for most ATV's and small engines. Good luck on finishing. As to the broke bolt Davefrombc is correct.
  8. This is what I would do with a machine that has had all this done. 1. I would set the valves. 2. Recheck the time making sure the timing chain tensioner is set so that the chain is tight and timing marks line up. 3. Close off the fuel to carburetor. Drain bowl. Leave fuel Off. 4. Check the oil level and make sure it is not thin which would indicate fuel in the oil. If run with fuel in the oil several things could happen. Engine damage from lack of lubrication, fire due to fuel in oil chamber. If oil is good do the following. 5. Turn engine over spraying a small amount of starting fluid in carb and see if it starts for a few seconds. The reason for this is to ensure you have everything set correctly before actually running the engine. If it does not run a few seconds then you have a firing problem or the carburetor is not allowing fuel/air to get through the throttle air control. I have actually done this with the carb off and it would fire off for a second but that is not advisable be cause a back fire could start a fire with carb off. 6. If it runs for a few seconds then I would take a clear hose and attach to the drain port on the carburetor and run it up the side of carburetor. Open the drain screw and turn the fuel on. The clear tube will show the fuel level in the carburetor and if the float is set correctly. Below is a pic of a Honda carb showing where the fuel level should be on most all the carbs. The fuel level should never get higher than 1/8 inch above where the bowl meets the carburetor if it does then it will flood and have fuel blowing back out of carb as the video you posted showed. Most carbs use where the bowl meets carb but some are 1/8 inch higher due to the way the carb is made. So check you manual for the proper level if it is shown otherwise use the picture belows level. 7. If it shows the correct level screw the fuel drain screw in to shut it off, remove the clear hose and put the drain/overflow hose back on. 8. Start the machine it should start and run. If it does not run then you have to start finding out why and most likely will be carb problem because it ran using the starting fluid. This is how I check one that I am having problems with and I usually find the issue faster doing this. Taking short cuts by not doing a step will cause you to miss somthing and you will end up going over and over the same things and still not finding the problem.
  9. If your battery on the bike is down the jumper battery may not bring the voltage up enough due to the connections, jumper battery state and wire size of the jumper cables so voltage drop may not raise up to a point of being good. The best thing to try is charging your battery, then starting it. Check and note the battery voltage before starting at the battery (should be 12.5 to 13 volts) then after it is started check the voltage again (this should be 13.5 to 14 volts at idle(just higher then the volatge noted before) and as the rpm increases this voltage should increase to a maximum of 14.5. This tells you you charging system is working. Your voltages may be slightly different as long as the voltage running is higher than the voltage with ignition off your charging system is working. Voltage readings depend on the meter you use which can differ from meter to meter so your meter may read 12.3 before starting and 13.3 running which would mean your charging system is working.
  10. I would like to see them going up hills and cross country. I don't know just got the feeling they will not be as good as a good old gas burner. Also what happens when they run out of juice you just can't run and get some fuel 😂
  11. opps, Did not see your coment above. For some reason while I was writing my comment you last comment was not showing up. You are correct to set the valves at .06mm and .11mm Reason being to loose will cause lose of rpm and power. But to tight will cause blow backs in carburetor. But be aware of what I said above your CDI uses 12 volts and if this gets low it will make it not start or hard to start.
  12. Yammy and Dave may well have hit on your problem. I would like to add one thing. Checking a regulator/rectifier may check good ohming it out by the manual but be bad. I just had one on a Honda that checked good by the test methods used in the manual but was bad and would kill the battery after and hour or two. The rectifiers checked good but inside the rectifier/regulator there is 6 transistors also that control the voltage output and there is no way to check these and that is what was bad in the one I just repaired. It also had a light bar on it. I did not look into it but it may be the light bars draw more current then the rectifiers can put out and causes these regulator/rectifiers to go out.
  13. I just had a Honda in for repair and found a problem that might be part of alexwv1863's problem. The honda came in with a charging problem. It would not charge the battery and would drain the battery if left connected. I started trying to figure out if the rectifier/regulator was good or bad. Lol 😂 The darn regulator checked good checking it using the method in the manual. All 6 Rectifiers checked .570 ohms forward and open reverse test. So I said must be the stator but since I am an Electronics tech I know that ohm tests do not allways prove true. I decide to check the Alternating voltage from the stator by starting the vehicle and measuring the voltage with engine running and that is when I ran into something that might be giving him a problem. You see by the time I had tested the system I had started the machine about 6 times and the battery was down to about 70 to 80% charge level(battery came in and was not full charge). Now It would not start (turned over fast) and acted just like he is describing his is doing trying and sounding like it would fire occasionally. Well I started trying to find out why the honda would not start and read the manual on what was supposed to read what on the CDI/ECM. It turns out that the CDI module on this honda has to have 12 volts supplied to it for it to fire and according to the print on alexwv1863"s machine it also has to have the 12 volts supplied. I measrued this voltage at the CDI and found it had while turning over only 9.5 volts. It stated in the manual it had to have 12.5 +- 2 volts for it to operate correctly. So it had low voltage. So I charged the battery and it started right up. I checked the voltage again at the CDI and it had 12 volts turning over and 13 volts at battery. The problem was the battery did not have high enough charge to prevent a voltage drop when the starter was turnung engine but it did show firing at the plug. I think what it was doing with the plug out was not dropping as much voltage and allowing it to fire but with the plug in the engine was harder to turn and so had a greater voltage drop. So it is possible that he has a voltage drop from his battery during turning over the engine causing it not to fire properly. BTW it turned out the rectifiers were good but the regulator part witch there is no check for in the manual, was bad so it was a bad regulator/rectifier. I proved this by checking the AC voltage from the 3 legs coming from the alternator to ground and got 37 volts AC on each leg. Then pluged in the old regulator to the stator with the battery connection disconnected at the regulator and check the DC out it had 6 volts DC output so regulator was bad. Bought a new one and fixed his problem. I am stubborn because I have to prove what is bad and why before I order parts. I am not just a part swapper.
  14. Davefrombc. Thank you. I have a degree in electronics and my Father was a master mechanic. I worked with him from time I was knee high to a grasshopper lol. I worked as a mechanic in service on hellicopters and then on trucks and cars for a few years. Then I decided I had enough of low pay(back then it was low) so I went into Industrial electronic. I am retired now, got burnt out doing electronic repair, 45 years of it is way to long and have a hobby that is trying to turn into a business of working on small engines. These electrical prints, ECM/CDI electronics are simple on small engines though the manufactures are tring to make them complex so shade tree mechanics can not work on them. I started out just doing some work on friends mowers and Atvs. I have never advertized but now have about 75 - 85 people that use me to repair everything, mowers, Atvs, motorcycles and Boats. But I draw the line and work only on smaller engines. I have had people wanting me to work on Trucks and cars because they know I know how but I am to darn old to do all the crawling around on them. As for parts and manuals I use the internet to hunt down what i need and sometimes I have to purchase those manuals.
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