Take it apart and have another look. How did you clean it? I tore the carb apart again and blew out all of the passages again. Is there a procedure for adjusting the air mixture control setting and the idle control setting??? Do you think a new choke cable would maybe resolve this? I did not examine the port very well. It has less than 1 quart of oil, the dipstick just sits on the case-dont screw it in. If the motor turns freely and there is spark, chances are good that the motor will run. I have tried everything to try and stop the fuel leaking out the overflow but its still happening.
Check the floats for damage by taking them out and shaking them lightly to see if there is gas in them, which would indicate a hole in the float, if thats the case. What, exactly did you do to the carburetor?? Yamaha 350 Moto 4 Carburetor - Welcome, thank you for visiting this simple website, we are trying to improve this website, the website is in the development stage, support from you in any form really helps us, we really appreciate that. Hey Guys; I have this Moto-4 80 that I purchased for my granddaughter. Not sure if this is correct, but it's running and idling pretty good. Seems like the choke is stuck but the cable moves freely. After charging the battery, which miraculously seems to still hold a charge after sitting all winter, I put some gas in it and with the help of some pliers turned the petcock to the reserve setting and turned it over.
It starts great, but misses and back fires when hold a stead rpm. Did you ever do a compression test? Had it running pretty darn good yesterday, but once it warmed up it started spewing oil out of what I think is a case breather tube, thought maybe the oil was low, and it was a little low so I topped it off. Anyways my question isnt what problem Im having Im sure some tinkering will figure it out, my problem is, adjusting the carb right, since theres several differant adjustment points, Im not sure which does what at the moment other then the bowl drain needle. It hangs straight down about an inch or two past the botom of the 4 wheelers frame. Hi all, I am new to this forum so please be gentle lol. So a little background on this little atv.
Your carb is now tuned simple. Still stalled when it was jostled around. I have checked play in the steering, ball joints, wheels, tyre pressure etc. The quad ran really well until I took it onto some rough ground to have a ride around, a few hours later the engine started to run really rough as if the engine was flooding. Put it all back together and I got it to idle by backing out the air mixture screw right hole almost all of the way out.
There is an adjustment screw just beside the choke lever, theres another one right next to that screw, and another one on the lower part of the carb near the bowl. Or is this a buy once, cry once deal? For now, some new carburetor parts are on the way and a fresh oem fuel petcock. In the course of riding over the years, the front air filter housing became broken, the seat was recovered by my mother who sewed a new one. If you have had good luck with aftermarket, where did you get it? With how it ran in the past, it might be due for a new top end rebuild but I was not able to test compression yet. The last issue was the tires being dry rotted and cracked and one not holding air at all. You will now have to source a carb and fit it to the 4 wheeler.
Noticed that both the idle mixture screw and the air mixture screw look about the same and are interchangeable. I have stripped the carb out and cleaned everything, but still the same. If this doesn't help get to idle, you will need to rebuild the carb. Fitting the carb is not too difficult. . I figured if I got it all back together and there was low compression or it still had issues that I could always redo the top end fairly cheap. Registration is free and will only take a few moments of your time.
This does not mean that the motor is in a good condition. We will share this website for you articles and images of wiring diagrams, engine schemes, engine problems, engine diagrams, transmission diagrams, replacement parts, fuses, electrical diagrams, repair manuals, wiring harnesses, fuse boxes, vacuum diagrams, timing belts, timing chains, brakes diagrams, etc. Then, with the engine idling fast, turn the mixture adjustment screw brass in several turns keep a count and out several turns again, it helps to keep track of how many turns and listen for the moment when the engine runs the fastest. I ordered some new tires Kenda K530 18×7-7 which are an inch bigger than the stock size but they still fit the bill. Check all of your vent lines on the carb. The two atvs were almost identical except the other one had red fenders instead of black. I plugged it and it spewed out of a crack in the breather hose a little further down!! Once I got the carburetor back on and the pod filter installed, it only took minor adjustments of the idle mixture and idle speed screws and she was purring like a kitten.
Idle speed is set to a smooth low idle. I had cleaned out the carburetor and fuel petcock, changed the fuel filter but the problem would not go away and made no sense why it was happening. Took my 250 to the mountains for the first time this year and blue smoke, too much gas again. I didn't have a carb kit is it available anywhere? The carb was varnished up, so I pulled it apart and cleaned it. When i pulled the carb apart I saw the screw doesn't even touch the linkage, it's too short.
Thread Thread Starter Forum Replies Last Post josh l. Somebody must have lost the spring for the pilot screw, as it's no longer in the carb. On most Mikuni carbs The screw that lines up with the middle of the slide and often has a spring on its shaft to stop it moving is the idle screw, it merely lifts the slide to increase engine revs, the same as opening the throttle and will not change mixture or jetting. I seem to remember some going up under the tank that would get pinched and starve it for fuel. Has anyone got any thoughts on the problem or could suggest whats causing the fuel leaking out the overflow.
I have fixed many and many bikes by simply removing the carb bottom and cleaning it with carb cleaner. However, here are some basic tests. New tires, air filter, and freshly rebuilt carburetor, and she runs like a champ! Has anybody seen this before on a Yamaha? I have a yamaha moto 4 yfm200. Routine servicing of the aircleaner would keep the carb clean for life. Oct 09, 2014 yes there is a tube that goes on it.