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mxrider250br

04 yz450f carb leak

19 posts in this topic

my carb leaks after I park the bike out of the very last hose. The one on the bottom of the bowl. I clean and it won't leak for couple hours when I ride. Like I rode today and it was pouring gas at the end off the day. I have to change my fuel cock because even on off leaks a lil bit of gas but would it be my jetting? The needle ? Float getting stuck? Someone please help. This is pissing me off and makes me not wanna go ride. Thanks:worthy:

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did you tighten the fuel drain screw to much, I did and cracked the inside of the float bowl, had to get a hole new float bowl, if that is the case JD Jetting has one for a KTM that fits, I have not tryed to start my bike yet with it on, could be float needle but I am not sure, Hope this helps, please asks me any questions

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I tightened the screw that is like right above the line, yes. I will check that. I heard it could be float wit a hole and filling up wit gas and keeping the needle open from not being able to move up or down. Heard the needle could be old/worn. And heard jetting. Like a clogged and/or dirty jet.

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You have either got dirt trapped between the float needle and its seat, or the needle is worn out, and needs repalcement.

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Nothing yet. I had the petcock problem also. I bought a new petcock so I can stop the fuel when it's parked. It don't run out if the motor is running soit don't bother me too much with the new petcock, except it makes my bike look a little cheap...

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i pulled my bike in my garage today and started to take the carb out. i saw in another post her eon tt that to connect fuel line to carb, then run the gas and slowly mess with the float and see if it stops or not. i did first time right when i pulled it off and it leaked, so i went to show it to my friend and i came back put it back and when i pushed up on the float it stopped. and he said my needle valve dont look worn out and it doesnt really look like it either, so what im doing tonight is taking my carb to my buddies house and doing a theral (or how ever you spell it) cleaning, like spray air in the jets and stuff, and hopefully i'll find my troubles. i'll let you know tonight the outcome of that.

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My bike had similar problem. I took out the float and bent the little tab on it a little but up. I had to do it twice until it didnt leak at all but that's what fixed my problem

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did you have any more problems with it?? and mine did kinda look like it was a lil bit bent down. but even after you rode it still didnt leak?? cuz i fixed my yesterday before i rode, then when i was done it was spilling out gas like crazy.

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Yea no leaks i only went for a 15 min ride cause its still snowy and cold up here. But 2 drops came out when i put it on the stand. And i have a see-thru hose so I would stop every 5 mins riding or so to see if it leaked and no more leaking.

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My bike had similar problem. I took out the float and bent the little tab on it a little but up. I had to do it twice until it didnt leak at all but that's what fixed my problem
Bending the tab on the float is how the level is set. Bending it blindly without measuring the level that results from it is an invitation to a different set of problems you may not have yet, and don't need.

Download a manual and check/set your float level the right way.

http://www.yamaha-motor-europe.com/community/service/manuals.jsp

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Note that the method shown in the manual requires the carb be off the bike. You can, however check it in place, but you must be careful to take your measurements at the right position.

There is a spring pin in the needle itself to keep the bouncing of the float from affecting the seating of the needle. The level must be checked at the point where the needle has just contacted the seat, but the spring pin has not begun to compress.

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i just got my carb out of the bike and ill measure in a lil bit. i just barely got to squeeze a flat head in there. like a very thin one. maybe one or two millameters. but ill check.

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so i eye-balled it and looks like i have it at just a lil over a quarter of an inch. i got a petcock on the way and soon as its here ill asseble everything and see what happens. hopefully no more leaks

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man that's what fixed it. I rode it this past weeknd for about 4 hours and not one drop. Well except when my dumb a$z fell riding but that's normal. So yes people, try bending the tab. It worked for me. But make sure your needle is

not worn out or anything and that the seat is pretty clean.

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Very unlikely anything broken as mentioned. Most likely your needle/seat are just varnished from old fuel (I have a trx450 I just cured of the same problem). The right way is to take the carb off, the fuel bowls and wipe the varnish off the needle (of the needle/seat-not the slide needle). Reassemble. Cleaning a carb is FREE BTW.Your fuel petcock shouldnt matter if the carb stops fuel as advertised.

The half-ass way would be to pull the fuel line off, open the bowl drain screw, and spray carb cleaner into the fuel input on the carb. This in theory should eat away some of the varnish. If fuels leaking out the overflow tube, its probably also leaking into your motor. Hope youve been changing the oil frequently, or order some crank bearings too...:)

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