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wr426f help?????????

By bakeyz426f,
in WR400F/426F/450F

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jbrooks26

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I'm going to say this about the compression one more time. If you are concerned about compression loss, do a Leak Down Test. This will tell you if you are in fact losing compression, as well as leading you to where you are losing compression. If you have compression, fuel, and spark, and it is timed right, the engine will start.

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bakeyz426f

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i sprayed starting fluid in the air intake and the bike fired. i did this about three our four times and it fired everytime but stopped once the either ran out. im thinking its not getting fuel because a line is clogged or frozen. i have new gas in the tank. it still doesnt seem to have a ton of compression though. im going to try to heat the bike up and try starting it agian. is there anything that i could check in the carb without removing it?thanks for the help everyone im learning a lot from everyone on this site

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jbrooks26

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Sounds like the float could be stuck. On the bottom of the float bowl, you will see a small allen head screw, loosen this screw and fuel should flow out of the bowl drain. Make sure that the fuel is turned on, and it might be worth letting this run for a few minutes to flush any suspect fuel from the bowl. If you can't get any fuel out of the bowl, then you will have to remove it and clean thoroughly. This would indicate that the float is stuck, and if this is the case then you are due for a good cleaning. Let us know what you find.

Josh

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bakeyz426f

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it still will only run on starting fluid and when i try to give it gas while its running it dies. it does not seem to be getting fuel. i took the allen screw out that i think you were talking about. when i did gas poured ot for 10-15 seconds and didnt continue. i had the fuel on when i did this. i guess this means i have a clogged float? the screw i took out was not underneath the carb it was in the bottom right conner if your looking at the bike from the side with the rotor. Is it real diffucult to remove the carb and clean the float? ive never removed a carburetor before and from looking at the manual it looks like it has i thousand tiny pieces in it. thanks

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jbrooks26

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The screw I'm speaking about should be on the bottom center of the bowl, and it is right next to the float bowl drain tube. I'm not certain which one you removed. If you are not certain, you can remove the large nut from the bottom of the bowl, it gives you access to the Main and Pilot jets. Then turn on the fuel and see if it runs out of the bottom of the bowl. I would say that you probably need to remove the carb, and give it a good cleaning. Possibly even replace the needle and seat. There are a lot of small parts in there, but if you are careful, and take your time it is not difficult. No more so than changing your cam timing, just be careful and take careful note of the orientation of each part. Specifically with the slide and plate, those parts can be put in backwards and cause other problems. Good luck, and let us know what you find.

Josh

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bakeyz426f

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got the carb off and looked at the float. it wasnt real dirty but it was kind of stuck so when i pushed it it freed up. the pin on the float henge was pushed out unevenly to one side i think that may have been the problem. are all the jets located in the spacer by the float? also does the gas intake on the carb where the hose from the gas tank connects come out? in the manual it doesnt show it having threads and i was wondering if that could be clogged up some how and how it comes off? should i strip the carb of all its parts or should i just focus on the jets and float? would the float sticking have caused the engine not to get gas? when i remove the float bowl drain with the carb on the bike and the gas on should gas keep flowing out of the carb untill i run out of gas or shut the valve off? sorry for all the questions. thanks

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jbrooks26

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OK, this is a little out of order from your post, but I think I can clear this up for you.

Fuel comes intot he carb Float bowl fromt he fuel line into the swivel fitting (not easily removable anyway) and past the Needle and Seat (attached to the float by the pin you mention) and into the float bowl until the bowl fills to the set float level, and as the float rises in the fuel, the Needle contacts the seat to stop the flow of fuel. This reserve of fuel is then metered into the intake by several jets located in different locations within the float bowl. The Main, Needle, and Pilot jets are centrally located in the bowl. They are brass or copper colored, and difficult to miss. I recomend downloading a Yamaha manual for your bike and thoroughly going over the carb section. At a minimum, while you have the whole carb off, I would soak it overnight in some carb cleaner. It wont' hurt to submerge the whole unit. It would be better to take each part off of the carb, and soak them individually, but this should get you going again. I think you probably could re-install it and get the bike to run now that the float is free, but it may not seal up properly, and you may have some debris in the jets now. You should be able to blow (Low Pressure) air through the inlet swivel and feel it coming through the Neelde Seat area into the float bowl. Hope this helps, sorry if I'm rambling.

Josh

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bakeyz426f

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well i took out the jets in the spacers and blew them out(none of them were clogged.) the inlet swivel is where the gas line connects to the carb right? i tried blowing air through the gas hose while it was connected to the the swivel and i couldnt get any air to go through the carb it seemed.will this only work with low pressure air? i was thinking something in the swivel inlet could be clogged because i couldnt seem to blow any air through the gas hose. while i was putting everting back together i couldnt get one of the float bowl allen head screws to tighten up and when i took it out to look at the threads some of the threads came out with the bolt so now i have another problem. could i tap it out bigger or does it have to be heil- coiled to fix it? its in one of the corners where the idle adjusment attaches to. going to try to get this fixed tommorow so wat should i do aboult the srew? where could i get i heil coil that size at?

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bakeyz426f

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the pliot jet was the only jet that was dirty that i removed. it had green discoloration and some partilcles fell out when i removed it. When i blew through the inlet swivel i couldnt hear or feel any air comming out so could the needle and seat be the problem? is the float suspossed to make any clicking noises when it is completly up or down? so if i blow air through the gas line and hold my hand by the float i should fell the air flowing if the float isnt pushed up? also is it normal for the jet needle to not stay centered in the hole when you remove the needle jet? i think my wr426 still has the stock throttle stop as well because when i twist the throttle all the way open the throttle valve only looks a liitle more than half way opened up. thanks for taking the time to help me out its much appreciated

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jbrooks26

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This looks like it should work for you. Good luck, and be gentle with this thin area of your carb.

the pliot jet was the only jet that was dirty that i removed. it had green discoloration and some partilcles fell out when i removed it. When i blew through the inlet swivel i couldnt hear or feel any air comming out so could the needle and seat be the problem? is the float suspossed to make any clicking noises when it is completly up or down? so if i blow air through the gas line and hold my hand by the float i should fell the air flowing if the float isnt pushed up? also is it normal for the jet needle to not stay centered in the hole when you remove the needle jet? i think my wr426 still has the stock throttle stop as well because when i twist the throttle all the way open the throttle valve only looks a liitle more than half way opened up. thanks for taking the time to help me out its much appreciated

OK, sounds like you are getting there. The inlet swivel is where the gas line connects to the carb. Yes, if your needle is not in contact with the seat (Float Down), you should be able to move air through the inlet and into the carb. You can also do this with a spray type carb cleaner. If this is clogged or plugged, then you will never get enough fuel into the bowl to run the engine. This is likely your problem. I said to use low pressure so that you don't accidentally damage anything in the carb. I've seen needle and seat get lost in the garage before, I've also seen diaphrams and such get damaged on other carbs due to high pressure air guns. Anyway, you're on the right track, I would remove the float and inspect the needle and seat, might be a good time to replace them anyway. Not sure about the clicking noise, but this could be just the needle rattling around in the needle jet, not sure without actually looking at it myself.

Yes, the needle will be loose in the carb when the needle jet is removed, this is OK.

Could be that the throttle stop is still stock, if you do some searching on here you can identify the proper length for the YZ stop, and then you can either cut yours off, or replace with the YZ part.

Hope this helps.

Josh

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bakeyz426f

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took the float out and the screw holding the needle in but couldnt get the needle or seat out. how do you get the needle and seat out, are they supossed to just fall out i tried some needle nose pliers lightly but couldnt get the needl out. i also sparyed i can of carb cleaner all over the carb and through the inlet and by the needle. still cant blow air through the swivel inlet so im pretty sure the needle and seat are clogged up or something. also do you know any store that would carry heilcoils because i went to a coulple auto part stores and couldnt find any heilcoils that were small enough. the carb might not even leak because it still holds tight with the three good corners. im a little nervous about drilling out the hole any bigger because on the coners where it bolts there isnt much extra metal to drill into and it could crack. thanks

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jbrooks26

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OK, so the needle is stuck in the seat like shown in the pucture? Definately time for a new needle and seat, and I think that once you have the retaining screw out, the seat is only held in by an o-ring. You need are on the right track with the needle nose pliars, maybe a pair of needle nose vice grips. Since it appears to be siezed, you will want to try and turn the seat to break it loose. Then it should come out pretty easy. You might be able to get a large easy out in there to break it free. Just don't pry against the carb housing. If you mess up the internals of the seat, you are going to replace it anyway. This is definately your problem, if you go pick up the replacement needle and seat, you will get a better idea of how it is held in there. Hope this helps,

Josh

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