yamaha wra 650T

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  #1  
Old 07-08-08, 08:29 PM
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yamaha wra 650T

I have a Yamaha wra 650T. It starts good and will idle but will not pick up. It also sounds like it is missing. I have put new gaskets in the carb and it still runs the same. I put new plugs in with no better results. When I checked the plugs after it had run for a while one looked just like new and the other had a little used look to it. any ideas on what I should check next. thanks for your help.
 
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Old 07-09-08, 04:48 AM
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Your carburation is messed up.
 
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Old 07-09-08, 06:56 PM
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thanks i will go over the carb again.
 
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Old 07-16-08, 07:14 PM
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I am still having the same problem with this thing. I have rebuilt the carb and still flooding. Does anyone know the settings for a mikiuni BN44. The needle valve is even with the carb floor( i think thats what you call it). The high and low needles are out one turn. Just about ready to give up. Thanks for any help. susie
 
  #5  
Old 07-17-08, 05:08 PM
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Don't give up - it's just a machine that forgot how to work right.

What year is it?

If you're running with a common carb to both cylinders and there's a significant difference between the plugs, you could have an ignition issue = CDI or coil or signal generator.

Try checking the spark for each cylinder to see if there is a difference. Also make sure the basics are OK, like the air filter, exhaust, oil in the injectalube, fuel flow to the carb.

Then run the engine through an rpm range of 1000 through 4500. See if the miss you're suspecting is there throughout the whole rpm range.
 
  #6  
Old 07-17-08, 07:33 PM
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Thanks for reply. Its a 1995 wra 650T waverunner III. I checked everything I could think of. The plugs look wet and it is smoking a lot They seem to be sparking about the same. Must be some kind of carb setting. I understand there is something call a pop off setting that has to do with the needle valve and changing the high and low speed jets. The needle valve I put in was the one called for on the parts list so it looks like it would be right. I didn't change the high and low jets. summer will be over by the time I ever get this running.That is if I ever do. thanks for help
 
  #7  
Old 07-18-08, 07:47 PM
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It sounds like your problem is with the needle valve. It's allowing too much pressure to be built up in the fuel chamber that the jets draw from. That valve operates under a pop off pressure setting (or rather a pop open pressure setting).

There could be a chance it isn't seating or you have a mating surface leak. Or it could be the wrong valve for the engine. You should be able to cut the fuel flow with the metering screws, but if you don't have the correct valve, you'll still have the flooding at low to mid range = no response on a two stroke.

You can cut the flow with leaner jets also, but I would start with the needle valve and go to a higher pop off.
 
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Old 07-20-08, 01:46 PM
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thanks very much marbobj for your help. I will get a pop off gauge and check that. but should i change the needle size or the arm spring size?
 
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Old 07-20-08, 06:46 PM
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Spring arm size. A word of caution, though, don't over do the higher pop off pressure. You don't want to lean it out too much in the higher rpm range = over heating.

What is a short history of your Waverunner. Did you put an OEM kit with a needle valve in the kit or source the needle valve separately? Was it an engine that suddenly started acting up or did you just get it and it needed work on it?
 
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