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ponyhorscroft

frustrated dad and a PW80!

10 posts in this topic

Hi to all;

my son recently inherited a non-running PW80. I knew the problem was with the carb as every time you turned the pet cock fuel would flow out of the overflow hose.

So...

I disconnected the air intake boot, the fuel line, oil injector hose and loosened the clamp on to the reed valve assembly and managed to rotate the carb enough to get into the bowl. sure enough the float was stuck up - I cleaned it with a good spray of carb cleaner and got it moving and put the bowl back on - no leak and she starts fine. Now however it wont run under throttle, it will idle fine but bogs down and stalls when given throttle?

Any ideas?

I assuming the place to start would be to pull the carb completely and give it a thorough cleaning but I have 2 questions:

1 - how do I disconnect the throttle and choke cables from the carb, I have no manual yet and I'm stumped?

2 - how do you measure the float height and does anyone know what the correct height is for a 2005 PW80?

Thanks to everyone who reads/responds.

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hey there

your guess would be the same as mine and i would do just like you, start at the carb.

take the carb off, clean all jets, and set float height.

float height should be set & measured within specs, but if its not the next best thing is to make it parallel to the tang when holding on about a 45 degree angle.

to take the carb off, you usually have to take the top of the carb off, and the slide should come out with needle attached.

would be a good time to check the condition of the needle.

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I'm sorry I do not have the specs for that bike, but you might try searching this forum, someone may have asked it before.

I would agree with you though on the carb being the issue. If the bike idles fine then you pilot circuit is clear. But when you give it gas, different circuits deliver the fuel. Those circuits could be gummed up from old gas.

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When you open the throttle, you're getting too much air because your jets are plugged shut.. Either clean the goop out or buy some new brass.. You'll be :ride: in no time

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When you open the throttle, you're getting too much air because your jets are plugged shut.. Either clean the goop out or buy some new brass.. You'll be :ride: in no time

+1 If the float was gummed up and stuck, the jets probably are too.

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Thanks for all the info' so far.

I'll try pulling the carb totally off - if I can figure out the choke/throttle cable attachment - I hope Sykal is right and the slide and needle will just pull our with the cables?? If I can't get it out i'll just take the jets out from the bottom and soak them overnight.

Would love more info' on setting float heights as it's something I've never done before?

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here's another link to manuals, Australian this time:

http://www.yamahaownershandbook.com.au/index.php

As long as you didn't beat the poo out of the floats, I would suspect that the level is within spec. Those little carbs have very small passages in both the body casting and the jets themselves, use carb cleaner and compressed air, they'll clean up. do not use metallic objects to clean jets. really gummed ones can be heated with a propane torch and dropped in water to burn the congealed gunk off, but never use metal things.

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Just looked it up:

1: go here and download your year:http://www.yamaha-motor.eu/eu/services/owner-manuals/index.aspx?pl=EN&c=MC&m=PW80&y=2012&l=EN

2. Look at pages 68-73 (written at bottom of the pages) and it covers everything you need to know about your carb, shows how to check float level, etc.

3. DO NOT let it run out of injector oil, and if you want to have less work with this, I'd suggest using a good synthetic injector oil like BelRay Si7 or similar. Check to see if whatever you use is compatible with whatever is in the reservoir before pouring it in. You can prove that by putting a little of whatever is in there in a glass container, then pouring an equal amount of whatever you plan to use into the same glass, see if they mix, and stay mixed.

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Did you ever get this resolved and how did you do it?  My son's PW80 is doing the exact same thing where it will idle fine but as soon as I give it any throttle it dies.  I also have fuel dripping out of the overflow tube unless I turn the fuel petcock off between starts.  This leads me to believe it's float related.  I have taken the carb off and cleaned all jets, adjusted the screw to 1.5 turns out (was at 1) and put in a new spark plug.  It will run better if I have the choke halfway on (straight out) in which case you can rev up the throttle all though you have to work the throttle to get the rpms up because it will hesitate or bog at times.

 

It ran fine when I bought it and then my son rode it about an hour before it started flooding out or whatever it's doing.  It's older and probably been abused pretty good.  Should I just get a new carb or is this a fairly common issue that can be resolved easily? 

Thanks for the help!

 

 

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