04 pw50 not starting

[jayb8008]

Hi everyone, I'm having problems getting my sons 04 pw50 running again. It was running just fine a few months ago, but after sitting a while I can't get it going again. I want to start out by saying that I am a novice when it comes to engine repair and problems, so please bear with me. I have read a few different things to try and have tried them so far.

First thing was spark plug. I pulled it and checked to see if it was getting a spark. It is. I put a brand new one in (proper gap and torque) and tried that and nothing. I also put about 1/4 tsp gas in the head when I removed the plug before replacing it. It started for a split second until the gas burned and then stalled. I pulled the plug again to see if it was wet and getting fuel and it was dry. Not sure what to do about that.

Another thing was bad gas. I can't remember if I put stabilizer in it or not over the winter, but I am pretty sure I did cuz I always do with my R1 and YZ450. I drained the gas anyways and tried to pull the carb to clean it. That is where I am running into a problem. I can get everything off on the carb except the OIL DELIVERY PIPE and that won't let me completely remove the carb to clean it. It looks just like the other black tubing for the gas, but it will not pop off. It has a brass fitting at the end that slides over the tubing, which I can move, but the tubing does not pop off. I am afraid if I try to force it off I will break it. being unable to remove it completely, I tried my best to remove all the gas from the carb and I sprayed it with cleaner. I am not sure how else to drain it so I just turned it in every direction and let the fuel come out. I want to pull it off, but cant get that one tube off. Any suggestions? I want to be able to clean the jets if that's what it is.

I also read about the spark arrestor. I pulled the tailpipe and tried to loosen the screw, but it is almost stripped and I can't get the muffler out. I read that could be a problem too if it's gunked up in there. There is oil around the tip of the muffler and I read that was a problem but I can't remember why.

So that's about where I am. It ran fine in the fall and never gave any problems. The carb seems to be the most popular opinion from google, but I can't pull it off to clean the jets and everything else if thats the case. Sorry so long winded! I am just trying to get this fixed as soon as I can so my anxious boy can ride! Thanks for the help.

 

[IndyMX]

Well.. If that tube for the oil is just a rubber hose, cut it. Get a new one. Those aren't expensive.

I'm going to guess that the jets are plugged up. You're going to have to get to them and blow them out with compressed air.

 

[jayb8008]

Yeah, it's been bugging me so much that I went back out again and got it off! I was just using my fingers before, but I used a nice set of needle nose pliers this time and it came off no problem. So once I get it off, what's next? Do I take the two halves apart? (not sure what they are called, so i just call em top and bottom.) If so, where are the jets and how do I get em out and cleaned? And most importantly, is it easy to screw up or break something?

 

[IndyMX]

The float bowl is on the bottom. Take that off.

But first, pick up a service manual.

Once you get it open, you'll see the jets..

Spray them with carb cleaner and then blow them out with compressed air.

 

[jayb8008]

I have the yamaha owners service manual. Good enough, or were you talking one of the clymer type ones? As far as the jets, are they removable or are they just left in place?

 

[IndyMX]

That manual might be ok...

The jets should most definitely be removable.

 

[jayb8008]

Do I have to remove them? I ran a wire through whatever holes i could find and there was no gunk to be found. I could pull it and clean it some more if that would be better. I have them soaking right now in that yamaha carb cleaner. Should I pull it and let it soak? And how long should it soak? I let it soak for about 5 mins, ran the wire through and put it back together and tried to start it back up with no luck. Does it need to soak overnight? I am starting to get frustrated that I can't get it to start.

And now for a really dumb question......I figured I would change the transmission oil and air filter as long as I am changing everything else. I changed the filter no problem, and have the proper oil and am ready to drain it, but how do I know how much to put in? The manual says .3 liters or .32 qts. I have no idea how to measure that out, and I don't see a check bolt or screw or anything, or one of those little glass level checks. How do you measure the proper amount? Sorry for all the dumb questions, but I am pretty new at all of this. I really want to get this bike started back up, along with my son!

 

[IndyMX]

Well.. first of all, don't run wire thru the jets.. you could easily gouge one and ruin it.

Use compressed air! Once the carb is clean, you may need to do some adjusting to get it right.

Yes, best bet, remove the carb, remove the jets from the carb.

As for the oil.. 1 liter = 1000 ml, .3 liter = 300 ml

Use a metric measuring cup.

 

[jayb8008]

Ok, another dumb question......how many jets are there, and how are they removed? They are un-screwed to reemove correct? I have removed the main one that kinda looks like a brass screw with a spring on it when you pull it out. I really hope thats a jet at least and that I am not screwing things up. Do the jets have to be readjusted to get it running right once clean?

 

[jayb8008]

Alright....she's running! Not perfectly, but she's running. Now I think I'm gonna have to tweak it and undo whatever I loosened or tightened. The one problem I am having right now is that while in the start position, it is not running like it did. I used to be able to rev the throttle in that position and it would rev up and spin the rear wheel no problem. Now it doesn't spin the wheel. It sounds a little different as well, making a "popping or poppy" noise. When I switch it to run it runs and revs and spins just fine.

The only thing that it seems to be doing is blowing a lot more smoke from the exhaust. It seems to be running fine now, but I am sure that will foul up the plug quickly. Does that mean it's running rich or lean? I always mix the two up. Rich is too much fuel right? Or is it oxygen? Do I have to adjust the air pilot screw or the fuel mixture one or something else? Sorry to come off like a complete idiot, but that's pretty much what I am at this point with this stuff. Thanks again for the help.

 

[jayb8008]

Well, good news.......number one I don't feel like as much of an idiot anymore, and number two she is running perfect! I was a little intimidated at first, but once I got in there and figured everything out it wasn't that bad at all. Now she's starting up first kick every time.

I adjusted the throttle screw and air pilot and it seems to be running perfectly. And as far as the start/run switch, one of the connectors was not connected, so it disabled the throttle control on the start switch and just made it like it was in run. I connected it and read that the start mode is so if the kid accidentally throttles the bike it won't spin the wheel. So everything seems to be all good!!! Thanks Indy for all your input and for putting up with my dumb newbie questions.

 

[IndyMX]

Glad you were able to get it running.

 

[Archie tosaif]

Hi All
I'm New to the site, could some one help me please ,My son's PW50 will not start, he had rode a couple of days ago and then parked it in the garage. I had tried to start it today morning but it wouldn't start. So i changed the spark plug and it is getting plenty of spark but still wouldn't start i then took the carb apart and cleaned it, I had also used a air compressor to blow the jets out, still no good. I had also drained the fuel thank and put in fresh fuel. I had then attempted start the bike but it still wouldn't start. I had also cleaned the exhaust system out but it didnt help.