Carb issues Please Help!

Joined
Mar 3, 2004
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#1
OK guys now I have had this account a while and I have a problem. (I lost my bike so I have not been here in a long while, but I know you guys know your stuff and really need help, so please help me with ATV questions!)

I have my friends Yamaha Warrior 350.
Yeah 4 wheels, I am sorry! But I know you guys know your stuff and I don't know where else to go.
I have had this quad running for some time now.
My friend had some issues when riding it, basically at higher revs it starts popping and backfiring as if it was running out of gas. If you let off the gas- it goes to a solid nice idle. Hit the gas and it goes fine again.

Now - the other day it started doing that- and permanently.
It idles great, and as soon as you give it some throttle, it starts popping and not revving up. If you floor it it will stall sometimes, and sometimes it will just pop more violently.

Now we have removed the carb probably 20 times by now. Sprayed the whole thing out, taken everything we could get out and replaced it, checked seals, etc. NOTHING works. It starts up fine, idles fine, any throttle causes the popping.

Now here's the tough part. From what I can tell are the jets (never really done a LOT of carb work before) you know the screws with the open circle in the middle and its a flathead screw, really tiny and there are a couple of them? Yeah those.

The one that is in the bowl I turned and turned and it only seemed to come out a little bit. Then it got harder to turn. All the screwdrivers I have seem to just not be the perfect size for it. Now the piece I believe is the main jet is deep deep inside a tube. That one I can't get any screwdriver into and nothing to get it to turn. On the inside of the barrel it is 3 holes, and the little front needle adjustment seems to be connected to those holes as well. (if I take that needle out and spray carb cleaner in the tube it comes out the 3 holes AND that front hole)

It does allow some flow, but its barely a dribble and I don't think it's enough, which leads me to believe it is clogged. I could be wrong, maybe it's plenty, but it seems to be a dribble.

Now the local dealership said all they can do is soak it in a bath, then reassemble and tune it up. That is $90. Now I can take out and adjust anything in that carb, except the small screws with flo-thru (which I think are what you call the jets?)

Also, if I were to do this soak, who's to say it is something dissovable? What if it's something like sand?

I really appreciate any help here guys, my wedding is this sunday, I was hoping to take my friend out on a trip for our "batchelor party" and that is TOMORROW. We have tried everything we could without dropping it at the dealer and having them screw us out of cash.

So, any suggestions? Do you know what to soak it in, and where to get it, how long... is there a trick to removing those jets, do you think it's stripped, do you think it is ruined? I am so angry at this thing I really want to get it going it would make my life.

I could be completely wrong- there may be something I don't know about that would cause something like this... but from my experience stuff like this is usually carb related.
Any help is truly appreciated... thank you guys!
 
Joined
Mar 3, 2004
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#3
It ran 100% for quite a while, did this pop thing randomly every now and then... would come back for a bit, then happen again. Then it just won't go away now, but it wasn't anything gradual like a blown piston etc. Oh by the way it's a 4 stroke. And I assume the spark system is OK because it tries to rev up, and you can adjust the idle low to high and it sounds great, flawless infact. I am beginning to suspect a plugged exhaust pipe but I have never dealt with that. Hopefully we will see that as the case- we are going to remove the white brothers end cap and rings to see if that is the cause.