87 Warrior Carb Problems

[2cycletriker]

I recently got an 87 Warrior in good condition really cheap. The only problem it has is when I stab the throttle wide open from idle it falls on its face and dies. I have had the carb off and cleaned and checked it several times. The accelerator pump works, all jets and passages are clear, new air filter, fresh gas, new plug, valves are in spec. Everything seems as if it should work fine but it doesn't. Other than this problem, the quad runs great. I have been working on ATVs for a long time, but this one is getting aggravating. Found out about this forum yesterday so I signed up. I'm there are several users who have experienced the same problem. Any help will be appreciated. Thanks.

 

[deerman2701]

I would like to know how to solve this issue also. When I had my warrior running i had to not jab the throttle until the quad raised in RPM a little

 

[2cycletriker]

Hello?

Anyone have any input on this? I have read in several places that it is a common prooblem and that the factory carb is essentially junk. Will the Z400 Carb conversion cure this?

 

[1998yamahawarrior]

Anyone have any input on this? I have read in several places that it is a common prooblem and that the factory carb is essentially junk. Will the Z400 Carb conversion cure this?

ive never done the conversion but everyone that has says its a big difference but you do have to get it tuned right.

 

[tyler]

Do the spring mod and make sure your jetting is right mine use to do the same thing.

 

[2cycletriker]

I've done the spring mod and tried raising and lowering the needle with no difference either way. Changing the needle position either way seems to make it worse. I'm thinking about trying a bigger pilot jet. The engine is entirely stock and the carb has the factory jets in it. I have tried everything though, so increasing the size of the piot jet is my next plan of action.

 

[1998yamahawarrior]

this probably doesnt have anything to do with it but you can also check the carb boot for cracks. thats the only thing you didnt list off so i figured id put that out there.

 

[2cycletriker]

Yeah, checked the carb boot too, but thanks for the input. There's always the possibility that I overlooked something basic.

 

[1998yamahawarrior]

ya im trying to think of other stuff ive been a little brain dead today, so im trying to imagine every thing to see if you missed any of the basics.

 

[bomber315]

the motor is stock but is the air filter and exhaust?

 

[2cycletriker]

The exhaust is stock. The air filter is UNI but I'm still using the stock airbox and lid. Tried running it without the airbox lid to see if that made a difference but it didn't.

 

[bomber315]

are you sure the carb is good and clean on the inside? there really shouldnt be any reason why it wouldnt run right in stock setup

 

[2cycletriker]

i'm sure it's clean. been through it a few times double and triple checking. i thought the exact same thing, that in stock form there shouldn't be a problem. everything else about it running is fine, starts right up, idles fine and will idle all day, penty of power, revs all the way out without a miss, but if you stab the throttle 3/4 or all the way open from idle, it dies. I can trail ride all day and its not a problem because seldom do you go from idle to wide open in an instant. it's just the fact that the probem is there and it shoouldn't be. i like my machines to run the way they're supposed to.

 

[DeadLastRacing]

3/4 to WOT is your main jet.

You read these? It might help? I dunno.
http://www.yfm350.com/forums/showthread.php?t=21231
http://www.yfm350.com/forums/showthread.php?t=21877

Can you lean into WOT? Is it just when you quick jab it, it dies?

 

[2cycletriker]

If the engine rpms are slightly above idle I can jab the throttle wide open and its fine. Riding on trails is fine also. On stretches I can open it up all the way and rev it out with no problem. Any gear will rev out. But if I stab the throttle open from idle it dies.

 

[elwood]

maybe your idle is set too low, it should be at 1600rpm

 

[2cycletriker]

I don't have a tach to measure the idle rpm but I'm confident that it is not too low. I actually have it set a little higher than my other machines, which run fine, although they are not Warriors and every machine is different.

 

[We1Dont7Die]

I too would like to know what causes this. I have a '00 and EVERYTHING is stock. runs great except when i gun the throttle from idle, it just dies. Oddly enough, my '84 xl600 does the same thing and runs great otherwise. Maybe this is just the nature of the beast?

 

[deerman2701]

I just upped the idle screw and now its fine