Rebuilt but won't Start. No Fuel?

[hybridpower]

Ok guys; after the saga with the crank (which was fixed free of charge with great service), I have put the whole bike back together.

Now my problem is that it won't start!

I've got spark, and I have compression (though I don't have a guage, I can feel and hear it), but my fuel is not getting there! I check the plug, it's dry.

The only thing I see, is that fuel is running out of one of the lines that comes off the carb (and drains to the ground). What does this mean? I'm getting nothing here, not even a puff of smoke.

Thanks guys.

[ossagp1]

usually it means that the float needle is stuck open or set poorly. you are flooding your engine. along with fuel running down your vent tubes which have now become overflow tubes, you have some leaking into the intake. You may have to turn it upside down if it is exremely flooded. Dont continue to kick until you pull the plug and figure that out. You may learn what a hydraulic lock is.

Did they have to repress the crank??

[hybridpower]

Yeah, they did have to repress the crank, but when I got it back it spun great. They re-trued it as well.

As far as the fuel goes, I don't seem to have a wet plug? If I'm flooding the engine, shouldn't I be just dripping with it? It all seems to be coming out of the carb vent line.

[ossagp1]

If it was running into your cylinder you sure should have a wet plug. Open the carburetor and have a look. You can put a hose to blow throw on the fuel inlet and see at what point the float is cutting the fuel flow off etc. There is a post by faded in the KB on setting floats if you havent read it already (pictures too).

How much side clearance did the crank end up having with the cases when you got it back?

[hybridpower]

You know what? That's a great question! I know it sounds dumb, but I was so excited to have it back in one piece that I didn't check?

I'm going to go break down the carb now. Thanks again ossagp1, you've been a great help through all of this.

[hybridpower]

Ok, the carb is clean, and I've even put in a new spark plug. And get this, the other plug was dry. I've even put my finger over the plug hole (to create pressure) and still got no fuel out of the cylinder.

I cleaned the carb (which really didn't seem that dirty), and tried to start it again. This time I got no fuel out of the overflows, but still none to the engine (I could hear it fill the fuel bowl).

Frustrated, I put about a thimble sized amount of fuel directly into the cylinder via the spark plug hole, and one kick fired it right up! I didn't get a chance to see how long it would run, as it's 10:30 out here, and the 30 seconds I had it running turned my neighbors bedroom lights on! At least I know that a dirtbike is good for making friends late at night!

So, why am I not drawing any fuel?

[KKXR400R]

What kind of bike do you have?

Heres a few things I would check. Kinda simple but its easy to eliminate various problems.

Towel in the airbox? I know you said you were getting fuel to the float, but try starting with gas cap loose. You could have a bit of vapor lock going on. Have you adjusted the floats recently? You mentioned you cleaned the carb, did you pull all the jets out and checked to see if they were physically clogged?I made this mistake a year ago and ended up running around in circles for 2 days. I also use carb cleaner with the straw and run it through all the passageways and to clear out the jets. Float upside down?....don't laugh...I did this once on an XR250...I still get harassed for that one. Good luck bro and don't worry...you laugh at me about the float thing.

-Kevin-

[hybridpower]

It's a '96 yz125. And I'm sure the floats are in the right way! Actually, I don't think they could go in upsidedown in this set up.

I did take the carb all the way apart (with my manual as reference) and cleaned all the jets and everything.

I looked, no towl in the airbox (I like that idea though, that something I could see myself doing). I'll clean the filter and see if that gets me any closer.

The only other thing I can think of, was when I put the reed intake back in I looked at the reeds for any damage (there was none), but I remember thinking that one side didn't look like it was fully touching the face of the reed cage? Do they have to seal compleatly? How much gap is to much, and would that cause the problems I'm having?

I've got a three day weekend starting this afternoon, and I'm hoping one of you has a quick fix for this so I can do some riding! Thanks!

[ossagp1]

There are probably a few posts around where I suggested to people to do just like you did with the fuel. It seems like you can get air trapped (for lack of a better"guess") in the pilot jet passage. Usually doing just what you did with the priming is enough to create adequate vacuum to where you will end up with a full fuel passage the next time you startup. I have had this happen when running something out of gas, almost always it is a mikuni or bing carburetor, and generally comes along with a plugged fuel vent. I have yet to have it happen to me when or after I had fuel pouring out the vents. I suposed there could be a pocket of fuel caught at the vent juncture (where the brass inlet and the aluminum body come together) that was keeping fuel from flowing up into the passage. No joke, I watched a Swedish Husqvarna race mechanic put a long clear line on a carburetor he had just installed and suck lightly on it until he had fuel begin to move up the line. I was told he did that to keep from having to do a bunch of kicking when he got ready to start it. Oddly those carburetors (or the similar one on my Husqvarna) had a tickler (button that you pushed down on which held the float down so fuel went directly into the intake for starting) which I never had a problem getting fuel flow with.

Yours has me a little bit surprised, but I am betting it works like intended now.

[hybridpower]

I'm about to blow this thing up! If I didn't think it might alarm the folks living around me I'd be out there beating it with a stick right now!

Ok, yes it will start if I put fuel right in the engine, but then the rpms go up really high right way. It wants to rev up and the only way to control it is to hit the kill switch alternatly to keep it from reving all the way up, or dying! It continues to run until I shut it off.

If I then turn it off and try to to restart it with no fuel in the cylinder, it won't start!!!

On top of all this, I just realized the clutch doesn't work. The clutch lever will only move about an inch (and I already filed down the notches in the cluch basket, and they were small; the hub is a hinson).

So, do I push it off a cliff now?

[crdude]

Sounds like you have an air leak some where. How long with it run with you playing with the kill switch?
I'v had somthing like this happen to me when I had a rip in the carb boot that led to the reeds.

[ossagp1]

The high reving can be an air leak. I would check to make sure that your throttle slide is coming all the way down first. It sounds like the cable is hanging up or the slide has something holding it up. That will keep one from getting enough varcuum to activate the low speed circuit too. Even my cr500 wont start cold if the throttle is up, and it has lots better low speed vacuum than my yz125 does.


On the clutch, I am guess that you put the clutch cover on wrong. That little rack and pinion has to be engaged to a point where the arm on the case ends up being about 90 degrees to the cable.

On the plus side, it sounds like everything is about ready to go and be ridden.

So check the throttle first,,you should be able to hear it hit bottom. You may even want to see it do that so, take off the subframe and air cleaner.

I think you are well on your way to riding this weekend.

[YZ125motoracer]

yea sounds like a vacuum leak. check for any way that air could bypass the carburator, or prevent the crank cases from not sealing and pressurizing. check your crank seal, you could've torn it on install. air boot could be ripped, damage to the cases that would cause it not to seal. thats all i can think of.

[hybridpower]

Thanks guys. No damage on the cases; I'm trying to picture the crank seals, but I don't remember any problems there either. As far as the carb goes, it looks like the slide is up about the thickness of a sheet of paper from it's stop, so I'll try there first. How else can I bring down the idle speed?

The clutch lever is set like my manual said between these two marks on the case, at a 45 degree angle toward the engine. It just can't move enough...

I feel better, I had dinner an a beer, so I'm ready to think about this again. I realized that I didn't have the airbox boot tight, could that cause any issue? I wouldn't think that it could do anything on that side of the carb?

Oh, on more thing, when I put fuel in it manually, I have to have the choke on a little bit to get it to start. Weird.

[ossagp1]

Ok you are in the position of taking the clutch cover back off. Unless we are looking at things from a different angle, I am lost on your 45 degrees. IF YOU DONT HAVE an angle of 90 from the cable approach to the arm when it is up against the rack then you WONT BE ABLE to pull it far enough. Those two marks don't mean squat unless that is where the clutch are comes to rest when you push it to the point of contact with your finger. Just having the cable hold it there does nothing to assure proper action. When my cable is removed the arm returns by way of the spring to point almost straight back. If I push it forward to contact the inner rack (the point it gets almost impossible to move and is about to go to "work") the pointer is between the two indicators and the arm is at a 90 DEGREE ANGLE TO THE CABLE. See if you are getting that. I sometimes take a try or two to get it right each time I disassemble a YZ.

Nothing too weird about the enrichenor and the prime you have to dump in. You mention crank seals,,,did you reinstall them? If they aren't there, you will get just exactly what you are describing. I would back the idle screw adjuster out all the way and see if your slide drops. Make sure the cable end is all the way seated down in it's adjuster on the top of the carburetor and at the throttle and at any adjustment points.

You are getting closer. Just dont try any shots with the beer until you have it right.

[hybridpower]

Ok, I do have something wrong (besides my angles)! Yes, the arm is adjusted to sit between the marks on the case, but it goes no where when I release it; this would tell me I'm not moving the springs at all. This would explain why the arm will only moves forward about half an inch (as this is the only time I'm working the springs). The shaft is probably hitting the inside of the cover before it does any work.

In the morning, I'll back off the idle screw and try again.

I looked at my manual, it really gives no real help with setting up the actual clutch lever; any idea on where to find a walkthrough of one?

Now for the good news; yes, my crank seals are in.
Thanks guys.

[ossagp1]

the clutch springs dont really return the arm. that is the little spring on the case.

It sounds pretty close. I will look at the schematic on mine and see if i can do a better job of explaining, but it is kind of hit and miss.

[Shoei_391]

Hybridpower,


Did you get it to work?