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Post by carpaltunnel on Jun 16, 2014 10:51:30 GMT -6
Okay, at idle she seems to be okay, but when I throttle up she starts to spray gas in to the air filter. She doesn't leak gas otherwise from anywhere. I've changed the float height a bit and it seemed to make no difference. I've read a lot about the float needle not seating properly as the cause, but that also seems to be linked to the bowls leaking when the bike is not running. So before I go order new needles I'm trying to see what else I could be doing wrong.
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Post by Blaine on Jun 16, 2014 14:40:23 GMT -6
Okay, at idle she seems to be okay, but when I throttle up she starts to spray gas in to the air filter. She doesn't leak gas otherwise from anywhere. I've changed the float height a bit and it seemed to make no difference. I've read a lot about the float needle not seating properly as the cause, but that also seems to be linked to the bowls leaking when the bike is not running. So before I go order new needles I'm trying to see what else I could be doing wrong. If your float needle wasn't seating it would flood with the bike not running.Sounds like your floats are still high.They need to be set with the carbs off & inverted so you can get correct setting.   |
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Post by carpaltunnel on Jun 16, 2014 16:23:04 GMT -6
Yeah, I was figuring it would be more of that. I've lowered it past stock (I believe, will need to get a picture of my method) at this point so hmm...will update tomorrow perhaps.
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Post by carpaltunnel on Jun 17, 2014 15:35:14 GMT -6
Okay, see below for my method of measuring my floats. I've got them at 18mm currently and that's to the center of the float and not the slightly larger edges. Note that the picture isn't perfect; it's meant to show my technique and not real results. The carbs are rotated far enough that the floats "fall" and close the needle and that's when I measure the distance.  Stock main/pilot jet, pilot screw a little lean, needle at stock height, spring stock. Just an example of what I'm dealing, a before and after: at idle and warm, and after I've throttled the engine a bit. Not long and not terrible high RPMs.   |
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Post by eaglerider on Jun 17, 2014 16:56:04 GMT -6
Gas spraying into filters means the carbs are flooding.
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Post by carpaltunnel on Jun 17, 2014 18:14:44 GMT -6
Gas spraying into filters means the carbs are flooding. So, perhaps the fact the bowls are not flooding when the bike is off is simply because the petcock operates under pressure, and if there is none to pull more fuel that's why there isn't a free flow? Does this mean I need new float needles? |
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Post by Blaine on Jun 17, 2014 20:06:22 GMT -6
Gas spraying into filters means the carbs are flooding. So, perhaps the fact the bowls are not flooding when the bike is off is simply because the petcock operates under pressure, and if there is none to pull more fuel that's why there isn't a free flow? Does this mean I need new float needles? Not sure whats going onBut I don't think it float needles.Does both cards do it or just one?? |
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Post by carpaltunnel on Jun 17, 2014 20:59:08 GMT -6
So, perhaps the fact the bowls are not flooding when the bike is off is simply because the petcock operates under pressure, and if there is none to pull more fuel that's why there isn't a free flow? Does this mean I need new float needles? Not sure whats going onBut I don't think it float needles.Does both cards do it or just one?? Both are doing this. I figure if I continue lowering the floats I'll just end up not allowing the jets to get enough fuel so it won't run anyway so I'm trying to not get lower than 18mm. Also, is my measuring method correct? Perhaps I'm measuring it wrong? When I had the bowls off I put some gas in the line and closed the needs with the floats and nothing came out until I released the floats so I don't think it's the needles either. |
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Post by Blaine on Jun 18, 2014 5:13:50 GMT -6
No I think your measurement method is correct. |
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Post by carpaltunnel on Jun 19, 2014 11:52:24 GMT -6
So the holes in the intake of the carb: I've done some research and found what they are and am pretty sure now that the gas is coming from the Main Air Jet in the intake. I'm guessing that due to there being no gas at idle when the Pilot Air Jet is in use, and gas when the Main Air Jet is in use with throttle. Anyone fathom why this might be? Perhaps my main jets are gummed up somewhere (though the removable parts are clean) and that's why it's spitting in the wrong direction?
Also, does anyone know what the vent at the top of the carb intake is? If you look at the picture above you'll see clearer - two holes on the bottom of the intake (left hole - Pilot, right hole - Main) but what's that section at the top of the opening?
EDIT - perhaps now is the appropriate time to snip the spring coils? If the needle has less resistance to rise, perhaps the gas will flow out the main jet towards the butterfly instead of backwards out the MAJ?
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Post by carpaltunnel on Jun 23, 2014 15:35:51 GMT -6
If anyone is still reading this...
I snipped two coils of the springs to no change. I also did another valve adjustment at someones suggestion that my valves might be work and are not opening enough as a result. I only stepped them up one point and saw no change in this blowback. I've also read that perhaps my timing is off and the piston is rising while the intake valves are still open?
Now that i think about it - I was getting a hissing noise as I rotated the pistons with a socket while doing the valve job. It was as though while compressing (if i recall correctly) the valves were leaking the pressure before they shut? Does this sound plausible?
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Post by eaglerider on Jun 24, 2014 6:37:50 GMT -6
I forget...have you done a compression test? The only way timing can change is if you have removed the cams and did not set the timing when you replaced them. But the timing cannot be off, as the engine starts and runs. Your problem lies within the fuel system somewhere.
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Post by carpaltunnel on Jun 24, 2014 10:23:00 GMT -6
I forget...have you done a compression test? The only way timing can change is if you have removed the cams and did not set the timing when you replaced them. But the timing cannot be off, as the engine starts and runs. Your problem lies within the fuel system somewhere. I'll check compression this evening. My Haynes manual is crap apparently and I've looked around but the only number I could get to compare to was 160 psi - does that sound good? |
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Post by eaglerider on Jun 25, 2014 7:32:24 GMT -6
That's a good number....remove both spark plugs when running the compression test.
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