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Post by nestaulrich on Apr 24, 2014 20:27:06 GMT -5
Hi there, it's my first time posting on the forum.
I've got a very weird problem. It seems like too much fuel is getting to my carb. I installed a new carb last month but had the same problem with the old one. If I go over a bump the engine bogs so I have to rev it a bit to keep it going. It runs fine at higher speeds but if I rapidly let off the throttle around 25mph, it bogs. I put it on the center stand to test my theory. If I rock it so the front wheel hits the engine bogs every time. If I pinch off the vacuum hose going to the fuel pump and rock it, it never dies. If I stop pinching it and continue rocking the bike it dies within 5 seconds. I disassembled the float bowl and the float isn't stuck. Idle mixture is one and a half turns out. I recently changed out the fuel filter to one of the glass ones, put in a new spark and adjusted the valves to .005mm.
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Post by alleyoop on Apr 24, 2014 21:14:34 GMT -5
Can you take a picture of the carb area and hoses, that would help see if anything can be seen as causing the problem. Alleyoop To post pics this is easy and free: 1. Click on this link: tinypic.com/index.php2. Click on Browse, that will link to your computer. 3. Find what you want to load. 3. Click on the name of the picture 4. Click on OPEN 5. Click on UPLOAD 6. Click on the LINK that starts with IMG. 7. RIGHT CLICK and CLICK on COPY 8. THEN Come here to your THREAD ON DOC. 9. RIGHT CLICK and CLICK ON PASTE. |
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Post by bashan on Apr 24, 2014 22:24:41 GMT -5
What is your bike? There is no set idle screw setting, it is in or out until the wheel stops on the center stand. Depending on the bike it's around .004" on the valves....not mm. Are you sure it's a fuel pump? People confuse a vac valve with a pump all the time. I agree with Alley...need some pix. The A/F screw is 2 and 1/2 out...maybe that's what you're thinking? Rich
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Too much fuel?
by: nestaulrich - Apr 25, 2014 10:19:14 GMT -5
via mobile
Post by nestaulrich on Apr 25, 2014 10:19:14 GMT -5
Thanks for the quick response guys. It's a Znen 150t-e. Since the fuel tank is below the carb I do have a pump, not a vacuum actuated petcock. Yes .005" not mm, my mistake. It's a little clattery but much easier to start than when the valves were set at .003" and much better for my riding style which uses two throttle settings, fully open or fully closed.
I'll post some photos when I get to work. I'm trying to rule out a vacuum leak so I just ordered 10' of clear fuel line (neon green!) so I'll be able to see if fuel is backing up into the vacuum lines. My intake manifold isn't cracked but the O ring looks suspect. I had the idle set a little high because of the bogging issue.
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Post by nestaulrich on Apr 25, 2014 14:30:02 GMT -5
Engine pics. I'm going to warm it up and upload some video of the problem.   |
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Post by nestaulrich on Apr 25, 2014 14:31:59 GMT -5
Also I should say I'm getting horrible gas mileage. I used to get around 60-65. Now it's down to 40.
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Post by nestaulrich on Apr 25, 2014 14:43:14 GMT -5
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Post by alleyoop on Apr 25, 2014 21:28:52 GMT -5
Well surging means an AIR LEAK or running LEAN. Now you said your tank is below the carb but I see the Fuel Pump is higher than the tank. That is not good the fuel pump pumps and it does not have much suction action to get the gas To The Pump so it can pump it Up to the carb. Did you move the pump up where it is currently attached. Normally you would want the PUMP low enough so that the gas from the tank FLOWS FREELY to the pump so it always has gas to pump up to the carb.
So I think that is why when you put the front wheel down the angle from the tank to the pump is worse and it starves the pump of fuel to pump up to the carb and it dies, Liquids do not flow uphill very well.
Alleyoop
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Post by nestaulrich on Apr 26, 2014 11:58:38 GMT -5
I haven't changed the location of the fuel pump. That's where it was when I bought it. Since fuel outlet is on the top of the tank there's got to be a pick up tube.
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Post by alleyoop on Apr 26, 2014 12:55:34 GMT -5
Yes if the fuel outlet is on top of the tank then I would suspect the pickup inside the tank is not reaching far down enough and has deteriorated. One way to test that out is fill up the tank and see if it then runs better.
Alleyoop
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Post by nestaulrich on Apr 26, 2014 17:14:37 GMT -5
OK I did order 10 feet of fuel hose so I can replace all of the fuel lines and the vacuum hoses. Just for giggles I snipped the ends of all of the vacuum hoses (some had small cracks) and now it runs much better. I don't want to jinx myself but I'll report back once the lines are replaced.
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..BAD TO THE BONE..
