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Post by ital on May 4, 2015 10:00:52 GMT -5
I recently upgraded to a 180cc big bore kit for my GY6 ruckus and I am noticing the carb is constantly overfilled, which is evident by the excessive fuel pouring out as soon as I loosen the screws to the carb bowl and the fact the overfill tube is always full of gas. The scooter will randomly cut out when I am cruising mid-throttle. I am running an OKO 30mm D-slide carb, which is brand new, and I made sure the needle and seat are working properly. I currently have a round Mikuni DF52-21-D dual output 35L/hr pump installed, with both fuel outlets T'd to a single hose that runs to my carb. Does the stronger vacuum pressure at the intake manifold of my 180cc engine increases the fuel pressure or flow rate the vacuum pump operates at? The fuel delivery setup I have now is the same setup I used with my 150cc and I never ran into flooding or overfueling the carb. In fact, I had to use the Mikuni dual output setup because the rectangular DF-44 single output Mikuni pump wouldn't be able to provide enough fuel during WOT sessions. I would actually run the carb bowl dry only after a few minutes of WOT. Once i switched to the Mikuni dual outlet pump, I would be able to WOT all day and not starve the carb of fuel. Now it seems with the 180cc build, it's the opposite problem of overfueling. The first thing i tried was installing a vacuum restrictor (basically a hose coupler with a small hole restrictor inside) inline between the pump and the vacuum nipple on the intake manifold. I thought by restricting the vacuum, it would lower the pressure or flow rate of the pump. Turned out it didn't change anything. Carb was still getting overfilled just the same. Again, i verified the needle and seat are working properly. One friend recommended I switch my vacuum line to a smaller diameter line, but seeing how the vacuum restrictor didn't make a difference, I don't see how changing to a smaller diameter vacuum line would help either. Would switching back to the single output 14L/hr Mikuni pump fix this issue? did you resolve the issue? |
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Post by rcq92130 on May 4, 2015 12:26:30 GMT -5
I recently upgraded to a 180cc big bore kit for my GY6 ruckus and I am noticing the carb is constantly overfilled, which is evident by the excessive fuel pouring out as soon as I loosen the screws to the carb bowl and the fact the overfill tube is always full of gas. The scooter will randomly cut out when I am cruising mid-throttle. I am running an OKO 30mm D-slide carb, which is brand new, and I made sure the needle and seat are working properly. I currently have a round Mikuni DF52-21-D dual output 35L/hr pump installed, with both fuel outlets T'd to a single hose that runs to my carb. Does the stronger vacuum pressure at the intake manifold of my 180cc engine increases the fuel pressure or flow rate the vacuum pump operates at? The fuel delivery setup I have now is the same setup I used with my 150cc and I never ran into flooding or overfueling the carb. In fact, I had to use the Mikuni dual output setup because the rectangular DF-44 single output Mikuni pump wouldn't be able to provide enough fuel during WOT sessions. I would actually run the carb bowl dry only after a few minutes of WOT. Once i switched to the Mikuni dual outlet pump, I would be able to WOT all day and not starve the carb of fuel. Now it seems with the 180cc build, it's the opposite problem of overfueling. The first thing i tried was installing a vacuum restrictor (basically a hose coupler with a small hole restrictor inside) inline between the pump and the vacuum nipple on the intake manifold. I thought by restricting the vacuum, it would lower the pressure or flow rate of the pump. Turned out it didn't change anything. Carb was still getting overfilled just the same. Again, i verified the needle and seat are working properly. One friend recommended I switch my vacuum line to a smaller diameter line, but seeing how the vacuum restrictor didn't make a difference, I don't see how changing to a smaller diameter vacuum line would help either. Would switching back to the single output 14L/hr Mikuni pump fix this issue? FYI: I went to an electric fuel pump, so a different setup but a similar problem. The pump was rated at 4psi to 6psi, which should in theory be fine with the 30mm carb I have (like yours). But i kept getting over fueling - especially after shutting the thing down ---- the pressure in the line would be released gradually, and the gas level would rise too high (sometimes so gas would flow out the inlet of the carb body). Took it apart a few weeks ago and the needle valve had been damaged after only about 1K miles. So, new needle valve ---- but also a pressure regulator just before the carb to solve the underlying problem. There is a perfect little device made for VW Beetles - small round chrome regulator that is easily set anywhere from 1psi to 6 psi. I have it now set to 2psi, which seems fine for what the carb needs. Note: the regulator does not cut down the flow RATE - same amount of fuel is available if needed. All it restricts is the max PRESSURE. Might want to consider something similar. |
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Post by userix on May 4, 2015 23:51:33 GMT -5
I recently upgraded to a 180cc big bore kit for my GY6 ruckus and I am noticing the carb is constantly overfilled, which is evident by the excessive fuel pouring out as soon as I loosen the screws to the carb bowl and the fact the overfill tube is always full of gas. The scooter will randomly cut out when I am cruising mid-throttle. I am running an OKO 30mm D-slide carb, which is brand new, and I made sure the needle and seat are working properly. I currently have a round Mikuni DF52-21-D dual output 35L/hr pump installed, with both fuel outlets T'd to a single hose that runs to my carb. Does the stronger vacuum pressure at the intake manifold of my 180cc engine increases the fuel pressure or flow rate the vacuum pump operates at? The fuel delivery setup I have now is the same setup I used with my 150cc and I never ran into flooding or overfueling the carb. In fact, I had to use the Mikuni dual output setup because the rectangular DF-44 single output Mikuni pump wouldn't be able to provide enough fuel during WOT sessions. I would actually run the carb bowl dry only after a few minutes of WOT. Once i switched to the Mikuni dual outlet pump, I would be able to WOT all day and not starve the carb of fuel. Now it seems with the 180cc build, it's the opposite problem of overfueling. The first thing i tried was installing a vacuum restrictor (basically a hose coupler with a small hole restrictor inside) inline between the pump and the vacuum nipple on the intake manifold. I thought by restricting the vacuum, it would lower the pressure or flow rate of the pump. Turned out it didn't change anything. Carb was still getting overfilled just the same. Again, i verified the needle and seat are working properly. One friend recommended I switch my vacuum line to a smaller diameter line, but seeing how the vacuum restrictor didn't make a difference, I don't see how changing to a smaller diameter vacuum line would help either. Would switching back to the single output 14L/hr Mikuni pump fix this issue? did you resolve the issue? Actually, I swapped out my velocity stack and threw on a UNI filter and that immediately fixed the cutting out problem when cruising between 1/4-1/2 throttle. I discovered this one day when I randomly decided to hold my hand over the velocity stack when it started cutting out. As soon as I placed my hand over the stack, the engine jumped right back to life. So I guess it was sucking in way too much air, making the mixture extremely lean in that throttle range? But even now with the UNI filter on, when I'm cruising in the 1/4-1/2 throttle range, I still get some sputtering, intermittent cutting out, but it's definitely a lot better than with a straight velocity stack. But the weird thing is the plug readings have always been near dry black color, indicating richness. As of now, I'm still having the weird bog issue when I crack the throttle wide open from idle. I have swapped out, as a process of elimination, the CDI, the ignition coil, spark plug, fuel pump, intake manifold, OKO 30mm carb, and air filter. The problem remains exactly the same even after individually testing each of the aforementioned components with known working/new ones. There are no leaks in the intake manifold, as tested by spraying carb cleaner all over it with no changes in idle. Exhaust gasket and flange are prefectly sealed and no leaks there. It's truly a mind boggler. |
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Post by userix on May 5, 2015 0:08:39 GMT -5
I recently upgraded to a 180cc big bore kit for my GY6 ruckus and I am noticing the carb is constantly overfilled, which is evident by the excessive fuel pouring out as soon as I loosen the screws to the carb bowl and the fact the overfill tube is always full of gas. The scooter will randomly cut out when I am cruising mid-throttle. I am running an OKO 30mm D-slide carb, which is brand new, and I made sure the needle and seat are working properly. I currently have a round Mikuni DF52-21-D dual output 35L/hr pump installed, with both fuel outlets T'd to a single hose that runs to my carb. Does the stronger vacuum pressure at the intake manifold of my 180cc engine increases the fuel pressure or flow rate the vacuum pump operates at? The fuel delivery setup I have now is the same setup I used with my 150cc and I never ran into flooding or overfueling the carb. In fact, I had to use the Mikuni dual output setup because the rectangular DF-44 single output Mikuni pump wouldn't be able to provide enough fuel during WOT sessions. I would actually run the carb bowl dry only after a few minutes of WOT. Once i switched to the Mikuni dual outlet pump, I would be able to WOT all day and not starve the carb of fuel. Now it seems with the 180cc build, it's the opposite problem of overfueling. The first thing i tried was installing a vacuum restrictor (basically a hose coupler with a small hole restrictor inside) inline between the pump and the vacuum nipple on the intake manifold. I thought by restricting the vacuum, it would lower the pressure or flow rate of the pump. Turned out it didn't change anything. Carb was still getting overfilled just the same. Again, i verified the needle and seat are working properly. One friend recommended I switch my vacuum line to a smaller diameter line, but seeing how the vacuum restrictor didn't make a difference, I don't see how changing to a smaller diameter vacuum line would help either. Would switching back to the single output 14L/hr Mikuni pump fix this issue? FYI: I went to an electric fuel pump, so a different setup but a similar problem. The pump was rated at 4psi to 6psi, which should in theory be fine with the 30mm carb I have (like yours). But i kept getting over fueling - especially after shutting the thing down ---- the pressure in the line would be released gradually, and the gas level would rise too high (sometimes so gas would flow out the inlet of the carb body). Took it apart a few weeks ago and the needle valve had been damaged after only about 1K miles. So, new needle valve ---- but also a pressure regulator just before the carb to solve the underlying problem. There is a perfect little device made for VW Beetles - small round chrome regulator that is easily set anywhere from 1psi to 6 psi. I have it now set to 2psi, which seems fine for what the carb needs. Note: the regulator does not cut down the flow RATE - same amount of fuel is available if needed. All it restricts is the max PRESSURE. Might want to consider something similar. I have tried the round, 1-6 psi selectable fuel regulator, but it leaked from the dial area straight out of the package. Since then , I haven't gotten a new one to test out yet. |
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Post by ital on May 6, 2015 10:01:15 GMT -5
I would try using a bigger main Jet. Go two sizes up and see if it resolve the issue. Just give it a try you got nothing to lose but time :-)
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Post by userix on May 8, 2015 4:29:50 GMT -5
I would try using a bigger main Jet. Go two sizes up and see if it resolve the issue. Just give it a try you got nothing to lose but time :-) I just tried a bigger main jet, it still has the bogging when cracking open the throttle and now 1/4 to 1/2 still sputters. When I'm cruising at half throttle and then suddenly go WOT, the engine bogs for 1 sec and then immediately picks up well. I also notice sometimes when I start the bike, I get some white smoke coming out. I just finished breaking in this new engine, does the white smoke indicate richness of fuel mixture? I hope I didn't already ruin the oil seal rings on the piston |
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Post by ital on May 8, 2015 14:49:50 GMT -5
I would try using a bigger main Jet. Go two sizes up and see if it resolve the issue. Just give it a try you got nothing to lose but time :-) I just tried a bigger main jet, it still has the bogging when cracking open the throttle and now 1/4 to 1/2 still sputters. When I'm cruising at half throttle and then suddenly go WOT, the engine bogs for 1 sec and then immediately picks up well. I also notice sometimes when I start the bike, I get some white smoke coming out. I just finished breaking in this new engine, does the white smoke indicate richness of fuel mixture? I hope I didn't already ruin the oil seal rings on the piston so it got worse when using a bigger jet? does the bogging go away when you cover the air filter? I would seriously doubt you ruin the oil seal rings, the smoke is probably un-burned fuel. You need advise from one of the experts like the buddies alleyoop and geh3333  |
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Post by onewheeldrive on May 8, 2015 19:46:31 GMT -5
/////////// EDIT
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