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Post by userix on Jun 28, 2014 1:09:41 GMT -5
A new problem has arisen. I have the vapor speedo installed along with the TTO tach hour meter. The vapor speedo has the tach wire hooked up to the connector at the ignition coil coming from the CDI. The TTO Tach hour meter has its sensor wire wrapped around the ignition coil wire right before the spark plug. I just recently started having weird stuttering issues while riding. It's random stuttering that comes usually during WOT, but can occur throughout the throttle range as well. There are no popping or backfiring sounds and it idles fine. It doesn't feel like a fuel delivery issue or carb tuning, since nothing has changed in those aspects when it was running fine. It started having the stuttering issue after I removed the spark plug from the engine. After I reinstalled the spark plug and the boot securely, that's when I started having the weird stuttering issues randomly throughout my ride.
What I do notice because of my dual tach setup, I'm getting two different readings for my RPM during my rides at greater than 50% throttle. For instance, when I'm at ~8000rpm according to my vapor speedo, the TTO tach hour shows 4300rpm, almost half of what it should be. But at standstill idling, both tach reads correctly ~2000 rpm. I rode around longer and the problem is consistent, the RPM reading at the coil wire near the spark plug is almost always half of what I am reading from the CDI unit. The PPR setting is the same for both TTO hour and vapor trailtech, which is set at '1'.
So do I have a bad ignition coil? Or can the spark plug boot go bad? I notice the spark plug boots sold online have different type of resistance on them. Does the resistance matter for our gy6 engines? I currently have an NGK spark plug boot installed.
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Post by userix on Jun 21, 2014 3:35:36 GMT -5
Is there anyway to straighten out the steering stem? I notice my wheel is slightly off-centered from the handlebars. Holding the handlebars straight will cause my scooter to go slightly right. It's not severe off-axis, but I can notice it
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Post by userix on May 27, 2014 13:29:15 GMT -5
i agree you may be over carbed, and with the cone air filter on instead of air box, you will get too much air and i think you will hav vacuum problems too. might hook a vacuum gauge to the bike and see what readings you get. also are you sure the idle isnt 1250-1500 (these engines have waste spark so they fire on every revoltuion, th tach should be set to accommodate that.) Well, the carb is a stock 24mm keihin carb. I have both my vapor speedo and TTO tach hour meter set to PPR of 1 (Pulse Per Revolution of the crankshaft). Not sure how to fit a vacuum gauge to the small 3/16" vacuum hoses. But I do have the problem of air bubbles getting into the fuel line between the pump and the carb. I'm not sure where air is getting in. The vacuum hoses and fuel lines are well sealed to the connectors and there are no leaks anywhere. |
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Post by userix on May 24, 2014 5:43:26 GMT -5
I flipped the carb around already from last time you stated it was backwards. But the fuel starvation issue is something separate. Even with the carb mounted facing backwards, I still have fuel delivery issue, as evident in the carb bowl being almost empty after a long wot session.
In reality, even though I was idling around 2500-3000, my bike wasn't moving by itself at a standstill. I could get off my bike, without any of the brakes on, and it would stay put and not move at all, even though it was idling so high. I know it's not suppose to idle that high, but just letting you know, it wouldn't move by itself in spite of the high idle speed.
But now that I see the carb bowl is nearly empty after a long wot session, I know it's a fuel delivery problem. It seems like the pump isn't getting enough fuel to the carb on extended wot sessions. I read somewhere else in this forum that the vacuum pressure of the GY6 engines at high RPM produce considerably less vacuum pressure, thus reducing in the amount of fuel pumped by the mikuni vacuum pump. Not sure how valid that is.
But like I said previously, I checked all the vacuum lines for leaks and the fuel lines as well. There are no leaks. It seems that the gas tank is working because if I disconnect the fuel line going into the mikuni pump, gas freely flows out, which means there is no obstruction to the free flow of gas from the gas tank. There is no gas leaking out from any of the lines either, so I'm not sure where the bubbles or air in the fuel line from the pump to carb are coming from. The mikuni pump is brand new, so I know there are no tears in the diaphragm of the pump.
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Post by userix on May 23, 2014 22:21:37 GMT -5
Ok. I carried some tools while riding today and turns out I was runnin into fuel starvation issues. As soon as I hit the bogging problem at wot, I pulled over right away and dropped the float bowl. The level of fuel is very low. Now I have since them replaced the pump with a brand new mikuni and checked all vacuum lines and fuel lines. There are no leaks anywhere and the connections are all good. I noticed the check valve that was between the pump and carb was seemed very restrictive. So I removed if completely. I still have the problem though after all this. I still run into fuel starvation issue on long wot sessions. Even with a pump and the check valve removed, I still see bubbles appearing from the pump outlet to the carb. But again no fuel leaks from any hoses from the tank to pump to carb.
Do I need to upgrade to an electric pump setup?
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Post by userix on May 19, 2014 14:43:12 GMT -5
Idling at 2500-3000!!! You have that thing all messed up, no wonder you are having a lot of problems, it should be idling at 1500-1800 no more. The First thing to do is ADJUST the Valves, and may I say mounting the carb backwards is one of your first problems. Reason is the front of the scoot there does not get much air and the filter has a cap on the end(but be it as it may). Alleyoop Valves have been adjusted .004 for both. If I drop the idle any lower, it will stall out after letting go of throttle from wot and coming to a stop. I tried 105, 108, 120 main jets and I still have the same problems. Tried. 36 and 38 pilot jet As well. The air filter of the carb is suppose to face towards the back of the scooter?? All the custom gy6 I have seen have the carb mounted with the air filter facing the front of the bike. But anyways. I tried various main jets and pilot jets and the problem is still there. Changing the carb float height didnt help either |
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Post by userix on May 19, 2014 1:43:45 GMT -5
The POPPING when you let go of the throttle completely closes the BUTTERFLY really quick it snaps shut to where you have the idle set. That is a LEAN condition, it could just be that the IDLE is set to low and is closing to many of the PILOT jet fuel outlets and it runs lean and POPS. So if the idle is below 1500 or lower raise it to mayabe 1600 and see if that stops the POPPING if not then turn the FUEL RATIO mixture 1/4 Turn Counter Clockwise to feed it a little more fuel. Alleyoop My idle is around 2500-3000. And I still get the occasional pops. But the bigger problem is when I start stalling out during wot, like I am running out of fuel. The engine will start to die like there was no more fuel. This happens only after say 3-5 min of straight WOT. the carb bowl is still full of fuel after immediately pulling over when I lose power, so it's not actually out of fuel. But the engine still loses power as if it was running out of fuel, but it can start right back up after maybe attempting to start it for 10 sec. I'm at a 114 main jet now and it still has the same problem as when I was using the 105 and 108 jets. Now I'm thinking could this have something to do with the pump not pumping enough fuel due to the lower vacuum pressure during wot? But then I think if that was the case, there should have been very little fuel in the carb bowl when I pulled over immediately after stalling to check. I'm not sure what the problem can be now. As of now, I have jumped from a 102 main jet to a 114 and still encounter the loss of power after a straight 5 min wot. It doesn't feel like it got any better. I'm baffled as to what the issue really is. And it just doesn't happen all the time either. |
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Post by userix on May 18, 2014 17:21:36 GMT -5
I changed the main jet to 114 and pilot to 38. Just to test out. And I still get the random dying on wot issue. It really feels like it just runs out of fuel. But I pull to the side and drained the carb and a good amount of fuel drained out. It's so weird. There fuel in the bowl And the main jet is huge and I still get what feels like fuel starvation accompanied by popping when I let completely go of the throttle.
The problem doesn't happen consistently. That's what confuses me. I switched a cdi too
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Post by userix on May 15, 2014 12:59:56 GMT -5
So I upjet to a 105 jet on the carb and took it for a ride. I went wotting for a good mile and near the end of the mile, the engine started stalling out, as if it ran out of fuel, and I lost power and speed, I let go of the throttle partly and it still loses power, as if no gas. Then I let go of the throttle completely, and I get a bunch of popping. Then I come to a stop, and the engine idles fine and doesn't die and I can take off immediately afterwards without anymore issues. Does this mean I'm still running lean? Do I need to go up in jet size again to maybe a 108?
Does going to large a jet reduce top speed and low end accelration performance?
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Post by userix on May 15, 2014 3:20:23 GMT -5
Here's a vid of my scooter idling. Is it normal for the idle to dip every so often like in the video above? I'll try to get a video of the scooter revving. Again, I made sure there are no air leaks anywhere around the carb, intake manifold.
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Post by userix on May 14, 2014 11:20:31 GMT -5
You set it for firing once per revolution. Our plugs fire on every stroke on a gy6. @pssthpok: The Trail Tech TTO is a combo tachometer and hour meter. The tach works off pulses from a wire wrapped around the spark plug wire. The Total Hour Meter works based on a simple digital delay, if the circuit doesn't receive a pulse within a certain number of milliseconds, the engine is not running. Thanks! So it's set at the default of 1 PPR. |
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Post by userix on May 14, 2014 2:38:58 GMT -5
What's the correct setting for the TTO tach hour meter in terms of the PPR ( pulse per crankshaft revolution) for the 150cc gy6 engine?
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Post by userix on May 11, 2014 16:39:00 GMT -5
I thought you said the main jet was too small. The popping is still only happening on decel. What jets would you recommend I use for my setup as stated previously? Sorry I might have been unclear before the quick twist of the throttle test, the idle dips below normal idle after I release the throttle. Not during the quick twist of he throttle. When I quickly twist the throttle, the rev goes up normally and when I let go, then the idle drops way below normal but return back to normal after a couple seconds.
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Post by userix on May 10, 2014 19:53:11 GMT -5
POPPING AT WOT is TO MUCH FUEL your main jet is TO BIG. What exactly do you have on the scoot?  Free flow Filter--?YES OR NO? Free flow Muffler--?YES OR NO? What size Carb--? What size Main jet--? What size Pilot jet-- 36 Free flow exhaust yoshimura. Free flow filter. (Mushroom looking cap) Carb size is keihin 26mm Main jet 102 Pilot 36 But I still have popping on decel and I lose power right before the popping starts during wot. It still feels like "running out of gas" feeling, which. I believe means it's lean right? |
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Post by userix on May 10, 2014 19:15:29 GMT -5
Well a #36 Pilot jet is to BIG plain and simple, if it came like that its to big for you motor. People think dump a gallon of fuel in and the scooter or put on a bigger carb to get more speed WRONG, it actually floods the motor and the motor looses power with to much fuel. So first go down on the pilot jet to stop it from loading up the motor at idle. Then we can work on other problems, one thing at a time. Alleyoop But what about the popping on decel? Is that not caused by the pilot jet being too small? Because the throttle is completely closed during the deceleration pops. Update: just took a ride out and wotted it straight for a mile. At the end of that mile, I started losing power as if I ran out of gas but I kept the throttle wide open and I started getting pops while the throttle is held open, but I am losing power and speed at the same time, as if running out of gas. I checked the gas lines during this time and there are no bubbles at all. Fuel is flowing well. But as soon as I pull over and stop, the bike is idling fine and I am continuing to ride right now. Is this still a lean condition of the main jet? I haven't messed with the main or pilot jets yet Just throwing this out here but could a faulty cdi cause any of these symptoms I am experiencing? |
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