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Post by steve on Jul 2, 2015 12:52:00 GMT -5
I am glad you tried bypassing the petcock, as those can be an issue. With the carbs, you only really can adjust the idle. There is no adjustment that would make it go from running really rough, and cutting off, to running right, with the A/F adjustments. Unless the carb was defective, it came from the factory ready to run under throttle.
So, you have eliminated the carburetor, and the fuel delivery system. I think that it is one of 2 things.
1: the valves. The valves get really hot, and do go out of adjustment. It is gradual, but the effect can be sudden. The gap can start getting smaller, or larger, and you won't be able to tell a difference until they get past a certain threshold. Then, the effect can be that the engine goes from running relatively fine, to running really rough.
2. You have an air/vacuum leak somewhere. After adjusting the valves, if it is still running roughly, I would like you to replace the intake manifold, and all of the vacuum hoses coming off of that intake manifold, that are attached to 1 or 2 nipples.
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Post by steve on Jul 2, 2015 7:30:33 GMT -5
All the clutches do that, that's why you don't go back to idle RPM when you let off of the throttle. The new spring just has you at a "lower gear". It just is creating a little more vacuum during decel. It's not malfunctioning, that is normal clutch behavior.
Raise your idle a bit with the idle screw. Not the A/F screw, the idle screw. You may have to adjust it so you idle at about 2500 RPM, or so. Mine did the exact same thing, and this fixed it.
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Post by steve on Jul 2, 2015 7:24:48 GMT -5
I don't know what you mean by hang, but I haven't noticed any issues with it. When you release the throttle, the clutch stays engaged until around the 1700 rpm range Yes. When you let off of the throttle, the engine doesn't go back to idle speed. It works exactly like the factory clutch, it just "shifts" you to a lower gear quicker on hills, and during acceleration. It works with the RPM very much like rollers. If your scoot runs at 6K RPM, installing the 1500 clutch spring will make your scoot hold steady at 7500. It affects acceleration and hill climbing better than just rollers, or sliders, IMO. Just get some heavier weights to accomodate the spring raising your RPM. |
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Post by steve on Jul 1, 2015 15:36:14 GMT -5
Hey, ya'll.
This morning, something happened kind of strange. This is the 2nd time this has happened, but 1st on this carb.
I was going down this very long, very steep hill. Most 50cc's are going 15mph when they get to the top of this hill, for reference. Anyways, I get to the bottom of the hill, and I go back to the throttle, and it stutters a bit, but then keeps going. When I get to the next stop sign, it dies. I smell gas, get off, and look at the carb. Gas is pouring out of the vent hose. I mean pouring. I quickly turn the gas off of my manual petcock, wait a bit, start it up, drive it until it uses all the fuel in the bowl, and stop again. I get out, turn the gas back on, and it runs fine all day.
I had this happen, on a different carb, before I put the BBK on, about a year ago.
I guess the float valve just got stuck, going down that big hill. Weird.
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Post by steve on Jul 1, 2015 13:08:44 GMT -5
I would think that multiple cylinder engines can idle at a lower speed than single cylinder engines.
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Post by steve on Jul 1, 2015 13:06:43 GMT -5
I have a CDI that has an LED that flashes every time it fires. I got my scoot idling to where the stock tach said about 1100 RPM. You can count the flashes when you are turning it over to start it. Once it starts idling, when the tach says 1100, or less, that thing is flashing VERY rapidly. I borrowed my mom's digital video camera, and it will slow down to 1/2 speed, and it is still firing so fast you can't count it. I bet it is flashing 15-20 times a second. The only way to tell that it is just not lit up solid is if you watch it when you are cranking it, and you can see how bright the light actually is when it lights.
I'm going to take the fan off, and look at the flywheel here pretty soon.
I would say the tachs are close to right.
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Post by steve on Jul 1, 2015 10:55:06 GMT -5
I hear about it all the time. Somebody told me about it yesterday, as a matter of fact.
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Post by steve on Jul 1, 2015 10:29:49 GMT -5
That is the seller's info.
He responded to me. I broke a ring, and he emailed me back, and sold me some rings a little cheaper. Then, I emailed him back, and asked for a new cylinder, and he just responded with a link to that same kit.
I didn't want to post about it, but I had the exact same problem, with the exact same BBK. Ended up losing compression pretty badly, after a couple of days. Holes in the cylinder, and the cylinder head. I replaced just the cylinder, and it got better. Then, I replaced the cylinder head, and voila, it was fixed. It really is crap. I think he either owns, or is in tight with a factory in China, and makes stuff cheap by cutting corners.
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Post by steve on Jul 1, 2015 10:21:51 GMT -5
Yes. But if you are asking if I did something dumb, and pulled the cylinder out, looked at the hole, and put it back, the answer is no. Already learned that the hard way.
I didn't take the cylinder out. I just loosened it, and raised the jug a bit. That 37mm jug is in there pretty tight. The normal 139qmb's have a good bit of room. This one doesn't.
I have a 47mm, and a 50mm cylinder that I compared.
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Post by steve on Jul 1, 2015 10:15:00 GMT -5
Not to be the pessimist here, but are thieves really taking the excess time to hotwire and drive off your scooters? A 50cc doesn't weigh that much, nor is it that big. Why not just throw it in the back of a pickup or SUV? And work on starting it when they're somewhere else? Seems it would be faster and easier, and less likely to be observed/stopped. As for fixing the locking peg/s, from reading on the forum how easy it is to pop them (case in point) I'd say skip fixing them unless they served some other purpose. And go with the guys' suggestion to install a kill switch somewhere hidden. >'Kat Yes. It's mostly kids. People that can afford trucks don't need to steal scooters. I also got one stolen when I was going to college. Somebody pushed it a block down the road, and tried to hotwire it. |
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Post by steve on Jul 1, 2015 10:11:48 GMT -5
That looks nice. Great price, too.
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Post by steve on Jul 1, 2015 10:07:40 GMT -5
Go up to a 120 main. The more fuel you add, the cooler it will run. I really think you need to upjet. You noticing how hot it is running is another symptom of being lean.. Upjet the main.
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Post by steve on Jul 1, 2015 7:07:37 GMT -5
Remember, that Shinko you picked out is going to wear out pretty quickly again. That one has a really busy tread pattern, so it's going to wear faster. It is nice looking, though. To be honest , the tread pattern should have little impact on the tread wear. Its the treadwear rating that really matters. It has a HUGE impact on my Zuma. The Zuma has really good low end torque, and it just eats up back tires. The tires with the fewest grooves, and "less busy" tread pattern, last way longer for me. I don't think I've ever put an L rating on there, so that may make a difference. But, for tires with the same rating, the tread pattern makes a large difference, for me, at least. |
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Post by steve on Jul 1, 2015 6:57:03 GMT -5
No, as long as the little hole that the fuel goes through is not damaged, you are fine.
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Post by steve on Jul 1, 2015 6:55:24 GMT -5
There is not much to go on in that video. Hard to tell anything, really. You need to check for "the big 3", and tell us your results. Spark, fuel, and compression. I would start with a valve adjustment, to get that out of the way, then check for the 3.
Do you know how to do this?
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