It died again.

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white noise
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It died again.

Postby white noise » Mon Sep 18, 2006 9:47 pm

My scooter sucks.

Or I suck as a mechanic.

Either way, it sucks.

Someone please advise me what to do. Here the story:

My scooter died a couple of weeks ago. We thought either a spark problem or a fuel line issue. Both were in question, so I changed the spark plug cap, the spark plug, the fuel tap, cleaned and jetted the carb. It wasn't dirty but now it is clean like a baby popo.

With some problems we got it started and running but there was this weird metallic or rather tinny sound. After some riding it started to stall on me everytime I slowed down and wouldn't give it enough throttle. Also I could only get it started when I pulled the choke.

So Tony took a look, cleaned the already clean jets, gave it a gentle stroke and it ran again. Nicely. The whole day, the next morning and afternoon. Great puff-puff sound and start at first kick. I was surfing clouds.

And then this evening I kicked it and hear again this suspicious tinny sound. Two blocks later it started to get clumsy and eventually died. I can't get it started and roll it seven blocks home.

What the hell is going on? I don't think it is the carb. Did I perhaps kink the fuel hose or something? What else can it be?

tony
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Postby tony » Mon Sep 18, 2006 10:20 pm

Sorry to hear! When it died out tonight, is it just dead? No chance of restart?

The thing that would worry me the most is the sound. If it is making that tinny sound again there is a good chance it might be one of the bearings going out on you. A quick way to check is by removing the plug and shining a flashlight down into the hole. If you can see any metal shavings, one of the bearings is probably no more. Also, check remove the fill screw for your gearbox and sniff the oil within - if you can smell gas, this can also tell you that something more worrysome has gone on.

If it were not for the sound, I would say it sounds like a fuel obstruction issue - especially due to the fact that it would run with the choke on. We cleaned out the jets and the passages that they sit in, so they should be fine. You put in the new fuel tap, and that should have included a new in screen filter, correct? Another place to look would be the screen filter that is located within the carb.

Do you know how many miles you put on it from when we finished on Sunday until it died tonight? There is a chance it could be an obstruction in the fuel line or something of this nature, but that usually only lets you run for a couple miles or so at best before dying.

The odd thing is that the problem isn't happening all the time - the scoot definatly ran pretty good on Sunday, and I didn't hear any odd noises when I was riding around on it.
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white noise
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Postby white noise » Mon Sep 18, 2006 10:44 pm

tony wrote:Sorry to hear! When it died out tonight, is it just dead? No chance of restart?.


Not tonight, no.

If it were not for the sound, I would say it sounds like a fuel obstruction issue - especially due to the fact that it would run with the choke on. We cleaned out the jets and the passages that they sit in, so they should be fine. You put in the new fuel tap, and that should have included a new in screen filter, correct? Another place to look would be the screen filter that is located within the carb.


Yes, the filter at the fuel tap is new. I didn't change the filter in the carb b/c I couldn't get one at that point. It is a bit yellowish but no cracks or so. I cleaned it.

Do you know how many miles you put on it from when we finished on Sunday until it died tonight? There is a chance it could be an obstruction in the fuel line or something of this nature, but that usually only lets you run for a couple miles or so at best before dying.


Less than five miles. Around the neigborhood, work and back.

I look into the plug hole first thing tomorrow morning.

One thing: When I had the problem with the fuel tap control and unhooked the fuel hose I clamed it up tightly with a vice grip. I checked it before I connected it to the carb, and it kind of looked o.k. (a bit squashed), but now I wonder if there might be a hole...

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white noise
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Culprits

Postby white noise » Tue Sep 19, 2006 7:54 am

I checked some things this morning:

Spark? The spark plug looks good; brownish as it should be. I checked if I have spark - positive.

Bearings? I looked into the spark plug hole but couldn't see any metal shavings. It looks clean. I sniffed at the gearbox and it only smelled oily - even after a couple of kicks.

Fuel obstruction? I checked the fuel hoase and clam in the carb box but it didn't feel wet, so I figure this is not the problem. I opened the top of the carb body in order to take a look at the filter. Of course I forgot to to close tha fuel tap and I had lots of gas spillage. I closed it again, switched off the fuel and lifted the top again. Still lots of gas spillage and it wouldn't stop. When the container filled I quickly closed the carb body because I didn't want to get into trouble with my landlady over fuel spots in front of our house (there are severals already :oops: ).

The gas flow is supposed to stop at some point, no?

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Susan
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Postby Susan » Tue Sep 19, 2006 8:50 am

I have the answer!

Well, actually, I had the answer. I think this is the last thing I looked at before I went to sleep last night, and I managed to dream about it and figure it all out.

I'm really embarassed that I'm dreaming about scooter tech stuff, actually.

No, I can't remember what it was. But it made perfect sense at the time.

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spoffy
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Postby spoffy » Tue Sep 19, 2006 8:52 am

I'm not a great mechanic by any stretch of the imagination, but I also had recent airleak problems with my Rally. The first carb rebuild didn't make any diff. I did it a second time (just to be sure) but used a gasket sealant, which totally did the trick.

Worth a try. The mechanic I spoke to at SCOMO highly recommended the NAPA/Permates High Tack Gasket Sealant (came in a can with one of those rubber cement brushes in the lid - nasty stink and reddish brown color). Stuff reeks, but worked a treat.

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Postby AirborneVespa » Wed Sep 20, 2006 11:25 am

If your gas flow isn't stopping when you turn the tap off then you have a faulty tap, or your float needle has gone to shit and isn't closing, or you didn't install the float needle correctly if you had the carb apart.

Edit. Your fuel hose should be 24 inches long exactly. I'm sure you knew this.
byelaya smert

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white noise
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Postby white noise » Wed Sep 20, 2006 2:02 pm

I have just replaced the fuel tap and the float needle, they are both new. I have installed the needle so that the float can move. But I didn't see that there was another way of installing it. Is there?

Dunno about the hoase. It came with the scooter and the guy who used to own it knew how to fix it, so I guess it is 24 inches long.

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AirborneVespa
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Postby AirborneVespa » Wed Sep 20, 2006 2:18 pm

white noise wrote:I have just replaced the fuel tap and the float needle, they are both new. I have installed the needle so that the float can move. But I didn't see that there was another way of installing it. Is there?

Dunno about the hoase. It came with the scooter and the guy who used to own it knew how to fix it, so I guess it is 24 inches long.


If I remember correctly there is a little slot in the float itself that the bottom (hex) of the float needle fits into. It has to slide into this slot, then you slide the needle with the tapered in into the hole. Heh heh I said tapered in into hole.
byelaya smert

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white noise
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Postby white noise » Wed Sep 20, 2006 2:24 pm

I believe this is how I did it. I'll rebuild the carb again on the week-end and will check.

Thank you.

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Spiny Norman
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Postby Spiny Norman » Wed Sep 20, 2006 11:58 pm

Check to see if your choke is sticking. In other words, when you push the choke in, make sure its actually doing something on the carb end. I had rough running stalling problems for a while and it turned out to be that simple.

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AirborneVespa
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Postby AirborneVespa » Thu Sep 21, 2006 9:01 am

AirborneVespa wrote:
white noise wrote:I have just replaced the fuel tap and the float needle, they are both new. I have installed the needle so that the float can move. But I didn't see that there was another way of installing it. Is there?

Dunno about the hoase. It came with the scooter and the guy who used to own it knew how to fix it, so I guess it is 24 inches long.


If I remember correctly there is a little slot in the float itself that the bottom (hex) of the float needle fits into. It has to slide into this slot, then you slide the needle with the tapered in into the hole. Heh heh I said tapered in into hole.


God am I fucking retarded? Tapered in? WTF is a Tapered in? Tapered END maybe?

Either I was just tired, or I have alzheimer's.
byelaya smert

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white noise
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Postby white noise » Thu Sep 21, 2006 9:32 am

Alzheimer? Impossible. You just turned 28, didn't you?

Image

tony
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Postby tony » Thu Sep 21, 2006 10:08 am

I know that some people do not understand how a motorcycle works as well as me so I am happy to pass on some of my wealth of knowledge now and again.

Having a more in-depth understanding of the basics of carb design and function will likely make it far easier to get them set up correctly.

The basic secret of carb function is that inside each carb are
thousands of tiny gnomes; each with a small bucket. As you open the
throttle, more of these gnomes are allowed out of their house and into
the float bowl, where they fill the buckets and climb up the carb's
passages to the intake, where they empty their buckets into the air
stream.

But, if you don't ride the bike for a while, bad things can happen.
Tiny bats take up residence in the chambers of the carb, and before
long the passages are plugged up with guano. This creates a gnome
traffic jam, and so not enough bucketfuls of fuel can get to the engine. If it gets bad enough, the gnomes simply give up and go take a nap. The engine won't run at all at this point. Sometimes you'll have a single dedicated gnome still on the job, which is why the bike will occasionally fire as the gnome tosses his lone bucket load down
the intake.

There has been some research into using tiny dwarves in modern carbs.
The advantage is that unlike gnomes, dwarves are miners and can often
re-open a clogged passage. Unfortunately, dwarves have a natural fear
of earthquakes, as any miner should. In recent tests, the engine
vibrations caused the dwarves to evacuate the Harley Davidson test
vehicle and make a beeline for the nearest BMW dealership. Sadly,
BMW's are fuel injected and so the poor dwarves met an unfortunate end in the rollers of a Bosch fuel pump.

Other carb problems can also occur. If the level of fuel in the float
bowl rises too high, it will wipe out the Section 8 gnome housing in
the lower parts of the carb. The more affluent gnomes build their
homes in the diaphragm chamber, and so are unaffected. This is why
the bike is said to be "running rich".

If the fuel bowl level drops, then the gnomes have to walk farther to
get a bucketful of fuel. This means less fuel gets to the engine.
Because the gnomes get quite a workout from this additional distance,
this condition is known as "running lean".

The use of the device known only as the 'choke' has finally been
banned by PETG (People for the Ethical Treatment of Gnomes) and
replaced by a new carb circuit that simply allows more gnomes to carry
fuel at once when the engine needs to start or warm up. In the
interests of decorum, I prefer not to explain how the 'choke'
operated. You would rather not know anyway.

So, that's how a carburetor works. You may wish to join us here next
week for electricity 101, or "How your bike creates cold fusion
inside the stator, and why the government doesn't want you to know
about it."
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white noise
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Postby white noise » Sat Sep 23, 2006 2:48 pm

Carb is rebuild again. Everything is perfectly fixed in there and around it. Fuel runs as it should. There is spark. Nothing leaks.

But it still doesn't fire. :(

And now?


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