I think I overfilled my gas tank

[Fogie]

Hi All

I have a 2012 Yager GT 200i that I've owned for 2.5 years; it only has about 5.5K KMs on it. When I gas it up, I always fill it so the gas is within sight when looking down the filler hole; I know this is high, but I like to fill it to a visibly-repeatable level so I can keep detail track of my mileage, and it's never caused a problem.

Whenever I've filled it, I've either ridden it for some distance afterward (and thereby used up some gas), or taken it straight home and left it on the sidestand. The other day, I filled it, but took it home and put it on the center stand, because I needed it that way to switch to my large winter windscreen; I then left it like that for several days. When I next drove it, I noticed that it now misses under hard acceleration, which seems to me like something is inhibiting the free flow of fuel. For now, I'm assuming that excess gas has somehow gotten into someplace that it shouldn't. I'm basing this assumption on a Leader-engined Piaggio product that I previously owned, that dumped excess gas into the air filter, and would cause the bike to behave similarly or die, until the filter was cleaned out.

I've looked at the service manual, and see that there's a "breather tube" coming off the filler pipe, but without taking the bike apart, I can't tell exactly where it connects into the filler pipe, or where it leads to. I have a suspicion that it connects on the right side of the filler, because I've never had a problem when the bike is parked on the sidestand (i.e. leaning left), but when the bike is on the center stand, it may be that excess gas could then drain out through a right-side breather. As for where the breather might drain, I can't believe the tube would run all the way from the filler at the front of the bike to the air filter at the back. So I assume it goes somewhere else, but I can't see it in the manual.

Ant Knowledgeable opinions on this situation would be greatly appreciated.

[CROSSBOLT]

Goes from filler neck to vacuum valve which, when open, routes liquid gasoline to vapor cannister. This cannister is at lowest level aft of fuel tank. This being wet with liquid can make for crappy running of engine. It must be dried out or replaced.

There is also a "puke tube" that must be drained periodically. It is engine left, just forward of variator. Has a removable plug. Put plug back in after draining.

Karl

[Yager200i]

No! The Kymco Yager GT 200i has no vapor canister. It has a PAIR filter canister below and forward of the engine (behind the gas tank), but no vapor canister. The "burp line" that gets air out of the gas tank runs from the top of the gas tank to the top of the filler neck.

There's no way to "overfill" the Yager's gas tank. I've filled it all the way up to the lip each and every fill-up with no problems.

Look at page 82 of the Yager parts list catalog, you'll see where the "burp line" connects. There's no vapor canister.

[CROSSBOLT]

I stand corrected by Yager200i. He IS one of the true experts on the Yager!

Karl

[Fogie]

No! The Kymco Yager GT 200i has no vapor canister. It has a PAIR filter canister below and forward of the engine (behind the gas tank), but no vapor canister. The "burp line" that gets air out of the gas tank runs from the top of the gas tank to the top of the filler neck.

There's no way to "overfill" the Yager's gas tank. I've filled it all the way up to the lip each and every fill-up with no problems.

Look at page 82 of the Yager parts list catalog, you'll see where the "burp line" connects. There's no vapor canister.

Many thanks for the info. I don't have a  parts list catalog, but I do have the service manual. I spent a bunch of time trying to find the vapor canister in the manual, all to no avail. So, I ended up dropping the bike off with the dealer (I don't have it back yet, and don't know for sure what the problem is). The dealer seemed to think the most likely cause of my symptoms is a faulty coil (that coincidentally began acting up after I filled the bike).

A few "by the ways":

1) Just as Karl suggested, I talked to another Kymco technician who also thought the problem might be a saturated vapor canister. He suggested that a high-speed run would result in some valve opening and causing air to pass through the canister, drying it out. I didn't try this (it's too damn cold for a lengthy high-speed run).

2) Is there any site where I can download the parts list catalog? It sound like it could be useful.

3) Precisely what is a "PAIR filter"? Google hasn't been much help. I assume it has something to do with filtering the gas as it leaves the tank.

I'll post an end to this story when I get the bike back (probably sometime next week).

Thanks again

[Yager200i]

Many thanks for the info. I don't have a  parts list catalog, but I do have the service manual. I spent a bunch of time trying to find the vapor canister in the manual, all to no avail. So, I ended up dropping the bike off with the dealer (I don't have it back yet, and don't know for sure what the problem is). The dealer seemed to think the most likely cause of my symptoms is a faulty coil (that coincidentally began acting up after I filled the bike).

My missing problem under hard acceleration was due to a tiny, tiny hole the spark punched through the spark plug wire, right where the wire goes through the frame, between the spark coil and the spark plug. You might check that. I wrapped it with a thick wrapping of electrical tape, but it wore (or sparked) through it again. Not a problem, though, my electronics guy informs me he's got the bEMF spark coil isolator circuit done (it isolates a hot spark coil from the ECU to prevent blowing out the ECU), so I'll be swapping out the spark coil and spark plug wire soon.

But check for a very small hole in your spark plug wire... you'll likely need a magnifying glass to see it unless it's been there a while and had a chance to get charred a bit.

A few "by the ways":

1) Just as Karl suggested, I talked to another Kymco technician who also thought the problem might be a saturated vapor canister. He suggested that a high-speed run would result in some valve opening and causing air to pass through the canister, drying it out. I didn't try this (it's too damn cold for a lengthy high-speed run).

2) Is there any site where I can download the parts list catalog? It sound like it could be useful.

Here you go:
Kymco Diagnostic Tool Users Manual (PDF format):
http://www.filedropper.com/kymcodiagnostictoolusermanual

The maintenance schedule I use (OpenOffice.org .ODF spreadsheet format):
http://www.filedropper.com/maintenanceschedule

Yager 200i Parts List (PDF format):
http://www.filedropper.com/yager200ipartslist

Yager 200i Wiring Diagram (PDF format):
http://www.filedropper.com/yager200iwiringdiagram

And the Yager 200i Service Manual (PDF format):
http://www.filedropper.com/yager-200i-service-manual

3) Precisely what is a "PAIR filter"? Google hasn't been much help. I assume it has something to do with filtering the gas as it leaves the tank.

Pulsed AIR (PAIR) system... it pulses air into the exhaust manifold to allow any unburned hydrocarbons to burn, thus reducing emissions.

[Fogie]

Wonderful info ... thank you so very much!

[CROSSBOLT]

I got to thinking about this and there IS  vapor can on the Yager! The PAIR device is where I incorrectly said the vapor cannister was. The vapor can is all the way to the rear of the bike, rubber mounted to the rear cross frame which is just forward of the tail light.

Have you tried a TPS-ISC reset? Also called initialize. I know I harp on this but it is ignored by most techs for various reasons. Requires no tools and there is no downside.

Karl

[Fogie]

I got to thinking about this and there IS  vapor can on the Yager! The PAIR device is where I incorrectly said the vapor cannister was. The vapor can is all the way to the rear of the bike, rubber mounted to the rear cross frame which is just forward of the tail light.

Have you tried a TPS-ISC reset? Also called initialize. I know I harp on this but it is ignored by most techs for various reasons. Requires no tools and there is no downside.

Karl

I haven't tried anything; I left it for the dealer to sort out. They were going to get to it today; so, I should  know something tomorrow or the next day.

Another thought that crossed my mind: Since the problem started shortly after I filled the bike, I may have gotten a tank full of bad gas. We'll see.

[CROSSBOLT]

Keep an eye on your dealer until he proves trustworthy is my recommendation. This kind of "open-ended" problem can be a real money-maker for a shop. Yes, you could have gotten a bad tank of fuel, even in Canada!

Karl

[Yager200i]

I got to thinking about this and there IS  vapor can on the Yager! The PAIR device is where I incorrectly said the vapor cannister was. The vapor can is all the way to the rear of the bike, rubber mounted to the rear cross frame which is just forward of the tail light.

Have you tried a TPS-ISC reset? Also called initialize. I know I harp on this but it is ignored by most techs for various reasons. Requires no tools and there is no downside.

Karl

No, that "vapor can" is a valve and the "rocks and bugs" air filter that goes into the PAIR system, I believe. It should have an open-ended hose to suck air in, one hose to go to the main PAIR filter, and a vacuum tube that connects to the intake manifold. When the engine is decelerating or idling, engine vacuum opens the valve and allows exhaust vacuum to suck fresh air into the exhaust manifold so unburned hydrocarbons can get the oxygen needed to burn.

I've been all over the fuel system on this bike, there's no vapor canister nor any hose connections to the fuel tank or filler neck that go to one. The only hose on the filler neck is a "burp line" that runs from the top of the tank to the top of the filler neck to get air out of the tank, so as you fill it all the way up, that air trapped at the top of the tank has somewhere to go.

Unfortunately, that "burp line" is too small to get all the air out quickly enough when you're filling. That's why it's a good idea to put the bike on the main stand to fill up, and rock it back and forth a couple times after the fuel level gets up into the filler neck. I generally fill it up until it's a few inches from completely full, rock it back and forth (a huge air bubble will come out), fill it back up to within three inches or so of completely full, rock it again (a small air bubble will sometimes come out), then fill it right up to the lip of the fill opening.

[Yager200i]

Oh yeah, I almost forgot about the TPS... I've fiddled with it quite a bit, too. In trying to get the engine to run a bit leaner so it'd get better fuel mileage, I shifted the position of the TPS, thinking that the ECU would think the throttle wasn't open as much, and thus would inject less fuel... that doesn't happen.

What happens instead is that the ECU becomes confused because the engine is operating outside of its fueling map, thus it'll cut out. You can make it run richer (at least until the O2 sensor heats up and starts inputting to the ECU and leans it back out... so you could adjust the TPS to get a richer cold idle mixture), but not leaner.

But that's not load-dependent, that's engine speed dependent. If you're getting a miss on high engine load (say, you're pulling up a long up-sloped freeway onramp at WOT) and it starts cutting out as the engine works harder, that's likely the spark wire or spark coil... the harder the engine works, the higher the cylinder pressure. The higher the cylinder pressure, the harder it is for the spark to jump the spark plug's gap. The harder it is for the spark to jump the spark plug's gap, the higher the spark voltage. And if you have a faulty coil or spark wire, it might just reach a high enough voltage to arc, which is what happened in my case.

It ran fine once I was on the level, even at WOT and full speed... but acceleration up a long slope caused it to miss... at least until I backed off the throttle and accelerated slower, then it ran fine.

[Yager200i]

I haven't tried anything; I left it for the dealer to sort out. They were going to get to it today; so, I should  know something tomorrow or the next day.

Another thought that crossed my mind: Since the problem started shortly after I filled the bike, I may have gotten a tank full of bad gas. We'll see.

It'd have to be really bad gas to affect this engine... it's kind of an omnivore when it comes to fuel. I've put as much as 200 ml of acetone and 200 ml of water into a tankful of fuel and it ran better than ever!

If you think you've got water in your fuel, your best bet is to put acetone into the fuel (mix acetone and fuel together, pour it into the tank, then flush the filler neck by pouring in some straight fuel with no acetone). The acetone will bind the water and fuel together and your engine will burn it just fine. In fact, the water expanding to steam in the cylinder should give you a bit of a power boost.

Although I must say, I did get a bad batch of fuel once... it wasn't water, it was sediment smaller than 12 micron, and it coated everything downstream of the fuel injector. Had to tear the bike apart and clean it from the fuel tank to the intake manifold, including the fuel injector itself.

The Yager doesn't have a fuel filter installed from the factory, so that crud ends up in the fuel injector. That could have happened to you. I'd recommend installing a 5 to 12 micron fuel filter in the fuel line (make sure it's a metal-bodied fuel filter that can withstand the pressure).

I use 12 micron Wix 33031 / Napa 3031 filters. They're good up to 60 psi. I can't find any 5 micron fuel filters that would fit on the bike, or I'd install one of those instead.

[CROSSBOLT]

It has  been a couple of years since I had the Yager and I may not remember things right. Gets that way with old guys! I think I recall a vent line from under the fuel cap that ran to a vacuum valve lower side of machine left. The two other ports ran to vacuum source at the manifold and the other ran to that can all the way aft. That way the tank was vented when the engine was running. That part correct as you see it?

Do you agree with my caution about the dealer?

The mission, as I see it, is to attempt to assist in a solution for a fellow enthusiast. That seem right to you?

Karl

[Fogie]

It has  been a couple of years since I had the Yager and I may not remember things right. Gets that way with old guys! I think I recall a vent line from under the fuel cap that ran to a vacuum valve lower side of machine left. The two other ports ran to vacuum source at the manifold and the other ran to that can all the way aft. That way the tank was vented when the engine was running. That part correct as you see it?

Do you agree with my caution about the dealer?

The mission, as I see it, is to attempt to assist in a solution for a fellow enthusiast. That seem right to you?

Karl

Thanks for all your help and interest Karl

My reading of the technical info shows the vent from the filler running directly to the gas tank; my current understanding is that it simply allows air to escape from the tank. I stopped looking into the problem after I took it to the dealer. When the weather is warmer (probably in the spring), I'll pull the covers and see what's actually going on.

The bike has been with the dealer for over a week, and they haven't touched it yet. This is their busiest time of the year, due to the shop being full of bikes taken in for winter storage; they want to complete the service component of their storage package and get them moved off site. Since I can live without my bike for a while, I'd rather not push them. My theory has always been that, with any job, letting the supplier do things at their convenience, tends to result in lower costs. That of course assumes that the supplier isn't screwing you around; in this case, the dealer has a sterling reputation, and my past experience with them has been solid.