Q: I have a 2003 Yahama V-Star 1100 Silverado, a fine bike, but with one problem that other Star owners have as well. When I ride the bike and return home, park in the garage, and close the door, about half an hour later there’s a very heavy gas odor. If I crack the door a few inches, it helps a lot, and after cooling off it’s okay.

I know the smell is just from the gas cap venting, but this seems like way too much. I also smell the odor when I’m sitting in traffic, or when it’s hot outside as I walk up to the bike. The cap has been changed by the dealer, but that didn’t help. There are also no raw gasoline leaks; the dealer and I have checked many times. (By the way, the same dealer told one Star owner that he smelled gas, even outside, because he had a windshield.) I put a baggy on the cap once, and it blew up like a balloon. — Ken Neubauer, Via e-mail

A: On any bike, the entire fuel tank and carburetor system must be vented to atmosphere to equalize the pressures with ambient pressure. To comply with emissions regulations, many bikes, in particular those sold in California, are equipped with charcoal-based evaporative recovery systems. In my experience, assuming all else on the bike is stock, a charcoal canister that has fuel trapped in it is the culprit. These canisters are designed to have all of the various sources of fuel vapor (fuel tank vent, float bowl vents, cap overflow, etc.) channeled through the charcoal before venting to the atmosphere. Sometimes, either by overfilling, fuel expansion on a hot day, a crimped or improperly routed hose, or some other fault in the system, the canister can get loaded up with fuel and allow raw gas to get to the atmosphere. The fix, if this is the case, is to remove the canister and shake it around, draining it and the hoses.

Doug Meyer
Muzzys Motorcycle Performance

A: Have the dealer check the gas tank vent. It should vent into a carbon canister that is part of the evaporative emissions equipment on all 2003 models. The carbon canister should absorb vapors and eliminate the smell of gas. I doubt the gas cap has a breather on it.

Nigel Patrick
Patrick Racing

Q: I’m considering having my ’02 V11 Sport dual-plugged over the winter, and I’m just curious as to what hoops I'll have to jump through if I go ahead with it. Where do I put the second plug, and is it the same as an OEM one? How do you trigger the second set of coils? And will this mod void the warranty?

Jeff Drake
Virginia

A: The only thing really involved is the amount of machining required on the heads, though adding a second spark plug also requires relocating the oil supply lines for the rocker arms.

The second plug will be positioned on the opposite side of the combustion chamber from the current plug. This places the new plug in about the same location as the rocker arm oil feed line, requiring the line to be relocated. The heads are machined for the second plug and for the oil feed line inlet, and the old oil feed line inlet is plugged. Accessing the second plug will require removing the fuel tank on most models.

To reduce the amount of aluminum that must be machined off the head, the second plug is usually smaller in diameter but has a similar heat range as the current plug. In addition, dual high-tension lead coils with similar resistance are required to replace the single lead coils.

The new coils fire both leads and both spark plugs simultaneously when triggered by the original ignition signal.

What’s the advantage? The current California and V11 Sport have a large intake and exhaust valve with an included angle of 60 degrees. This configuration creates a very long path from the spark plug on one side of the combustion chamber to the opposite side of the chamber. Having two plugs in this combustion chamber configuration dramatically shortens this path, providing more complete combustion, resulting in more power, better fuel economy, and lower emissions. However, while this modification will produce dramatic results on carbureted Moto Guzzis, the improvement may not be as pronounced on fuel-injected models which have more consistent fuel/air metering. And, yes, it voids the warranty, at least on the drivetrain.

In general, I would recommend that a dealer or very good technician carry out this mod.

Shelby Kennard
Moto Guzzi North America

RB