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Paul Dean

Arctic RI

I recently did something so dumb that even I marvel at it. I live in Alaska and race a Yamaha Rl that normally has WaterWetter in it, but no anti-freeze. When I put the bike and trailer in storage this fall, I forgot to drain the cooling system. A month later, after some really cold weather, I accidentally kicked the bottle that was supposed to contain the drained WaterWetter (it was under my lathe) and saw that it was empty ! So I dutifully took the Rl out of the trailer and put it in the garage to thaw it out, and now I need some advice. I want to either make sure I didn’t harm the bike by leaving it out in sub-freezing weather or figure out what to do if something has gotten damaged so I can fix it before spring. Any ideas?

Jamie Linxwiler Anchorage, Alaska

I have no experience with Rls left for weeks in a deep freeze, and neither has anyone I spoke to at Yamaha’s U.S. headquarters in California. My contacts at a couple of local dealerships looked at me like I had a rack of antlers growing out of my head when 1 queried them; after all, the temperature here very rarely gets down even close to 32 degrees, let alone what would be termed “really cold weather” in Alaska. I also called a couple of Yamaha dealers on the East Coast, but none of them had any first-hand knowledge about what might happen to an Rl left in sub-freezing weather without anti-freeze in its cooling system.

What we do know is that water expands as it freezes; so any damage that your bike has incurred would have been caused by the untreated water in the cooling systern expanding as it froze. Logically, then, only the parts of your Ri `s en gine that contain coolant should have been affected. When expansion results in damage, it usually causes hard, inflexible components (cylinder head, cylinder block, water-pump housing) to crack, softer parts (cooling-sys tem hoses) to burst or get pushed off their fittings and gaskets to rupture. In any case, the symptom would be a coolant leak-maybe a small, cheap one, maybe a big, expensive one.

If coolant is leaking out of the en gine, it should be fairly easy to detect. First, check the cooling system to make sure it is full, then start the engine and let it run until warm. If there is an ex ternal leak, it will make itself known one way or another-either as a visual loss of coolant somewhere on or around the aforementioned components or as a growingpuddle of water on the ground, which can then be traced back to a source on the engine.

:,UUf(.~e Ufl i!ie efi~Lfie. If coolant is leaking into the engine ` interior the source can be much harder to determine, usually calling for at least partial disassembly. If that kind of internal leak is siz able, it generally evidences it self in the oil, which will ap pear milky and lighter than normal in color~ If the leak leads into one of the cyl inders, there are two likely clues: steam will exit the exhaust, even after the engine has warmed up; the high pressure of combus tion pushes through the leak~ source and into the cooling sys tem, emerging as bub bles visible in the radia tor filler neck when the cap is removed. In any event, see "disassembly" Of course, you may have lucked out. Maybe your bike suffered no damage whatsoever. If there is no evidence of a leak after you have run the engine for a while, about all you can do is ride the bike Y~AH~N andsee what, `4NJ,CoULI' if anything, M4G~~ happens.

Atieadot evidence

A friend and I were discussing tires and tire-tread patterns the other day (it's been raining a lot here lately), and we got to wondering why the front tread pattern is the opposite of the rear pattern as on the Avon Viper or the Bridgestone BT-014. Could you please point us in the right di rection? Mitch Green Siletz, Oregon

The purpose of tread grooves in tires is to help prevent hydroplaning by channeling water out from between the tread and the road and pushing it to one side or the other. Even when there is insufficient water on the road to cause hydroplaning, the grooves help a tire maintain traction by giving that thin film of water someplace to go as the tire rolls over it.

Any differences in the shape or direction of front and rear tread patterns are usually the result of the differences in the roles played by front and rear tires. A front tire, aside from having to steer the bike, is the major player in allowing the bike to stop, whereas the rear tire transfers the power to the ground and drives the bike forward. In other words, the forces acting between tire and road at the front are the opposite of those acting at the rear; so the tread patterns are reversed to facilitate better directional water channeling. It s that simple.

Pipe dreams

-I-~ -I want to put a new exhaust system on my 2004 Harley-Davidson Ultra, but I don't know if I should replace the complete system or just the mufflers. The stock pipes have a crossover between the header pipes. If I replace the headers, what will this do to the engine's performance and reliability? Ray Walls Aiken, South Carolina

You didn `t mention which model of whose pipes you might be installing, so I can `t give you a concrete answer about their impact on performance. The afiermarket offers dozens upon dozens of exhaust-sys tem options for Harleys, and their effects on engine performance are all over the map. But regardless of which pipes you choose, chances are pretty good that your Ultra `s per formance will be somewhat improved. Stock H-D mufflers are so restric` tive thatjust about anything that relieves some of the back pressure in the exhaust tract will benefit perfor mance-sometimes by a little, sometimes by a lot. And unless you install some weirdo exhaust that causes the en gine to run excessively lean or rich-afld you don `t recalibrate the carburetor or fuel-injection system to compensate-there won't be any reliability issues.

won ‘t be any reliability issues.

In any event, you ’ll probably get your best bang for the buck by changing only the mufflers. The crossover on the stock head pipes serves two purposes: 1) to give the exhaust pulses from each cylinder access to both mufflers, thereby helping to reduce exhaust noise to the legal limit; and 2) to increase the overall volume of the exhaust system, which gives Harley s engineers more latitude in tuning the big-inch, large-bore engine for a wide powerband.

Since whichever mufflers you select will make the exhaust louder (no one sells aftermarket H-D pipes that are as quiet as stock), you obviously aren’t concerned with Item 1; but if you retain the stock headpipes and change only the mufflers, the engine will probably end up with a marginally broader powerband than it would without the crossover. The operative word here, though, is “probably ”; with so many pipe combinations available, it’s impossible to make a blanket statement that will hold true for all of them.

Shadow boxing

The engine on my 1983 Honda VT750 Shadow shuts off at `/4 to ¾ throttle, typi cally under load in the higher gears. After three weeks at the local Honda shop and a new fuel pump, the dealer gave up. The engine starts hard and only with the throt tle in the idle position; The carbs have been rebuilt and synchronized, and compression is 130 psi on both cylinders. Help! Neal Scott Bennington, Nebraska

Recall Roster

NHTSA Recall No. 05V566000 Suzuki VL800 Volusia/C50, VZ800 Marauder/M50 Model years: 2005-06 Number of units involved: 23,839 Problem: On certain motorcycles, the ignition-switch wiring harness may have been improperly routed at the time of production and could rub against the clutch and throttle cables. Continued rubbing may eventually lead to a short circuit, which can cause the engine to stall or the lights to go out, increasing the chance of a crash that could result in serious injury or death. Remedy: Suzuki dealers will, free of charge, reroute the ignition-switch wiring harness and replace the lockset, including the ignition switch, along with the clutch and throttle cables. Owners not receiving this free remedy should contact Suzuki at 714/572-1490.

Since I don’t have the motorcycle here to examine and can’t experience the symptom first-hand, I can only resort to mechanical logic in offering a possible solution. According to your description, the engine shuts off only as the result of throttle position. This tells me that the problem is in the carburetors, not in the ignition, the valvetrain, the cylinders’ compression or the location of Venus relative to the Crab Nebula.

One likely culprit could be the neoprene diaphragms atop the throttle slides in the CV carbs; if they have cracked due to the effects of age and exposure to ozone, they could leak just enough vacuum to prevent the slides from being lifted as they should. That would cause the very kind of fuel starvation you describe.

If the diaphragms are okay, the problem would then seem to lie somewhere in the fuel delivery system-the fuel pump (re gardless of what the dealer claims), the fuel lines, the fuel tank itself etc. You ei ther need to find another dealership or repair shop to go over your Shadow, or, if you `re a half-decent shade-tree mechanic, start at the fuel tank yourself and work your way through the carburetors to en sure that everything along the way is al lowing fuel to flow properly and without restriction.

Got a mechanical or technical problem with your beloved ride? Can't seem to find work able solutions in your area? Or are you eager to learn about a certain aspect of motorcycle design and technology? Maybe we can help. If you think we can, either: 1) Mail a written inquiry, along with your full name, address and phone number, to Cycle World Service, 1499 Monrovia Ave., Newport Beach, CA 92663; 2) fax it to Paul Dean at 949/631-0651; 3) e-mail it to CW1 Dean@aol.com; or 4) log onto www.cycleworld.com, click on the "Letters to the Editor" button and enter your question. Don't write a 10-page essay, but if you're look ing for help in solving a problem, do include enough information to permit a reasonable diagnosis. And please understand that due to the enormous volume of inquiries we receive, we cannot guarantee a reply to every question.