Service
SERVICE
Paul Dean
The sump of all fears
My 1985 Harley-Davidson Low Glide has less than 15,000 miles on the odometer. As the numbers indicate, the bike sits for long periods of time. On occasion, when started after a period of nonuse, oil belches out the breather hose and the air-cleaner canister, making quite the mess. Does the engine create pressure while dormant? My college-student nephew has been dormant all summer and he does not seem to be under any pressure. Gregg Week
Lemont, Illinois
Perhaps your nephew isn’t under pressure because no one has attempted to kick-start him. Try it and see what happens. Could be fun.
Your Low Glide, meanwhile, is not building up pressure when it sits unattended for long periods; it’s doing what is referred to as “wet-sumping. ’’ It has a dry-sump oiling system, which means the engine lubricant is not stored in the crankcase but instead is kept in a tank outside the engine. The system uses two separate oil pumps: One pump draws oil from the tank and delivers it, under pressure, to the critical engine components through an external feed line; the oil then drains down to the crankcase where a second pump, called a scavenge pump, picks it up and delivers it back to the tank via a return line.
This scavenge system is the source of your Low Glide’s problem. The oil tank, which is located on the frame, is higher than the crankcase; so, to prevent gravity from allowing oil to drain from the tank into the crankcase, the scavenge pump is fitted with a little one-way check ball that only allows oil to flow through the return line from the crankcase to the tank, not the other way. If that ball is not sealing properly, oil will seep down into the crankcase, and enough can accumulate there over time to cause the mess you encounter when starting the engine.
What makes wet-sumping especially problematic for Harleys is that there is very little excess room in the crankcase; the cases are virtually shrink-wrapped around the flywheels. The engine has two very large pistons pumping up and down, however, causing huge pressure fluctuations in that crowded crankcase. Normally, the breather system easily handles these pressure variations; but when a lot of oil gets into the crankcase, those variations become much more extreme, and the resultant turbulence forces the oil out through the breather and into the air-cleaner housing.
On some bikes with dry-sump oiling systems, the engine cases are equipped with a threaded plug that can be removed for easy drainage of accumulated oil from the crankcase. Unfortunately, your Harley is not one of them. When it wet-sumps, your only quickand-easy option is to grab a drain pan, put it under the air cleaner, start the engine and let crankcase pressure force the excess oil out.
Another alternative is to start the engine frequently between rides and let it run it for a few minutes to evacuate what likely would be a lesser amount of oil. The best remedy, though, is to remove the oil pump, clean it thoroughly and replace the little check ball. The bike is 20 years old, after all, and has only been ridden an average of 750 miles a year, so the check ball may have gotten slightly pitted or corroded during those long periods in which the engine was dormant. Kind of like your nephew.
Timing is everything
In your August “Free torque trick” response, you said that opening up the valve clearances to their maximum allowable specification would cause the valves to open later and close sooner, and also decrease valve lift, all of which would result in an increase in torque. I’m sure this is true, but I cannot fathom the logic for it. How can a reduction in the ability to draw in mixture, and a reduction in the ability to exhaust spent gases, result in an increase in combustion force? I ride a 1400 Intruder that’s fed by 36mm carbs. It develops tons (so to speak) of instant torque but develops asthma long before reaching redline as a result of those tiny carburetors. Is its increase in low-end torque combined with the loss of top-end power part of this same counterintuitive situation? Gary Steinweg
San Diego, California
You ’re bringing factors into this matter-carb size and combustion forces in particular-that aren’t directly relevant to the question, making it a lot more complicated than it really is. Look in any cam manufacturer’s catalog and check the specs of its line of cams for any given engine. You ’ll see that cams designedfor good low-rpm and midrange torque generally open the valves later, close them sooner (which equates to shorter open duration) and have less lift than those that yield bigger peak power numbers. By increasing the valve clearances to the far end of their permissible levels, you essentially turn any given cam into one with very slightly milder specs. This may achieve tiny performance gains at lower rpm but also will likely have an equivalent negative effect on peak power.
Camshafts need different timing specs for different power outputs because the time between combustion events decreases in direct proportion to increases in engine rpm. For a cam to be more productive at higher revs, not only must it open the> valves farther and keep them open longer to let more combustibles in and wastes out, it has to begin the intake and exhaust cycles earlier It takes time for the movement of intake air and exhaust gases to stop and start between cycles, thereby requiring those events to begin sooner at higher rpm so the cylinder can fill and empty more frequently and effectively.
At lower revs, though, long cam timing has a negative effect on performance. The stop-and-start frequencies of the incoming/outgoing intake/exhaust masses are enough lower that they aren’t well synchronized with the early-opening/late-closing events of the valves. As a result, producing more torque means that the valves need to open later and close sooner, and generally have less lift. Actually, some aftermarket cams designed for optimum midrange performance produce more torque by using relatively short open duration in combination with rather high lift.
Long cam timing also tends to produce “valve overlap, ” which is what happens when a cylinder s intake and exhaust valves are briefly open at the same time. This works well at higher rpm because the columns of gases are moving fast enough that their inertia prevents their respective flows from getting confused and commingling; but at lower rpm, those flows can become intermixed during overlap, reducing the efficiency of the combustion process.
Brandon & the Bandit
I'm thinking about getting a used Suzuki Bandit 1200. The one I'm looking at is a 2001 in great shape, but I've read about Bandit oil-consumption problems on the Internet. The owner says the bike does not burn any oil. I'm not sure this has been covered by Cycle World in the past, but what I need to know is if! should pass on the bike because of this issue.
Brandon McClure Spartanburg, South Carolina
Some 2001-2002 Suzuki Bandit 1200s did have a problem with excessive oil con sumption, but neither I nor Suzuki can tell you for certain whether or not the bike you want to buy is one of them. On the pistons of affected models, the holes behind the oil-control rings were made too large, allowing a bit of oil to slip past the rings and into the combustion chambers. In January of2003, Suzuki issued a technical bulletin, #127, acknowledging that such a problem may exist on some Bandit 1200s but not all of them, and that any affected bike that consumes oil in excess of one quart every 600 miles would be repaired under an extended warranty provision.
Recall Roster
NHTSA Recall No. 05V326000 Victory 8-Ball, Hammer, Kingpin, Ness Kingpin, Vegas, Ness Vegas Model year: 2005
Number of units involved: 4244 Problem: On certain motorcycles, the fuel supply hose leading from the fuel tank to the fuel rail may be incorrect for use in a pressurized fuel system. An incorrect hose may crack and leak fuel which, in the presence of an ignition source, could result in a fire.
Remedy: Victory dealers will inspect the markings on the fuel hose to determine i replacement is required. On machines that fail the visual inspection, dealers will replace the hose with a new one of the correct material. Owners who do not receive this free remedy should contact Victory at 763/4 1 7-8650.
Given that, I suggest you either convince the owner to issue you a moneyback guarantee that his Bandit does not use oil, or get a Suzuki dealer to agree to repair it under the terms of the service bulletin if it does. If you can’t do either, you ’ll be rolling the dice by buying the bike. □
Got a mechanical or technical problem with your beloved ride? Can’t seem to find workable 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 CW1Dean@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 looking 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.
