Service
Service
CHAIN TENSION CRUISE WOES QUICK SHIFTERS INTAKE PODS ASK KEVIN
MYSTERIOUS MONSTER
Q: My 1999 Ducati Monster 750 loses proper chain tension every time I put it on the rear stand. Is tiis normal? At 24,000 miles, I noticed that the chain and sprockets were worn (roughly 7,000 miles on this set), so I changed them. It didn't help. Even if it's just overnight, the chain is too loose the next day and has to be adjusted. The stand I use is a rocker-type that cradles each side of the double-sided swingarm. I always use a torque wrench when tightening the axle nuts after setting chain tension. If you're wondering why I always put my bike on a stand, I have young children and like the added security (less likely to tip over and hurt them) it provides. Please help. JOHN ALLEN NEWORLEANS, LA
A:The idea that a properly adjusted chain could somehow loosen overnight when the bike is on a stand is bizarre. Due to the position of the countershaft relative to the swingarm pivot, the chain will tighten as weight is put on the bike and the suspension is compressed. When you put the bike on the stand, the rear end's weight is supported not by the rear wheel but by a spot nearer the midpoint of the swingarm. Consequently, the rear suspension is not compressed as far when on the stand, resulting in more free play in the chain. So if you are checking the chain in the morning while the bike is on the stand, that could explain the "overnight" slack.
Also, when torquing the axle after setting the chain tension, you might be throwing the chain out of adjustment. Make sure the adjustment plates and corresponding bolts are seated; if they are not secure when the axle is tightened, the wheel could slip forward. Before torquing the axle, carefully wedge a screwdriver or a rag between the chain and the rear sprocket, and then slightly rotate the wheel against that resistance. This ensures that the wheel is tight up against the adjusters on both sides.
Also, Ducatis of that era have a conical spacer on the chain side that is very easy to install backward with the cone facing out. This would cause the spacer to machine itself into the swingarm, causing chain tension (and wheel-bearing) issues.
LOSING YOUR CRUISING
Q:I own a 2004 Honda Gold Wing and have been having problems with its cruise control. Recently, I h~.re needed to push on the front brake lever to use the cruise. It worked fine for a while; but now, after I get cruise turned on, if I hit a bump, it will kick off. Also, if I just touch the front brake lever, cruise will kick off. Ever heard of this problem? RANDY VA EGLE WARREN, PA
A:For safety purposes, the front brake and clutch levers on your Gold Wing (and on all bikes with OEM cruise control) have little tabs that engage adjacent micro-switches that cancel the cruise control when either lever is squeezed. As the pivot bushings in the levers wear, the levers can get floppy, causing intermittent on-and-off operation of the micro-switches. The same thing can happen if the micro switches become loose. If the screws holding the front-brake switch in place are tight, you'll need to replace the leveL
NOT-SO-QUICK SHIFTER
Q:Ihave a 2010 BMW SioooRR with a quick shifter and traction control. The bike has 20,000 miles on T~ and has been a joy to ride, but it's out of warranty and has developed a strange problem with the quick shifter. It shifts from first to second with no problem. But from second up, when I try to shift, the lever moves and I feel the killing of ignition, but the next gear does not engage. Works fine with the clutch in. What could be the problem? The dealer cannot figure it out. After using a quick shifter, I do not want to go back to clutching while upshifting. MANJESH LINGAMURTHY CORAL SPRINGS, FL
A:The micro-switches in quick shifter mechanisms have a tendency to be finicky and fragile. Quick shifters, for the most part, are designed for use in full-throttle/high-rpm situations at the track-not part-throttle upshifts on the street. Also, the first-tosecond shift requires a little more lever movement than do the other shifts. The mechanism has to disengage first gear, move through neutral, and then continue on to engage second gear, whereas the other shifts do not involve going through neutral. So if the switch mechanism on your quick shifter has become worn, it's possible that only the first-to-second shift has enough movement to provide sufficient "kill time" to allow the transfer of power from one gear to the next. Replacing the micro switch would seem to be the logical remedy.
THE PODS ARE AT ODDS
Q:I have a little fluid-dynamics balance-equation question for you. I cannot find the right mix of jetting to match the air-filter pods for a 1980 Honda dohc 750 with CV carbs. The bike ran great with the original jets and airbox, but the snorkels began to crack. A smear of silicone would seal the crack, but the end was near, so I installed aftermarket filter pods on each carb, along with the suggested jets. She does not run well now; I even need to keep the choke closed to keep her idling. I searched the web and found several tuners suggesting replacing the carbs with $1,000 Keihin or other race-carb sets or just staying with the stock filter box. Back in the day, I remember seeing several dohc Hondas running just fine with pod air filters. How do I solve this? SHAUN HARRIS COLLEGESTATION, TX
A:With an opening sentence like that, you must be an engineering student at Texas A&M! After installing airfilter pods on a set of CV carbs, many ;ore components need to be adjusted, modified, or replaced in addition to the jets. Because you have eliminated the "still air" effect provided by the sizable volume of the airbox, a Stage 3 kit from Dynojet is necessary for proper fueling. This kit comes with jet needles that are significantly different than the stock CB750's, providing more fuel for the transition from idle to larger throttle openings. In addition, the Stage 3 kits usually include a different-rate CV slide spring and require you to drill a larger communication hole in the slide so it opens more quickly. Once these modifications are complete, it's critical that the fuel screws are adjusted to the position recommended in the kit then fine-tuned with vacuum gauges after the throttle butterflies are synchronized.
GOT A MECHANICAL OR TECHNICAL PROBLEM with your beloved ride? Perhaps we can help. Contact us at cwservice@cycleworld.com with your questions. We cannot guarantee a reply to every inquiry.
WHY DID MY DIODE DIE?
My `03 Suzuki Bandit l200S has developed a problem with the neutral indicator-light circuit. After I've been riding for five or six minutes, the indicator light does not illuminate when neutral is engaged. Everything else seems okay, and the bike shifts normally, but with neutral engaged, putting down the kickstand engages the kill switch, shutting off the engine. The problem goes away the next day, and the light operates again until the bike is ridden a few miles. My best guess is that a relay is failing or overheating. If not, could there be a broken wire or something upstream of a relay that is going bad? I am not happy to chase an electrical gremlin or to start replacing electrical parts one at a time. ROB SEELA SAN OIEGO, (A
The neutral-light circuit of your Bandit 1200 contains a diode, which is essentially a check valve
for electricity allowing it to flow in only one direction. It's likely that the diode's designed-in failure mode stops the flow of electrons when the diode exceeds a certain temperature; at that point, the neutral light will no longer illuminate. Find the diode (it has three wires: one blue, one green, and one blue with a black tracer) in the harness and replace it.
TO RUN OR NOT TO RUN
Help. My recently purchased 1991 BMW K75RT is running better all the time-when it's run~hing, that is, which is oniy most of the time. Shortly after I purchased it, I rode around 5 miles, stopped for about an hour, got back on the bike, and fired it up. Then, it quit. I shut off the key and tried to start it again. This time, the battery light and oil light on the dash were very dim and the engine would not start. I turned it off and on again and, vrooni, it started, but I only got about 10 feet before it stopped again. Key off, key on, it started. In traffic, at about 45 mph, I lost ignition again, regained it, then rode a half mile more before it all happened again, though I did not turn the key either time while moving. Then, everything was fine for the rest of the day! I've had the bike a little over two months and checked all ground connections and battery terminals. The battery is relatively new and holds a charge. I've wiggled the ignition key switch and wires with no negative response. The local BMW shop mechanic doesn't have any suggestions. Might you? The bike can go seven to 10 days with no problems. j.P BPAOY MARIETTA, GA
One or two possibilities: The ignition switch might be failing or the engine stop switch is intermittently making contact. Disassemble both and look for corrosion or signs of arcing. You may, however, need to simply replace the ignition switch with a new or known good used one because they can be difficult to disassemble.
ASK KEVIN
Let me begin by stating that I respect Kevin Cameron's skills, experience, and knowledge. However, the answer he gave to Greg May in the August issue ("Ask Kevin," Service) regarding the harm in overfilling an engine with oil was incomplete.
Yes, when an engine is overfilled, oil is picked up by the rotating crank and rod(s), and it does reduce power. But the major concern is premature wear. When oil contacts the reciprocating assembly, air is introduced into the oil. As we all learned in science class, liquids are not compressible and air is. So instead of a solid film of oil being present between parts to prevent them from touching each other, the air in the oil compresses. This allows the parts to contact each other, causing premature wear. Wear is accelerated the more the engine is loaded. That is why manufacturers warn against overfilling engines with oil. TOM CURRAO FRASER, Ml
Mr. Currao makes an excellent point about air entrainment in the oil. In
that case, the issue is not just wear but the possibility of failure, as a good-sized slug of air in a pressurized oil stream can push the oil out of a bearing, leading to prompt failure. For this reason, piston aeroengines (and some other types as well) were equipped with
oil de-aerating systems. It could be argued that this is a major function of so-called "dry sump" oil systems, in which used oil picked up by the scavenge pump is returned to a separate, remote oil tank. Circulation of all the oil in the tank may take some minutestime during which gravity can accomplish the removal of air from the oil.
Kevin Cameron
