Service
SERVICE
PAUL DEAN
Ghost in the machine
Q My 2007 KTM 990 Adventure, which has about 3000 miles on it, was stored for many months in a garage in Upstate New York. Last fall, I rode it the 300 miles home with no problems whatsoever, then it spent the winter stored in my garage in New Jersey. I rode it this spring for the first time with no problems, but the next time I took it out, the rear brake locked up after about six miles. The brake pedal would not move and the bike wouldn’t roll. After sitting for a while, the brake cooled off and I was able to continue on my way. But after five or six miles, the rear brake locked up again. I got it home and replaced the brake fluid with new DOT-4, but the problem remains.
The weirdest part of this story is that the same thing just happened to my 2004 Moto Guzzi Coppa Italia. I received the Coppa from a guy in Arizona last week and it happened on my very first ride. In 36 years of riding motorcycles, I’ve never had this problem on any bike at any time, and now it’s happened twice in a month on two different bikes. Can you shed some light on this matter? Martin D. Katz
Princeton Junction, New Jersey
A I’m going to go out on a limb here, but before I do, I need to explain when and why this sort of thing usually happens.
Master cylinders have a little bleed hole at the bottom of the fluid reservoir, and its purpose is twofold: 1) to allow additional fluid to enter the brake system as the pads or shoes wear, a slow process that gradually increases the internal fluid volume of the system; and 2) to allow some of the fluid already in the system to re-enter the reservoir. Re-entry is necessary when new pads are installed (which requires the extended pistons to be pushed back into a fully retracted position in the calipers or slave cylinders) and when the fluid heats up and expands. The hole is located just ahead of the master-cylinder piston so that as soon as the piston begins moving to actuate the brakes, the hole is blocked, effectively sealing the system to maintain brakeline pressure.
On your KTM and Guzzi, that hole is being blocked while you ride. So, when the brake fluid heats and expands as the result of braking (and also due to the light friction that normally occurs between rotor and pads, which “kiss” when the brake is not in use), the excess fluid cannot return to the reservoir. Instead, it continues to build pressure in the brake line until the caliper clamps the rotor tightly enough to prevent the rear wheel from turning.
This condition normally occurs when someone improperly rebuilds or reassembles a master cylinder so that the bleed hole is blocked. But that’s not the case here; all you have done is just ride the bikes—or at least I assume so, since you did not mention adjusting or otherwise fiddling with either bike’s rear brake. So, unless you have been the victim of the greatest coincidence I have ever encountered in more than 53 years of riding, repairing and building motorcycles, this is where I climb out on that very fragile limb and say that 1 think the problem very well may be.. .you! If you ride with your right foot lightly touching the rear brake pedal, you may be inadvertently moving the master-cylinder piston just far enough to block the hole, preventing re-entry of fluid into the reservoir when the fluid gets warm.
Yes, I know, you’ve ridden for many years without ever before having such a problem, but I have encountered this very same situation before—twice, in fact. Once was when the rider suffered a mild right-knee injury that caused him to place his foot on the peg at a slightly different angle; the other occurrence was when the rider wore new boots that did not bend easily at the ankle. In both cases, the rider’s right foot was rotated forward on the peg just far enough to contact the brake pedal, causing their bikes to have the same rear-brake lockup problem.
To find out if this is the origin of your problem, take each of your bikes for a ride and do not touch the rear brake pedal under any circumstances. If the brake still locks up, then my assumption about the placement of your foot on the pedal is all wrong and I sincerely apologize for the implication. You will then need to do the obvious and have both bikes’ rear master cylinders rebuilt to ensure that their reservoir bleed holes are not blocked by their pistons.
Flood alert
QI Star have Classic. a 2006 Every Yamaha time 1100 I ride Vit and then let it sit for a little while, I smell a strong gas odor, and then it is hard to start. I feel like it is flooding, but most of the time I have to give it some throttle to get it to start. I would appreciate any help you could provide.
David Helms Lincolnton, North Carolina
Alt would appear that the engine indeed is flooding; and the reason you have to apply some throttle when starting the flooded engine is to get enough air into the combustion chambers to let the raw gas in there ignite. Yes, that incoming air also contains fuel; but the mass of air in the mixture is somewhere around 15 times greater than the mass of fuel. So, even though the incoming mixture introduces more fuel to an already flooded engine, it also provides enough air to permit ignition, even if it momentarily results in rich, inefficient combustion.
QuickFix
Okay, so it finished midpack in our June-issue MasterBike competition and dead-last in the “Alternative Energy” literbike shootout the following month; I love the KTM RC8R anyway. I love the way it looks, the way it sounds, the way it handles and the way it feels. It works like it was made just for me and the way I ride.
My wife Megan and son Eddie also were pretty stoked about the KTM, but they were put off by the fact that it had no passenger accommodations. They both like to ride behind me, and Megan is one of the world’s greatest passengers; she not only doesn’t fear my aggressive riding, she actually likes it—wheelies, stoppies, peg-dragging and all that.
So, because we were going to have the KTM around for a while, I decided to look into finding a way to get them a reserved seat on the RC8R.
I didn’t have to do much looking: KTM’s sells a passenger seat conversion made just for the RC8 and RC8R. So, after a trip to our local KTM dealership, 3 Brothers Racing (www.3brosracing.net/home.html), I was equipped to solve the single-seat situation.
First, I only had to unlock and remove the rider’s seat, exposing a lever that releases two black plastic plugs that hold the tailsection’s cover in place. I then just plugged the pillion pad (part #69007047100; $192.14) into those same openings. Next, I assembled the passenger footpegs, which are sold as separate pieces. The footpeg brackets (part #6900304800033S left; 6900304900033S right) are $141.74 apiece, and the pegs themselves (#6900305003333S left; 6900305103333S right) go for $56.69 each. Each peg pivots on a $5.99 pin (#60003044000) that requires two $3.71 spacers each (#60003152000 left; 60003052000 right) so they’ll stay in place when folded up and not in use. Two $.23 tab washers (#0799060003) hold everything together.
The hardest part of this job was done by the guy at the parts counter who had to keep track of all these incredibly long part numbers and then add up the $616.28 worth of second-row seating.
After installing the footpegs, I lowered the RC8R’s adjustable seat/subframe. This made it easier for me to hold up a passenger at a stoplight. I also raised the handlebars, and that made the riding position much more comfortable for me and the passenger leaning on my back for support.
Six hundred bucks is a whole lotta loot for passenger seating, but for me, it was worth it. Megan was really glad that I made these mods so she could accompany me on the KTM. She said that her seat was noticeably higher than most, and that caused her to feel like she was going to roll over my shoulders when I would do a stoppie. But that didn’t bother her at all; she was just happy she could finally ride behind me.
Mark Cernicky
Why it floods is an entirely different matter. In all probability, the culprit is a leaky float needle in one (or perhaps both) of the V-Star’s carburetors. Many years ago, carb flooding was common if a rider did not shut off the fuel petcock every time a bike was parked, even for a short while. But once motorcycle carbs were equipped with neoprene-tipped float needles, the problem all but disappeared, only occasionally surfacing when the tip would wear out or a tiny bit of contamination would get between the needle and its mating seat. This would hold the needle open just far enough for gas to trickle unabated into the carb and overflow into the engine. That could very well be what is happening with your Yamaha.
Heat can also be a contributing factor. When you park the bike after a ride, heat from the engine rises up under and around the gas tank, causing some of its contents to vaporize and expand. The tank has a one-way valve in the filler cap that allows air to enter (to replace the volume vacated by spent fuel as the engine burns it) but, for emissions control, does not allow vapors to escape. Pressure therefore can build up in the tank, possibly exerting enough additional pressure on the float needles to push them open and cause a leak. There’s also a small electric fuel pump between tank and carbs on your V-Star, but it should not be playing a role in the flooding problem.
One way to prevent flooding is to simply turn the petcock to the Off position every time you shut off the engine. That way, any pressure in the tank—caused by expansion and/or the weight of the fuel the tank contains—will not be transferred to the carburetors. And to ensure that the petcock does not leak when closed, remove the fuel line between the tank and the carbs when the petcock is Off. If the petcock still flows gas, you have a second issue that can be fixed with about $9 worth of replacement O-rings and packing. The flooding problem can be solved either by carefully cleaning the existing float needles and seats or by replacing them. They’re sold in sets for around $45 each.
The devil’s triangle
QI have a ’93 Honda CBR1000F that is in very good original shape. It’s the second one I’ve owned, and after 3000 miles or less on both, the front tire gets so badly worn on the sides that it becomes triangular in shape The center of the tire is still round and the tread acceptable, but the sides are gone. The rear tire looks good with only a slight flat spot in the middle but otherwise is only halfway worn at best. I ride an average of 6-8K a year, mainly to work and back (50mile round trip) through the backroads of Kentucky (known to be a bit twisty), with a dozen or so weekend trips. My riding ability is intermediate; I’m not quite a knee-dragger (half-inch chicken strips). I keep the air pressure around 40-42 psi front and rear, and I’ve tried a few different tires, multi-compound models performing the worst.
I was thinking of making some suspension changes such as new springs calibrated for my weight (220 lb.) or maybe just a 20mm preload spacer to hold the front end up a little bit more as there are no external adjustments on the fork. Do you have any ideas?
FeedbackLoop
QThis ing for is a in buzzkill” response letter to the in “Lookthe June Service section in which you responded to a gentleman whose right hand goes numb when he rides his Yamaha FJR1300 at cruising speeds. I have a 2008 Honda CBR1000RR that also has a buzz in the bars that used to put my hands to sleep in just 15 miles at backroad speeds (around 5500 rpm). I installed Vibranator-brand handlebar ends in place of the original bar-end weights, and they significantly reduced the vibration in my bars. Since installing them, I’ve ridden the CBR at track days and on a 90-mile ride to Napa, and I’ve felt much less vibration than I did with the stock bar ends. I’ve included a photo that shows the difference between a stock weight (top) and a Vibranator. You can check them out at www.vibranator.com.
This product has greatly enhanced my riding experience. Don Nohai
Campbell, California
Y Thank you very much for the feed_ back. This is a product I had not seen before your e-mail informing me of its existence—and its effectiveness.
Rather than being a solid weight, the Vibranator’s mass is cantilevered on a
spring that fits inside the handlebar end. According to the company’s website, the Vibranator uses the same principles that high-end helicopters employ to reduce or eliminate secondary vibrations. It responds to the energy of a high-frequency buzz by oscillating out of phase, thereby largely canceling the original vibration and eliminating or greatly reducing the involuntary muscle response that can lead to arm pump, hand numbness and tingling. Vibranators are available for most streetbikes, dirtbikes and quads for between $69.95 and $109.95, depending upon the application.
Ordinarily, we would reserve judgment on such a product until evaluating it ourselves. But in this case, we appreciate and value input from a reader who has successfully used the product. Thanks once again.
Gordon Gravelle
Glasgow, Kentucky
A You’re not alone, Gordon; every CBR lOOOF of that era that I ever rode ate front tires at an exceptionally high rate, and I got lots of mail from
owners of those bikes who reported the same problem. In a liter-bike comparison test CW conducted back then, we burned both sides of the CBR’s front tire down to the cords in just one 400-mile day of riding in the Sierra Nevada. A few days later, I wore the brand-new replacement tire down to the wear bars on a 350-mile solo ride along the twisty
Recall Roster
NHTSA Recall No. 10V232000 Manufacturer: Bombardier Recreational Products Inc. Model: 2010 Can-Am Spyder Roadster RT SE5 and RS SE5 Number of units involved: 1200 Problem: When bringing one of these semi-automatic-transmission vehicles to a full stop, the computer-controlled clutch may remain engaged, stalling the engine. Once the engine stalls, it could be impossible to restart, and the rear wheel could be locked. If this happens, pushing the vehicle off the roadway may be impossible, increasing the risk of a crash. Remedy: Dealers will repair the vehicles free of charge. Owners not receiving this remedy can call BRP at 888/638-5397.
roads of California’s Central Coast. I’ve never fully investigated the cause of this problem, but it most likely is related to steering geometry. Even though the affected CBRIOOOF and GSX-R750 both steer nicely, their front-end geometries are not “happy,” causing the tires to scuff across the surface almost as much as they roll. I also know that in roadracing, Suzuki struggled with the GSX-R’s geometry that entire season. As such, I don’t think you’ll be able to effect much improvement in fronttire wear. You could try the fork-spring spacer modification, since it’s cheap and easy to implement, and you also might experiment with fork-oil level, raising it in both legs by 15 or 20mm. That would reduce the amount of fork compression that occurs during the gloading of cornering. But realistically, neither tactic is likely to have a major effect on tire wear. You may ultimately be faced with either replacing front tires quite often or buying a different motorcycle. If any of our readers inform me of success they’ve had in remedying this problem, I’ll gladly pass that information along to you.
Got a mechanical or technical problem and can’t 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.conr, or 4) log onto www.cycleworld.com, click on the “Contact Us” button, select “CW Service” and enter your question. Don’t write a 10page essay, but if you’re looking for help in solving a problem, do provide enough information to permit a reasonable diagnosis. Include your name if you submit the question electronically. And please understand that due to the enormous volume of inquiries we receive, we cannot guarantee a reply to every question.
