Service
Service
DOT 5 BRAI(E FLUID? CHRISTINE BEST USED BIKE ASI( I(EVIN CLICKING 919
RAY NIERLICH
One reader wants to use silicone-based DOT 5 brake fluid in the fully rebuilt brake system of his old Yamaha. Our advice: Don't do it.
DOT 5 BRAKE FLUID? OR NOT?
Q: What do you think about my using DOT 5 brake fluid in a completely cleaned and rebuilt brake system in a 1979 Yamaha? I used new caliper kits, NOS Yamaha master cylinder kits, and Goodridge hoses. Everything was washed in brake cleaner. I will rarely ride the bike. Any thoughts?
STEVE HAICH CYCLEWORLD.COM
A: I have been mightily tempted to put silicone-based DOT 5 fluid in some bikes, since it doesn’t hurt paint or absorb moisture over time, but I chickened out and didn’t. The various pitfalls are scary.
If you go ahead with silicone fluid, be aware that silicone can and will seep out of the smallest of imperfections, so sliding surfaces (especially the master bore) need to be flawless. Silicone, if it gets on a brake pad, might be invisible, but she will now be greased lightning. Any banjo washers must seal perfectly. Silicone will swell the seals more than conventional fluid, sometimes causing sticky return action of the pistons. The swelling may cause the reservoir hole in the master to be partially blocked when the piston is released (off). Some small amount may need to be removed from the end of the piston to uncover this hole fully.
The system must be completely taken apart and spotlessly clean, as you have done. Flushing it out is not good enough. Never mix silicone with conventional fluid; even trace amounts will cause a disaster later. They don’t mix: Any moisture will go to the bottom and corrode the crap out of your pretty bores. Be especially careful not to foam up the fluid when bleeding. Silicone fluid will hold air bubbles in suspension for a long time. Any tiny leak or overly ambitious pumping will aerate the fluid. You might as well go have a beer and come back tomorrow before attempting bleeding again.
CHRISTINE, THE DT400E
Q: I have a 1978 Yamaha DT400E that I am resurrecting. It has been sitting outside my brother’s
barn in Pennsylvania for at least five years. I had to use an ax to hack it out of the ice and loaded it into my truck. When I got it home to Florida I cleaned the carb, cleaned the rodent nest out of the airbox, and put gas in and got it to run. After brakes, tires, new chain, and sprockets I have been taking rides to test and tune. Here is the problem: After a ride, I pulled into my backyard and turned off the gas to run the carb dry. But after idling for a short time, the engine, by itself, revved up to 9,000 rpm. And when I quickly turned the key off, it made no change. I pulled the plug wire off and no change, still revving at 9,000 rpm.
Is it running on the oil from the injection pump, like an old Cox engine? Is something acting like a glow plug? Freaking out, I misted the engine with my garden hose and the engine stopped almost instantly. After it cooled, the engine started right up and ran just fine. I have been riding it since then with no more problems, but I have not tried to run the carb dry again.
Is my bike possessed?
¡EFE ROSE HOLLYWOOD, FL
A: No need to name her Christine yet. You’ve almost got this figured out. I’m betting there was no small amount of varnish in the crankcase. When you resurrected the DT400E after its long hibernation, the new fuel softened the varnish and then she did that possessed Cox glow plug thing once it got good and hot. I’m betting the next time you attempt to run the bowl dry, the problem will have vanished.
A couple of other things to check: The old crank seals might allow a tiny bit of gear oil to be sucked into the mixture. Also, peek in the spark plug hole to see if there are any heavy carbon deposits in the combustion chamber. Heavy carbon may be acting like a glow plug. A light, black coating is good, so leave that alone. If the carbon is chunky, pull the cylinder head to carefully scrape any deposits off the head or piston. Don’t let any loose carbon fall down the cylinder between piston and bore.
¿NG0T 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.
ASK KEVIN
HYDRAULIC TAPPETS FOR MOTORCYCLES?
Why doesn’t every modern street ■ motorcycle come with hydraulic valve lifters? Cheaper maintenance, engine always in tune, and no more praying that the tech knows what he’s doing.
LARRY NEWTON CYCLEWORLD.COM
A If there was substantial demand ■ for this feature, motorcycle makers might make automatic clearance adjusters capable of operating at the 16,000 rpm of higher-revving 600cc sportbikes. It’s no problem using them in the pushrod valve trains of relatively low-revving engines, as they can be built into the tappets just as they are in automobile engines. In some engines, Honda has pivoted one end of each rocker arm on a hydraulic clearance adjuster. In one variation, the rocker pivots on a rotatable eccentric spindle that is rotated toward the zeroclearance position by an assist spring plus a hydraulic clearancing device. For many years, inverted bucket tappets were the choice for high-
rpm OHC operation. In this design, a hydraulic clearance adjuster would have to be inserted between the tappet and the end of the valve stem. But there are objections. It’s difficult to plumb engine oil to a tappet in this position. The lengthofthetappetwouldbeaddedto cylinder head height, increasing engine bulk. And the added mass of the tappet would require stiffervalve springs.
In recent years, short pivoted finger followers have often replaced inverted buckets in new designs (those in BMW’sS1000RRare1-1/4incheslong and just over1/4 inch wide). These could incorporate hydraulic clearance adjusters at their pivots as described above. Then the problem would be to develop reliable check valves for the adjusters that could operate at the very high cyclic rates of modern sportbike engines. Cylinder heads would have to provide accurate bores in which such adjusters could operate, all provided with engine oil pressure from suitable drillings. Do the manufacturers perceive enough demand for this feature?
FEEDBACK LOOP: PULSING ROAD KING
I experienced the same I ® pumping-fork symptom while ■ braking on my 2005 Electra Glide (“Pulsing Road King,” April). It was so pronounced, the front tire would “chirp-chirp-chirp” under hard stops! After doing everything described in the letter and your response (except replacing the rotors) with no relief, I happened to notice the alternating sets of holes drilled through the rotors lined up on both sides. Since some sections had up to five holes close together and others only three, I thought I’d try moving one rotor to a different orientation so they would no longer be lined up exactly side to side. All it took was removing the mounting screws from one rotor and spinning it in place to a different spot and replacing the screws—no other disassembly required! Problem completely solved. For free!
SCOTT PEIRCE HOLLAND, Ml
A ■ seen Scott, or you’re heard a of genius. this, but Never it ■ makes sense, so we’ll try it if the opportunity ever arises.
VULCAN STATOR? SOUNDS LIKE STARTREK
QI • 900 have Classic a 2006 LT. Kawasaki It was purchased Vulcan • used with 11,400 miles. After one year and 10,000 miles, the stator burned out. Another year and 5,000 miles later, I am having issues with the bike starting and suspect the stator again. Do you know if this model has issues with the stator? Is there a permanent fix other than trading out of the bike?
JEFF MITCHELL CYCLEWORLD.COM
A permanent. Depends on The your earlier definition Vulcans of ■ are known to have some stator failures. Check out the extensive, wellwritten thread on vulcanforums.com. Don’t assume the stator is bad again until you check the obvious first. Check the battery, then connections (especially the grounds), a short in the stator to ground, and then the rectifier/regulator. Not all replacement stators are created equal. If she is a goner, I’d go with one from Rick’s Motorsport Electrics (ricksmotorsportelectrics.com).
BRIGHT IDEA
QI recently purchased a pristine, * low-mileage, completely factory■ stock 2003 Honda VTR1000F Superhawk. I’d like to improve the headlight brightness for night riding, and I thought it would be a simple thing to replace the factory headlight bulb with a more powerful one. But I am getting a lot of conflicting information regarding how changing to a different bulb will affect the Superhawk’s electrical system and battery. Can you give me any recommendations or advice to improve the stock factory headlight?
JIM HURLEY SANTA BARBARA, CA
A Casting a shadow in the high beam of that Excursion bearing ■ down is getting old, eh? Your Honda came with a 45/45-watt H4 bulb. Average at the time but not exactly state of the art now. Many remedies have been tried before, including, in
no particular order: 100-watt bulbs, Xenon bulbs, dual headlights, and HID conversions.
Forget all that trendy stuff. A 90or 100-watt bulb will melt the housing in short order. The duals look cool, if that’s the primary goal. As far as any of the higher Kelvin “blue spectrum” lights, I hate them. Firstly, as the guy you’re blinding when I come at you and, secondly, because my eyes can’t see any better with harsh blue light than with yellow light. The HID light conversion technically may be illegal where you live as well.
Here’s what I’d do. Wire up a relay for the existing bulb if you consider yourself handy, or buy a sano relay/harness from Eastern Beaver (easternbeaver.com). This alone will make a noticeable improvement. Then install a high-quality 60/55-watt H4 auto bulb. The slightly higher wattage will help now that you have a relay in the circuit, without doing a Chernobyl on your housing or wiring.
CLICKING 919
I recently purchased a 2006 I * Honda 919, and after riding ■ it for a couple of days I have started noticing a rhythmic clicking noise whenever the clutch is engaged (any gear...) and the bike is accelerating. The harder it accelerates, the more pronounced the clicks. The bike starts right up and shifts fine.
Its clutch action is light and solid. All things considered, it’s a nice bike. I just know it is not supposed to make this noise, so what do you think?
SCOTT JOHNSON CYCLEWORLD.COM
A an Honda anvil, 919s albeit are faster. as reliable That as ■ stated, here’s what you need to do: Check the drive chain for kinks in any of the links. Also check for a missing roller and, obviously, overtightened adjustment. Look at the sprockets, especially the front one, for any hooking of the teeth. Much less likely (but possible) culprits include a bad countershaft bearing and or a failing rear wheel bearing.
ANY LASTING IMPACT?
I am helping a friend fix a I ® broken balancer chain on a ■ Kawasaki KLR650 (which did not occur due to failure of the infamous doohickey), a task that involves removing the flywheel. I normally use an air impact wrench to remove and install the flywheel bolt so I don’t have to deal with a special tool for holding the flywheel. But people are claiming online that impact tools can damage the main bearings. We certainly don’t want expensive bearing damage, but I’m struggling to understand how a little rotational impact on the end of crank could cause any real bearing damage. Is this the truth, or just an Internet rumor?
BRIAN EDWARDS PORTLAND, OR
A exhibit So long some as you small are going measure to ■ of common sense, an air or electric impact wrench won’t hurt anything. Just don’t use that bitchin’ 900 pound-foot, 3/4-inch-drive impact to spin the engine over! C1U
