Service
SERVICE
We welcome your technical questions and comments, and will publish those we think are of interest to our readers. Because of the volume of mail received, we cannot return any personal replies. Please limit your “Service” letters to technical subjects only, and keep them as brief as possible. Send them to: “Service, ” CYCLE WORLD. 1499 Monrovia Ave., Newport Beach, Calif. 92663.
STICKING SLIDES
The twin Mikuni carbs on my Suzuki 350 Twin are driving me to my wit’s end. If I bolt them on tight enough, that is, to where they won't leak, then the slides stick in the bores. If I loosen them until the slides slide, they leak and the machine is hard to start, runs rough, and idles fast. Out of desperation, I will take them off and. using a piece of ground plate glass with fine emery, attain a reasonably flat flange again. This will last for a while and then they will blow again. I hate to think of a machine with four of this sad hookup. Anyway, I haven’t been able to find a lasting cure for these miserable carbs.
John D. Jenkins
Port Orford, Ore.
This sounds like a perfect place for silicone seal, the rubbery kind of sealant which can form a gasket that should solve your problem. When you use it, form an even bead around the outside edge of the mating flange, keeping the silicone away from the inside of the port. Use the silicone in addition to a fresh rubber O-ring. Unless you are taking special measures to hold the carbs perpendicular to the plate of glass you're using, there's a good chance your homebrew milling machine isn't really grinding a flat surface on the carb or head flange. Most of the Suzuki Twins used a fiber insulating block between the carbs and the cylinder. Fresh insulating blocks will ensure that the surfaces are flat. There's also a possibility that the intake leak is coming between the insulating block and the cylinder, so make sure you use a sealer between those surfaces, plus a new gasket between the surfaces.
FOULED SPARK PLUGS
1 am having a problem wdth fouled plugs on my Yamaha ATI. My dealer suggested a hotter plug but the problem still exists. Please help.
Gary Russell Weaver Unncansville, Pa.
Several things can cause plug fouling. Since you didn't say what was fouling the
electrode, we'll try and cover the main prob-+ lem areas. ( We assume you are using a twostroke oil and not four-stroke engine oilf The first thing you need to check is your air cleaner. Make sure it is clean and oiled, Also inspect for holes and tears, and look closely at any glued seams. Glued seams oft foam cleaners sometimes come apart if gasoline has been used to clean the element. Next inspect the intake hoses on both sides^ of the carburetor for tears and holes. If metal particles are fouling the plug, remone^, the cylinder head and barrel and check for piston damage. If the piston is damaged have your dealer cheek the CDI unit for proper advance. If the oil injecter is still otf the machine, check for proper adjustment.
NEED MORE SUSPENSION
I need more suspension on my 125 Puch Enduro. The Betor forks only have 6.5 in. $f travel. The rear is worse, with Girling shocks furnishing 3.9 in. of wheel travel. Tfte frame and engine are fine so I would like to update the suspension. Who can Ti%lp?
Kenneth Russel Troy, Mich.
Write to Al Baker R&D. They have some excellent suspension fixes available. The ¿ijfiress is Al Baker R&D, 13588 Central, Apple Valley, Calif. 92307.
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LEAKING HONDA
I own a 1973 Honda CB350 Four with '22,000 miles. It’s in good condition except for two problems. One, the head leaks oil.
as always leaked and it’s getting worse. ^T^vo, the engine sometimes loses rpm and stalls while it’s sitting at idle. Are these common problems with my bike? What can be done to rectify it? And is it worth it tb fix?
Frank Yezzo Jr. Flushing, N.Y.
Oil leaks from the cylinders of the Honda *f50 Four were common. In most instances tfie problem wasn 7 a leaking head gasket, but leaking heads. Where the studs came through bosses in the head, the head can develop a tiny crack which allows oil to seep out, weeping through the head gasket and out from between the head and cylinders. Or the oil can leak out from around the cylinder base gasket. You'll have to pull the head, clean it carefully, and check the bosses around the studs for tiny cracks. This isn 7 the same problem experienced on the CB400 Four which had a cylinder porosity problem on some models. As to the idle problem, chances are you store your motorcycle in the winter and the gas sitting in the carbs can partially plug up your idle jets. Pulling the carbs off and running the pieces through curb cleaner should solve the problem. As to your last question, if you like the motorcycle, it's worth fixing.
SEEING EYE MOTORCYCLES
Having been here and there, I have seen several Canadian bikers with either fairing or handlebar mounted radar detectors such as the ever-popular Fuzz-Buster. What are the possibilities of installing such a unit on my Honda CB750K, and do many state boys object to them?
Rick Menard
Newport, Vt.
It is possible to mount a radar detector on a Honda CB750K. We, too, have seen radar detectors on motorcycles. They do work. Many police agencies using radar don 7 like radar detectors and at least one state, Virginia, has tried to outlaw radar detectors. According to the Federal Communications Act of 1934, all citizens are entitled to have any radio receiver, including a radar detector. The Act also says no agency can confiscate any radio receiver, which includes radar detectors, although there are reports of Virginia patrolmen confiscating radar detectors. In most states, however, a radar detector won 7 cause you any problem. Because your motorcycle presents a small area to the radar-equipped policeman, the range of police radar is not as great for spotting motorcycles as it is for spotting cars or trucks. This means a radar detector can provide the motorcyclist with an even greater margin than a car driver would have.
DUCT TAPE ON HELMETS
I recently applied several strips of di*ct, tape to my helmet. Will the tape harm the helmet or effect the protection value any?*] notice pictures of top MXers with a strip of tape across the top of their visors. *
Scott Yingling Allison Park, Pa.
The tape is a security device. It keeps bill on the helmet if the rider crashes. Enduro and desert riders also tape the bill on soirees etc., won V knock it off. A better way is to install two more snaps and use a five-snap bill. To our knowledge the tape won’t hurt the helmet.
HOPPED UP HONDA
I have a Honda 750 with a 900cc kit in it. I had the cylinders and head face milled to stop an oil leak. The shop had to take 0.010 in. off the cylinders and 0.018 off the head for a total of 0.028 in. Is this too much? Do I have too much compression or will I haf^ enough clearance?
Ed Harris Beattyville,
Providing all other work was done properly, your operation should be successfaiU Removing 0.02§ in. shouldn’t cause interference between' the valves and pistons Isd long as you are using the stock cam. A hotter cam could have greater valve lift and could conceivably cause problems, though. The increase in compression may make premium fuel mandatory for your bike, that shouldn’t be a serious problem. If yoni develop excessive detonation on availahdk fuel or want to use a hotter cam, you could always use a thicker cylinder base gaskk (and larger stud-sealing O-rings) to compensate for the milling.
