The Vibrator
The vibrator
SERVICE
My 1981 Honda CM400T is a great streetbike around town, but at comfortable cruising speeds (65 or so) the vibration jiggles me off the seat and threatens to unscrew every bolt on the machine. Can a sixth gear be installed or the drive sprocket ratio be changed to help this situation?
Chris Colm
Port Royal, Pennsylvania
Technically, you could install the six-speed gearbox from a 1980-model CB400T Hawk. But you would end up spending an awful lot to gain very little, since the low-gear and top-gear ratios of your five-speed CM400T are very close to those of the CB400T; the main difference is that there are four gears between low gear and top gear on the CB, but only three on the CM.
Realistically, the best solution may be to use taller final gearing to reduce engine rpm at cruising speed. Try about three orfourfewer teeth on the rearwheel sprocket and see f the re sults please you. The cost of this modification will be very low, and you
can always revert to the stock setup (or even try taller gearing yet) if you aren't satisfied. Keep in mind, though, that this re-gearing will detract proportionately from the CM400T's maximum acceleration in any given gear, and have a negative effect on its ability to pull away from a dead stop in low gear. While you `re at it, check the tightness of all the engine-mount bolts. Loose engine bolts can amplify vibra lion enough to make a bike shake like a cat that's been doused with water.
Belt-Drive Honda?
I would like to know if anyone out there in Motorcycle Land offers a belt-drive conversion for Japanese motorcycles? My 750 Honda is nearly maintenance-free except for the final drive system.
Tony Petersen Dekalb. Illinois
No, not to our knowledge. But a good-quality O-ring chain needs considerably less-frequent adjustment and lubrication than a standard chain.
Stop-and-go Yamaha
My XT550 Yamaha has a problem: It will suddenly sputter and quit running. Sometimes this occurs at low engine speeds, other days it happens at higher revolutions. After coasting to a stop, the bike always starts right up again. My dealer has cleaned the air filter and carburetor, adjusted the valves and changed the sparkplug, but the problem still exists. Can you help?
Burt Metzger
Esterville, Iowa
If your dealer has done a competent job of rebuilding the carburetor, the problem most likely resides in the capacitive-discharge ignition system, probably in the little pulser unit that sits at about the 1 o'clock position on the outside of the ignition flywheel. It 's fairly common for a faulty ignition component to stop working because of normal heat build-up caused either by its proximity to the engine, or by the flow of current through it—or both. And in the short period of time required for the bike to coast to a stop, the component cools enough to resume normal operation.
Diagnosing such a problem can be a real bear, though, because the component usually works perfectly until it gets hot enough to fail. Often, a dealer can detect a weakness in a suspect ignition component by subjecting it to standard tests with an ohmmeter or some other type of electrical tester; but more often than not in cases like this, the most practical test is to replace the part with a new one and see if the problem recurs. Either way, it seems that at least one more trip to your dealer is inevitable.
Coiled
Depending on who I talk to, I get a different opinion about the performance of aftermarket ignition coils. I have a 1987 Honda Hurricane that’s stock with the exception of a Uni-filter air cleaner and some fiddling with the carburetor adjustments. Will new coils improve this bike’s performance?
Jeff Volk
Berkeley. California
The original coils do a good job of supplying spark on a stock engine as long as they aren 't damaged or extremely old. Replacement coils may be needed on an engine that's been modified extensively for racing, though.
Hopped-up tourer
My ’84 Yamaha RZ350 is equipped with enough highperformance extras to make it competitive with 600cc four-strokes.
I normally use this bike locally, but would like to ride it to Daytona this year. I’ve heard stories about smalldisplacement two-strokes overheating when run at a constant 55 mph on the road. Are there any modifications I can make to this high-strung sportbike to turn it into a reliable sport-tourer?
John Krutke Oshkosh, Wisconsin
You didn 7 say exactly what modifications were made to your 350, but it sounds as if the bike is a bit too high-strung for extremely long rides. In its stock state of tune, an RZ350 could handle the Daytona trip with no problems, but yours sounds like a candidate for roadside repairs. We would recommend either taking a different motorcycle, or trucking/irai lering the bike most of the way, then riding the last few miles into Florida.
Touch it up
I own a 1986 Kawasaki Ninja 600R that has some small scratches in its red, white and blue paint scheme. Where can I get touch-up paint for it?
Kevin Lynn Shelton FPO New York, New York
Your Kawasaki dealer either has, otean order, touch-up paint for almost any year and model of Kawasaki. The factory colors come in a variety of forms: a spray can, a bottle with a small brush, and one-quart containers suitable for application with professional spray equipment. E3
ILLUSTRAtION BY LORI TYSON
