Service

SERVICE

JOE MINTON

Saving a Seca

I own a 1983 Yamaha Seca 900, and I have a few questions about it. The bike’s been garaged for about a year and a half. Before I put it away,

I drained the fuel tank and float bowls. I also squirted some engine oil into each cylinder and cranked the engine a few times. I'm wondering if the bike's prolonged storage could have caused any damage, and if I should rebuild the engine, transmission or fork.

And. do you know w here 1 can get stiffer fork springs to fit my relic?

Rick Jones

St. Louis. Missouri

You did die right thing to drain the fuel and oil the cylinders. It is unlikely that there has been any significant corrosion. The relatively even temperature of a garage with its cement floor tends to reduce condensation and the resulting corrosion.

Go ahead and fire it up. Run the engine a few minutes at fairly low (23000) rpm, then ride your Seca long enough to bring everything up to normal operating temperature. This typically requires 20 miles of interstatespeed travel. Then, drain all the oils and change the filter. You should then be ready for a new season of riding.

Fork springs are available from Progressive Suspension (11129 "GT Avenue. Hesperia, CA 92345:019/ 948-4307) or Works Performa nee (8730 Shirley Ave., North ridge, CA 91324:818/701-1010).

Blue boo-hoo

1 have a 1988 Honda Hawk 650 GT. 1 love the bike and have absolutely no complaints regarding its performance, however there is one aspect of the bike that bothers me. The exhaust pipes are severely discolored: blueish-purple near the heads with straw coloring down to the muffler. Obviously, they're getting hot.

Honda clearly specifies in the service manual that it set the motorcycle up with lean carburetor settings to assist in emissions control. I attribute the discoloring to these settings.

Do you agree with my assessment? Is there an exhaust system that would withstand the intense heat any better than the stock pipes?

Jeff Birmiz

Milan. Michigan

It's all a matter of temperature.

Most four-stroke engine exhaust-gas temperatures will range from 1200 to 1500 degrees Fahrenheit when operating at full throttle. Overly lean mixtures tend to produce such exhaust-gas temperatures at low throttle settings. Chrome will turn blue at about 1050 degrees; yellow at 700 or so. If the chrome-plated exterior of an exhaust system reaches any of these temperatures, it will discolor accordingly. The presence of oil on the chrome will accelerate the bluing proprocess.

B/uing was an accepted part of motorcycling back when Triumph Bonnevilies and Harley Sportsters ruled the road. These machines had singlewalled exhaust systems which, essentially. ran at or near the temperature of the exhaust gasses passing through them. Japanese manufacturers, in an effort to eliminate bluing, introduced double-wall exhaust pipes. The small air space between the inner and outer pipes usually provided enough insulating effect to prevent the chromed surfaces from reaching temperatures high enough to initiate bluing. Because the effectiveness of these measures varies from one system to the next, it no longer is possible to interpret an engine's tuning by “reading" the color of the exhaust pipe.

All aftermarket systems are singlewalled and will turn color to some extent. Unless, that is. they are painted or the mixtures are so rich that exhaust-gas temperatures are suppressed by the cooling effect of excess fuel.

Chained down

As the proud and happy owner of a 1987 Suzuki GSX-R1 100. 1 decided the time had come to replace its chain and sprockets. So, down to the local dealer I went to purchase these items. Sprockets were priced as would be expected, but the price of the chain was absolutely unbelievable. Two hundred dollars for a drive chain!

It seems Suzuki, in its infinite wisdom, has created a special-size chain just for this bike. 1 understand it was designed to handle the brute horsepower of this beast, but surely there must be a cheaper alternative.

Is there any company which makes a replacement that is more affordable? Maybe there's an aftermarket chainand-sprocket kit that converts the GSX-R to a standard chain size?

Dennis M. Dally

Laconia, New Hampshire

You may substitute a Tsubaki 530 Sigma O-ring chain for your original.

The Sigma w ill cost you about $110.

}Vhile field experience indicates that the 530 Tsubaki will work with the Suzuki sprockets, you ought prefer to buy a set of sprockets cut for the 530 chain.

Sunstar the maker of most stock Japanese sprockets. has both front and 'rear 530-sized sprockets to ft your GSX-R /100. The rear sprocket carries the part number S-27A03R. The front sprocket is number 5114.

Contact U.S. Tsubaki at 18031 Cornier Ct., City of Industry. CA 91744; 8141913-1344 and Sunstar Engineering USA Inc. at 307 Paseo tesoro. Walnut. CA 91789; 714/5989660.

Warned about radiais

I have a 900 Ninja that is currently running on Metzeler Comp &s. I want to change the bike over to Dunlop's new Sportmax radiais. Dunlop offers a 120/80 ZR 16 front tire, which is the size my Ninja came <vith. The problem is that my bike came with a 1 30/80 V 1 8 rear tire, but Dunlop’s smallest 18-inch Sportmax is a 1 60/60 ZR 1 8. Would this combination work?

Mike Kobleur

Camp Pendelton, California

Radial tires require wide rims. Dunfop recommends a 4.5-inch rim for the 160160 ZR 18. Your Ninja 's rim is too narrow to properly support the Import max. Dunlop recommends against running radiais on any bike that did not come with them.

Tires are an essential part of any motorcycle's stability, particularly at high speed. The suspension components Kawasaki developed for your N^nja were tuned for bias-ply tires. It is possible that your bike would not be stable at high speed with radiais, no matter who made them.

* If you want to run Dunlops, I suggest that you use the high-performance belted/bias K591 Sport Elites. These tires will work just fne with your Ninja's wheels and suspension tuning. 0