Service

SERVICE

Slowing an Interceptor

In early June I am making a crosscountry trip on my 500 Interceptor. Since my bike has such a high-revving engine, I wanted to install a much larger front sprocket to lower my engine speed. I want to make the trip as easy as possible for my machine.

Is this advisable? How much larger should I go? I would like to drop my engine speed from about 5600 rpm at 60 mph to about 4500 rpm if possible.

Ronald Leon Tampa, Florida

The stock front sprocket size on the VF500F is 15 teeih, the largest that can be installed is a 17. That would reduce engine speed 12 percent while cruising,from 5600 rpm at 60 mph tc nearly 4900 rpm.

T/i'at 12-pe~rcent reduction of engine speed would be reasonable, though it would noticeably detract from the

VF500 `s acceleration. We'd suggest trying the 17-tooth sprocket first, and if that doesn `t drop engine speed enough to suit you, then install a slightly smaller rear sprocket. Keep in mind that the VF engine was designed to run at high speeds, and cruising at 5600 rpm isfarfrom a hardship for it.

Chain size elaboration

I think that your answer to a Service column letter (March, 1986) concerning chain size is wrong. I have always thought that the last two digits in a chain number, like 530, for example, pertain to the distance between sideplates in eighths of an inch, not to the width of the chain. Have I been confused on this?

Richard W. Wilson Farmington, New Mexico

You 're right about the distance between sideplates. That was the dimension we were referring to when we said “width, " simply because as far as the sprockets are concerned, or for chain interchangeability, the distance between sideplates is the controlling width dimension.

Gasoline stabilization

After reading the Service column in the March, 1986, issue, I would like to clear up some misunderstandings about gasoline left unused in the fuel tank and carburetors.

Gasoline, when left sitting for more than 45 days, starts to change into something with the consistency of varnish. Gasoline makes its way through the carb via very small passageways, especially the pilot jet. Left sitting in the carburetors long enough, this gasoline/varnish will eventually block off the jets altogether, and the engine will not run. If the jets are only partially blocked and the bike does start, the blockage may cause the engine to run lean, which could result in anything from poor performance and bluing pipes to burned valves and holes in the tops of pistons.

Anybody who stores their machine for more than a month should stabilize the fuel system. All that is required is to add Sta-bil or any other brand o'f fuel stabilizer, which

is a product that prevents the gasoline from degrading and is available at most auto supply stores. Mix the product with the gas per the instructions. Shake the tank and then run the engine 10 minutes {very important). Unless you do this, the treated fuel won’t get inside the carburetors.

So every time you put that motorcycle away for storage, take a few extra minutes to stabilize the fuel. It will save you in the long run (my shop gets a minimum of $40 for each carb cleaned), and more important, it will save your engine.

Kenneth Vanhorn Algonquin, Illinois

Handy seal driver

I have a suggestion that may help readers who do their own work. Recently, while replacing the fork seals on my Interceptor, I ruined the first seal trying to install it with a hammer and screwdriver. After purchasing another seal, I went to the hardware store and bought a twofoot length of 1.5-inch PVC pipe. This made an excellent seal driver; and being plastic, it won’t damage the fork tube or the slider. This tool cost only $ 1.50, and can be made for almost any bike by buying the right diameter pipe.

Michael T. McCabe Brockton, Massachusetts

Your idea will work nicely if you can remove the old seal without disassembling the fork leg. Generally, seal replacement requires removing the stanchion tube, but there are some cases where that 's not necessary. For those, PVC pipe would make an exce/lent seal driver.

Heavy handlebars

In August of 1985 I got a great deal on a “new” 1982 Honda CB900F. It’s a great machine except for one problem. I installed a set of K&N Superbike bars for comfort and riding position. In doing so I discovered the stock tillers were steel-filled. Now, after a 50 mile ride, my hands and fingers are dead numb. Have you any suggestions how I can modify the K&N bars to absorb the vibrations?

Scott Sellin Redford, Michigan

The bike companies frequently weight the ends of their handlebars to reduce the intensity of handlebar vibration, and adding weight to your K&N bar would have the same beneficial effect. With some creativity, you could probably adapted existing handlebar-end weights to your motorcycle, but finding the weights may require becoming friendly with the parts man at your local dealer on a slow day. (If anyone knows of specific handlebar weights that work with aftermarket bars, let us know, and we'll run that information in a future service column.)

Alternatively, any small machine shop could whip up some weights that fit. The heavier the weight, the more the effect on vibration, so a denser metal such as brass would be better than steel. Better yet would be filling the ends of the bar with lead, a practice that was actually used on a few motorcycles in the early Seventies. 3