Service

Speedy Sporty update

SERVICE

JOE MINTON

Our Harley-Davidson Sportster 883/1200 conversion as detailed in last month's "From Sportster to Speedster" story has been more of a success than the stock clutch could handle. We smoked it. Our high-compression engine makes about 20 more horsepower than stock, and continued powershifting through the gears has shown a need to upgrade the clutch.

At this time, there is only one aftermarket clutch available for the five-speed Sportster. Barnett Tool & Engineering (9920 Freeman Avenue, Santa Fe Springs, CA 906 70; 2 J3/ 941-1284) has a new Kevlar-reinforced friction-plate material that will survive considerable abuse. The firm makes two five-speed Sportster clutches with this material. One has the standard eight friction plates, the other has nine. We installed the $ 139 nine-plate version to get its greater area and improved tolerance to abuse. The Barnett clutch material has a higher coefficient of friction than the stock material, a good thing because, at this time, there are no stiffer clutch springs available.

As a final precaution, we filled the gearcase with a 75w-90 synthetic gear oil, in this case from Redline Oil (3450 Pacheco Blvd.. Martinez, CA 64553; 800/624-7958). h costs $7.25 a quart, but allows the clutch plates to hook-up harder and greatly increases gear lubrication.

We have also had trouble suppressing detonation on hard rides or when the quality of fuel is suspect. Moderatelift aftermarket cams will eliminate this problem, but we want to stay with the factory cants, which make good power over a wide rpm range and are quiet in operation.

If you are not going to install aftermarket earns, you should do something to lower the compression ratio. Harley's method (to open-up the combustion chamber) is the least desirable. It eliminates the possibility of establishing a high-turbulence squish area between the pistons and heads.

Both Wiseco Piston Inc. (720 J Industrial Bark Bird.. Mentor. OH 44060; 800/32 J-1364) and S&S Cycle (Box 215. Route 2. County Highway C, Viola, Wl 54664; 608/627-1497) sell 883/1200 conversion kits. Both have dropped-center pistons designed to lower the compression ratio.

Wiseco 's $190 forged-piston kit establishes a 9.5:1 contpression ratio. S&S's 8110 cast-piston kit 's compression ratio is 9.0:1. —Joe Minton

Charge it

I have a big problem with my Honda GL 1 000 Gold Wing. Its electrical system charges when the motor is cold, but discharges when it is hot. And sometimes it charges too much and burns the battery out.

I have already changed the voltage regulator and rectifier.

Jim Carstens Dickinson. North Dakota

The fact that your Honda charges when it is cold and not when hot suggests that there is a broken wire (probably in the alternator windings), the ends of which remain in contact until temperature expands them away and out of contact. Get the hike well up to operating temperature and quickly run a continuity test on the system. You 'll stand a good chance of finding the problem.

You mentioned that the system sometimes overcharges the battery.

The early Gold Wings had a high charging rate and would overcharge and lose battery water to electrolysis. Watch the battery-water level. Also check the charging rate according to (he factory shop manual just to be sure that your bike's system isn 7 too Jar out of specifica t ions.

Rest in peace

At 31 years old, I decided it was time to ride, so I purchased a new 1991 Suzuki GS500E. My lack of time to ride causes the bike to sit unused for one or two weeks at a time. The bike is kept in a nonheated garage.

My concern is, does the bike have to be prepared for storage when not in use for extended periods of time, or should I just start and warm up the engine on a regular basis? I would hate to ruin a brand-new motorcycle.

B. Darconte

Bayside, New York

With the exception of their batteries, motorcycles are no more sensitive to short dormant periods than any other motorized vehicle. We often let bikes sit for several weeks with no damage or significant deterioration. A couple of weeks should not be a problem at all.

However, there are some things that can go wrong with time. The gasoline might deteriorate and clog the tiny idle jets in the typical motorcycle carburetor. This will make starting difficult and idling impossible. If the battery is allowed to discharge, it will sulphate at a much higher rate than a larger automotive battery. Sulphation reduces or completely destroys a battery's ability to deliver current or receive a charge. And motorcycle tires lose air pressure at a higher rate than automotive tires. Instead of tire pressure dropping off at about I psi per month, a motorcycle tire will typically lose air at the rate of about l psi per week.

By the way, if you are going to warm your engine up, you should do it by riding it at least 10 miles at interstate speeds. If you just warm it up in your garage, without load, you'll fill the oil with unburned fuel and water. They will, in turn, form acids and attack those finely finished and expensive internal working parts. Either warm it up completely or leave it alone. Œ