Service

SERVICE

Paul Dean

C-c-cold b-b-blooded

I own, among several other bikes, a 1996 Suzuki Bandit 600, and I love it except for one annoying characteristic: the lengthy warm-up period. No matter what the ambient air temperature, the bike always requires a minimum of five miles of riding before the choke can be switched off and the idle speed returns to a reasonable rpm. It is embarrassing to be sitting at a traffic light with the bike idling at 3000 rpm. But if the choke is turned even partially off too soon, the engine will stall under acceleration. Is there a jetting change or some other engine modification that can remedy this aggravating situation? Randy Ober Mechanicsburg, Pennsylvania

That long warm-up is a direct result of the lean carburetion that allows the Bandit to meet federal exhaust-emissions requirements. Different engines react to lean mixtures in different ways, depending upon certain engine-design factors such as intake-port and combustion-chamber configuration. One of the ways in which the 600 Bandit-as well as numerous other later-model Suzukis—exhibits its lean carburetion is by taking a long time to warm up. Both Dynojet and K&N make jetting kits for the Bandit that should eliminate most, if not all, of its extreme cold-bloodedness. The Dynojet kit is part number 3120; the K&N kit is number 81-9254.

Coins in the coils

Your reply to B. Petibon’s centerstand spring problem (“Can’t stand it,” December, ’98) sounds like a recipe for scratched paint and rapped knuckles. Here’s the simple solution: Bolt the centerstand onto the bike, then expand the spring by inserting coins or washers between the coils until the spring becomes just long enough to slip over its locating pegs with the stand up. Now place the bike on the stand and remove the aforementioned packing. It’s that easy. Pete Morgan Aude, France

Thank you for the ingenious tip, Pete. This could prove an invaluable technique when installing many different kinds of springs.

I would, however, add that getting the washers inserted into the coils of the spring also requires a special technique in itself Probably the easiest method is simply to bend the spring in a U-shape until you separate some of the coils on the outside of the bend far enough to allow the washers to be easily pushed into place.

Basic draining

I own a 1994 Harley-Davidson Softail. I am only able to ride the bike about once a week, sometimes only once every two weeks. It was recommended to me that any time I put the bike away between rides, I should run all of the fuel out of the carburetor. I have been doing this for about a year now and nothing bad has ever happened. When I start the bike to go for a ride, I just turn on the gas tap, pull the choke knob and hit the starter button. It fires up almost immediately. I have talked to a Harley mechanic about this, though, and he disagrees. He says that this practice is harmful. Could you please set me straight and tell me what you recommend? Jorge A. Sanchez La Jolla, California

If the bike is going to sit only for a week or two between rides, emptying the carburetor won't cause any problems, but it’s actually just a waste of time. The supposed purpose of draining the carb is to prevent the volatile ingredients in the fuel from evaporating and leaving behind a residue that can clog jets and corrode surfaces inside the float bowl. But that evaporative process takes quite a bit longer than two weeks. If the bike were to sit for several months, though, draining the carburetor would be more meaningful. Under those circumstances, you would also be wise to use one of the fuel stabilizers on the market that help prevent the formation of this residue.

What s more, you cannot completely drain the carburetor float bowl by running the engine with the fuel tap turned off. For reasons related mostly to where the jets pick up fuel in the float bowl, an engine running in neutral will conk out before the bowl is completely empty, leaving behind a small amount of fuel. To empty the float bowl completely, you either have to remove the large drain plug at the bottom of the bowl or take the entire bowl off the carburetor.

Head case

I am in the process of having a Harley-Davidson WL “45” motor restored. The cylinder heads I have are different in that one is a #5 regular head while the other is a #6 high-compression head. Should I look for a matched pair of heads or would it be okay to use what I already have? Rick Floding Detroit Lakes, Wisconsin

You definitely should try to scare up another #5 low-compression head. The #6 head is from a WR racing engine, which, like the WL, uses flat-top pistons, but achieves higher compression by virtue of the smaller-volume combustion chambers in its heads. The difference in the compression ratios of the heads is about 1.5 points; and unless you have no intention of riding the bike very often, you don’t want a significantly higher compression ratio in one cylinder than the other. That would make adjusting the carburetor for smoothest running much more difficult, and you might even have to use a different sparkplug heat range in each cylinder. Besides, the #6 head is comparatively rare and considerably more valuable than a #5. You could probably get someone to trade you several #5 heads for your #6.

Incidentally, I find it curious that you are having the motor restored by someone who apparently is unable to answer questions about the compatibility of the heads. Any engine builder worth his salt should appreciate the importance of having the same compression ratio in all cylinders.