Cycle News - Archive Issues - 1980's

Dirt bike pr~: Part 1 Wrenching lor maximum reliability By Tom Kolnowski Wrenching rundown We've all heard the story about the guy who went out and bought the latest dirt weapon, pushed it up the ramp into his van, and with little more effort than adding petrol to the tank, drove straight up the interstate highway to the nearby motocross/enduro/hare scrambles/ISDE qualifier and effort- 16 1 • lessly sailed to the win in his class. Sure, it happens, at least as often as the local trophy-grabber who signs a mega-buck factory contract. We would like to suggest a slightly clifferent approach to o[[-road bike maintenance, rather than the add-gas-and-forget-it method - basic preventative wrenching. Try to resist the temptation to immediately put your new scooter through its paces. Instead, boost it up onto your favorite work stand and give it a thorough examination. As you scope out the bike, try to imagine what could go wrong. It doesn't hurt to adopt the attitude that every single component is a potential problem area. Your bike takes enough abuse in the dirt - don't give Murphy's Law an open invitation to strike. Most of our recommendations for preparing a sparkling new machine for competition or heavy duty use as a weekend trail bike are quite basic. We're working from the premise that common sense set up and maintenance is the best route to consistent finishes, or in the case of trail riding, for a successful outing. Everything we'll be talking about can also be applied to a well-used machine, but you might find that various parts will need replacing before you can continue with the • bike's dirt preparation process. Before you start In adclition to a bike in need of attention, chances are that you will need to pick up at least some of the items on the following list. Most can probably be found in the tool box of the average dirt rider. A few are specialty tools, and in that case it helps to know someone who might have one to lend. The rest are basic lubricants, reaclily available from the local bike shop or auto parts store. Make a list of what you will need, along with replacement parts required in the case of a used bike. Here's a recommended list: Torque wrench Metric sockets Open and box-end wrenches Assorted screwdrivers Allen wrench set Flywheel holder Air pressure gauge Hack saw Safety wire Duct tape Plastic electrical tape Zip ties Extra fuel line Graduated or baby bottle Funnel In-line fuel filter Silicone sealant Air filter oil Fork oil Transmission/sump oil Chai n lubricant Spray silicone lubricant Waterproof grease I ) J •J ~ • ) )' t If you're like most clirt riders (and we include in that category members of the Cycle News- staff), we would be willing to wager that your new bike already has at least a modicum of foreign matter scattered about its oncepristeen exterior. A new machine simply begs to be ridden, but as we said before, try to exercise your wi II power and leave it at rest until after the basic preparation has been completed. At this point, your mission will be to get the machine as clean as possi ble. Since you will be clisassembling various components, the lack of accumulated dirt can only help your cause. To remove orne of the more stubborn blemishes, try a dose of household spray cleaner (such as Formula 409). Once cleaned and dried, your bike is ready for dissection. Our attention will be devoted to a pair of Husqvarnas, which are good examples of the current state of the art in dirt machinery. The first, a 1984 Husky 250WR, is one of the most sought after enduro bikes. (Special thanks to Barry and Patti Higgins of H&H Maico/Husqvarna/KTM of Mableton, Georgia, for supplying the machine and offering their advice.) The second is a Husky l75XC of 1983 vintage, which has seen many hard miles of o[[-road action at the hands of a Cycle News staffer. J[ you're a moto.cross devotee, remember that nearly all of our recommendations are equally pertinent to your bike. With tools, lubricants and other required items close at hand, begin by removing the side panels. To make reassembly easier, locate a small container in which to store the various fasteners and washers. That will keep them from getting lost or rolling away. Remove the seat, making a mental note as to the proper order of washers i ! J f and rubber grommets on each fastener you remove. Turn the fuel petcock to the off position, slip the fuel line off and pull the gas cap breather hose out of its mounting. Remove the tank mounting bolts and any rubber straps which may be at the rear of the tank. Before pulling the tank 0[[, note the proper routing of cables and wires which run under it. Your bike should resemble the one in photo A at this point. The ignition coil should be in plain view, nestled near the main frame backbone. Snug down the coil mounting bolts, as well as the ground wire. Note that we said "snug" and not overtightened - keep in mind that a stripped or broken fastener can easily ruin your ricling day. A dab of silicone sealant at the point where the ignition wire enters the spark plug cap will keep moisture out and the sparks [lowing. Most bikes have a mass of wires which converge at the frame backbone. A few zip ties will keep them in their appointed places away from the cylinder head. Trace the ignition wires down the frame, again securing them as needed with zip ties or duct tape. The point where they enter the crankcase is normally sealed with a rubber grommet and is another potential problem area. A coating of silicone sealant will give a measure of extra protection from moisture or clirt in the flywheel/magneto area (see photo B). Make one last check to make sure all wires in the area are fully plugged into their respective sockets. On enduro mounts, the power to keep your lights burning is generated in the flywheel/magneto area. Again, trace these wires to 'the respective switches and lamp sockets, securing them to the frame as needed. For an extra measure of protection for the I" ... I ~ 1 I ~' t 'J J I j ~ ) 1 C

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