Cycle News - Archive Issues - 1990's

WORKBENCH $100. P RHCE. By Michael Ross Clearing the air about air filters resent day motorcycles use three basic ty pes of air cleaners: pleated paper, pleated gauze and foam . These air clea ners were developed to satisfy the demands o f di fferent types of ridi ng environments and all three do their job with elegant simplicity. First, the pleated pap er filter (p leats increase surface area) is the type you will find on most road bikes. It has the ability to filter out the sma llest of dirt particles, but a drawback is that it is restrictive compared to gauze filters and th at it has a limited storage capaci ty, i.e. a limited amount of "dirt" can be filtered from the air before the filter is overloaded and th us non -efficient. In addition, paper filters cannot be cleaned a nd reused. Second is the pleated gauze filter which uses a p iece of gauze surro u nded by wire mesh tha t holds it i n pl ace and maintains its shape. By itself, the ga uze filte r has holes far too large to filter p art icles that are large enough to damage your engi ne . Instead , it relies on a special filter oil sprayed onto the filter which is soaked up by the gauze. T he oil filt ers and ho lds the dirt particle. These filters are generally used on high performance street bikes because of their ability to all ow mo re airflow tha n paper filters an d they can be clea ned and reused. Gauze filters are al so seen on some off-road bikes, in th at use th ey usually have a secondary foam filter stretche d around them to increase their storage capacity. O ne nega tive asp ect of this filter type is that ma ny customers install the filter wi thout oiling it . T hat allows dirt to enter th e engine with damaging results. The third type is the foam filter which also must be oiled to filter dirt. It works on the same basic principle as gauze but has a very high storage capacity. The foam filter is also much easier to clean than th e gauze type and will last longer. Although foa m filters pass the largest particles, the y usually have the highest flow rate and, like gauze filters , their sto ra ge capacit y can be extended by the use of a filter wrap around the outside. Whatever type of filter you use on your bike, be sure to oil it with th e proper oil. There are different oils for gauze and foam filters whi ch are not interchangeable. And remember to grease the edges of car tridge style filters which have to seal arou nd th e edges of an airbox. Heavy axle or bearing grease will make sure the sea l is airtight. Avoid the use of high pressure co m p ressed air to clean filters. It is particularly damaging to gauze filters because it blows holes in the del icate filte r membrane. An often overlooked aspect to filte r operation is the integrity of the air boot leading from the air box to the car b(s). These rubber boots shrink with age and may not reac h the carb mo u th p ro perl y. They can a lso be p ulle d partially out of the ai rbo x by ow ners try in g to make them reach the bell mouth of th e carbo Air boo ts shou ld he replaced when they become stiff. aI P Workbench is a column dealing with motorcycle maintenance, performance and equipment. Have som ething that Workben~ can address? Drop a line to Workbench, Cycle News, P .O. Box 498, Long Beach, CA 90801-0498. rORCO IS 10 0 ICING FOR A FEW FASr MOrORCYCIE AND JEr SICI RACERS ro JOIN rEAM rORCO. CLIP AND MAIL TODAY Ifyou are successful enough to become a memberof Team Torco, you will have the chance to win a great deal of cash! You're going racinganyway, so why not race your way onto Team Torco? Andwhen you buyyouroil,why not buy Torco...the oil that pays you $100. per win! All motorcycle and jetskiracers are eligible. ~-------------------lYE 5 • I Send me at no obligation-details on how I can win $100. per race. I I I I I I Name: - -- - - - - - - - - - , - - - " - - - - - - - --1 Address: City: Stale: _ Zip: Type of Racing/Class: Mail 10: TORCO INTERNATIONAL CORP. 9916 Pioneer Blvd. Santa Fe S rin s, CA 90670 1 METZ~lJ.l~" Street Legal Knobbies MEl2ELER int roduces the NEW MCE re ar knobby for aggressive Dua l Sport offroad riding. Pair this up w ith o ur world famous M010 X front tire - now DOT approved! This set of DOT knobbies are intended for 10% street and 90% offroad app lic atio n. . Choose your Dual Sport Ride MEl2ELER also offersthe Enduro 3 Sahara for 50% street - 50% offroad and Enduro for 80% street - 20% offroad . The tires that took the Gold at the 1991 ISDE 6-days. MCE 120/90 X 18 MCE 140/80 X 18 *M C E 120/80 X 19 * Available early 1992 FOR MORE INF ORMATION CONTACT : METZELER@ FEEL THE DIFFERENCE 4520 l07th Street s.w. Muknteo. WA 98275 (206)348-4000 29

• Cover