Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/125994
Supply) with an clastic nut. The best so lution to all t hese low -pipe problems is to chuck it an d buy an up-pipe, This will save roughly six p ounds over the rein forced pipe, and ground cle arance is increased .th ree and one-hal f inches. Pipes are avai lable from both AI Bak er ($9 0) and DG Enterprises ($ 70 ). The Baker installation kit. wh ich also incl udes a new number plat e, will r eq uire some cu tt ing and welding of the fram e. This all ows the p ipe to fit snuggly under the tank so you won't bum yo ur leg. On th e intake side. th ro waway the st oc k fuzzy filte r and get a Filtron . It has a b ett er seali ng arrangemen t and m ore .filterin g area. Also , t he special Filt ro n o il will abso rb and hold dust better than motor o il. As a last step, seal th e sides of t he airbo x to th e fram e and th e airbo x floo r [ Fig. 3 ] with o ne inch wid e foam strips to keep water and dust o ut. Installing the wide ratio gea rbox from the MT 250 is an excellent m odificati on for the de sert. be cau se th e spread bet ween first and fifth is inc rea sed 33%. This will let y o u pick yo ur way ove r roc ks an d still leave alm ost an y other 25 0 be hind o n the fireroads. Th is gear box is available from Tom Sawy er Ho nda fo r $ 175. installed. If yo u are go ing to buy a new bike, check with him first to see abo u t a straightacross swap o f th e gears. Stock final gearing (14/47) works well . but a 15 tooth co un tersha ft sproc ke t can be used to raise top spe ed a bit. If yo u stay with the stoc k close-ra tio box. use a 16 tooth sp roc ket. In-gear starting is great ly he lped by runnin g multi-visc osity o il (we use 20 W·50) because cl utch drag is re duced when the engine is co o l. Here are some it ems to watch out for ~il&3firn®[P@ 8~®g DESERT SURVIVAL MANUAL One of the thrills of owning a race bike is finding its faultson the way to the smoke bomb. • By Wi lliam T. Del Hagen and Darold B. Cummings Since few bikes are designed for desert racing, each rider is faced with his own development project, usually on a break-it and fix-it • basis . Like a lot of racers in the 250 class. we decided to develop the Elsinore in to a desert bike. because its basic design o ffered light weight. good power, and high-speed handling . Based on personal experience with fo ur Elsinores and advice from ot her riders, we have put together this gu ide for improving reliability, com fort . and pe rformance. We can 't gua rantee yo u 'll become th e terr or of t he 25 0 cl ass. bu t at least yo u can prepare your b ike ' to finish well, race after race. Power train 52 Let's start with th e engi ne. The Elsinore co mes wit h pl en ty of peaky po wer fo r the average Novice, a vuln erable pipe. and a few built-in weaknesses. Our advice is no t to fool with the insides un less yo u can run y o u r b ike WFO all the t ime; what you need instead is a mo to r that provides tractable power. and will last under sustained high-temperature conditions. Start tuni ng with 14 8 or 150 m ain jets an d run the needle in the mid - (of five) position. Go ld pa lladium plugs. such as Champion N· 3G and NGK B9EV. or sta ndard p lugs. such as NGK B9ES or AC 42XL. arc recommended. If the main je t and t iming are set righ t. b ut th e eng ine st ill detonates in the upper mid-ra nge, try o ne o f th e special needles m ade by AI Baker spe cific a lly fo r curi ng this pro b lem . The power co me s on quite suddenly because of the large ports and no fly wheel effect. The addition o f a good muffler (Trapp - $15 or J&R/Krizman - $2 9.9 5) , with no o ther changes. will smooth out the power band with little or no expense to the top end. Weld , repeat wel d , the muffler in place. as no other method works reli ably fo r racing. If the bike is still too peaky for yo ur style of riding the MT altern ato r can be ada p ted to increase the flywheel effect (an d run lights if yo u wan t). o r a special two pound flywheel is available from AI Baker. If the low pipe is retained, it should be protected from rock damage. Bash p lates (abo u t $25) arc available . but a large ro ck ca n still crumple the p ipe and plate. A better method is reinfo rcin g the p ip e itself. Tom Sawyer Honda has developed the design shown [Fig. I J which has wo rked quite well. Weld ing sho uld cost about $30 - $40 . If you usc the rei nfo rced pipe. the extra weight will stretch the springs o n ha rd landings allo wing t he pipe to pop o ff the cylinder. Yo u can prevent this by do ub ling all the spri ngs on t he pipe. us ing t he extra loo ps and a second exhaust flan ge bracket I Fig. 2 ] . For the same reason, the upper rear mu ffl er supp ort will fatigue and crac k unless some rubber doughn uts are added on either side to give it some play. Th is is best done by drilling straigh t t hrough the frame and using a three-eigh t h inch aircraft bolt (available from Earl's in the engi ne de pa rt men t . The rings are st ro ng. but their useful life is only about 10 races. When yo u have to rebor the cylinde r , Honda has four o versi zes, and Wiseco mak es two more bey ond th at. Be sure to relieve the exhaust port brid ge as shown in the Honda man ual; it runs hot an d tends to expan d in to the cy lin der . Keep an eye on all the motor mount bolts. especially the two in th e rear. If they co me loose d uri ng a race . the ho les in the cran kcase will become egg-shaped an d will have to be drilled out and bushed ($ 153 ) b efore t he motor can be bolted so lidl y in place. Countershaft sp ro ckets (especially accesso ry sprockets) have been kno wn to fail at th e splines lon g before the y are wo rn by th e chain , so chec k th em periodically. Hand ling The Elsinore 's lon g wh eel base and exc ellen t geo me try give it fine desert hand lin g right out of the crate . But longevity an d performance can bo th be improved. Th e stock shocks will work well for abo ut 10 races before th e seals and flu id d isappear . Yo u can rebuild the shocks with stock Honda seals, or use the $ 14 kits from Hiiesalu wh ich have stro nger sha fts and American seals . Lo ng travel suspension can be ob taine d in a num ber o f ways , using co m me rc ially-availa ble comp o nen ts. We ha ve fo und th at long-travel (4 . 7") Curnutts, mounted as sh o wn [Fig. 4] will y ield ove r six and o ne -half inches of whe el tr avel without an y modifications to the frame, airbox, o r fender. The set-up will run abo ut $64 fo r cust o m-d esigned sh oc ks and $3 5 for welding. While yo u are welding the swinga rm , rein for ce the flims y st ock chai n guar d. Mo dified swingarms should Figure 1 l/S" thick "scab-plate" l /S" xl " xl " angle iron o n pipe seam Reinfo rcing stock p ipe