Cycle News - Archive Issues - 1980's

; Cl Z ~ >- 0:Il: ~ >- '" III o b :I: a.. lo-o Cl) ..c S Cl) ;> o Z The Project XR 600 is shown here before the installation of the Lockhart oil cooler. with a SuperTrapp exhaust silencer. Honda XR500 Proj ect By Larry Langley Let's get something straight right away. This is not a fantasy project bike article. You know, the ones that have seemingly unlimited mega-bucks behind them, projects out of reach for you and me. Therefore the decision was made to utilize the stock frame and not tear into the engine, two items 38 that really drive the cost sky-high in a project bike. Modifications undertaken were such that the average owner could make them himself or have them done at a reasonable price. My goals included identifying and correcting any weak points, personalizing the XR500 to my individual tastes, improving the suspension, improving the power (without highcost internal mods), improving engine reliablity and reducing weight. Obviously some of the above goals overlap. But after riding the bike a few times I was able to identify a few things that I definitely wanted to change: The very first item to be replaced was the stock skid plate. I ride in the desert a lot since I layout enduros. Enduro-type terrain demands a sturdy protector to keep those very expensive magnesium side cases intact. Unfortunately the stock plate is a very thin, stamped steel unit that I realJy didn't have much confidence in. After researching what was available, I ordered a Malcolm Smith Products skidplate from Countdown Engineering (part number 68-917, $44.95). The MS skidplate is made from sturdy aluminum and is very solid. Mounting was easy and only took a few minutes. The MS unit mounts a little differently from stock, being held on by four clamps. The MS plate offers much more protection for the side cases than the stock plate - proved in subsequent desert testing - with a very slight penalty in added weight. Taking the advice of a Honda mechanic, I drilled some holes in the plate for air flow to the right side case. I was warned that the big thumper ran hot and this was a small effort to try and keep it as cool as possible. The MS Skid Plate comes coated in blue to match the blue trim on the Honda: Rating - 10.0. The next thing that had to go was the stock, vinyl tool bag. The stock bag lasted one ride before the zipper broke. Another product from Malcolm Smith Gold Medal Products made its way onto the bike, a leather tool bag (part number 03-415, retail $32.95). Mounting was easy using the stock plastic insert and stock bolts. Three twist locks provide access into the bag which has room for tools and a can of pressurized flat tire repair. The MS tool bag even had the elastic strap sewn inside (just like the stock bag) to hold the multi-purpose wrench. The sturdy bag has held up welJ and the only complaint is that it is somewliat tall. It's most noticeable wearing a fariny pack - occasionally I'll bump into it. It's also colored blue to match the color of the stock bag. Rating - 9.0. The stock IRC tires were junk, providing little traction on hardpacked terrain, skating around roo much. I waited until the rear one was worn out before replacing it but I just couldn't wait for the front one to wear. I replaced it with a Dunlop 3.00 - 21 KI39 that worked very well in most instances. However, in my experience, with the quick steering of the Honda, a 3.25 - 21 Metzeler works even Jxouer in the desert. The only drawllack of the Meueler is the larger diameter which causes the odometer to lose 0.1 mile every three miles. Whether this is a handicap or not depends on the odometer used at an enduro (if the bike is used to compete in enduros). A Metzeler also wears better than the Dunlop but is more expensive and harder to find. The rear tire was replaced with a 5.30 - 17 Cheng Shin C755 Metzeler copy. Admittedly the Cheng Shin is not quite the equal of some of the premium tires but I went with it for economy's sake. It costs considerably less than the premium tires such as the Dunlop' K499 at a slight cost in performance. This was important to me since the rear tires wear much faster than fronts. The Cheng Shin provides average-to-good traction and has a good wear factor. Heavy Duty Cheng Shin red tubes were used front and rear with good results. Ratings: Dunlop 3.00 - 21 K1399.0; Metzeler 3.25 - 21 - 9.5; Cheng Shin 5.30 - 17 C755 Meueler copy 8.0; Cheng Shin tubes, 5.00 - 17 and 3.00/3.25 - 21 - 9.0. I have never owned a dirt bike with disc brakes before, and after many, many miles, I do not think I could ever own one without a disc. The Honda unit is absolutely the finest brake available. But using a hydraulic brake system has it vulnerabilities - the first being the master cylinder.. A crash or even dropping the bike could be a very expensive repair Honda master cyclinders retail for around$IOO. So for insurance I bolted on a Ihterrtational Motosports brake cylinder guard (part number BR-I, retail $12.95). InstalJanon was easy and the guard has already proven itself in a couple of tip-overs right onto the cylinder. The guard is available in black or chrome. Rating 10.0.. I had heard of problems with the stock plug cap needing a fix to avoid high-rpm miss. One cure is to take the resistor out of the plug cap and replace it with a piece'of welding rod or copper wire. This seemed like a sort of a Mickey Mouse fix to me to I replaced the plug cap with one from International Motosports (part number HT-I, $3.95). I have used their plug caps in the past with excellent results. The cap went right on and has a clamp to make sure it stays on. Rating - 10.0 A big weak point surfaced when the right footpeg broke while riding through some deep gully-whompers in the desert. Asking around, 1 found that this was a common occurance on the XRs. The footpeg itself didn't break - the mounting tab broke off from the frame when the bolt broke. Rather than replace the whole frame, I opted to have the tab welded back on. I took the bike to The Frame Factory in Stanton, CA, where they heliarc welded the tab back on with a much beefier weld. The bolt holes were then re-tapped and new, stronger bolts were used rather than the stock bolts. If you own an XR, I highly recommend that you replace the stock bolts before you ride the bike again. If the bolts break, I can tell you what happens: Your right foot plays tag with the ground very suddenly and you crash, instantly and with great pain. Another International Motorsports item installed on the bike was a folding shift lever. While the stock unit is also a folder, it is bulkier than the IMS lever and again, I have used their levers for years on my previous bikes and have never broken one (part number HO-9, $18.95). Rating 10.0. The next step was to install a Super Trapp 4-in. pipe. I hoped to pick up a little performance and lose a little weight. Also the Super Trapp sounded better; Maybe a little louder, but not by much. I got mine from Countdown Engineering. Installation was easy but the pipe was designed to fit over the stock headpipe without the gasket at the junction. The instructions weren't clear on this. Once the gasket was removed, the pipe slid right on and a hose clamp (supplied) secured the Super Trapp to the head pipe. It's okay but if Super Trapp would have swedged their pipe, it could have bolted right Onto the stock header pipe, gasket and all, and use the stock clamp - which is superior to the supplied hose clamp. As it is, the Super Trapp has not come loose but does leak slightly, a fault the stock set-up does not have due to the better sealing with the gasket. Without a dyno, it's hard to say if the Super Trapp makes more power than stock. Throttle response does seem crisper and 1 like the tone of the exhaust better. It eliminated the harsh bark of the stock system. A few pounds were saved over stock which is a bonus. The Super Trapp is also Forest Service-approved spark arrestor, . mandatory if you are going to use the bike for rides in our ational Forests. Rating - 9.0 (Utilizing the stock mounts would have bumped it to 9.5). The stock handlebars were okay but bem rather easily. They were replaced by a pair of Answer Products Chrome-moly RC Type III Honda bar. I cut one inch oU each end for the width 1 prefer - I don't like a real wide bar. The extra distance that wide bar ends travel in their steering arc add to shoulder fatigue during a -long ride or race. Shorter bars provide more than enough leverage and actually quicken the steering slightly. Rating - 10.0. The stock grips are just fine. In fact many riders prefer Honda grips but they probably get them free. At $8.00 a pair, they are somewhat expensive. When they need to be replaced, I will replace them with a pair of aftermarket grips at a much more reasonable price.. As I mentioned before the Honda runs hot, so a good oil is crucial. I have had good luck with Castrol so I change oil often and use Castrol 20W-50 Heavy Duty Racing. 1 buy mine on sale at the automotive discount stores, usually for around $1.00 per quart. At $2.00 an oil change, i1's cheap insurance. Honda recommends 20W-50 in hot weather; the use of other weights may void the warranty - the Honda comes with an unlimited mileage 6 month warranty, unheard of in dirt bike warranties. Only time and a lot of miles will determine how the Castrol works in this motor so I will leave it unranked for now. Suspension! After riding the bike with the stock suspension for awhile, I found that the front forks were less than adequate. Can we be honest here? They sucked. Too much compression damping (even after changing the fork oil) was·the main culprit. Hitting sharp-edged terrain would send a harsh jolt throuRh the bars. Very uncomfortable. The forks worked better in more rolling terrain. A fork kit was an option, but I didn't want more travel, since the bike was on the verge of being too tall in slock form. Besides, I believe 11 inches of good travel is more than adequate. The rear shock seemed vague at times. I didn't have a real feel on what improve.ment it needed. I did know the stock spring was inadequate - it bonomed with spine-jarring regularity. (Langley weighs 240 lbs. ... Editor.) Obviously some work was neede.d to the suspension to improve the handling and to eliminate by backaches. There were a number of suspension specialists I could call on to make a big improvement on the big thumper. While talking to John Bailey at International Motorsports, he mentioned that they have been doing some heavy development work with Gator Products, one of their suppliers, on the XR suspension. In fact Ron Gibson of Gator Products has been racing a XR500 in the Expert class in motocross and doing extremely well against the twostrokes. Gator Products is located in the high desert just outside the small town of Phelan. Open desert near the shop allows instant testing after installation, a big plus while trying to develop products or dial-in suspension.

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