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Racebike Secrets Revealed By Paul Wright 2001 There are secrets to building a racebike that only a handful of top racers and tuners know, right? There must be - I hear it all the time. "So-and-so only won because his bike is so fast." And, "if I was on his bike, I could win too!" Maybe. The truth is, most of the supersport bikes in the winners circle are not very far from what you can have for a realistic budget, some time and effort, and knowledge of what to do with your bike. I can't make you put in the time and effort, and believe me, those are the hardest parts of the equation, but I can impart some knowledge of the "secret" information that will allow you to build a great racebike on a limited budget. Now don't give me that "yeah, RIGHT!" crap. Our Team 1-888-FASTLAP supersport bikes win races and championships year after year with a very small budget. And so do other teams and racers without big money sponsors. Money helps, no doubt, but most of the process you can do yourself for a reasonable and realistic sum. Reasonable and realistic does not mean you can get by for a hundred bucks, but you won't have to take out a second mortgage either. For this article, we will use a RC51, but it couild be a GSXR or a R6 - the principles remain the same. The whole point here is to show you what to do, what works, what doesn't, and why. Most of the "secrets" you read about in this article can be used on any bike, not just an RC51. Proper Break-In Some people will tell you that the new generation of bikes doesn't need any break-in time. Wrong. Although the manufacturing that goes into the newer bikes is better and they may not need as much time for all the moving parts to rub off imperfections, they still benefit from some easy time before they see constant use at maximum rpm. Hard to call proper break-in a secret, but I know many racers that don't do it. We ran the RC through several low rpm heat cycles on our dyno, and then took it for a ride in the North Carolina mountains while we were doing a show in Asheville. Scott Long and Charles Huffstetler went with me to help with the show, and they brought along 2 more street bikes - a GSXR1100 and a YZF750. The idea was to get in a street ride in the mountains and put some easy break-in miles on the RC51 after we were done with the show each day. Seven O'clock, the show is done, so we bolted back to the hotel and managed to suit up and pull out of the parking lot about 8pm. First thing I notice is that first gear on the RC is REALLY tall, almost like a TZ250, and the overall gearing makes sixth gear seem about right for Daytona, but nowhere else. Mental note: bring spare gearing to the track. Second thing I notice is there are no mirrors. Hmmm... wonder where they went? Riding a street bike without mirrors is less than desirable. Is there a car speeding up on my rear end? Is it a State Trooper? The next thing I notice is the missing left-hand bar switch, and the turn signals are gone too. I found out later that one of the guys at the store had already started pulling street parts off the RC. Guess I'll use hand signals and look behind me a lot... There was also no tag on the RC, and believe it or not, I don't have a motorcycle driver's license, only race licenses, so I decided to ride behind Scott who has the map on his tank, and in front of Charles. (maybe if I hide between the other bikes cops won't notice me as much??) Dark settles in quickly in the mountains, and we are just flying around tight, narrow mountain roads. I am doing my best to keep the revs down on the RC by keeping my corner speed up so I don't have to flog the throttle on the straights, and the ‘51 was a willing partner. There is abundant torque in the lower rev range, and this bike scoots off tight turns really well at low rpm and just a little throttle. However, Scott's' GSXR11 pulls really hard down every straight, and on one particularly long downhill straight I had to juice it up a bit to catch him…. just as his brake light comes on. Uh-oh, he's on the brakes hard. No biggie - the RC has great brakes, so I grab a handful and uh-oh again - the bike nose dives badly and now the headlight is pointing ten feet in front of the fender. Instead of the turn, all I see is dark with a red GSXR taillight in the middle. I flick on the high beams, or not, cause - you guessed it - the left bar switch isn't there! The Force was with me, my Jedi powers worked, and I got to practice them more times than I wanted that night. Mental note: check the spring preload and compression damping on the forks. We rode a hundred mountain road miles that night, with guardrails, cliffs, and rock walls everywhere, then did another hundred the next night. I used to think racing was pretty dangerous! Mass is Your Enemy OK, break-in is over - lets get to work on the bike. If your bike weighs 400 lbs and makes 100 HP, you have a 1:4 power to weight ratio, or 1 HP for every 4 pounds (excluding rider weight). That means loosing 20 lbs off the bike is the equivalent of gaining 5 extra HP. Besides being faster, your bike will brake better and handle better. If you could ride a faster, better handling, better braking motorcycle, you would cut faster laps assuming you have the talent to do so. Is this a secret? Maybe not, but most racers go for the horsepower first and worry about the weight and handling later. We always attack the evil monster of mass first thing when prepping a bike for the track. We have had several stock RC51's on our dyno, all making around 112-115 rear wheel horsepower. Let's see what this one does on our dyno so we can determine our starting power to weight ratio. A few runs later, we see 112 horses is all she will manage, and the graph looks like the motor is hitting a wall at 9000 rpm. The line on the graph gets erratic at 9000 rpm and that puzzled me. Checking other RC51 runs in the computer I noticed they all have a barrier at about 9000 rpm where it looks as though they run into a soft rev limiter before the 9500rpm redline. That seemed odd, so we did a little experimenting, and found that if you disconnect the electronic speedometer at the wiring connector on the right side of the bike, the graph cleans up at 9000 rpm, and the motor will pull all the way to redline with 2 to 3 more HP all the way up! Peak HP is only one more than it had, but now it holds maximum HP past the 9000 rpm "soft" rev limiter all the way to redline where we find the "real" rev limiter. Totally bizarro, so we did some more checking and found that according to the factory Honda service manual, there are two fuel injection (FI) maps in the electronic control unit (ECU). One is the standard USA spec map, and the second is a default map that is used when the ECU thinks there may a problem with the normally used FI map. Still more checking around and we found that some other RC51 pilots have another way to kill the soft rev limiter but still retain the speedo. A jumper wire from connections B2 to A15 on the ECU kills the soft rev limiter and allows the speedo to continue registering. We never could get this method to do as well on the dyno as just unplugging the speedo sensor wiring, and my theory on that is that with the speedo hooked up, the ECU presumably uses the indicated ground speed as well as the air flow and pressure sensors to adjust the FI mapping, because the faster you go, the better the ram air system should be supplying air to the motor. With the speedo sensor unplugged, that information is not available and the ECU would have to rely on the information provided by the two air sensors to make FI mapping adjustments. On the dyno there is no ram air effect, so the map using the speedo information could be making the mixture too rich at higher RPM because it thinks the bike is going faster and faster when in fact it is sitting still on the dyno. OK, so after figuring out our little speedo sensor problem we are back to that evil monster of mass once again. Carrying some fuel and a steering damper, the stock RC hits 484 pounds on the scale. Not good. Some easy math shows our stock RC has a 1:4.3 power to weight ratio. Still not good. Break out the Sawsall and cutting torch! Remove everything you can that is not essential to racing. Lights, reflectors, turn signals, funny little brackets that only Honda would design. Don't forget to connect the kickstand switch wires together so it will start again. As we remove and replace stuff, we are doing our safety wiring chores along the way and checking everything for any problems. We found one loose bolt on our test bike but everything else was OK. As we began weighing the street stuff, we realized what a great job Honda has done with cutting weight where they can on the ‘51. The whole rear taillight assembly only weighs .55 pounds, and the entire upper fairing assembly with windscreen, headlights, etc only hit 8.5 pounds on our calibrated digital shipping scale. Wow. Trimming weight from the RC is not easy, and it seems the motor and frame were indeed built to withstand 170hp and the rigors of World Superbike racing, as Honda claims. Nothing like tearing apart a brand new bike! How about the battery? Most racers overlook this. The stock battery is a YTX9, like most late model sportbikes have, and it weighs 8.15 pounds. Too fat! Yank it out, drop in a YTX7 and save 3.5 pounds in less than 5 minutes. This is a race bike, and there will be no big demands on the battery for lights and such. We are leaving the charging system intact, and the smaller battery easily starts the stock motor. A little bit of seat foam on one side of the smaller battery keeps it snug in the spot once occupied by the porky "street" battery. That may not seem like much of a secret, but I'll bet you still have the heavy street battery in your race bike - don't you? (check your rulebook to see if replacing the battery is OK for the classes you will race) Next we eyeballed those stock handlebars, and although the clamp part is aluminum, the bar part is steel and has anti-vibration weight inside and screwed to the ends. Off they come, over to the digital scale, and we see 2.60 pounds on the LED readout. A quick run to the parts department to grab a set of 50mm Vortex clip-ons and we see they only weigh 1.50 pounds. This is an easy choice. The Vortex units weigh 1.1 lbs less, are very strong, have replaceable bars, and can be moved around a bit to a more comfortable position. While we are in the handlebar area, we did the clutch hydraulic line and the front and rear brake lines. We use Fastline stainless steel lines because we have seen some of the other brand Kevlar lines fail occasionally, and the small weight savings for Kevlar over stainless lines is not worth that nightmare. The Fastline woven stainless is covered with a slick glossy black and ultra tough coating that eliminates any rubbing problems either on your bike or the lines themselves. They look cool, they cure any sponginess you had when the fluid and stock rubber lines get hot, and they saved .3 pounds over stock. Another secret - use only a high temperature DOT 4 brake fluid like Motul or EBC. Never use DOT 5 silicone based fluid. The silicone fluids do not have the same lubricating properties as DOT 4 fluids and can cause premature seal failure in your master cylinder. While working on the brakes, we put in the killer EBC HH kit pads, which are simply the best, they pay contingency money, and actually weigh slightly less than the stock pads. Although the RC51 takes the same pads as the F4, the RC weighs more, and EBC is working on a new version of this pad specifically for the RC51. I am going to share another secret with you here. Most brake calipers are not in perfect alignment with the rotors due to manufacturing tolerances when machining, drilling, and tapping the various surfaces and holes used by the rotors and calipers. This can cause brake drag, and sometimes it can really be quite bad. This RC51 is one of the best bikes I have come across for proper rotor/caliper alignment, but we still had to shim the left front caliper .020 inch between the fork leg and the caliper on the lower mount bolt to get the front wheel to spin freely. The right front and rear calipers took no shims or filing to get them aligned. Again, this bike was good from the factory, but I have seen others that were actually hard to push around because the brakes were dragging so badly. Dragging brakes eat up horsepower and adversely affect handling, so pay attention to this area when building your race bike. To check this out, put your bike up on your front stand (you do have a front stand right?) and try spinning the front wheel with your hand. It's normal to have a little drag, but if it rotates less than two full turns, you have a problem that can add seconds to your lap times. Also be sure your pads are not warped - take them out, hold them back to back and try to rock them against each other. If they rock at all, they are warped and will cause brake drag. Back to the parts department for more stuff. Time for a set of race bodywork. If you have never bought race bodywork before, let me just reveal another secret right now- buy Cheetah or something equivalent, like Sharkskinz perhaps. The regular fiberglass resin-based bodies are too heavy and crack way too easily. Cheetah uses an different epoxy type of resin that that allows the bodywork to be thin and light but very crash worthy. You can actually bend a piece of Cheetah (or Sharkskinz) bodywork way past the point where you know other bodywork cracks and not even get any small spider web fractures. We could save several more pounds by using the carbon fiber stuff, but remember we are on a tight budget. After removing and weighing unnecessary brackets and all the old bodywork along with the lights, the scale says we saved another 10.65 pounds with the bodywork, plus we can sell the stock bodywork for way more than we paid for the race stuff, and offset some of our expenses. You just can't beat what you get - crash worthy bodywork that saves weight and can take a beating, and money in your pocket when you sell the stock stuff. Now I know some of you are saying "I need to keep my stock body so I can put it back on my bike and sell it as a streetbike to some unsuspecting buyer." Well, I say worry about that later, because it will probably never make it back to street trim again anyway What's next? Well I happen to know that Michelin Pilots weigh less than Dunlops 207's, which is what this RC51 came with, and besides being great race tires, the Michelin Bib Buck contingency program rules. Off with the Dunlop 207 streets, grab a set of 207GP's and a set of Pilots from the parts dept, carry everything over to the scale, and we see the street 207 Dunlops that came off the bike weigh 21.6 pounds, and the Dunlop 207GP's right off tire rack weigh 22.75 pounds! Go figure. The Michelins weigh in at 20.6 pounds, so using the kick-ass Pilots saves 2.15 pounds of rotating mass over the 207GP's. While we are getting rid of unsprung and rotating weight with the tires, lets walk back up to the parts department for a 520 chain and sprocket set. The only 520 chains we use on race bikes are the EK premium MVX and RXO "X" ring chains. They have drilled side plates to make them light, and the X rings have very little drag, but the real trick is the alloy they use to make these chains. Whatever alloy it is, it hits 100% on the manly chart. The published tensile strength for the EK RXO 520 is 8800 foot pounds! That's more than most bigger and heavier 530 chains. Besides weighing less, the EK has less rolling resistance than the stock chain. We used a set of lightweight aluminum Vortex sprockets to match our EK 520 chain, and these are of course lighter than the stock sprockets, but they are also machined, not stamped, and so have much stricter tolerances than many other aftermarket sprockets. Vortex makes a great product, and they have a contingency program too. The front sprockets are made from heat treated chrome-moly steel. Vortex rears are made from billet 7075 aluminum and then heat treated to T-6 specification. The EK RXO chain weighed .9 lbs. less than the stock chain, and the Vortex sprockets weighed 1.1 lbs less. Total weight savings on the chain and sprockets: 2 pounds. Dyno Time OK, it's about time for a Dyno run. Our main goal so far was to lose those ugly unwanted pounds, and we have not only saved weight but also rotating mass, and lessened the amount brake drag. This means less horsepower is used simply to turn the wheels. A quick run shows we are up 2.3 peak horsepower from stock, and as much as 5 hp in the mid-range, just by carefully choosing our tires, chain, and sprockets, and unplugging the speedometer sensor. While on the dyno, I am going to let you in on another secret - oxygenated race fuel, like VP MR-1. Don't even think you're going to tell me it's too expensive, because I am going to show you right now that it is not the budget breaker you think it is. First, let's drain the tank and pour in the VP. No other changes, just start ‘er up and make another dyno run. Bingo, we instantly have 1 to 2 hp all the way up and 2.9 extra for the last 1500 rpm before redline. OK, we know it works, but it is too expensive - or is it? VP MR-1 costs about $15 per gallon, and you don't have to run it all the time, just for the races when you need some boost. Budget-minded racers can run pump gas or regular race fuel during the first practice sessions, concentrating on turn entry and exit, corner speed, and braking points. Then pour in the oxygenated VP for the last practice before the races start. The difference is quite remarkable, and you need that last practice to get used to the extra horsepower and changed shift points around the track. This works at tracks you have been to before and already know well, including what gearing you need, but at tracks new to you, run VP consistently to get the gearing, shift points, etc, dialed in. Now let's go back to the budget part of the equation. If you already buy race fuel for around $4 per gallon, the difference using VP MR-1 is about $11 per gallon. To make the math easy, lets say you use 2 gallons for a typical sprint race, and you run 2 sprint races for 10 race weekends, or 20 sprint races during the season. Calculate in some practice sessions and that works out to about 60 gallons at $11 more than you already spend for race fuel, or $660 extra in the budget for the entire season! That's about the same as two sets of tires, and I will gladly pay $660 over the season for an extra 3 HP during my races all year long, won't you? That's cheap horsepower, my friend. One more secret while we are working on the dyno - change your oil and filter, and when you do, use the new EMGO Hi-Flow filter and a superior lightweight synthetic oil like Redline 20 wt race oil. We did a lot of testing for EMGO as they developed this new technology filter, and we have seen it produce 2.4 extra peak rear wheel horsepower on a GSXR600 and at least 1.4hp on every bike we tested. The right oil can add another 1 to 2 HP. Amazingly, the high-flow EMGO filter uses a new filtering material that filters better (10 micron particle size) than the standard filter while allowing less flow restriction. Less flow restriction means the oil pump turns easier, robbing less horsepower from the motor. We use Redline 20 wt. synthetic oil because it is not too thin to cause problems, but it still makes extra hp , and it is made from the best base stocks available (most synthetics are made from less expensive base stocks a grade below what Redline uses). We have seen Redline oil save many motors that were terribly overheated in a race due to various problems. Later when you tear it down to inspect the damage, you don't find the typical metal galling and smearing you were expecting! Good stuff. And it's no secret that a top shelf synthetic oil is better than the low dollar car oil from K-mart. With the oil and filter change, the dyno tells the story: another 2.6 hp - just by changing the oil and filter. OK, back to the Parts Dept for a cost saving stainless steel slip-on system. Ther are brands out there like GPR and M4 that are high quality, make good power, and don't cost two arms and three legs. We will try a full system later, but in the interest of racing on a budget, lets see what we get with the slip-on. We used a carbon can model since that is what our parts dept. happened to have on the shelf at that moment, but the aluminum and stainless cans are barely heavier and cost about $100 less! Horsepower output will be the same for all versions. The dual can slip-ons fit perfectly, went on quickly, and look 10 times better than the stock units. And the sound - everybody comments on how good the RC51 sounds with the new slip-ons. Deep and authoritative, but not too loud. Or just call it like one guy that walked up while it was running on the dyno: "that's total bad-ass!" I agree, and so does the dyno, showing a solid 3.2 hp gain from a slip-on system with no re-mapping of the fuel injection system. Did I mention the exhaust change saved 10.4 pounds over the clunky stock cans? That's worth the cost all by itself!  What about re-mapping the fuel injection? Well, as luck would have it, our wonderful parts dept had a Dynojet Power Commander II for the '51, so we plugged it into the wiring harness and went through some more dyno runs to dial in the low, mid, and high RPM mapping. It wasn't long before we had the RC pushing another 2.0 horsepower with the Power Commander in place. There are lots of maps available for download via a laptop, and we are quite sure we can find one that will work better than just making a few changes to the settings that come on the PCII, but we will worry with that later when time permits. Time for another secret, specifically for the RC51. One look at the rear head pipe and you will say, "Hmmm, that's really close to the shock." And you would be right - it snakes by less than an inch from the shock, and you know that much heat that close to the shock is going to create a damping problem in a long race. We used our trick infra red digital temperature gun to measure the temperature of the shock after several track practice sessions, and it always read about 225 -235degrees (Fahrenheit). That can't be good! It was so hot from hard use and the header pipe heat that you could not even touch it more than a split second. There is no room to route the header anywhere else, so we used some woven header wrap and covered the section of the pipe that routes next to the shock. After the next session on the track we checked the shock temp, and we were pleased to see the temp had dropped to 176 degrees - about 50 degrees less than it was before using the header wrap! Math Lesson Review We made some fast, easy, and cheap changes that resulted in significant weight savings, reduced rotating mass, less unsprung weight, and a net horsepower gain at the rear wheel. Vortex clip-ons and sprockets, EK RXO chain, Sharkskinz bodywork, Michelin tires, Redline 20 weight synthetic, EMGO High-Flow filter, slip-ons and a Power Commander got us from 484 pounds to 429 pounds and from 112hp to almost 125hp. To look at it another way, our power to weight ratio went from a portly 1:4.3 to a respectable 1:3.4, and most of these changes will work on any bike, not just the '51. Maybe not worthy of a TV segment on Good Morning America, but not at all bad. And we did nothing here that you cannot do at home in your garage, with the exception of checking your HP gains on a dyno. There is always more that can be done, but at some point we have to get out on the track. You can thank me later for all this "secret" information. Next the RC51 project goes racing and I will reveal lots more information that will show you step by step how to get a bike to handle properly on the track, and how your lap times will drop dramatically as you get your bike chassis and suspension dialed in properly. You just have to know the secrets. |
