Spark plug cleaning, save ole sparky for another day

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Hard core racers change spark plugs before every race to insure that they don’t have a DNF from a simple inexpensive part.  But for the rest of us that cannot afford to throw a plug away after every ride or race.  Especially because some of our machines require those iridium style plugs that can be up to $14 each!  Here is a nifty tool that can make worn or carbon fouled plugs new again, or at least new enough to be a spare back up plug to carry in case of emergencies.  The tool runs off of air with some abrasive that “blasts” the plug to remove deposits to allow the fouled plug to fire again.  It only takes a few blasts of air to clean a typical carbon or oil fouled plug, so you could do this with a portable air tank.  This makes it possible to bring it (with air tank) with you in your tool box.  Now obviously this will not fix plugs that failed because of cracked insulators, eroded electrodes, or other physical damage.  Best part about this tool is it can be had for under $10, well worth the price to extend the life of a plug that has electrodes that are in good shape but just is fouled to the point that electricity will not jump the gap.

Quick tip, installing hand grips

If your like me and you go through hand grips almost once a season, installing grips is one of those jobs that is so easy, yet sometimes frustrating that you dread doing it. You know the drill. You get all ready to install them and fight them on the bars, and then after all your muscling, you come to find out that after one ride they just spin allowing your hands to slip of the bars. Well in this article I will outline some good practices that will ease the installation and increase safety.

First remove the old grips and ALL the old glue or what ever adhesive was left behind. A little trick to removing old grips is to score with a razor knife a few times down the length of the grip. Then just peel it off the bars. A 50/50% mix of rubbing alcohol and water will make quick work of the left over adhesive. This same procedure can be used on the throttle side as well regardless of the type of throttle your using (twist or thumb), although I recommend removing the twist throttle housing to prevent breaking the housing.

Installing can be aided with use of some heat from a heat gun, a hair dryer I have found ineffective as it fails to get hot enough. Just be careful to not to overheat the grips, just enough to soften them a little. Likewise I recommend installing on a twist throttle housing with it removed.

Adhesive choices: lots of debates can be had on this subject, I personally follow the recommendations of the grip manufacture that I am using. For example, Pro-Grip brand grips, use Pro-Grip brand glue, Renthal grips, Renthal glue, and so on. Now some see this as a marketing ploy, and its possible, but in my experiences different grips are made of different compounds and various percentages of natural and synthetic rubbers, thus different glues react differently. My theory is Pro-Grip branded a formulation that best adheres to THEIR grips, likewise with Renthal ect… I have also heard people using spray paint as a grip glue. I have had mixed experiences with the spray paint method so I don’t recommend using it as the only means of affixing the grips to the bars.

Safety wire: regardless the method you use to secure your new grips I suggest using safety wire as an added protection of grips breaking loose, slipping or turning. You can use a light gauge mechanics wire or places do sell wire labeled as “safety wire”, ether way I highly recommend getting a pair of dedicated safety wire pliers as it makes the whole job easier of wrapping and twisting then cutting the wire.

Use these tips and your grip will not only be better but safer.

Looking back, my 1973 Kawasaki F11

For most of us the winter weather interrupts our riding adventures and forces us to burrow ourselves into our garages and ultimately onto our computers. It also allows us to have more time to think about past events, rides, and even machines. I spoke briefly about this in an earlier post http://www.atvmagblog.com/2008/12/02/reflections-of-machines-gone-past/ As I was writing I thought to myself, everyone has some stories about their machines, past and present. Well this is my story about one of those bikes in the collection.

The bike I chose for this blast from the past for this week is the 1973 Kawasaki F11 (250cc).  First off just a little bit of history on the bike when it was new.  The bike itself was not really a revolution in motorcycling.  Loosely based on the frame and engine of the KX250 works bikes released the same year, the F11 was the “enduro” or dual purpose version of the KX.  For those too young or ignorant to read up on the evolution of offroad motorcycling, motorcycles in general sold in the US had to have some street legal prowess to even be considered by most potential buyers, partially because of the oil embargo of the 70’s.  At the time public perception was that if the bike was “offroad only” it was not a good value because you had to have a means of transportation to the track or trail, at a time when pickups were strictly for work or utility and the sport ute was 20 years away.  The F11 was a bargain with a MSRP of $495 compared to say a (superior) European offroad only race bike had MSRP’s of $1,000 or more and were not street legal.  This was also at a time when the term big bore machine meant 250 and 350cc machines.  Designed to compete head to head with Yamahas DT1 it fared well with the “green streak” modifications (similar to Yamaha’s GYT-kits, pronounced “git-kit”).  The F11 was a departure from Kawasaki’s traditional rotary valve 2 strokes being a more typical piston port machine.  The F11 only had a production run of 2 years before it was dropped and the KX250 was the only bike that filled the 250cc single cylinder spot.

Ok with a little background on the bike out of the way here is my experience with the bike.  I didn’t acquire the bike new of course, and I was not necessarily looking for that particular bike, lets just say it found me.  Back in the 90’s my family always took vacations around the country, with regular trips back and forth to Denver from our home in south central Nebraska.  One trip back from a vacation we stopped by an old Kawasaki dealership in a town of about 7,000 total population, (McCook,NE).  From time to time we would stop in to “shop” their back lot and storage room, well this time they had acquired a 1969 H1 500cc triple (street bikes we collect) and as we dickered on the price of the for the 500, the dealer asked “Is there anything else you want back here?”  I had spy-ed the F11 sitting way in the back under a good layer of dirt. ”I said what do you want for that?”  The dealer replied, “Well I will just give you that since your already buying the 500, anything else you see that you would like to take off my hands?”  We also came home with a DT175 that had been hit by a car, but that’s another story.  We paid for the 500 and a day later I made a trip back to the dealer for the 3 bikes. 

After getting it home and doing some preliminary cleaning and adjustments, I proceeded to try to fire the bike.  Everything was in spec, carburetor, ignition points set correctly and in time, but it just would not fire and run.  Upon a compression test revealed very low compression, I kinda suspected it in the beginning but I have made bikes in worse shape run and run well, so I didn’t think a whole lot about it. A tear down for a top end was in store.  Now I found out why the dealer gave it away with the other bike, the piston had a small piece missing on the crown near the edge of the ring land.  Ok not a big deal, I have done top ends before, no biggie.  Sourcing the parts was the real challenge and probably the reason the original owner abandoned it at the dealer years ago.  The piston, rings, and wrist pin were obsolete from the OEM and Wiesco.  In the days before Ebay and the Internet, my only shot was either find a bone yard bike/engine that was in better shape that I could rob the parts out of (not my first choice) or find some NOS (new old stock) parts.  Through many phone calls to dealers spanning the country, I got a tip of a guy that buys up dealers parts inventories when they go out of business.  I thought SCORE!  Well this was a mixed blessing as the guy only has the parts cataloged by part number on micro-fiche.  So without an OEM part number he could not tell me if he had the part(s) or not.  With some digging on some old micro-fiche parts diagrams I got my numbers, and sure enough he had all the parts I needed NOS.  Fast forward a month or two later I had basically a “new” 1973 F11M. 

Many good memories were had on that bike.  I hate to fathom how many hours I put on that machine.  At the time it was all I had for a motocross bike, even though it was not a true mx bike.  The thing was heavy hovering around the 300 pound mark, and suspension was sub-par even for its day, 4 inches in the front and about 3.5 in the rear with little to no damping to control the springs.  I felt I handled the bike well considering its drawbacks and ultimately I believe made me a better rider for the future when I would update my equipment.  I am a firm believer that ANY rider should cut their teeth on a vintage or lower performing bike for a while before they go head first in to one of these cutting edge machines.  Below is a link of me and my friends riding these bikes back in the day.

http://www.youtube.com/watch?v=d9O1pdW1o4g

Going into hibernation, long term storage of your ATV

For most of us living in the continental US the riding season is coming to an end or at least becoming abbreviated with the changing weather. This brings up a common occurrence. What to do about storage and how to go about it? Its unfortunate that most of the offroading public just shut the fuel tap off and push it into the garage/shed and start piling the holiday decorations on to of their machine to only then try firing it up in the spring finding that (A) it doesn’t even turn over (B) turns over but does not start or (C) turns over starts but runs for only a few seconds or very poorly. Not to mention other things like flat tires, mice eating the wiring or seat and other upholstery and even broken parts that never got fixed last season. This article will try to go through a few basics for some long term storage for both those that have to store their machines for 6 months and the ones that can ride sporadically throughout the “off” season.

First we should define what long term storage is. One thing to note is the phrase “long term” can be subjective as some may consider it to be 3 months or more while others consider it to be 1 month. I am of the latter, I believe if your machine will sit more than 1 month at a time at least some precautionary steps should be taken so the machine will (A) fire the first time (B) run well and in at least an acceptable state of tune and (C) be just as reliable as if you were riding it at least once a week.

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Cosmetic surgery, give your machine a facelift

If you ride a Yamaha with blue plastic or a Honda with red, you know that your machine can start looking old before its time. Crashes, tree limbs, and just normal wear and tear can cause that plastic. All colors of plastics are susceptible to damage and those white spots from flexing, for some reason Yamaha’s blue plastic is the worst when it comes to this. No matter what brand and color you ride, read on for a quick and easy tip to restore your plastic to near new appearance. I actually picked this tip up from some of my fellow motorcyclists and I thought I would pass it on.

Removing flex marks (those white marks)

Tools needed: cleaner, heat gun (adjustable works best)

Clean the plastics, take the heat gun and slowly heat it from the back side. Slowly heat until the plastic is changing the color. Let it cool and you´re done. In some cases you need to treat both sides. Test the procedure on some old parts first to get a feeling for the right temperature.

How to remove scratches.

Tools needed: Sand paper (#100 - # 1000), cleaner, heat gun (adjustable works best)

Wet sand the plastics starting with the more aggressive grain first (choose the grit to match the depth of the scratches) Now finish with #1000 sand paper. Clean the plastics. Slowly heat (with the heat gun) until you see the plastic changing the color sort of like starting to melt. Let it cool down and you´re done. Always test the procedure on some old parts first to get a feeling for the right temperature to avoid inadvertently ruining your plastics.

After using these techniques it might still need a bit of “brightening” if the color has faded over time from the UV rays of the sun. A product that I have had pretty good success with is Plastic-renew. It comes as a kit, just follow the directions to bring back some of the shine and color.

Another option that can bring back to life the cosmetics of your machine would be a fresh set of graphics, preferably aftermarket as the stock graphics are pretty thin. Really who wants to keep their machine stock anyways? There are numerous places to purchase “kits” as well as companies like Decal Works can work up some nice custom graphics with your logo or design. The benefit of any graphic kit (other than a little personalization) is that most kits use every square inch of usable plastic to put a graphic on, thus covering imperfections and protection from future damage and fading.

Common questions answered … well sort of

We get frequently asked questions (FAQs) all the time, just like all those performance shops and manufacturers. I’ve tried to compile a few of these to let you know our thoughts or answers. These FAQs are in no particular order, I just wrote them down as they came to mind.

Which model is your favorite?

Surprisingly, there is no straight answer. We feel it varies from person to person and depends on what type of riding they want to do, where they ride, how they ride, experience level and budget. And fortunately we don’t necessarily need to buy ATVs as we partner with the manufacturers to test their products. Yes, we try to ride every model and form an overall opinion, but even then it’s hard for us to select one model. Certain models from each maker we think have proven (or will prove) themselves are: the Raptor 700R for its versatility; the 250X and its SportClutch feature for the entry-level rider; the Renegade 800R X for its look, 4×4 and exhilarating acceleration and speed; Suzuki Z400 for its reliability and fun factor; the KTMs for their racy look and performance skills, the Arctic Cat Mud Pro 700 for its warranty and bogger makeup; Kawi’s KFX700 for its unique configuration and sound; the Polaris Outlaw 525 IRS for its comfort and ground clearance or the RZR S for sporty UTV enjoyment. Even then, each editor and freelancer (based on their size, experience and handling desires) may have their own favorite for a specific track, riding area, environment, etc. That’s why we do shootouts and comparisons and factor in everyone’s thoughts.

How do I get your job?

The first thing you need to do is stay in school. A journalism or writing major and experience at either a magazine or a newspaper are strong positives. Act and dress professional (even if you’re a kid at heart) and have a love for ATVs and off-road powersports. Other skills that are important include, photography, public speaking, Internet knowledge, public relations, marketing and a team attitude.

You have the best job in the world, right?

Most would think so, but it’s not all about riding and racing quads. We spend lots of time writing stories, proofing stories, working on design and layouts, planning, sitting in meetings, taking the advice of our bosses, traveling and being away from home and families, working on weekends and some holidays and much more. I will say the job seems really sweet when we spend more time riding, wrenching and attending racing events than it does sitting in our office on a warm sunny day!

Do you have a favorite trail or riding area?

Again, this will vary by editor and by what machine they can ride. However, we’ve been several places over the years and have a few favorites. Glamis in Southern California will always be a special place for us. Why? There’s nothing like sand riding (We don’t have a sand area in Minnesota). The Oregon Dunes are special, too. Brushy Mountain Motor Sports Park in North Carolina is a fun place to ride, too. We also, enjoy the Hatfield-McCoy trails, the Hungry Valley ORV area in California, Millville, Minnesota’s, Spring Creek motocross park, Ashtabula, Ohio’s, dirt track, the Ironman and Big Buck GNCC courses to name only a few.

Best place you’ve ever ridden?

Well, this depends on the editor. However, riding outside of Missoula, Montana, was very fun and the scenery was amazing. I’ve also ridden dirt bikes in South Africa. Although that was fun, I still wish I had an ATV during that trip. We don’t get to travel aboard too often, so most of our experiences have been in the States. However, freelancer Bill “WBGO” Lanphier has ridden in Europe many times and has always enjoyed himself. A few other times, some editor’s have hit the trails in Austria and Canada, and did testing in Japan and Taiwan. We’re still waiting for South America or Australia. We’d even “make do” with a trip to Iceland or Greenland or maybe even China.

How do you decide what to test?

We assume the person means both parts and ATVs. For parts, we test things we think our readers would want for their ATVs, including hot new parts from the INDY dealer show, or new parts for new machines. We also partner with performance shops to build project quads and test their parts. You should check out the 2009 Buyer’s Guide issue to see our test with Sonic Offroad (on newsstands Dec. 16)

For quads, it comes down to new models of course. But popular models and machines we think deserve more attention also get space in the magazine. That could be a race quad, an updated model or an aging unit we know many people own.

Are your shootout winners determined by advertising?

(Laughing) Not a chance. Give us some credit, please! This is the biggest myth in the industry. The manufacturers and readers would see right through us if we stooped so low. Our shootout winners are based on compiling our test riders’ evaluation forms/notes and opinions as well as radar numbers and other facts and figures.

Which pipe should I put on my (insert model here)?

That depends on lots of things, really. Where you ride is one factor. Decibel levels restrictions are important to us and should be for everyone. Price is always a factor (or your budget). Trust of the pipe maker is another key point. Reliability, customer service, proved performance gains all factor in, too. Plus, in the end, it’s your money and quad, so it really comes down to YOUR choice, NOT ours. But thanks for asking.

I own a (insert model here) and it’s running terrible, what’s wrong?

It could be several different things. Jetting, valve clearances, dirty air filter, electrical, EFI mapping, the driveline and so on. The most important thing for any person trying to diagnose a problem is to know every possible thing about the ATV. Plus, they need to see it, smell it, ride it and tear into it. Sure, with the right info, an educated guess can be made, but it’s still only a guess. We try to assist readers by sharing our experiences and working with professionals and companies who make the parts and can diagnose familiar problems. We also have a tech answer man (Toby Reed of Moto-Xperts.com) who attempts to answer all your questions, but even a certified and trained technician like him finds it difficult to diagnose from only words. Regardless, keep your tech questions coming because we enjoy them, as does Toby. Send all your tech questions to e-mail:wrenchthis@affinitygroup.com.

Will you sponsor me?

Magazines don’t really sponsor readers, but we do give out stickers and issues. We’ve worked with a few local racers and test riders in exchange for their assistance with product testing and machine evaluations, but we don’t consider it a sponsorship. E-mail us at atvimages and put in your request. We’ll see what we can do.

How can I get my photo in the magazine?

We know have three different areas where your photo(s) COULD run. I say “could” because printing or running them on our Web site depends on their size, quality and the rider. We can post them on this blog, at atvsport.com (in the image gallery) or in our Inbox section of ATV Sport. The No. 1 rule is you should be wearing a helmet (and try to wear boots/long sleeves and other gear, too). Size matters (don’t send in a thumbnail image). Make it clear (try to send in an image that’s in focus). Hot women in the picture help (JUST KIDDING!). Send your images to atvimages@affinitygroup.com or the old-school way, at:

Affinity Powersports Media

ATTN: ATV Sport,

6420 Sycamore Lane, Suite 100

Maple Grove, MN 55369

Who is the best ATV racer ever?

Wow, this one is always tough. Like any sport, it’s hard to compare modern ATV riders with those of the past. Why? The machines are better, the sponsorship is better, the race courses have changed and the number of champions in various circuits all makes it hard to choose. Eight-time GNC champ Gary Denton is arguably the best. Of course nine-time GNCC champion Bill Ballance should be a candidate, as his run is truly amazing. Don’t forget Barry Hawk Jr., too, who won eight straight GNCC ATV titles before switching to bikes. We have to look at the early GNCC pioneers like Tom Tokay, Chuck Delullo and Bob Sloan as they were awesome in a different era. So were some of the other early ATV MX’ers and dirt trackers like Jimmy White, Marty Hart and Dean Sundahl. Doug Gust, Tim Farr and Shane Hitt are also multi-time champions and deserve credit (let’s just say they’d be in the ATV racing hall of fame).

How do I subscribe?

You can do that the old-fashioned way by filling out a sub card from within the magazine. You can log on to atvsport.com and click on that “subscribe” link. You can also e-mail e-mail:atvs@kable.com or call (386) 246-0107 to speak with someone from customer service.

Weight Watchers, get your machine on a diet part 4

If you have been following this series you know that the ultimate goal is to shave weight to increase the machines performance whether it be on the track or the trail.

The next area of study will be with rotational weight.  Some of these tips and tricks will require some internal engine work and may not be practical for the average rider but I will touch on some of the basics.

Any item that rotates on an axis has rotational weight.  Adding and subtracting weight on these various items have positive and negative effects.  Depending on your overall performance goals, this will determine which way to go.

The flywheel is an area that gets modified quite frequently by engine tuners.  Adding weight increases tractability and the ability to resist stalling in slow, tight, technical maneuvers at the expense of being quick revving.  On the converse lightening the flywheel provides a quick responsive revving engine at the expense of loss of tractability and makes the engine easier to stall in tight technical situations.  Examples of this are evident with removable flywheel weights and inner rotor kits.

Along similar lines as the flywheel is the clutch assembly (hub, basket, plates and springs) aftermarket companies have gone to great lengths to develop lightweight but durable components to replace the typical stock cast/machined aluminum piece. For example machining from a once piece of billet gives the engineer the freedom to make an overall lighter component while still maintaining sufficient strength and wear characteristics. The same can be said for the clutch springs themselves using titanium vs. spring steel.

The other major source is the sprocket, axle, wheel and tire combo that makes up a significant portion of rotational weight. In the previous articles I discussed ways to loose a few ounces and pounds by selecting lighter parts, for more information consult those articles.

Well there you have it a very brief look at some areas to focus on if a lightweight better performing machine is your goal.

Weight Watchers, get your machine on a diet part 3

Last week we took a look at unsprung weight and some ideas on to reduce its affect on the suspension and curb weight. This article will deal with the more daunting task, reducing sprung weight. As mentioned in the intro article sprung weight is everything else minus the suspension (see diagram in the intro). As always I must state a disclaimer that not all these techniques and ideas can and should be implemented by everyone. It is the responsibility of the owner/rider of the machine to determine what, if any, modifications are in the realm of his/her mechanical ability or particular situation.

Lets start with the frame. Other than the engine itself the lion share of the sprung weight hides out in the frame. There is not a lot you can do to lighten the frame without needing some expert fabrication skills. This is not an endorsement to start swiss cheesing your frame, but there are some areas like support brackets and such where some lightening can be achieved.

Other places to look for extra “pork” is with bolt on accessories, controls, handlebars and the like.  Take a look at replacing some of these items with lighter (and generally stronger) aftermarket pieces.  For example just replacing your stock steel bars with a set of aluminum taper or “fat” bars can shave up to two pounds depending on the bar.

One of my favorite ways to shave some weight and give your machine that little “works” touch is lightening as many of the fasteners as you can.  Next time your at the races, go down into the pits and really inspect the pros machines.  If you look very closely at the fasteners and washers you will notice that the washers look like swiss cheese as well as all non-crucial fasteners have a whole drilled through them.  All this to save a few ounces per fastener.  Do this many times and it will add up to a significant amount of weight shaved from the machine.  The big thing to remember here is to only drill fasteners that are not part of any structure or attach things like the suspension, brakes, or any other crucial part.  Fasteners that hold on plastic, mud guards, and controls are fair game though.

Obviously this is only the tip of the iceberg.  Stay tuned for next weeks tip on dealing with rotational weight.

Weight Watchers, get your machine on a diet. Part 2

If you did not catch the intro to this series you can read it here http://www.atvmagblog.com/2008/10/09/weight-watchers-get-your-machine-on-a-diet/

Before starting any of these modifications one tool I recommend is a small digital scale.  Its not a requirement, but if you want to chart your weight shaving techniques this is a good way to keep track of them.

First lets examine unprung weight. As mentioned in the intro article, this is weight attached to the suspension so in effect reductions here will help make the suspension work better and be more responsive. Reducing the unsprung weight also makes the suspension work less to try and keep all that weight controlled and the tires on the ground where they can do the most good. One of the biggest places weight hangs is the wheel and tire combo, examine yours and determine if you have the lightest combination for your particular situation.  Usually in trail and mx applications you can eliminate a few pounds (total) as aftermarket rims and tires are usually lighter than the stock equipment.  There are exceptions of course, but trying to find the lightest wheel and tire combo and still achieve other performance goals like traction (ie. mud boggers) might be difficult.  It will be up to the rider to determine if its an acceptable compromise.  Next, take a look at your lug nuts and studs, there are a few companies making titanium lug nuts and studs not only are they stronger, but lighter.

Brake rotors are another easy area to shave some weight by cross-drilling or purchasing “wave” style rotors. Also if you have access to a milling machine you can mill the rotors thinner but of course you will reduce the life of the rotor as well. Using aftermarket (or build your own) a-arms made out of lighter but stronger tubing. Recently companies have been experimenting with carbon fiber.  This would be the ultimate but at a considerable price as well.  A generally neglected part, the Final drive sprocket (rear) using an aluminum, titanium or bi-metallic sprocket (steel teeth ring on an aluminum or titanium hub) will save a few ounces over the stock stamped steel, although with an aluminum sprocket you do sacrifice some durability over time. Use a standard chain although most people (including me) really like the advantages of an O or X ring type chain, standard chain is still by far the lightest and most efficient at transferring power.  Rear swing-arm for those that use one building or using an aftermarket swing arm can shave some weight over the cast aluminum stock piece, as well as being adjustable and easier servicing of the bearings.  Removing the E-brake cable and mechanism is easy and eliminates somewhat of a useless device that will/can cause more problems than it saves.  One thing to note is most brake calipers require the mounting plate to stay intact so either a custom or aftermarket block off plate may be needed.  The last suggestion is the sprocket and brake rotor skid plate The stock ones are generally made of steel and not very strong. Swapping to an aluminum or fabrication a stronger steel plate then drilling numerous 1/2″ holes can shave weight and lighten the whole package. Also adding the holes lets water, mud, and other debris to fall through rather than get trapped. All these will reduce the effective weight of parts suspended by the rear end of the machine.

A word about a-arm skid and swing-arm skid plates.  Most machines do not come with them, but however most riders have them on their list of “goodies” to put on.  You might think that I am totally against adding these such parts.  Isn’t the point to reduce weight not add it?  My opinion on such parts are as follows.  If your primarily a casual rider like most of the atving population is, I think they are unnecessary with provisions, If all you ride is big rocky trails where getting hung up on obstacles is a regular occurrences they are necessary. However if you only encounter a few of these type of obstacles picking a good line will eliminate the need. MX riding is where they are definitely not necessary because of muddier days they just end up trapping mud (extra weight) to the machine. Although a sprocket and brake rotor skid plate is however a necessity to prevent damage to those vital parts.

Lastly picking up an inexpensive digital scale can be nice to sort of “chart your progress” by weighing the new or modified parts before and after.  If you keep good records you can actually get a good estimate of how much “pork” you have eliminated from your machine.

Of course this is just a few examples of where you can possibly reduce some weight. This in no way is a complete list. Check back next week for part 3 of this 4 part series.

Weight watchers, get your machine on a diet

A wise man once said “Watch the ounces and the pounds will take care of themselves”  Now I don’t know if this quote was used in the context of increasing performance, but it easily applies to our never ending search for maximum performance out of our machines (regardless of the type).

A general rule of thumb is for every 10 percent reduction in weight has a comparable 10 percent reduction in the force required to accelerate or decelerate an object.  Ok, so what does this mean for us enthusiasts?  Well its like adding horsepower and torque without having to do any engine modifications. Best part of it all is some of these modifications cost no money at all just some time and ingenuity.

Before we can go into some into some specifics its important to understand the 3 places (excluding the rider) weight (more correctly mass) lives and its general affect on performance. Note: I realize that weight and mass are not interchangeable but for the sake of discussion the lay person will more often use the term weight when the correct term would be mass, the discussion is written as if gravitational pull, altitude, and barometric pressure being constant.

Unsprung weight is the weight that is not held by the vehicles suspension. For example unbolt the a-arms and swing arm leaving everything else attached and the parts that got unbolted are what make up the unsprung weight of the machine.

Sprung weight includes everything that is supported by the suspension. Using the previous example everything that is left (basically everything attached to the frame) comprises the sprung weight of the machine.

Rotational weight is everything that has weight and spins on an axis. For example this includes but not limited to the axle, wheels, tires, flywheel, chain and sprockets.

A reduction in weight in any or all three areas reduces the total “curb” weight of the machine. Curb weight includes all fluids usually with 1/2 tank of fuel.  The question might arise from the lay person as “Why would there be any reason to shave weight, I paid $XXXX shouldn’t I be getting the lightest, best designed machine?”   In one word, no.   Their are many hidden factors that most consumers cannot fathom.  While light weight and high performance is nearly at the top of a design criteria list for an engineer, they do have to make compromises for things like ease of manufacture, machining, and cost of raw material.  For example using mild steel where carbon fiber would be stronger and lighter, but if the stress levels of the part will never exceed, the mild steel is what will be chosen.  Durability also is a big factor.  Not all lightweight designs and materials are suited for long term durability before failure or being out of tolerance, even though they may give the highest performance.

As you read (in the coming weeks) on the suggestions given are just that “suggestions” some may require a bit of engineering or fabrication skills while others will not. As with any performance tip it usually comes at a compromise, usually to gain performance means to reduce longevity or reliability of a particular part at times. It will be up to the reader to determine their skill level and confidence to attempt some of these modifications.  Also most of these modifications will void manufactures warranty because you will be modifing the orginal design or specs of the part or machine.

Subscribe to this blog to stay tuned to this, and other interesting tips tricks and stories.

See my videos here: http://www.youtube.com/mgracing

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