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SEASON OPENER: Prepping Your Bike for the Highest Performance


MXEditor

For many of our readers who don’t live in a temperate climate, spring means it’s time to get your treasured machine out of its hiding place and get ready for the riding season ahead. High performance off-road machinery hates to sit…and when it does, all kinds of bad things can happen.

“If I have to choose between opportunity and preparation, I’d choose preparation, without it opportunity is useless.” -- Saji Ijiyemi

So where should you start?

We’ve reached out to our off-road experts, riders and racers who have spent years figuring out how to be best prepared when hitting the road (or dirt) after an extended period of downtime…and we’ve tried to put it all together here for you. Don’t forget that a great source of knowledge of all things dirt is available on ThumperTalk.com

WHEN WINTER COMES

When storing your prized machine, a good offense is always the best defense. There are a number of steps you can take prior to retiring your steed to hibernation, and these simple items can make all the difference when warmer weather shows up.

WHEN GOOD FUEL GOES BAD

Gasoline and stabilizers: There seem to be two schools of thought on how to best approach this. One is to drain the tank and carb of fuel and “put her up dry”…but we’ve seen issues where the last bit of fuel doesn’t evaporate completely and leaves that dreaded gummy residue that equals death to carburetors and fuel injection components, so we don’t recommend this approach.

A better way to store fuel in your machine is to fill the tank with fresh fuel, adding fuel stabilizer such as Sta-Bil Fuel Stabilizer or Star Tron Fuel Treatment and run the machine until you are sure that the now stabilized fuel has run through the system, at least a few minutes.

Then top up any remaining space in the tank with fresh fuel and stand the bike upright.

When spring arrives, drain fuel, fill with fresh gas and go…although we’ve ridden out the tank of stabilized fuel with no issues more than once.

Two strokes and four strokes: Are fuel stabilizers used for both two and four strokes? Yes. And if gasoline with ethanol is in your bike, use the blue-colored Marine Formula Sta-Bil. It's formulated to prevent phase separation.

YOUR BATTERY: IS IT READY?

Intelligent chargers: Batteries don’t seem to like being off their charging cycle and this is especially true of the old lead acid batteries. The new type lightweight Lithium Ion units also like to stay at peak capacity and as such using an intelligent trickle charger such as the Battery Tender or similar unit has always been the way to go when it comes to our rides because it keeps it in the best health and tells it when it’s time for replacement.

First, we remove the batteries from the bikes and put them on a wood surface on our bench, we don’t leave batteries in the bikes in case of any leakage while charging from the lead acid units. We have multiple batteries here…and for that we like to use the Battery Tender Four Bank System and we’ve also heard good things about the cheaper PulseTech QuadLink which gives you the ability to charge four batteries at once with your 6-volt or 12-volt battery charger, regardless of the brand.

It’s also simple to just alternate the leads every week between batteries. Even the singular units have a visual indicator as to how the battery health is so it’s easy to spot one that’s going bad during the charging cycles.

Now let’s look at items you should inspect before the season starts.

FLUIDS: DO YOU NEED CHANGE THEM?

Engine oil, brake fluid, etc. Do they “go bad” or expire during the off-season? After some research we’ve come to some findings:

Engine oil: As long as it’s fairly clean, engine oil should have no issues when sitting for six months. But dirty engine oil contains lots of contaminants, from blow by and leaky seals, gasoline contamination, etc. and these can work breaking down items like clutch plates and seals given enough time, so if it’s not clean and clear, replace it.

Brake fluid: Brake fluid also degrades over time when in use, so change it. Moisture in your brake fluid enters through seals and the master cylinder cover…that’s why there’s that window there, so you don’t have to keep opening (and contaminating) the fluid inside. Remember that brake fluid attracts water and given the chance it will become unstable and lack the heat resistance required to effectively stop you in the shortest distance, as well as corroding everything it comes into contact with.

There are a myriad of devices available to test brake fluid for contaminants, and we’ve seen everything from cheap ($8) test strips to LED testers ($20) and even bench mounted tester that go for up to $500. We’ve only used the cheap strips and we find them to be fairly effective when coupled with a keen eye.

Radiator fluid: Radiator fluid does break down and it's anti-corrosive and cooling properties become wholly ineffective over time as well. Most brands have a schedule that the manufacturer uses to determine when to replace it. We follow this in our bikes but we also do a visual inspection to be sure that the coolant is worthy of usage. It’s pretty simple…does it look the same as when it was put in? It the radiator still full as when you topped it off last? Does it look like it came on a spaceship from Mars with the bright green hue?

Dirty, contaminated radiator fluid can point to upcoming, more serious engine issues…if you notice any dark colors or residue in the coolant these could point to a failing head gasket or seal. Basically, if it doesn’t appear fresh and clean, change it and then keep an eye on it.

WHEELS & TIRES: VISUAL INSPECTION IS NECESSARY!

Spokes: Spokes play a vital role in your wheel setup but are many times overlooked during the maintenance of our machines. You should do a visual inspection of the spokes, looking for bent and/or broken spokes. Obviously broken spoke(s) require immediate replacement. Bent spokes are a judgment call, as long as they can be tightened correctly and without hassle.

To make sure your spokes are at the correct torque to support the wheel structure, you must use a spoke wrench such as the ones made by Motion Pro or Fasst Co. and spokes must be tightened in a specific order and each tool comes with detailed instructions for this procedure, follow it religiously for best results.

Rim locks: Off road bike’s rim locks can work their way loose during the riding season and once they do, they’ll flatten your tire quickly. And usually this will be at worst time, such as in the big race!

Normally, you can tell how the rim lock is aligned and whether it’s tight by simply insuring that the stud for the rim lock appears straight and is exiting the rim, pointing directly at the wheel axle and the nut is on the stem. If it isn’t, it’s best to let all the air out of the tube and (very gently) move the rim lock and stud assembly back to the optimal position. The hardest part is repositioning the rim strip back over the rim lock, so good luck with that.

Screw the valve stem nut all the way and fill the tube, and repeat two or three times to insure the tube is seated and tighten the rim lock so it's snug but not tight. Do not tighten the valve stem nut…just back it up against the stem cap and keep an eye on it to see if the tire/tube is slipping on the rim.

Dry rot: If you have been storing your bike for an extended period of time, especially off the stand, it’s best to do a visual inspection of your tires. Were they old when you mounted them? Vintage bike and vintage tires? Better check the sidewall, especially where it meets the rim for any cracking or blistering. Either of these two conditions would necessitate replacement.

BRAKES, BEARINGS AND DRIVETRAIN: EVERYTHING IN SPEC?

Disc Brakes: These are fairly easy to visually inspect for pad wear and as pads are so cheap, if I see any significant wear before the season starts, I’ll replace them just so I’ve got that added bite when competing. You should also inspect the brake alignment pins for corrosion and replace as needed.

Drum brakes: With drum brakes, the signs of wear can be deceiving, as you can’t actually see the brake shoes. Some bikes have a wear indicator that has a pointer on the hub which shows a “wear range” but we’ve never found these to be very accurate. Better to take the wheel off and take a look…it’s easy to see how worn they are and you can use calipers to determine shoe thickness.

Wheel bearings: Wheel bearings wear out, and when they do it can be ugly, so just put your bike up on a stand and rotate the wheels by hand. Is there any side to side play? Doesn’t spin freely? Clunking noises? Then wheel bearings may be an issue. With the sealed types, replacement is your only option but with non sealed bearings you can try removing, cleaning and re-greasing them. Make sure you inspect them for any obvious pitting, cracking or uneven wear…but if they still look good, they may have just been dirty.

Drivetrain: Your sprockets and chain take a lot of abuse when out riding because sand, dirt and water all conspire to shorten the life of a chain and sprocket set, no matter how tough. Drivetrain setups including sprockets and chain are inexpensive (about $100) and are easy and quick to replace. First off, take a look at your sprockets…how are the bolts, are they all tight and at the correct torque spec? Are the teeth all there and are they sharp and exhibit no hooking? How is the chain…is there a lot of play, is it getting to the limits of the chain adjustments, is it noisy or does it slap when landing from jumps?

These are all signs of excessive chain and/or sprocket wear and a sprocket or chain failure can lead to a hospital visit – and if the chain gets wrapped up in the engine case, it can lead to a cracked case (as happened to this author on my KTM)…and this is big money to fix. So don’t do what I did…make sure to replace these worn driveline components before they fail and endanger you and possibly others around you.

REEDS & VALVES: INSPECT, ADJUST OR REPLACE?

Reeds: If you ride a two stroke, you should visually inspect your reed valves as they tend to crack/chip over time. This will make your machine hard to start and stay idling, so best to make sure they are good. These chips and cracks can be very small and sometimes hard to see so look carefully, especially in the corners. The fingers of the reed valve should snap shut with authority when lifted and released, if not they probably need replacing.

Valves: If you ride a four stroke, you should take some time at least once a season to inspect the clearances on your intake and exhaust valves. Excessive play in valves can wreak havoc on a well-running engine, making it hard to start and idle as well as reducing power and because the valves open/close with such frequency, the valves and seats in the cylinder head wear out…causing the valves to loosen up into the head, and this adversely affects your engine. You can correct these tolerances by using shims to offset variances in the valve train.

Most bikes are different and you must consult the owner’s manual for your specific bike’s valve checking procedure, tolerances involved, tools and parts required. This can be a long and involved (as well as costly) inspection/replacement procedure so it is often overlooked by casual enthusiasts.

BREATHE EASY: EXHAUST INSPECTION & MAINTENANCE

Exhaust canister and packing material: Exhausts on off-road bikes are fairly simple, whether two stroke or four and most maintenance of the exhaust is centered on the “muffler” or “silencer” portion of the unit. Inside most silencers is a disposable packing (baffle) material that helps re-route and quiet exhaust gases, and this material can be replaced. Packing material for exhausts is quite cheap, and not replacing this material can lead to issues such as bad idle, hard starting and excessive noise.

To inspect your exhaust for baffle issues, it’s best to remove the rivets and replace when required, depending on how many hours the machine is operating. Signs of needing replacement include excessive noise and pieces of baffle material leaving (being blown out) the canister. You’ll have a good idea when it’s time, and keeping the noise down in our sport is a positive thing!

CABLES: STRETCHED TO THE LIMIT?

Control Cables: Cables are one of those items that are fairly simple and inexpensive to replace, but many riders don’t bother to address their condition until they fail. And when they fail you can really get stranded, so it’s best to visually inspect your clutch and brake cables prior to the season beginning and take corrective action where necessary.

Most cables wear points are at the entry and exit/pivot points along its route, so first check where the cables are adjusted and whether they have free play as recommended in the owner’s manual. Now work the cables via your levers and check to see that the pull (and release) are smooth and consistent. Any undue play or added tension in the pull are cause for concern as throttle cables for example, can stick and cause a major catastrophe.

Control cables are a high wear item and should be lubricated regularly using a cable lube device. Cables are relatively inexpensive and you should replace your cables when any visible wear/binding/bending/kinking is observed.

UNDER PRESSURE: ENGINE COMPRESSION TESTING

This is a maintenance item that when done regularly, can give you a good idea of how much and how fast your piston/rings and compression chamber components are wearing out. If your combustion chamber compression is not at least 100 PSI, your engine is in need of attention and saving it now before it grenades can save you lots of your hard earned money. Most engine builders are looking for a reading of 125 PSI to as high as 180 PSI as indication of a healthy compression. If the compression is reading low, it could be a sign of things like worn rings or valves/valve seats or even a bad head gasket!

The testing is fairly easy, and you’ll need an engine compression tester and these range in cost from $25-$500 depending on complexity and brand. Make sure that the included adaptors contain the size your bike requires (same as spark plug size, usually 12, 14 or 18mm).

Here is the basic drill:

  • Disconnect the ignition
  • Remove spark plug
  • Screw in tester
  • Open throttle
  • Rotate kick start
  • Take reading

If you get a low reading, you’ll have more homework to do…is it leaky valves, or maybe bad rings? Using a leakdown tester can add more to the mix by telling you exactly how much loss you have and potentially the cause.

THE FINAL WORD: In conclusion, preparing your bike by following the procedures above will significantly increase your chance of more seat time and less time fixing things. Items like the compression testing can indicate upcoming engine component failure quickly and inexpensively. Lower cost items like brake components and control cables are vital to get you home after a day on the trails and should be replaced whenever they require. A little homework up front can keep you from staying after class in moto-school.



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If the bike has a CV carb, simply opening the throttle doesn't do much when checking compression.  You need to either remove the carb or prop the slide open.

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How do you check compression with an automatic-centrifical compression release?

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How do you check compression with an automatic-centrifical compression release?

Wow good question!

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Wow good question!

Compression release usually does not work when engine spun in reverse direction I believe

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This is a bit late of a reply but I have run into that very thing a fair bit. The best way to over come it is to do a leakdown test. With 0% leak down at 100psi you know it is a definite pass.

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