Article: 15 Top Enduro Bike Mods
12th December 2014
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One of the questions that I’m asked a lot is “what are the top enduro bike mods?” Really what people want to know is how can they be faster, the bad news is there is no magic bullet that will see you riding like Graham Jarvis overnight. If you’re looking for drastic improvement ask yourself what is limiting my riding, is it fitness, skill or, a multitude of other factors? Ultimately improving your riding will deliver real results that said, an Enduro bike that is not set up correctly for the rider and their riding style is not going to flatter any rider’s talents. The list below is focused on delivering a compliant bike that will help you finish races or make it back from the trailer without needing to hitch a lift. If you want out and out power then you have probably been around the scene long enough to know what works for you, for the rest of you have a read and get your bike dialed for results!

15) Exhaust
Fitting an aftermarket exhaust header and pipe can transform the low end power of an engine, on most modern bikes the stock exhausts perform well but there are still gains to be had. The key here is that we want to add low end torque rather than high end power. Gas velocity is key to engine performance and there is an optimal size and shape to reduce turbulence and keep airflow high for every different RPM. For lower RPMs a thinner straight pipe would be ideal, for higher RPMs a wider straight pipe. The reality, as I often discuss with my super model, lawyer, beer drinking girlfriend is; that trades offs have to be made.
For Enduro riding we want the low end power that helps us tackle hard terrain and step climbs. If in doubt the FMF Gnarly pipe is generally a sensible choice.

 

FMF Scottish

The new FMF Scottish is selling well

14) Foot Pegs
Providing you don’t ride like my friend Matt (sorry Matt) you will be spending a lot of time stood up on the bike. Sharp and wide foot pegs improve the level of grip especially in unfavourably muddy conditions. If your peg cleats (the point bits your foot sits on) aren’t sharp break out the file and give them a good seeing to.
As a rule of thumb catching a foot peg with your shin in the garage should cause a suitable amount of pain to make you breathe in sharply for 5-10 seconds and inspect your leg for blood at least twice. Any less than this and its out with the file. Some aftermarket pegs come with adjustable/replaceable cleats and are often wider providing a more stable platform.

footboard

 

Kawasaki racing have been working hard on their factory parts range

13) Tyres
Often overlooked are the knobbly bits of black stuff that hold us to the dirt. I’ve lost count of the number of people on hard tyres at extremely muddy events. You heard it here first, not all knobbly tyres are the same. Choose a tyre that suits the surface you will be riding on. In Enduro riding this can often be a compromise due to the large number of surfaces involved in events. As a general rule of thumb let the tyre choice be decided by the surface you will be riding on most and accept the compromise.
For events tyres may need to be FIM certified, I’ll be writing an article on Enduro tyres soon so check back for that. Just know that if FIM tyres are mentioned by an event organizer your tyre will need to have the FIM mark on the sidewall to be compliant. If you want a road legal tyre you must make sure that the tyre has an “E” mark for use in the UK and Europe.
In general dirt tyres noted as soft are designed for riding in soft or muddy conditions, the knobs are spaced further apart to prevent mud clogging up the tyre and often at strange angles again to stop clogging.
Hard tyres are aimed at rocky or firmer surfaces, the knobs are closer together and the rubber a little harder to avoid tyre breakup.
Many different compounds and tread designs exist along with variations in carcass manufacture, it would be possible to write a book on tyres alone. If you are in any doubt speak to friends or a tyre specialist, let them know what you will be riding and be prepared to experiment to find a tyre you like the feel of. What works for you won’t always work for another rider, I love Maxxis fronts on rock surfaces but a lot of riders prefer Bridgestone’s or Dunlop’s. In the muddier conditions I hate the Maxxis, it’s all personal choice and choosing a design that works for the surface and the rider.
Lastly make sure you tyre pressures are suited to the conditions, for off road riding aroun 12.5 psi is a good starting point, anywhere between 10-15psi is fair game, at lower pressures there is more risk of pinching a tube ending in a devastating race exit. For road use the tyres should be more in the region of 20psi. Always follow the manufacturer’s recommendation for tyre pressures.
12) Bigger Tanks
Since man invented automotive transport people have been running out of fuel. For Enduro or any dirt/trail riding it is not just running out of fuel that can be an issue but also having to refuel.
A bigger tank can mean less pit stops and a faster race time, shorter races may warrant a smaller tank and the advantage of less weight. Larger tanks are commonly available from the likes of Acerbis and other manufacturers, look out for hidden extras in fuel caps or mounting costs. Also check that a tank will work with any radiator braces/seat modifications you have fitted.
11) Jetting
This one is purely for the guys running carburetors, if you have Electronic Fuel Injection you can relax and skip this section.
Carbs are responsible for deliver a mixture of fuel and air into the engine, they are clever devices based on Benoulli’s principle that essentially that a fluid flows faster as its pressure decreases.
Fuel jets are small and limited mainly by viscosity, so that the fuel flow tends to be proportional to the pressure difference not strictly following Bernoulli’s principle. A jet correctly sized for full power would starve the engine at lower speed and part throttle. The workaround for this is to use multiple jets, a pilot jet and a main jet.
There are a number of things that can affect the mixture of fuel and air, the most noticeable of which is altitude or thickness of the air. If the air is thinner we need less fuel as, well, we have less air… As a guide every 1000ft of increased elevation you should drop the Jet sizes by -1 (from OEM sizing). Remember if your bike is second hand it may have already had the jets changed so best to check in the service manual for recommended Jet sizes.
Running the fuel mixture rich can often help Enduro riders as it reduces the throttle response making for smoother (or less pokey) power, the trade of here is if the fuel is too rich it is possible to foul the spark plug. The opposite is true of a lean mixture which will make the bike more pokey but at the expense of smooth idling and starting can often be harder.
10) Flywheel
This is not as the name suggests a wheel made for flies. Rather it is a device for storing rotational energy. The inertia in a spinning flywheel helps the piston continue to spin in between detonations. Interestingly for Enduro riders the fly wheel also helps to smooth out power delivery. The heavier a flywheel the smoother the power delivery. That said if the flywheel is too heavy the engine will feel unresponsive. Lighter flywheels allow for a quicker and peaky power delivery.
Many different flywheel weights are available and finding the right balance for your riding style and engine is a matter of trial and error. That said this mod can really transform how you and the bike perform. The additional inertia stored in the flywheel can also help to prevent stalling.
9) Auto clutch
OK, let’s be honest. We don’t all have the clutch control of a trials champion and even if we do on occasion stalling due to running too low in the rev range is inevitable. In my view the better your riding the worse the problem becomes. Let me explain that, when I learnt to ride a bike with gears and I would stall the engine it was typically on a relatively flat surface, as my Enduro riding improves and I’m more consistently riding up terrains that would see me committed to psychiatric therapy if medical professional where to witness, I tend to stall about 2m from the top leaving 100-150m of sharp often uncontrolled decent. This kind of situation either arises from losing traction and spinning the rear wheel or from running too low in the rev range and stalling the engine. An auto clutch won’t stop the wheel spinning if you have the throttle control of an elephant but it will prevent stalling.
In situations like this I would sell my own mother for an auto clutch! Traditionally 4 stroke riders fitted these as a matter of course but recently they are appearing on 2 strokes as well.
Rekluse is by far the one brand in this arena and my friends have pretty much added this to the list of must haves on all their bikes. A number of top MX and Enduro riders also have these fitted. It’s something I have on my wish list for next season so expect a more detailed write-up then.

rekluse

 

When your friends say “get some balls”,  this is what they meant…

8) Radiator Guard Braces
I remember my first Enduro race well (it wasn’t all that long ago), I spent 9 minutes of each lap waiting for my Husqvarna TE 449 to cool down due to a failed radiator fan. Ironically I was 9 minutes 30 seconds of the top place in my class.
If my radiators had been damaged it would have been race/ride over, and upon returning to the pits, the guys beside me had retired one of their bikes due to a radiator failure. The long and short of it is that radiators are expensive and you can’t ride without them. Radiator braces are bars that prevent your radiator from bending in a typical drop. They won’t stop a rouge tree spearing through the center of the radiator but if you drop the bike onto its side chances are you’ll be OK.
The most interesting part about radiator braces is they only work if you fit them before the accident that breaks your radiator. They make the top 8 as one of the things that could mean the difference between a solid finish and a painful parts bill.
7) Bib Mouse/Tyre Balls /Heavy Tubes
I remember the first puncture I ever had on a motorcycle. I was riding a CZ 125 on the road, it was a hideous bike but all I could afford as a boy aged 17. I had been riding on a straight road from my house to a roundabout for about 2 miles, as I squeezed the break lever to negotiate the round about all hell broke loose. The steering violently wobbled as the tyre wrestled itself from the rim, my feet became road ski’s and I was forced to pretty much straight line over the roundabout only steering if certain death or vehicular impact was the alternative.
In the Enduro world a puncture can be a real hassle, either your race is over or you are forced into a tyre change in the middle of the woods. Either is not a great scenario. It is at this time when you are wrestling off a tyre with tiny tyre levers you will notice the shiny exhaust, auto clutch and other mods you have and start to think that a set of tyre mousses, tyre balls or a heavy duty inner tube was worth the investment.
Tyre mousses are the most expensive solution and are a ring of dense foam like material that inserts inside the tyre, as it heats it expands a little and you are good to go. There is no air in the tyre so punctures are not a worry. I have seen mousses crumble into pulp however my guess is this was caused by an aging mouse or improperly secured rim lock. Mousses feel a little softer than riding on 12.5 psi so may take a little getting used to, if you like higher pressure they may not be the choice for you. Tyre mousses are around £100-£150 per tyre in the UK.
Tyre balls, more like tyre balloons if you ask me, are little bags of air that are inserted into the tyre. You inflate them first then fit the tyre to the rim. With musses and tyre balls tyre fitting is a little trickier and you may wish to have a professional take you through it the first time. As there are about 20 bags of air per tyre a puncture is only likely to affect one or two tyre balls and hence the race/ride can be completed. A set of tyre balls and lube will cost wound £120 per tyre.
The final and cheapest option for avoiding punctures is to run heavy duty HD inner tubes, these are about twice the cost of a standard tube and the rubber is about twice the thickness, they are a little heavier so there is more unsprung weight but in my mind a reasonable trade-off for getting home. A reputable HD inner tube from the likes of Michelin will cost around £16-£30 in the UK.
6) Pipe Guard
Do you ride a two stroke? If you do fit a pipe guard, a dented expansion chamber (the large bag pipe style sections at the front of the bike) will affect the torque characteristics of the exhaust and set you back a few beer tokens in finding a replacement. Personally I run a small carbon fiber pipe guard and so far it has prevented serious damage. I have yet to fully crash test it a 30mph into a rock but then we aren’t Land Rover drivers.
pipeguard

If your pipe guard looks like this, you’re doing it wrong.

5) Skid Plate
Skid plate, bash plate or, frame protector whatever you call it riding without one is not a good idea. Small rocks can easily penetrate the thin cast walls of an engine when introduced at velocity. At this point the engine or gearbox oil makes a break for freedom damaging nature. The rider is politely informed of this environmental damage by complete engine failure (usually seizure) only moments later. A skid plate is relatively cheap, personally I like the plastic or carbon offerings as they fit tightly and tend to be bent around the frame more. If you are riding in rocky conditions decent fitting allow alternatives are available.
When conditions are really muddy adding some foam between the engine and skid plate will prevent the build-up of mud at that cost of additional weight. It will still hold a little but a good deal less than running without foam, in drier conditions remove the foam to let the engine cool more efficiently.

4) Handguards
Having your hands pelted with mud and small rocks is not cool, at best it stings a little at worst a bruise or cut. In Enduro riding things get worse catching a tree can crush your hand between the bars, break a lever or worse.
There are essentially two designs open or wrap-around. With open designs you are less likely to catch your hand on during a spill, these are typically favored by MX riders but many pro Enduro riders also use them. The wrap around type typically have an aluminium bar that bolts to the handlebars and a bar end type insert that screws into the end of the bars. These are far stronger and great for trail riding and Enduro, the trade-off for the extra protection is that you are more likely to catch your hand during a spill.

Hanguards

 

Never trust a green laner that doesn’t have a severely scratched set of Acerbis Rally Handgaurds

3) Seat
Enduro riding can be tough, one of the most overlooked mods on the market is upgrading your seat. If you’re tall try adding additional foam to help transition between sitting and standing a little easier. If you are short, why not remove some foam and make planting feet easier.
Get your seat height right and a cover with good grip and you will be able to ride faster and harder for longer.

Seat

 

The new Yamaha 2015 WR seat design shows the bike will have performance and comfort.

2) Cockpit
Sorting the cockpit of your bike for your height and riding style is essential, it can help save energy and provide a great excuse to not lend your bike to a crash happy friend!

  • Adjust handle bars or replace with taller or shorter bends.
  • Adjust the height of your levers to the position that suits you, I normally find just below horizontal and slightly lower on the clutch hand suits me nicely.
  • Change those tatty grips, finding a grip that you love will help you stay connected to the bike and prevent RSI type issues, I have big hands but hate thick grips, thinner tacky grips are a must for me.
  • Adjust your rear brake and gear shift levers to be about level with the foot pegs, some variation is OK here but too low and they may snag on the ground and break. Don’t be afraid to move your whole foot when shifting or breaking, anchoring your knee against the bike can help with this.

1) Suspension
Sorting your bikes suspension is without a doubt the best return for investment you will ever get. Enduro is all about the rough stuff, if your bike can’t get the grip it’s already over. Make sure the bike is sprung for your weight and that you have set sag (or pre-load) to the correct levels. When you sit on the bike there should be around 100mm or sag (depression) on the rear shock. Setting static sag so that when the bike is rider-less and you lift the rear end there should be about 35mm of extension before the rear wheel also starts to lift.

There are so many options when tuning suspension from re-valving or re-shimming to different springs and entire valve stacks. Even changing the fork oil can make a drastic difference if the task has been neglected for a while.

SuspensionCalibrating forks for tree impacts can be tricky…