DRZ400 adventure bike build

Back when I purchased my first DRZ400 to build up as an adventure bike I spent a lot of time researching different makes and models. The fact I do a lot of solo adventure riding means weight is a primary consideration. The terrain I prefer is technical and challenging so the bike needed to be off-road oriented. Riding in remote locations places importance on reliability; a kickstart is considered essential. The multi-day/week trips I do means that periods between oil changes and general maintenance etc was also a factor. 

Aftermarket part availability was crucial especially with the most important upgrade of a larger fuel tank to accommodate for the long distances between fuel stops. So, after weighing up a long list of pros and cons on many possible adventure bike candidates, a DRZ400E was selected.

To date I've racked up just shy of 100,000 km adventure riding a DRZ400. Although there have been some teething issues along the way, overall I couldn't be happier. A testament to this is that this build article is being completely rewritten as I have just purchased my third DRZ400 to be specifically built up using the RMOTO specs, and then freighted to Australia for a trip in June 2017. 

Photo 1 of DRZ400 adventure bike build
One of the many trips out on the DRZ400
Photo 2 of DRZ400 adventure bike build

Whilst the previous DRZ400 adventure bike build article was fairly basic on the details, this article will go into detail through every single step when building a DRZ400 into an adventure bike using the RMOTO specs. It is a work in progress but will be completed over the next 3 months as the bike must be completed and ready for shipping by May 2017.

2016 DRZ400E L7 strip down
Photo 3 of DRZ400 adventure bike build
For an older technology bike the suspension on the DRZ400 is fairly respectable. However it is sprung and set up for a midweight rider, not all the additional weight that comes with adventure riding such as extra fuel, water, tools, cooking gear, sleeping gear etc. With this in mind the first thing on the list was to strip the bike down and remove everything that needed to come off for upgrading plus pull out the suspension and send it off to Richard at Moto SR for a respring, revalve and 1 inch internal lowering.
Softening the DRZ400 throttle Ė Throttle return spring anchor relocation
Photo 4 of DRZ400 adventure bike build
The link below shows the process of how to reduce the tension of the throttle return spring and reduce fatigue on long riding days
Upgrading the Keihin FCR39 needle and main jet
Photo 5 of DRZ400 adventure bike build
After playing with a few different exhausts, needles and jetting combinations over the years I found a setup on the Keihin FCR39 that performs well for adventure riding. The needle is changed to a genuine Keihin FCR39 EMN (on the second clip groove) and the main jet is changed to a #160. The link below shows the process
Adding a hand tune pilot jet to the Keihin FCR39
Photo 6 of DRZ400 adventure bike build
There is nothing wrong with the standard Keihin FCR39 pilot jet (mixture screw) other than the fact it is tucked up into the carburettor body meaning it can't be easily accessed or tuned by hand. The link below shows the process of installing a hand tune pilot jet which will make life easy when making mixture adjustments.
Keihin FCR39 breather hose plumbing for deep water crossing
Photo 7 of DRZ400 adventure bike build
An upgrade to the Keihin FCR39 slantís breather hoses must be made in order to successfully tackle deep water crossings. The link below shows the process of replumbing the breather hoses
Fitting a S/SM subframe
Photo 8 of DRZ400 adventure bike build
The DRZ400S/DRZ400SM subframe has foot peg mounts that fit the RemoteMoto luggage racks so a new SM subframe was fitted
Helmet lock removal
Photo 9 of DRZ400 adventure bike build
The helmet lock is a heavy lump of steel that is rendered useless with the RemoteMoto luggage blocking access so it is removed. The link below shows how it is removed cleanly
3X3 airbox mod
Photo 10 of DRZ400 adventure bike build
The ď3X3 airbox modĒ is the opening up the airbox inlet to a size of 3 inches x 3 inches to increase airflow. Teamed up with upgraded jetting and a performance exhaust it provides a noticeable performance improvement.
Reference Link : DRZ400 3X3 Airbox Mod
Installing an oil temperature sensor
Photo 11 of DRZ400 adventure bike build
With aftermarket accessories that restrict the airflow across the engine and an increased luggage load, it can mean in the slow/steep/technical terrain, the engine temperature can rise alarmingly. This is amplified on days where ambient temperatures are high. Because of this, I install both water and oil temperature sensors to monitor temperatures and make sure the engine temps stays at a healthy level. The link below shows the article on installing an oil sensor to the DRZ400
Installing a water temperature sensor
Photo 12 of DRZ400 adventure bike build
The DRZ400E doesn't have a water temperature sensor installed from factory and while the left radiator does have a threaded bleeder hole that can be used to screw in a temperature sensor, there are two reasons I prefer not to use this location. Firstly the cable on the temperature sensor makes it a hassle when you want to bleed the radiator system of air. Secondly the DRZ400 can get small air pockets in the left-hand radiator resulting in the temperature sender giving incorrect readings. The link below shows fitting a Trail Tech 19mm inline temperature sensor unit which is a far more reliable and accurate way of monitoring water temperatures and allows you to still use the left radiator air bleeder.
Side stand switch removal
Photo 13 of DRZ400 adventure bike build
Side stand switches are always on the hit list for removal when aiming to build the most reliable adventure bike possible. The link below shows the process of removing the DRZ400 side stand switch in a clean, tidy and reliable way.
SH775 regulator/rectifier upgrade
Photo 14 of DRZ400 adventure bike build
The link below explains how the upgrade to a SH775 regulator/rectifier improves reliability and increases voltage
Photo 15 of DRZ400 adventure bike build
Wiring up an accessories power feed directly from the battery
Photo 16 of DRZ400 adventure bike build
I am a huge fan of steering stabilisers and the Scotts stabiliser and Scotts/BRP SUB mount provides both steering damping plus acts as a bar riser avoiding the need for stacker risers which donít look anywhere as nice as the billet machined Scotts/BRP SUB unit. The link below shows the process to install the Scotts stabiliser and Scotts/BRP SUB mount triple clamp
Fitting the suspension
Photo 17 of DRZ400 adventure bike build
Fitting the fully rebuilt suspension from MOTO SR and fitting the wheel set
Fitting the exhaust system
Photo 18 of DRZ400 adventure bike build
Fitting the Yoshimura RS-2 Comp Series full exhaust system
Installing a Trail Tech fan
Photo 19 of DRZ400 adventure bike build
Iíve never found the DRZ400 to overheat when there is plenty of air movement past the radiators, however when riding tight, steep, slow going tracks when air movement past the radiators is reduced and either/both the engine is working hard or ambient temperatures are high, the DRZ400 can overheat in fairly quick time. Installing a fan solves this problem and ensures the engine stays at the right temperature. The link below shows the install of a Trail Teck fan kit
Fitting a kick start
Photo 20 of DRZ400 adventure bike build
One of the key reasons I ride a DRZ400 is that it has a kick start. The S, SM and road registered E donít have one from factory but the DRZ400 engine does support both an OE and aftermarket kick start kit. It is a relatively straightforward install and can be knocked out in a comfortable 2 hour workshop session. For solo riding in remote places a kick start is invaluable and while I have only had to use mine about 5 times in the last 6 years, I have been so glad to have had it in each of those cases
Clutch cover protection
Photo 21 of DRZ400 adventure bike build
The factory DRZ400 outer clutch cover is thin magnesium and very susceptible to cracking in a drop or crash. Whilst case savers adhered to the outer clutch cover will improve protection, the billet machined alloy case cover offers a significantly improved level of protection. It also goes without saying the billet machined cases look very sharp. There are a number of companies producing billet machined alloy case covers for the DRZ400 however the one fitted here is produced by Force Accessories
DRZ400 decompressor
Photo 22 of DRZ400 adventure bike build
In combination with the kick start the decompressor is installed. The link below shows the install process
DRZ400 starter clutch bolts
Photo 23 of DRZ400 adventure bike build
The current DRZ400 models do not have the early issue of the starter clutch bolts loosening, backing out and then contacting the stator. With regard to the catastrophic results if this were to happen, I always check anyway as it is a simple 15 minute job and gives peace of mind
DRZ400 Gear Shift Lever Fix
Photo 24 of DRZ400 adventure bike build
From factory the DRZ400 gear shift lever has a sharp protruding section of metal. When the bike is dropped or crashed it can concentrate the impact on a small area of the magneto case and can crack it. The fix is simply removing the protruding section of metal
1 1/8 Renthal Fat Bars
Photo 25 of DRZ400 adventure bike build
A set of 1 1/8 bars are always a far superior option over the soft as butter stock 7/8 bars. There are a number of good options on the market but I am quite fond of the Renthal 603 bend in combination with the BRP SUB mount triple clamps for adventure riding
DRZ400 tail tidy
Photo 26 of DRZ400 adventure bike build
The link below has more info on taking the horrendously large and ugly factory tail assembly and exchanging it for a much smaller and tidier looking option
Reference Link : DRZ400 Tail Tidy
DRZ400 clutch switch bypass
Photo 27 of DRZ400 adventure bike build
The DRZ400 clutch has a safety switch from factory. Removing the clutch switch improves reliability as it is one less electronic component susceptible to failing and giving you grief out on the trail. The link below shows the simple process to bypass the DRZ400 clutch switch
Grips
Photo 28 of DRZ400 adventure bike build
While the stock DRZ400 grips arenít all that bad, Iím a fan of nice grips and to go with this bike's white, black and blue colour scheme, I installed some white and blue Scott Diamond Grips
Iridium CR9EIX plug
Photo 29 of DRZ400 adventure bike build
For the advantages over stock plugs, an iridium plug was installed. A temp range one cooler than stock (CR8E) is used to help on the hot days where the bike is loaded up and working hard in the slow going terrain
Breather hose clamp upgrade
Photo 30 of DRZ400 adventure bike build
Replacing the stock pressure clamps on the breather hoses with stainless steel hose clamps to ensure a 100% watertight seal when crossing deep water

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