Honda XR 400R

XRs like regular oil and filter changes. Oil works hard in an air-cooled engine so regular changes are cheap insurance for a long and trouble free run. When checking out a used XR, ask the owner what oil is in it, and what oil was used to run it in. Honda recommended running-in the XR400 on mineral oil for at least 1000 kays before switching to a semi-synthetic oil. Using a full synthetic for running-in can glaze the bore and cause excessive oil use, but a hone can correct this.

The air filter: Check the air filter, and if you don't mind getting your hands dirty, feel around to the other "out of sight" side to make sure it's seated properly. They can be fiddly to replace and if it hasn't been with care, dust may have entered the engine through the gap where the filter has failed to seal with the airbox.

Muffling and jetting: A secondhand bike should have been de-restricted but may not have been. If the engine hasn't been derestricted, do it yourself when you get bike machine home. It's easy. Remove the airbox lid and the muffler end-cap (both of which are immediately obvious) and the restrictor in the inlet manifold. Replace the standard main jet with a 158 jet.

 Gearing: Standard gearing is 15/40 but going to a 48-tooth on the rear makes a big performance improvement. It's easy to check the number of teeth, even for the numerically impaired; the number is nearly always stamped on the rear sprocket.

Steering head: Sometimes you'll find a grease stain on the front mudguard under the steering head. This caused by grease from the steering melting on a hot day and dripping onto the guard. Check the steering head for excessive looseness or notchy movement. High temperature grease is the thing to use. Packing the bearings is not a hard job but can be a bit messy.

Aftermarket goodies: Many like to personalise their bikes and there are still plenty of aftermarket cosmetic and performance goodies available for the XR. The only limit is price, how much can you afford to spend? Bark Busters are the first thing to put on any bike in my opinion. They save a lot of grief and injury in tight trees and silly falls.

Bars: Standard handlebars can be a bit low for the taller among us. If this is the case for you, a cheap fix is to buy two more top clamps and four longer bolts. You place the new clamps upside-down under the bars and put the originals back on top with the longer bolts.

Blinkers: Standard blinkers are large and damage prone but can be replaced with clearance lights available for a song from Repco.

Mount these on the rear guard and front number plate. Put the originals somewhere safe until it's time to sell the bike.

Rear guard extender: The rear mudguard extension is the first thing many owners remove but if it's still in place, move the numberplate higher and then trim the excess plastic from below it. This shortens the extender to a more sensible size and still keeps the bike street legal and the coppers off your back.

 Plastic chain guard: The plastic chain guard above the swingarm is an absolute joke. Remove and toss it if it hasn't already been torn off from trail use. A bashplate is a good investment, especially if you get serious about your tail riding, Whipps Alloy Products (02 6585 0944) do a plate for the XRs that's easy to fit and great protection.

Thanks to Brad Fitzgerald, in the workshop at Capitol Coast Motorcycles for taking time off to answer our questions.

FIXING THE XR SUSPENSION
Former Cape York tour guide, racer and mechanic, GERRARD SMITH has one of the best XR suspension set-ups we've seen. Here's how he did it.

The advantages gained by basic suspension set-up are often over-looked. Here are the simple steps I took to ensure my Honda was going to be able run hard and fast all day, with a minimum of cost and only a few hours in the workshop.

I weigh in at 105kg with kit on, a little heavier than average rider, and I knew I'd have to compromise on this job, because of budget constraints. In the end, with softish standard springs on the XR, the compromise gave away a little in top speed but improved my average speed through the bush. That was okay with me. Riding 8-10 hours a day for 4 years as a tour guide definitely refocused my self-preservation skills. I'd rather achieve good average speeds than smash into corners, hoping nothing is coming the other way.

What I wanted to improve on the XR was the soft fork, which I did by preloading the springs with easy to make spacers. I improved the fork action by getting all the basic ride height and sag measurements spot on, and I can't overstress the importance of doing that carefully and accurately.

My mods will usually increase the overall height of the bike from the average sagged set-up, however, I prefer to feel I'm sitting 'on' a bike rather than 'in' it. I also rarely, if ever, touch the ground with both feet simultaneously, but if you're short, ride height is something to consider before making the following changes.

SIMPLE STEPS TO PERFECTION
First, ensure all bearings, bushes and linkages are in good condition. Ensure the shaft and seal on your shock are in good condition, with no signs of oil leakage or pitting on the shaft. These must be first attended to in order to obtain good long term results.

Grab a flat screwdriver and back off the front and rear rebound and compression adjusters, by winding them anti-clockWise. On the front end, the rebound clickers are the top ones; compression clickers are in the bottom of each fork leg. At the rear you'll find a rebound clicker on the left side of the lower shock mount, and compression adjustment on the right-hand upper shock body.

Place the bike on a stand with rear wheel off the ground and measure the distance from the axle nut to a mark on the muffler, taking care to refer to the same points in the following steps. Note down this base measurement.

Next, place the bike on its wheels and bounce the suspension a couple of times and measure again. This will determine the static sag. Note it, then grab a mate or your missus for the next step.

With all your riding gear on, show your helper the measuring points, sit on the bike in a neutral riding position with your feet on the pegs and the bike upright and settled, then take a third measurement. Note it down with the others and soon you'll the ride sag.

These measurements are a useful tool in showing you whether or not the spring is correct for our weight.

 However, in staying with the standard spring, I want to obtain the best preload settings for average riding. The base measurement minus the second measurement is the static sag. The base measurement minus the third measurement is the ride sag. By loosening the lock rings on the shock with a C-spanner, or if you are careful a brass drift and hammer, then turning them up or down accordingly, you can adjust sag levels. Be sure to make this adjustment with the wheel off the ground. Trial and error, combined with a bit of patience, will give the desired result of 25mm static sag.

Once you have this right, jump on again and re-measure for ride sag. Hopefully it's in the ball park of 90-110mm. If it's much more than this you'll need an uprated spring to make the most of the XR's predictable handling. Don't wind down the spring any further than required to obtain the 25mm static sag, as this setting is important in allowing the wheel to stay on the track and provide traction when on rough ground. Be sure to lock the rings together to prevent them turning out of adjustment when riding.

MATCHING FRONT TO BACK
To enable the front end to compliment the rear end I add spacers and washers to the top of the fork springs, as shown in the pics. I also run slightly different oil specs to standard. These basic mods will see your bike's suspension operating in the correct part of its stroke, providing a well balanced feel, quick turning, stability at speed, giving you the confidence to back it into and out of corners with ease.

These spacers are simple off-cuts from an exhaust shop, 30mm diameter and 20mm long. The extra washer shown above spacer is to prevent it wearing on the alloy fork cap. You may choose to vary the length of the spacers, depending on how much work your suspension has done, but 20mm gets my vote as the optimum. Be sure to smooth off any sharp edges on the spacers before fitting.

Fork oil is prone to contamination and should be replaced at least annually on a trail bike. This job is also a great opportunity to re-grease your steering head bearings while you're at it.

It's best to have a competent person help you carry out these mods, as things need to be just right to keep you safe. Once the fork is removed, inspect the fork tubes and seals for leakage and pitting. Again, these must be attended to first in order to obtain good long term results.

Drain and thoroughly flush each fork, being sure to bleed and flush the rebound tubes by slowly extending and compressing them. I add 400ml of 5wt oil and 170ml of 10wt to each leg, making sure I bleed the rebound tubes before assembly.

When you're ready to tune your suspension, ride around your favorite tracks and have a screwdriver on hand to make the adjustments. I recommend starting out with everything backed off, front and rear, then, when you have a feel for how your suspension is responding, adjust both fork and shock compression clickers right in to get a feel for that. Usually somewhere in the middle will suffice, then carry out the same procedure on the rebound settings. A little patience now should bring many hours of trail bliss - along with a better understanding of what's doing all the work beneath you.