Buying A Used Dirt Bike

Buying a used off-road bike is very similar to buying any used bike. The only real difference is where the wear and tear occurs. Before thinking about anything else, realise that many competition bikes are never registered and therefore their provenance is very difficult to prove. Always be wary of bikes that look too good to be true, they usually are. Buying a stolen bike does nobody any favours and you should seek to find out as much about the seller as possible. The ideal situation is that the seller has the original receipt for the bike, but at the cheaper end of the market this is unlikely. Next, use your common sense – if the guy wants to meet in a lay-by on the A1 be wary. Ask questions about the bike, it should be obvious if the guy knows anything about the bike or has just acquired it with a pair of bolt-shears.

Is it knackered?

Off-road bikes have a hard time. Landing an MX bike of a 30ft jump or throwing a trials bike up a ten foot boulder is bound to lead to some wear and tear. The advantage of off-road bikes is that they are relatively simple and there are a few basic checks you can make to avoid an expensive purchase:

Obvious stuff first…

Before moving on to detailed stuff just look over the general condition of the bike. What is the paintwork like – if there are huge chips out of the frame paint then suspect either a cack-handed mechanic or a mental pilot. Take a look round the guy’s garage – if his toolkit is just a big hammer then suspect a bodger. What sort of oil has been used?
How many other bikes has the guy got – is he a trader? The best trick is when you ring up say “I’ve rung about the bike”, if he asks which one then chances are the guy is a trader.
Checking for outstanding finance can be difficult for non-registered bikes, but if the bike is newish and registered it may be worth a HPI check before shelling out.

Forks and head bearings

A bike’s steering is influenced by many factors but if the bearings that hold the forks in the frame at the headstock are knackered then you’ll be struggling to get round the first bend. To check the bearings put the bike on a stand so that the front wheel is off the ground and try to move the forks along the centre of the bike (back and forward). There should be no movement, other than suspension travel (up and down).

Also check that the handle bars move smoothly through their arc, if it feels notchy then chances are that either the cables aren’t routed correctly or the head bearings are worn and will need replacing.

To check the forks hold on the front brake and compress the forks, the action should be smooth and when you release the pressure the forks should extend in a controlled way – not pogo up and down. Look for a “tide mark” on the fork leg where fork oil has squeezed past the seal and is left on the stanchion. Also check that the stanchions are straight and that there are no chips in their surface that will destroy the fork seals.
DIY cost: new head bearings (tapered) cost between £20-30. A set of fork seals can run from £20 to £40. Forks can be straightened and re-chromed for around £100.

Rear wheel and swing arm

To check for play in the swing arm bearings get the back wheel off the ground and try to move the swing arm from side to side. The swing arm should only move up and down, any sideways play means that the swing arm bearings are shot. These are difficult to replace and if the play has gone untreated for too long can actually damage the swing arm, so that even new bearing won’t fix the problem. To check the wheel bearing grab the outside of the rim and try to rock the wheel from side to side, any movement means new bearings – not too much hassle
.DIY cost: needle bearings for the swing arm vary widely in price up to £50, wheel bearings are usually under £10 each.

Rear Shocks

Checking the rear shocks will tell you whether your backside is going to get a pummelling out on the trail. To check that the shock is working push down on the back of the bike and check that when you release the pressure that the back end comes up in a controlled fashion, i.e. if the back end pogos up and down the shock has lost its dampening properties.

On mono shock bikes also check the condition of the linkage under the swing arm (excluding recent KTMs). These hang down in the clag and need greasing regularly to avoid seizing and are expensive to replace. Visually you should check the shock to ensure that the main shaft is in good condition. Any corrosion on the shock shaft will mean that the shock won’t last too long.
DIY cost: new twin shocks can be had from around £80 to £200 for competition shocks. Mono shocks start at £200 and rise to £400 for a pucker Ohlin’s shock.


Is it nicked?
Is it knackered?
Can you fix it?
How much will it cost?

When you go to buy a bike take a mate, a cynical mate. One who isn’t blinded by the wad of notes burning a hole in your pocket. It’s amazing how much you will miss when you are about to blow all your hard earned on a bike.


OK, the nitty-gritty stuff all adds up when you need to shell out for new tyres, chain, sprocket and pads. These are a good negotiating point, but be reasonable…

Check the chain and sprocket to see what condition they are in, in the sprockets are hooked over then also check the engine cases for damage as a chain can easily fly off and smash the cases – watch out for a bodged araldite repair.

A competition bike will need this stuff on a regular basis anyway. But its worth checking the pads and discs – any deep scoring on the discs may mean they need replacing, particularly if the thing needs to be MOT’d. Pads wear quickly on a dirt bike, just check the pad depth to make sure there is some left and that they haven’t damaged the disks

Tyres also wear out quickly, particularly motocross tires where you are looking at the sharpness of the knobs – not the length. A bunch of rounded knobblies will spin like a bald tyre on a road bike. Don’t worry to much as you may need to buy different tyres for the conditions you intend to use the bike in. Check that the sidewalls aren’t splitting, particularly if the bike has been stood on its wheels for a long time. While your checking the tyres makes sure all the spokes are tight and the wheels run true – a set of wheels can cost up to £400!

Other stuff to check includes the air-filter. This is a good indication of the care and attention lavished on the machine. If the filter is in good nick and looks like its been oiled regularly you can assume that the guy has looked after the bike. If it is pitch black then assume that the bike has been trashed and the oil has never been changed.


An in-depth discussion of what to look for in an engine is beyond the scope of this piece, but here are a few pointers.
With a Four stroke engine make sure that you start (important that you start it – not the guy who is selling, who may have a magic technique) the bike from cold (check that the engine hasn’t been warmed before you get there). Listen out for any tapping noises from the top of the motor or rumblings from the bottom. Check the oil for any discolouration (white=water, black=camshaft failure down the line as the oil has never been changed.

Two stroke engines are a little easier to figure as there is much less to go wrong. Listen for any slapping sounds (piston slap). In reality a competition two stroke will always need a new piston every few hours use if its used properly. If you can try to hear a bike that you know is in good nick before you view your purchase, then all the better.
Most importantly take the bike for a test ride. Go through the gears and make sure that the bike pulls smoothly. If the engine revs rise without changes in throttle position (or you are going downhill etc..), then the clutch is slipping.

Check that the bike doesn’t get too hot too quickly. Chugging up your first big climb out on the trail is a bad time to find coolant all over your nice new boots. Check also that the coolant is clear and that there aren’t any bits of oil floating around in it.
DIY cost: depends what you need – varies widely a two stroke engine can be completely rebuilt for around £200 – some four stroke cams can cost that much alone.


Exhausts are crucial to Two stroke engines. Make sure that there aren’t any big dents or cracks in the pipe. If the pipe is non standard then ask if the bike has been re-jetted for the pipe. I once saw a Husky 125 with a CR80 pipe welded on to the cylinder and new pipe isn’t cheap.

Four Strokes are less dependent on pipes for power, but the key point here is to make sure it is legal – for on or off road use. Many enduro riders are dismayed that their magnesium silencer fails scrutineering on noise. Unless you have a noise meter this is difficult to check, but look for any e markings on the pipe that indicate road legality.
DIY cost: A new pipe for a two stroke can be £140 – £200 plus £60 – £80 for the tail-pipe. A four stroke silencer can run from £200 – £250, plus add around £80 – £100 for a new down-pipe.


It may sound obvious but check that all the controls work smoothly. New cables are cheap but make sure that all of them are OK. Look for stuff that has been bodged back on – particular problems are welded on gear levers (see our RM project). Make sure that all lights work if they are fitted. Remember that you don’t need lights for a daytime only Mot with an advisory note Daytime/Visibility Restriction, but if they are fitted then they must work.
DIY cost: new cables cost between £8-£15, a set of levers around £15 each (including perches). New bars might start at £20 rising to £35 for a decent set of Renthals.

Other stuff

Remember that some off-road bikes are also road registered so you need the paperwork: A V5 (registration document) and a current MOT are always useful. For competition machines there is no recognised paperwork, but any receipts etc. are useful.

So, there you have it – buy a new bike! If you want a used bike where should you look? Well Trials and Motocross News always has a well stocked classified section, but these tend to be priced at the upper end of the scale as the sellers tend to be racers with recent kit. If you are after a real bargain try your local paper or better still where you may get lucky and find a well intentioned mother selling little Johnny’s CR125 for £300 as she needs the space in the shed…