KTM 640 Adventure (1998-2007) Maintenance Schedule

This is the maintenance schedule and service intervals for the KTM 640 Adventure, one of KTM’s iconic single-cylinder adventure motorcycles, replacing the earlier shorter-lived KTM 620 Adventure.

The KTM 640 Adventure is an adventure motorcycle powered by KTM’s LC4 single. The engine is a 625cc liquid-cooled single-cylinder 4-valve engine with a single overhead camshaft and a balancer shaft, which leaves it quite vibey nonetheless

The final drive is via a 5-speed transmission and a chain.

The KTM’s LC4 engine has been used in a number of other motorcycles, for example the KTM 640 Duke and KTM 640 SMC.

KTM made some small updates to the 640 Adventure during its lifetime, but the maintenance schedule is overall the same.

KTM no longer explicitly makes single-cylinder adventure motorcycles. There are multiple successors for the KTM 640 Adventure:

  • The KTM 690 Enduro R: A single-cylinder motorcycle but mostly designed for shorter-distance enduro riding, rather than long-distance adventuring
  • The KTM 790 Adventure, a parallel twin-powered adventure bike
  • The Husqvarna 701 Enduro LR, an enduro bike with a long-range tank that’s a favourite for off-road explorers

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KTM 640 Adventure Service Intervals

Overall, the KTM 640 Adventure has 3000 mile / 5000 km or annual service intervals between all major service items.

At every service, you should change the oil and filter, check and adjust the spark plug (replacing it every two services) and valve clearances, and do a comprehensive once-over of the motorcycle.

Most items in the KTM 640 service schedule should be done at that 3000 mile / 5000 km annual service. But a few items are specified as being every two services, and others have distance-only or time-only intervals.

KTM 640 Adventure Maintenance

The manual for the 640 Adventure breaks maintenance up into multiple sections. We’ve simplified it a little below.

Pre-ride / post-cleaning or adventure riding checks

First, there’s the pre-ride / post-cleaning checks, with specific notes for cross-country riding.

TaskBefore each startAfter cleaningFor cross-country use
Check oil level
Check brake fluid level
Check brake pads for wear
Check lighting system for proper operation
Check horn for proper operation
Lubricate and adjust actuating cables and nipples
Bleed fork legs in regular intervals
Remove and clean fork dust sleeves in regular intervals
Clean and lubricate chain as necessary
Check chain tension
Clean air filter and filter box (depending on the dirt accumulation)
Check tire pressure and wear
Check coolant level
Check fuel lines for leaks
Drain float chamber
Check all control elements for smooth running
Check brake performance
Treat exposed metal components (except for the braking and exhaust systems) with wax-based anti-corrosion agents
Treat ignition/steering lock and light switch with contact spray
KTM 640 Adventure self-maintenance items

KTM 640 Adventure Maintenance schedule

Below is the maintenance schedule for the 640 Adventure in massively simplified format.

At every one of the time-based or distance-based intervals, consult the relevant checklist of items below.

The vast majority of items should be done at every 3000 miles / 5000 km or year.

mi x 100036912
km x 10005101520Every
Regular Service checklistYear
Change spark plugs
Annual service itemsYear
Two-year / 20000 km service items2 years
KTM 640 Adventure Maintenance schedule

KTM 640 Adventure Regular Service Checklist

Below is the annual service for the KTM 640 Adventure. Do this every 3000 miles / 5000 km / year (per the schedule above).

KTM 640 Adventure Service Checklist
Change engine oil, oil filter, and fine filter
Clean oil screens and magnet of drain plug
Check oil lines for damage and kink-less arrangement
Check and adjust spark plug (Gap: 0.9mm)
Replace every 6000 mi / 10000 km
Check and adjust valve clearances when engine is cold
Target clearance: 0.12mm – 0.15 mm
Check engine fastening screws for tight fit
Make sure all engine screws accessible from the outside are screwed tight
Check carburetor connection boots for cracks and leaks
Check idle setting
Check cooling system for leaks, antifreeze protection
Check radiator fan for proper operation
Check exhaust system for leaks and suspension
Check actuating cables for damage, smooth operation, and kink-less arrangement, adjust and lubricate them
Check fluid level of the clutch master cylinder
Clean air filter and air filter box
Check cables for damage and kink-less arrangement
Check headlamp adjustment
Check electrical system for function (low/high beams, stop light, turn indicators, headlamp, flasher, tell-tale lamps, speedometer illumination, horn, side-stand switch, clutch switch, emergency-off switch)
Make sure all screws and nuts are tight
Check brake fluid level, lining thickness, and brake discs
Check brake lines for damage and leaks
Check/adjust smooth operation, free travel of handbrake/footbrake levers
Check screws of brake system for tight fit
Check shock absorber and fork for leaks and proper operation
Check O-ring of shock absorber for wear
Clean fork dust sleeves
Bleed fork legs
Check swinging-fork pivot
Check/adjust steering-head bearing
Lubricate reversing lever
Check all chassis screws for tight fit (fork plates, fork leg, axle nuts/screws, swinging-fork pivot, reversing lever, suspension strut)
Check spoke tension and rim joint
Check tire condition and inflation pressure
Check chain and chain guides for wear, force fit and tension.
Check screws on pinion and chain sprocket for locking devices and a tight fit
Lubricate chain
Check wheel bearings and jerk damper for play
KTM 640 Adventure Service Checklist

Annual service items

Below are items to do on the KTM 640 Adventure every year, regardless of distance.

KTM 640 Adventure Annual Service Items
Perform complete fork maintenance
Clean and lubricate steering head bearing and sealing elements
Clean and adjust the carburetor
Treat the electrical contacts and switches with contact spray
Treat battery connections with contact grease
Change the brake fluid
Check all screws, nuts, and hose clamps for tight fit
KTM 640 Adventure Annual Service Items

Two-year / 20000 km service items

Below are items to do on the KTM 640 Adventure every two years or 20000 km.

KTM 640 Adventure Two-year / 20000 km service items
Perform complete shock absorber maintenance
Perform complete reversing lever maintenance
KTM 640 Adventure Two-year / 20000 km service items

Wheels and Tires for the KTM 640 Adventure

The KTM 640 Adventure, being an offroad-ready motorcycle, has an adventure-ready 21-inch front tire with an 18-inch rear tire.

The 640 Adventure has spoked rims and tubed tires.

Below are the tire sizes and recommended tire pressures (cold) to use as a starting point. These are for road riding. Adjust them for off-road riding.

WheelTire sizeTire pressure (cold)
Front90/90-21Solo: 1.8 bar / 21 psi
Passenger: 2.0 bar / 29 psi
Rear140/80-18Solo: 2.0 bar / 29 psi
Passenger: 2.2 bar / 32 psi
Tire sizes and pressures

Maintaining the KTM 640 Adventure Chain

Regularly maintain your chain, especially riding in adverse conditions (including along dusty roads), and after cleaning your motorcycle.

KTM recommends that you regularly

  • Clean your chain using a good chain cleaner, or kerosene as people used to do it
  • Lubricate your chain (use a compact adventure-friendly lubricant like Motul chain paste)
  • Check and adjust chain tension.
KTM 640 Adventure chain maintenance
KTM 640 Adventure chain maintenance

To check the chain tension on the KTM 640 Adventure, find the spot 30mm from the end of the chain slider. The chain should just touch the swingarm. If this tension is not accurate, you need to adjust the chain tension.

Target chain tension: 0mm (not a typo; it should be zero mm).

To adjust chain tension:

  1. Loosen the axle nut.
  2. Loosen the chain adjustment lock nuts.
  3. Turn the adjustment nuts equally (consulting the reference marks on either side of the axle) until the target adjustment is met.
  4. Tighten the axle nut to 80 Nm / 59 lb-ft, and then tighten the lock nuts.
  5. Re-check the tension to make sure it’s still in spec.

About the KTM 640 Adventure

KTM 640 Adventure Flickr
KTM 640 Adventure. Source: T.Wurm on Flickr

KTM is well-known at this stage for making high-quality adventure motorcycles, and the KTM 640 Adventure is one of the earliest incarnations of its now iconic Adventure line.

The 640 Adventure replaced the earlier 620 Adventure, introducing a higher-capacity 625cc single-cylinder engine (the 620 Adventure had a 609 cc engine).

For adventure travel motorcycles, the KTM 640 Adventure is quite unique. It set the tone for middleweight adventure travel bikes for quite some time. Let’s look at what makes it special.

Firstly, the KTM 640 Adventure has a huge 28 liter (7.4 US Gal) fuel tank. If you ride modestly and get its rated 48.5 mpg (4.9 L / 100 km) out of it, this should be good for range of over 350 miles or over 570 km. Massive!

Secondly, the 640 Adventure has very long travel suspension, with 270 mm (10.6 inches) in the front and 320 mm (12.6 inches) in the rear. This is the same territory as small dirt bikes. It gives you quite a bit of adjustability too, with compression and rebound damping at the front, plus full adjustability at the rear.

Thirdly, the carburettor-fed, liquid-cooled engine is quite a good performer, good for up to 36 kW / 49 hp at 7500 rpm, with torque peaking at 53 Nm / 39 lb-ft at 5500 rpm.

Finally, the KTM 640 Adventure is surprisingly lightweight for everything it has. Even with its huge tank of gas full, it weighs in at a surprisingly light 175 kg (389 lb).

The main fly in the ointment of the KTM 640 Adventure is vibrations. Many users say it’s unpleasantly vibey if you spend a lot of time on the road. That said, it’s still less vibration-afflicted than a Harley-Davidson of the era, and this is isn’t a bike made for road riding, anyway.

Secondly, the service intervals are quite short. That said, the valves don’t often need adjusting, and the adjustment procedure is fairly easy anyway as there’s just one piston and the adjusters are of the screw and lock nut type. This guide on Visordown for the LC4 engine is pretty good.

KTM made some significant changes in the 2004 model year, improving the engine’s reliability with internal changes, and giving the front twin disc brakes.

One thing to bear in mind is that the KTM 640 Adventure was somewhat unreliable until the 2004 model year. Among the things users complain about are:

  • Main bearing failures (total engine breakdown)
  • Clutch cables failing (happens on many bikes, but particulalry often on these)
  • Fickle electrics
  • Vibrations that can dislodge everything

But despite that, the LC4-powered KTM 640 Adventure is the RTW bike of choice for many denizens of ADVrider, and so why shouldn’t it be for you, too.

Reference — Manual for the KTM 640 Adventure

The above information came from manuals for multiple years of the KTM 640 Adventure. See screenshots below.

We omitted the break-in service as these motorcycles are all broken in.

You can generally get manuals for KTM motorcycles from here.

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