KTM 640 LC4 Enduro

KTM
LC4 Enduro
Manufacturer	KTM
Sales description	640 LC4 Enduro
Production period	1998 to 2008
class	motorcycle
design type	Enduro
Motor data
Liquid-cooled 1-cylinder 4-stroke Otto engine with balance shaft and electric starter
Displacement  (cm³)	625 cm 3
Power  (kW / PS )	approx. 37 kW (50 PS) at 7000 rpm
Torque  ( N m )	55 Nm at 5500 rpm
Top speed (  km / h)	Max. 169 km / h
transmission	5-speed claw shift
drive	Rear wheel drive O-ring chain
Brakes	Disc brakes
Wheelbase  (mm)	1510
Seat height (cm)	91
Empty weight  (kg)	approx. 150 kg (SC approx. 140 kg)
Previous model	KTM LC4 600, 620 and 625, 400 cm 3
successor	KTM LC4 690

KTM LC 4 640 Enduro

The KTM 640 LC4 Enduro is a motorcycle from the Austrian motorcycle manufacturer KTM .

The Enduro is available in the KTM brand color orange, but also in black and gray. The KTM 640 LC4 Enduro was produced from 1998 to 2008.

General

The KTM 640 LC4 Enduro enjoys a good reputation, especially because of its unmistakable single-cylinder engine in appearance, performance and sound, which KTM has been offering since 1987 (later in two displacement sizes, 400 and 600 cm ³ ) and continuously improved. The different stages of development of the engine can be recognized by the names of the LC4 models 600, 620, 625, 640 and 660. (The name SC refers to sportier offshoots ("Super Competition"), whose engines have a smaller oil circuit).

While the drivers of the first series occasionally complained of engine damage, the 620 model was already considered to be technically much more sophisticated, including a second oil pump.

The approximately 50 hp Enduro (400cc approx. 45 hp) is easy to maneuver thanks to its lightweight construction and high ground clearance.

The water-cooled four-valve engine is relatively highly compressed, has a short stroke and a very low flywheel, so that its engine characteristics differ significantly from other single-cylinders from Suzuki and MZ or from a BMW F 650. The frame of the KTM 640 LC4 Enduro is lavishly painted, the suspension of the chassis components are made of high-quality materials. Particularly noteworthy, however, is the motor, which, with good care, is robust and easily accessible for maintenance.

Technical data (model year 2004)

chassis

frame	Central tubular frame made of chrome-molybdenum steel tubes
fork	White Power - Up Side Down 4357 MXMA
Front / rear suspension travel	275/275 mm
Rear suspension	Central spring strut (WP BAVP) with PRO-LEVER linkage to the needle-bearing aluminum rear swing arm
Front brake	Disc brake with perforated brake disc, 2 piston brake caliper floating
Front brake disc	Diameter 300 mm
rear brake	Disc brake with perforated brake disc diameter 220 mm, brake caliper with floating bearings
Front tires / air pressure	90 / 90-21, air pressure road solo 1.8 bar, air pressure road passenger 2.0 bar
Rear tires / air pressure	130 / 80-18, air pressure road solo 2.0 bar, air pressure road passenger 2.2 bar
Tank capacity	11.2 liters, 2.5 liters reserve
Translation rear wheel	16:42
Chain	5/8 × 1/4 "X-ring
Headlight: H4 12V 60/55 W (socket P43t) Parking light: 12V 5W (socket W 2.1x9.5d)	Instrument lighting: LED Indicator lights: LED	Brake light: 12V 21 / 5W (socket BaY15d) Rear light: 12V 21 / 5W (socket BaY15d)	Indicator: 12V 10 W (base Ba15s) License plate light: 12V 5W (socket W2.1x9.5d)
battery	maintenance-free battery 12V 8.6 Ah
Steering head angle	62 °
wheelbase	1510 ± 10 mm
Seat height unloaded	910 mm
Unloaded ground clearance	300 mm
Dry weight	144 kg
max. Front axle load	150 kg
max. rear axle load	200 kg
max. total weight	350 kg

engine

design type	Single-cylinder four-stroke gasoline engine with balancer shaft and electric starter, liquid-cooled
Displacement	625 cc
Bore / stroke	101/78 mm
compression	11.7: 1
fuel	unleaded premium fuel with at least 95 octane (RON); 80–94 octane with a different ignition curve
control	4 valves via rocker arm u. 1 controlled camshaft, single chain drive of the camshaft
camshaft	249/1
Valve diameter	Inlet: 36 mm, outlet: 32 mm
Valve clearance cold	Inlet: 0.12-0.15 mm, outlet: 0.12-0.15 mm
Crankshaft bearings	2 cylindrical roller bearings
Connecting rod bearings	Needle roller bearings
Piston pin bearings	Bronze bushing
piston	Light metal, forged
Piston rings	1 compression ring, 1 minute ring, 1 oil control ring
Engine lubrication	2 Eaton pumps
Engine oil	only fully synthetic engine oils that meet the quality requirements of JASO MA
Engine oil capacity	approx. 2.1 liters including frame
Primary drive	straight toothed spur gears 31: 79 Z
coupling	Multi-disc clutch in an oil bath, hydraulically operated
transmission	5-speed, claw shift
Gear ratio	1st gear 14:35, 2nd gear 15:24, 3rd gear 18:21, 4th gear 20:19, 5th gear 22:18
Ignition system	contactless controlled DC-CDI ignition system with digital ignition adjustment, type KOKUSAN 4K5
Ignition timing	Map-controlled via TPS
generator	12V, 200W
spark plug	NGK DCPR 8 E
Electrode gap	0.9 mm
cooling	Liquid cooling , permanent circulation of the cooling liquid by a water pump
Coolant	1 liter, mixing ratio 50% frost protection, 50% water, at least −25 ° C
Jump start	Electric starter and kick starter

Other models

Versions with the designation SM or Supermoto differ essentially from the Enduro in that they have smaller wheels with road racing tires, larger front brakes and tighter chassis settings. The races in which these "supermotards" have been used since the mid-eighties of the last century take place on circuits with a high proportion of off-road vehicles.

Another model with only minor differences to the KTM 640 LC4 Enduro is the KTM 400 LS-E Military of the German Armed Forces . LS-E originally stood for "Low Seat - Electric Start". This model series was only available for a short time on the civilian market (with 400 and 609 cm ³ ), although astonishingly, with greatly reduced spring travel, it was as suitable for off-road use as the "high" normal version. (see "Enduro Magazin" 7/1997, "MO" 8/1997 e.al.)

In 1997, KTM introduced the "Adventure" model series with frame-mounted fairing and 30-liter tank, which was modeled on the rally machines (Paris-Dakar).

Individual evidence

1. ↑ KTM 640 LC 4 ► Tests & driving reports, current innovations and market offers - MOTORRADonline.de. June 10, 2008, accessed December 21, 2019 . 
2. ↑ KTM LC4 640. Accessed December 21, 2019 . 
3. ↑ 30 years of the KTM LC4 | hot cars. Retrieved December 21, 2019 . 

Web links

• The rocky road of the LC4 . In: Handelsblatt . June 28, 2011.