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Junak · Overhead-cam four-stroke single, wet sump, gearbox shares engine oil, chain drive

902

Library entry covers 2020

19 factory 51 guideline

Published source

Junak 901 / 902 Instrukcja obsługi, Harmonogram przeglądów serwisowych p.22 (junak.com.pl)

Factory source. Covers Junak 901/902 owner's manual (official junak.com.pl PDF; prints Junak 901 and Junak 902; no model year or edition seen).

70 items for a 2020 model, grouped by interval the way a factory chart is laid out.

How this bike is built (what the schedule is based on)

Engine cycle: Four-stroke
Engine lubrication: Wet sump (oil in crankcase)
Oil filtration: Replaceable cartridge or spin-on filter
Valve gear: Overhead cam, screw/locknut adjusters
Ignition: Electronic (CDI / transistor / ECU)
Charging: Alternator / stator with rectifier
Battery: Wet cell (flooded lead-acid, needs topping up)
Fuel system: Fuel injection
Cooling: Air / oil cooled
Primary drive: Gear or chain inside engine, shares engine oil
Gearbox oil: Shares engine oil
Clutch control: Hand lever, cable
Final drive: Chain
Front suspension: Telescopic fork
Rear suspension: Swingarm, twin shocks
Front brake: Disc, hydraulic
Rear brake: Drum (or band / belt rim)
Wheels: Spoked, tubed
Sidecar: No sidecar

Maintenance schedule

2020 Junak 902

On the road: every 300 km

1 item

Check engine oil level

Pre-ride / on the road

Guideline

Each fuel stop on old machines. Dry sump: check the tank hot, engine idling or just stopped, per your manual.

On the road: every 500 km

3 items

Check lights, horn, brake light switches

Pre-ride / on the road

Guideline
Check tire pressures

Pre-ride / on the road

Guideline
Lubricate drive chain

Pre-ride / on the road

Guideline

Lube warm, ideally at the end of the riding day so it soaks in overnight. Sooner after rain.

On the road: every 1,000 km

1 item

Check chain slack and rear wheel alignment

Pre-ride / on the road

Guideline

Every 300 km

1 item

Drive chain (lubricate)

Final drive

Factory

Factory: Harmonogram przeglądów serwisowych (Junak 901/902 owner's manual, Polish, official junak.com.pl PDF, section 13, printed p.22): every 300 km. Columns as printed: 300 / 1,500 / 3,000 / 4,500 / 6,000 km; beyond the table, continue with the same intervals. Key: S check, clean, adjust or replace if necessary; R adjust; C clean; W replace; D tighten.

Every 1,500 km or 12 months

1 item

Engine oil (replace)

Engine

Factory

Factory: Harmonogram przeglądów serwisowych (Junak 901/902 owner's manual, Polish, official junak.com.pl PDF, section 13, printed p.22): W at 300 km, then every 1,500 km, or once a year (once a year if under 1,500 km in a year). Columns as printed: 300 / 1,500 / 3,000 / 4,500 / 6,000 km; beyond the table, continue with the same intervals. Key: S check, clean, adjust or replace if necessary; R adjust; C clean; W replace; D tighten.

Every 1,500 km

12 items

Bolts and nuts of every part (tighten)

Engine

Factory

Factory: Harmonogram przeglądów serwisowych (Junak 901/902 owner's manual, Polish, official junak.com.pl PDF, section 13, printed p.22): D at 300 km, then every 1,500 km. Columns as printed: 300 / 1,500 / 3,000 / 4,500 / 6,000 km; beyond the table, continue with the same intervals. Key: S check, clean, adjust or replace if necessary; R adjust; C clean; W replace; D tighten.
Spark plug (adjust)

Engine

Factory

Factory: Harmonogram przeglądów serwisowych (Junak 901/902 owner's manual, Polish, official junak.com.pl PDF, section 13, printed p.22): R at 300 and 1,500 km. Columns as printed: 300 / 1,500 / 3,000 / 4,500 / 6,000 km; beyond the table, continue with the same intervals. Key: S check, clean, adjust or replace if necessary; R adjust; C clean; W replace; D tighten.
Spark plug (replace)

Engine

Factory

Factory: Harmonogram przeglądów serwisowych (Junak 901/902 owner's manual, Polish, official junak.com.pl PDF, section 13, printed p.22): W at 3,000, 4,500 and 6,000 km, so every 1,500 km. Columns as printed: 300 / 1,500 / 3,000 / 4,500 / 6,000 km; beyond the table, continue with the same intervals. Key: S check, clean, adjust or replace if necessary; R adjust; C clean; W replace; D tighten.
Valve clearance (check, adjust)

Engine

Factory

Factory: Harmonogram przeglądów serwisowych (Junak 901/902 owner's manual, Polish, official junak.com.pl PDF, section 13, printed p.22): S at 300 km, then every 1,500 km. Columns as printed: 300 / 1,500 / 3,000 / 4,500 / 6,000 km; beyond the table, continue with the same intervals. Key: S check, clean, adjust or replace if necessary; R adjust; C clean; W replace; D tighten.
Air filter (check, clean or replace)

Fuel and air

Factory

Factory: Harmonogram przeglądów serwisowych (Junak 901/902 owner's manual, Polish, official junak.com.pl PDF, section 13, printed p.22): S at 300 km, then every 1,500 km; clean or replace more often in dusty conditions. Columns as printed: 300 / 1,500 / 3,000 / 4,500 / 6,000 km; beyond the table, continue with the same intervals. Key: S check, clean, adjust or replace if necessary; R adjust; C clean; W replace; D tighten.
Fuel pump and fuel system (check)

Fuel and air

Factory

Factory: Harmonogram przeglądów serwisowych (Junak 901/902 owner's manual, Polish, official junak.com.pl PDF, section 13, printed p.22): S at 300 km, then every 1,500 km. Columns as printed: 300 / 1,500 / 3,000 / 4,500 / 6,000 km; beyond the table, continue with the same intervals. Key: S check, clean, adjust or replace if necessary; R adjust; C clean; W replace; D tighten.
Battery electrolyte (check)

Ignition and electrics

Factory

Factory: Harmonogram przeglądów serwisowych (Junak 901/902 owner's manual, Polish, official junak.com.pl PDF, section 13, printed p.22): S from 1,500 km, every 1,500 km. Columns as printed: 300 / 1,500 / 3,000 / 4,500 / 6,000 km; beyond the table, continue with the same intervals. Key: S check, clean, adjust or replace if necessary; R adjust; C clean; W replace; D tighten.
Clutch (check)

Primary and gearbox

Factory

Factory: Harmonogram przeglądów serwisowych (Junak 901/902 owner's manual, Polish, official junak.com.pl PDF, section 13, printed p.22): S at 3,000, 4,500 and 6,000 km. Columns as printed: 300 / 1,500 / 3,000 / 4,500 / 6,000 km; beyond the table, continue with the same intervals. Key: S check, clean, adjust or replace if necessary; R adjust; C clean; W replace; D tighten.
Drive chain and sprockets (check)

Final drive

Factory

Factory: Harmonogram przeglądów serwisowych (Junak 901/902 owner's manual, Polish, official junak.com.pl PDF, section 13, printed p.22): S at 300 km, then every 1,500 km. Columns as printed: 300 / 1,500 / 3,000 / 4,500 / 6,000 km; beyond the table, continue with the same intervals. Key: S check, clean, adjust or replace if necessary; R adjust; C clean; W replace; D tighten.
Wheel and steering bearings (check)

Front end

Factory

Factory: Harmonogram przeglądów serwisowych (Junak 901/902 owner's manual, Polish, official junak.com.pl PDF, section 13, printed p.22): S at 300 km, then every 1,500 km. Columns as printed: 300 / 1,500 / 3,000 / 4,500 / 6,000 km; beyond the table, continue with the same intervals. Key: S check, clean, adjust or replace if necessary; R adjust; C clean; W replace; D tighten.
Brake fluid (check)

Brakes

Factory

Factory: Harmonogram przeglądów serwisowych (Junak 901/902 owner's manual, Polish, official junak.com.pl PDF, section 13, printed p.22): S at 300 km, then every 1,500 km. Columns as printed: 300 / 1,500 / 3,000 / 4,500 / 6,000 km; beyond the table, continue with the same intervals. Key: S check, clean, adjust or replace if necessary; R adjust; C clean; W replace; D tighten.
Brake system, pads and shoes (check)

Brakes

Factory

Factory: Harmonogram przeglądów serwisowych (Junak 901/902 owner's manual, Polish, official junak.com.pl PDF, section 13, printed p.22): S from 1,500 km, every 1,500 km. Columns as printed: 300 / 1,500 / 3,000 / 4,500 / 6,000 km; beyond the table, continue with the same intervals. Key: S check, clean, adjust or replace if necessary; R adjust; C clean; W replace; D tighten.

Every 1,600 km or 6 months

2 items

Adjust rear drum brake and rod / cable linkage

Brakes

Guideline
Inspect tire tread, sidewalls and date codes

Wheels and tires

Guideline

Every 3,000 km

2 items

Oil mesh filter (clean)

Engine

Factory

Factory: Harmonogram przeglądów serwisowych (Junak 901/902 owner's manual, Polish, official junak.com.pl PDF, section 13, printed p.22): C at 1,500 and 4,500 km, so every 3,000 km. Columns as printed: 300 / 1,500 / 3,000 / 4,500 / 6,000 km; beyond the table, continue with the same intervals. Key: S check, clean, adjust or replace if necessary; R adjust; C clean; W replace; D tighten.
Timing chain (adjust)

Final drive

Factory

Factory: Harmonogram przeglądów serwisowych (Junak 901/902 owner's manual, Polish, official junak.com.pl PDF, section 13, printed p.22): R at 1,500 and 4,500 km, so every 3,000 km. Columns as printed: 300 / 1,500 / 3,000 / 4,500 / 6,000 km; beyond the table, continue with the same intervals. Key: S check, clean, adjust or replace if necessary; R adjust; C clean; W replace; D tighten.

Every 4,500 km

1 item

Fuel mesh filter (check)

Fuel and air

Factory

Factory: Harmonogram przeglądów serwisowych (Junak 901/902 owner's manual, Polish, official junak.com.pl PDF, section 13, printed p.22): S at 4,500 km. Columns as printed: 300 / 1,500 / 3,000 / 4,500 / 6,000 km; beyond the table, continue with the same intervals. Key: S check, clean, adjust or replace if necessary; R adjust; C clean; W replace; D tighten.

Every 5,000 km or 12 months

10 items

Check throttle cable(s) free play and return

Fuel and air

Guideline
Clean drive chain thoroughly (remove and soak, re-lube)

Final drive

Guideline

Non O-ring chains on old machines: remove, clean, soak in hot chain grease or lube, refit with the master link clip closed end leading.
Inspect chain and sprockets for wear (measure stretch)

Final drive

Guideline
Check steering head bearing adjustment

Front end

Guideline
Inspect fork seals, stanchions and fork boots

Front end

Guideline
Check footrests, pegs, rear brake and gear lever pivots

Rear suspension and frame

Guideline
Grease and check center / side stand and springs

Rear suspension and frame

Guideline
Check brake pads and discs

Brakes

Guideline
Check spoke tension and wheel true

Wheels and tires

Guideline
Check wheel bearings for play

Wheels and tires

Guideline

Every 6,500 km or 12 months

3 items

Inspect, clean and gap spark plugs

Engine

Guideline
Adjust clutch free play, lubricate cable and lever pivot

Primary and gearbox

Guideline
Lubricate brake cam spindles, check linings and drums

Brakes

Guideline

Every 8,000 km or 12 months

2 items

Change engine oil

Engine

Guideline

Pre-1970 machines: many owners run non-detergent or classic-spec oil with no filter, so short intervals matter. Dry sump: drain the tank and the crankcase/sump, flush the tank and clean the feed and return screens.
Replace oil filter

Engine

Guideline

Every 9,500 km or 12 months

6 items

Clean / inspect air filter

Fuel and air

Guideline

Mesh or oiled foam: clean and re-oil. Paper: blow out or replace. Some very early machines have no filter at all.
Check charging voltage and regulator / cut-out

Ignition and electrics

Guideline
Check swingarm bushes for play

Rear suspension and frame

Guideline
Inspect rear shocks for leaks and damping

Rear suspension and frame

Guideline
Lubricate control cables and lever pivots

Controls and cables

Guideline
Lubricate speedometer / tachometer cables, check drive

Controls and cables

Guideline

A dry speedo cable whips the needle and eventually kills the instrument.

Every 13,000 km or 2 years

1 item

Check and adjust valve clearances

Engine

Guideline

Every 16,000 km or 2 years

1 item

Compression test (or leak-down)

Engine

Guideline

Every 19,500 km or 2 years

3 items

Replace air filter element

Fuel and air

Guideline
Synchronize throttle bodies

Fuel and air

Guideline
Grease swingarm pivot

Rear suspension and frame

Guideline

Every 24,000 km or 3 years

1 item

Change fork oil

Front end

Guideline

Some early telescopic forks are grease filled or use very small oil quantities. Check your manual.

Every 24,000 km

1 item

Replace brake linings / skim drums (wear based)

Brakes

Guideline

Every 25,500 km or 4 years

1 item

Replace spark plugs

Engine

Guideline

Every 29,000 km

1 item

Replace chain and sprockets (wear based)

Final drive

Guideline

Every 32,000 km or 4 years

2 items

Repack / replace steering head bearings

Front end

Guideline

Many old machines use loose balls in cups and cones. Taper roller conversions are common.
Repack / replace wheel bearings

Wheels and tires

Guideline

Cup-and-cone and taper roller hubs need periodic repacking and adjustment.

Every 38,500 km or 4 years

1 item

Replace fuel filter

Fuel and air

Guideline

Every 40,000 km or 6 years

1 item

Replace swingarm bushes / bearings

Rear suspension and frame

Guideline

Every 48,500 km or 6 years

1 item

Rebuild forks: seals, bushes, springs

Front end

Guideline

Every 6 months

1 item

Clean battery terminals, check charge and strap

Ignition and electrics

Guideline

Every 2 years

4 items

Inspect wiring, bullet connectors and ground points

Ignition and electrics

Guideline
Inspect frame, welds and lugs for cracks

Rear suspension and frame

Guideline
Brake fluid (replace)

Brakes

Factory

Factory: Harmonogram przeglądów serwisowych (Junak 901/902 owner's manual, Polish, official junak.com.pl PDF, section 13, printed p.22): per the schedule or every 2 years. Columns as printed: 300 / 1,500 / 3,000 / 4,500 / 6,000 km; beyond the table, continue with the same intervals. Key: S check, clean, adjust or replace if necessary; R adjust; C clean; W replace; D tighten.
Replace brake fluid

Brakes

Guideline

Every 4 years

3 items

Replace fuel lines

Fuel and air

Guideline

Old rubber and modern ethanol fuel do not mix well.
Inspect brake hoses; replace old rubber

Brakes

Guideline
Rebuild calipers and master cylinders (seals)

Brakes

Guideline

Every 6 years

2 items

Replace inner tubes and rim tape with tires

Wheels and tires

Guideline
Replace tires on age (regardless of tread)

Wheels and tires

Guideline

No interval set

1 item

Exhaust emission level (check, adjust)

Engine

Factory

Factory: Harmonogram przeglądów serwisowych (Junak 901/902 owner's manual, Polish, official junak.com.pl PDF, section 13, printed p.22): regular checking and adjustment. Columns as printed: 300 / 1,500 / 3,000 / 4,500 / 6,000 km; beyond the table, continue with the same intervals. Key: S check, clean, adjust or replace if necessary; R adjust; C clean; W replace; D tighten.

Guideline lines: Intervals here are general guidelines for the machine's era and layout, compiled for this app. They are not factory manual figures. Check your workshop manual, and edit any interval in the bike's Schedule tab.