1986 Service and Tuning Data
Model- IBM ID Number | VMX540K 81k |
Starting Engine Number/ Frame Number | 81k-000101/ 81k-000101 |
Engine- Type/ Induction System | 2- Stroke, Liquid Cooled, Piston port |
Bore/ Stroke/ Number Cylinders/ Displacement | 73.0mm / 64.0mm/ 2/ 535cc |
Compression Ratio | 6.7:1 |
Piston Skirt Clearance New/ Max | 0.065~0.070mm/ 0.10mm |
Ring End Gap Top/ 2nd | 0.35~0.55mm/ 0.35~0.55mm |
Ring Groove Clearance Top/ 2nd | 0.35~0.55mm/ 0.35~0.55mm |
Coolant Type/ Mixing Ratio | Ethylene Glycol- Water/ 6:4 |
Carburetor- Mfr.- Type/ Size/ Qty/ ID Number | Mikuni- VM38/ 38mm/ 2/ L:80N-00 R:80N-00 |
Main Jet/ Main Air Jet | 290/ 2.5 |
Slow Jet/ Slow Air Jet/ Air Screw | Ø/ Ø/ Ø |
Pilot Jet/ Pilot Screw (Turns Out) | 40/ ½ |
Needle Jet/ Jet Needle- Clip Position/ Cut Away/ Air Jet | Q-0/ 6DH1-4/ 3.0/ Ø |
Power Jet/ Power Air Jet | L:135 R:130/ L:1.5 R:1.4 |
Fuel Inlet Valve/ Float Level | 1.5/ 18.1mm |
Idle Speed | 1500 rpm |
AutoLube- Pump Color / Control Rod Adjustment | Red/ Adjustment Mark @ Full Throttle |
Pump Plunger Stoke Min/ Max | 0.50~0.55mm/ 2.15~2.27mm |
Output @ 200 strokes Full Throttle/ Idle | 5.40~5.71 cc/ 1.26~1.38cc |
Drive- Engagement rpm/ Shift rpm | 4000 +/- 200 rpm/ 8200 +/-200rpm |
Belt Length/ Width/ Wear Limit/ IBM Number | 1175mm/ 31.6mm/ 26mm/ 8M6 |
Sheave Center to Center/ Offset | 305 +/-1.0mm/ 11 +/-0.5mm |
Primary Spring Color/ Length/ Rate/ Preload | Pink/ 75.5mm/ 2.31Kg-mm/ 32.8 Kg |
Secondary Spring Preload/ Color/ Length | 40° (C-2)/ Pink/ NA |
Secondary Drive Ratio/ Chain Free play | 18-33/ 10 +5 -2 mm |
Track Width/ Tension | 15 in/ 25~30 mm @ 10 Kg (1.0~1.2 in @ 22lbs) |
Capacities- Chain case/ Gear Case Cap. (Type) | 250cc/ 25cc (SAE 80W 90 API GL-4) |
Fuel Tank Capacity/ Type | 24lit. (6.3 ga)/ Regular |
Autolube Tank Capacity/ Type | 2.4lit. (2.6 qt)/ Yamaha Lube 2 |
Electrical- Mfr./ Type | Hatachi/ CDI |
Headlight/ Taillight/ Meter light Ratings | 12v 60-55w/ 12v 23-8w/ 12v 3.4w |
Lighting Coil Color Code/ Resistance/ Output | Yellow~ Black/ 0.25 Ohms +/-10%/ NA |
Handlebar Heater Coil Color Code/ Resistance | Yellow-Black~ Blk/ 0.77 Ohm +/-10% |
Ignition Coil Resistance Primary/ Secondary | 0.12 Ohm ± 10%/ 4.0 Kohm +/-20% |
Source Coil Color Code/ Resistance | Brn~Red/
245 Ohm +/-10% |
Pulsar Coil Color Code/ Resistance | White- Green~ Black/ 100 Ohm +/-10% |
Spark Plug Type/ Gap/ Torque | NGK BR 9EV/ 0.7~0.8mm/ 2.75 m/Kg (19.9 ft/lbs) |
Ignition Timing | 1.6mm BTDC |
VMX 540 K High Altitude Specifications
Standard Settings | High Altitude | |
Idle | 1500 rpm | Standard |
Clutch Engagement | 4000 +/-200 rpm | 4200 +/-200 rpm |
Shift Speed | 8200 +/-200 rpm | Standard |
Main Jet | # 290 | See Setting Chart |
Slow / Pilot Jet | # 40 | Above 6000 ft: # 45 |
Pilot Screw | 1/2 Turn Out | Above 6000 ft: 1.0 turn |
Jet Needle Clip Position | # 3 | # 3 or As Needed for Response |
Gear Reduction | 18-33 | See Sprocket Chart |
Primary Spring | Pink | Org- Sil (8U9-17643-10-00) |
Primary Spring Shim | As Needed for 4000 rpm Engage | As Needed for 4200 rpm Engage |
Secondary Spring Preload | 40° (C-2) for 8200 rpm Shift | 70° (C-3) or As Need for 8200 rpm shift |
Sprocket Selection Chart
Elevation |
Drive Sprocket |
Driven Sprocket |
Sea Level ~ 4000ft |
Std ~ 17t |
Std |
3000ft ~ 6000ft |
17t ~ 16t |
Std |
5000ft ~ 8000ft |
16t |
35t |
7000ft ~ Above |
15t |
35t |