Top 80 specifications

by Had Robinson & others – this page includes general info, torque values, & maintenance info & intervals
updated August 5, 2019

General

Exploded parts diagrams engine  redrive  redrive before 2004  exhaust  starter  carb (go to Mecafly for parts identification)

Carburetor – Here is everything pilots will need to know about the Walbro WG-8

Carburetor idle needle – 1 1/4 turns  (1 1/8 turns if above 4,000' MSL)  These values are for the initial setting only.

Carburetor main jet – size 116 (sea level).  We stock jets of all sizes including the high altitude (HA) jets.  Contact us to purchase.

Carburetor metering lever value – 0.7mm (0.28").  If your ML diaphragm has a tang instead of a button, set the value to 1.70mm

Carburetor pop-off pressure – 1.2-1.3 Bar (17.5-19.0 psi).  Rest pressure must be 0.69 Bar (10 psi) or greater.

Carburetor pop-off spring length, new – 15.0mm  Note: old springs can have the same height as new but be defective!

Carburetor priming lever depth below top of diaphragm cover < 4.0mm

Carburetor tubing – 6mm ID x 55cm length and 4mm ID x 20cm length

Clutch bell shaft to redrive housing clearance > 29.5mm.  See the clutch page for more details on this clearance.

Clutch bell housing minimum thickness 1.2mm

Clutch springs – overall length 31mm.  If more than this, they must be replaced.  The clutch should engage at 2,500 - 3,500 RPM

Clutch seals, bearings, etc. – see "Redrive" below

Coil – see "Ignition coil" below

Compression – see "Engine compression" below

Crankshaft – longer end is the flywheel side

Cylinder gasket squish – 0.60mm-0.70mm (0.024"-0.028")  For low octane fuel make the thickness 0.80mm-0.95mm.  Engines before June 2003 require 0.80mm-0.85mm.  New gaskets compress approx. 30%.  This must be noted when calculating the gasket size.  Most common sizes are .30mm & .40mm.  Excessive gasket thickness is always better than too thin.  Too thin a gasket can cause engine damage.

Cylinder head spacers – 6mm x 10.5mm aluminum

Cylinder head studs – long 6mm x 140mm; short 6mm x 120mm

Cylinder head temperature – max 200°C, cruise temp 120°C - 150°C.  Temperatures above 160°C should be for brief periods only.  Actual temperatures will depend on load, ambient conditions and altitude.  Engines run at seal level will experience greater operating temperatures.  These temperatures have been measured with the TTO CHT.  Other brands of CHT's may give different temperatures.

Cylinder piston sizes – This is a table of the piston sizes (letters) for the corresponding cylinder diameter after boring or honing.

Engine compression – about 150 psi (sea level); 135 psi (4,000' MSL).  Values can be 10% less without problems.  Do NOT put any oil in the cylinder before testing.  Compression will be less on a engine that has not been broken-in.

Engine connecting rod, upper bearing, inside diameter, new – 17.0mm.  Service limit is about 17.1mm.

Engine cylinder dimensions – This is a table of the piston sizes (letters) for the corresponding cylinder diameter after boring or honing.

Engine main bearings – SKF BB1B 447205A

Engine mounting screws – the screws on the harness side (M6x8) are shorter than on the engine side (M6x10).  Use blue threadlock!

Engine main seals – 18 x 28 x 7mm double-lipped type FPJ  (after Feb, 2014: 18 x 32 x 7mm) These are specialized seals available only from Miniplane.

Engine mounting screws – the screws on the harness side (M6x8) are shorter than on the engine side (M6x10).  Use blue threadlock!

Engine mounts, rubber – UPPER mounts 25mmL x 25mmW; LOWER mounts 30mmL x 30mmW (or 25mmW); all mounts M6 threads

Engine timing – see "Ignition timing" below

Exhaust flange springs/nuts – go here for more information and how to tighten.

Exhaust mounts, rubber (2) – 30mm x 30mm, M8 female x 8.5mm, M8 male x 17mm.  DO NOT TORQUE THESE DOWN!  See torque specifications below.

Exhaust system O-rings – there is one large O-ring where the exhaust pipe enters the muffler.  There can be none, one, or two, small O-rings between the two exhaust pipe sections.  We sell this small O-ring separately, if needed.  Contact us to order.

Flywheel diameter – 90mm

Fuel – aviation gasoline (AVGAS) or premium grade unleaded gasoline, ethanol free.  For more info, see the fuel-oil specification page.

Fuel filter – which filter does the best job?  Which ones do you avoid?  Filter quality is all over the place so pilots have to be careful.

Fuel line/tubing size – Use Tygon® LP1100 Low Permeation Fuel Tubing (ethanol resistant).  It is available from Miniplane-USA.  Do NOT use ordinary vinyl tubing as it will become stiff quickly and stress the connections on the tank and engine.  Auto parts stores do NOT have the right type.

Fuel & oil specifications – The correct fuel & oil is critical to engine performance and long life.  This is a thorough discussion of the issues.

Fuel pump vacuum – 5" H20 (dry) 7" H20 (wet w/ fuel)  It should be obvious why paramotors with fuel tanks way below the engine have fuel supply issues.

Horsepower – see "Output of Top 80 engine" below

Hub runout – see "Propeller hub face runout" below

Ignition coil – IDM #150, coil must be installed with wiring facing out

Ignition coil primary resistance = 5 Ohms or less (but not zero)

Ignition coil secondary resistance = 8.2K Ohms ±10% (measure with a needle stuck into the secondary wire right where it comes out of the coil.)

Ignition coil + secondary wire resistance (before early 2018) = 17.5K Ohms ±10%  With our secondary kit installed, the value will be 8.8K Ohms ±10%

Ignition coil + secondary wire resistance (after late 2018) = 8K Ohms ±10%  With our secondary kit installed, the value will be 8K Ohms ±10%

Ignition coil to flywheel gap – 0.38mm (0.015") Note: The Miniplane website specifies a gap of 0.30mm (0.012") but new engines from the factory have the gap set to 0.38 mm (0.015").  The gap can safely range from 0.35mm - 0.40mm

Ignition timing – Official value is 14.5° BTDC (0.90mm - 0.95mm/0.0354" - 0.0374") piston BTDC.  Check timing  Change timing

Muffler springs – Use paraglider line to stretch the springs for replacement/removal.  Do NOT use pliers to stretch the springs because this will nick the tempered surface of the spring and weaken it.  Here is a video on how to properly do it

Muffler system O-rings – see "Exhaust system O-rings" above

Oil – see our fuel-oil specification page

Output of Top 80 engine – 11 kW (14.8 hp.) at 9500 rpm at sea level

Piston ring, clearance .038mm (.0015")

Piston ring, end gap .178mm (.007") new, max .191mm (.0075")

Piston sizes – see "Cylinder piston sizes" above

Pop-off pressure – see "Carburetor pop-off pressure" above

Power – see "Output of Top 80 engine" above

Propeller hub – the propeller hub must be installed and removed with heat!  DO NOT USE FORCE!  YOU WILL DEFORM THE HUB AND IT WILL VIBRATE!

Propeller hub face runout – < 0.013mm (0.0005") A value greater than this will cause propeller vibration, the greater the runout the worse it is.

Propeller shaft runout – < 0.013mm (0.0005") A value greater than this will cause propeller vibration, the greater the runout the worse it is.

Redrive bearings – LARGE GEAR, prop side FAG 6003 C3, engine side FAG 6202 C3; SMALL GEAR, prop side FAG 6200 C3, engine side FAG 6002 C3

Redrive clutch bell housing minimum thickness – see "Clutch bell housing minimum thickness" above

Redrive clutch springs – see "Clutch springs" above

Redrive fill plug relief pressure – 1.5-2.0 psi (new redrive models only).  If this relief valve becomes clogged, the redrive will leak oil.

Redrive hub face runout – see "Propeller hub face runout" above

Redrive lubricant – Miniplane specifies 50 ml of SAE 80W-140 gear oil.  75W-90 100% synthetic gear oil may also be used.  Older models of the redrive (before 2004) use grease.  These models do not have a drain plug and must be completely disassembled in order to replace the grease.

Redrive seals – prop shaft 17mm X 30mm X 7mm; clutch bell 15mm X 28mm X 6mm

Redrive shaft runout – see "Propeller shaft runout" above

Safety net dimensions – these are needed if repairs are made to the safety netting or if pilots want to make their own.

Secondary wire + coil resistance – see "Coil + secondary wire resistance" above

Secondary wire resistance (only) – 8.5K Ohms ±10% (before early 2018) As the resistance of the wire is measured closer to the coil, this value will decrease  proportionately.  The secondary wire has a resistance of about 570 Ohms/inch (225 Ohms/cm).  If the wire from our secondary replacement kit is used, the resistance is about 13 Ohms/inch (5.1 Ohms/cm).  After late 2018 Miniplane changed the secondary wire in their coils to one like ours which has very low resistance (<15 Ohms).  It only took them 20 years to fix their poor quality secondary wire but at least they did it!

Spark plug gap (all types, all Top 80 models) 0.5mm-0.6 mm. (.020” - .024”)  Always set the gap to the minimum.  The greater value is the maximum value, not the range.  You cannot gap the plug correctly without a wire-type gauge.

Spark plug installation and information

Spark plug type – New Top 80 engines: NGK CR9EB  Older Top 80 engines NGK B9ES or B9EG (cold flying conditions) or NGK B10ES or B10EG (hot flying conditions).  Do not use resistor type plugs e.g. BR9ES unless you have replaced the secondary wire with our kit and notice interference in your 2 way radio.  The correct heat range for the plug is necessary to prevent fouling or overheating.  Always use RED threadlock on the terminal cap lug.  It will loosen if threadlock is not used, even if it is tightened with a pair of pliers.

Speed system pulley – Harken H404 (superior to any of the OEM brands, especially Viadana)

Spring removal and installation – see "Muffler springs" above

Squish – See "Cylinder gasket squish" above

Starter cord – 1.25m x 3.0mm Dyneema.  Miniplane-USA has this superior cord over the stock OEM cord.  It will last years.

Starter cord pulleys – Harken 082 (superior to the OEM Viadana)

Tachometer/hour meter – see "Cylinder head temperature" above.  Not having this gauge is like not having an odometer on a car.

Temperature – see "Cylinder head temperature" above

Timing – see "Ignition timing" above

Vibration – A badly damaged prop will cause vibration.  However, the usual source is the prop hub which is almost always bent from a prop strike

Weight, dry – 20.5 kg (45 lb) no fuel, includes the complete Miniplane frame

Torque values

Note: The Italian paramotor manufacturers continue to use button-head screws on their engines, regardless whether they are needed or not.  Button-head screws have soft heads which make them very easy to strip with a hex bit when attempting to remove them.  Replace them with hex-head or socket-head screws, as necessary.

A. Torque conversion chart (Newton meters to/from inch pounds).  Here is an online conversion program from Nm to ft-lbs or the reverse.

B. Torque Values – If you cannot find the value you need below, use this chart (in ft-lbs only) from the engineers at Fastenal.com for the proper torque for bolts into both steel and aluminum.  This chart from Kohler Engines is in both Nm and in-lb but is not as complete.

C. Threadlock – read this important page on threadlock and how to use it and when NOT to use it.  Studs should be installed with red threadlock and torqued only 2-3 Nm.  The threadlock is what holds them!

D. Engines running near or at sea level run hotter and have greater output which causes things to loosen, especially the cylinder head assembly.

E. Torque values of common fasteners.  If you do not see the particular screw, bolt, or nut below, use the general values in the table below which are for metric class 4.6 and 8.8 fasteners.  The lower value is for 4.6 and the higher is for 8.8.  Most fasteners are class 8.8 on Italian paramotors.  The lower values should be used on aluminum fasteners.  However, if the fastener (e.g. screw/bolt) enters threads that are aluminum (most paramotors), use the lower value.  Aluminum is soft and threads in this metal can be easily stripped.

Back plate, frame – 2 Nm  Use a very small amount of blue threadlock on the (6) screws to keep them from vibrating out.  Too much and the threaded stud will turn (bad) when you attempt to remove them.

Carburetor mounting studs – 4 Nm.  It is easy to strip the threads in the reed valve body when installing these screws so be careful of the torque!  Use of threadlock is not necessary.  It is rare that these screws are ever removed.  If you break them, we have replacements (cheaper than buying a completely new reed valve body).

Carburetor/airbox mounting nuts - 0.9 Nm (8 in. lb.) Over-tightening these nuts deforms both the air box gasket (which will then jam the choke in either the open or closed position) and/or the gasket between the carburetor and the reed valve body.  If these nuts are too loose, the carburetor will leak like crazy.

Clutch nut 38-40 Nm – Do not use threadlock on this nut.

Cooling air duct (cooling shroud) locknuts – DO NOT TORQUE THESE DOWN!  They should just be snug (2-3 Nm).  Put RTV between the bottom washer and shroud.

Cooling box to crankcase (4) bolts 10 Nm – threadlock is not needed

Cooling fan/starter to flywheel screws – see "Finger screws" below.

Cylinder head nuts 9 Nm  Tighten in a cross pattern to 4 Nm and then to 9 Nm.  Note: do not use thread locking compounds on these nuts. It is best to use a 1/4" beam-type torque wrench.  Wait (10) minutes after tightening and then re-tighten to 9 Nm.  Assy order:  Short bolt – washer, nut; Long bolt – spacer, washer, nut.  After engine assembly, put the large metal washer on the stud, then the cooling air duct, plastic washer, and locknut.  Failure to get the order correctly will damage the cowling.  The locknuts holding the air duct should be just snug (2-3 Nm).  If they are torqued down the same as the nuts beneath, they will damage the air duct.

Engine case screws (5) – 5 Nm

Engine mounting button head screws – 3 Nm  Be sure to use BLUE threadlock on these critical fasteners.

Exhaust button head screws – 5 Nm Install these AFTER the exhaust flange nuts have been tightened

Exhaust flange springs/nuts – see this page for notes and how to tighten.

Exhaust flange studs – 2 Nm.  Use RED (high strength) threadlock on these studs or they will loosen.

Finger screws – 10 Nm  A 10mm deep socket must be used to tighten these screws.  Threadlock is not needed.

Flywheel nut 38 - 40 Nm  Temporary torque for setting timing 2 Nm.  Do not use threadlock on this nut as it is not necessary.

Frame to engine mounting button head screws – see "Engine mounting button head screws" above.

Muffler mounting button head screws – 10 Nm  Note: BLUE threadlock must be used on these screws.

Muffler rubber mounts (in engine) – Tighten firmly with adjustable pliers that grip the steel washer on the side that has the stud.  Use BLUE threadlock on the stud – this is very important!

Propeller bolts 6-10 Nm – It is better to be on the loose side when tightening. Note: failure to keep these torqued properly can destroy the hub.  Note: A torque wrench cannot be used on the engine side.  Use a hex bit with the torque wrench on the prop side.  Do not over-tighten!  Wooden propellers are particularly prone to loosening and must be checked regularly.  Replace the locking nuts when they turn easily or use BLUE threadlock.  Make sure the rubber washer is under the outer flange and NOT between the propeller and the hub/spacer.

Propeller hub center screw 9-10 NM – Do not use threadlock on this screw.  Go here for critical information on removal or installation.

Redrive nuts – 20-24 Nm  When assembling be certain to check the clutch for drag before torqueing the nuts down.

Redrive fill & drain plugs – 5-6 Nm.  Note: drain/fill plugs are not designed for high torque values.  It is easy to strip them.  Never use thread locking compound on drain/fill plugs.

Redrive studs – these studs should be removed and reinstalled with red threadlock.  DO NOT TORQUE THESE STUDS DOWN!  Only 2-3 Nm should be used.

Reed valve screws – 2.5 Nm (22 in lb)  You must use BLUE threadlock on these screws.  The reed valve body must be firmly attached to the crankcase for fuel pump to work.

Spark Plug – 21 Nm (15 ft. lb.)  If you do not have a torque wrench, the plug is new, and you do not have a CHT installed you may use this method to tighten it.  1. First hand tighten  2. Tighten with a wrench an additional 90-120 degrees.  DO NOT USE ANTI-SEIZE COMPOUNDS ON SPARK PLUG THREADS!  Be sure to use RED threadlock on the spark plug terminal (NOT the part that goes into the cylinder head). It will loosen, even if it is tightened with a pair of pliers, if threadlock is not used.  Some newer plugs have the terminals applied tightly.  I have found out that they, too, will loosen if the terminal is not unscrewed and red threadlock applied.  A sure sign that a spark plug has not been properly torqued is the presence of black gunk near the base (where the washer is/was) of the plug.  This part of the plug should be CLEAN!

Starter center screw – 2 Nm  Be certain to apply Blue Threadlock to this screw!

Starter mounting screws – 2-3 Nm  Do NOT use threadlock!  It is not needed because the screws already have lock washers. 

Maintenance

General instructions

A. OVERALL CONDITION  If the ignition and fuel systems are in order, engine performance will be directly related to engine compression.  If the compression is around 150 psi (at sea level), the engine top end is in good order.  Use of the best fuel (AVGAS or premium ethanol-free MOGAS) and approved oil) will give your Top 80 the longest life before a major overhaul is necessary.  Use of gasoline with ethanol will increase engine maintenance and cause rapid deterioration of fuel system parts.

B. MONITOR YOUR ENGINE  Maintenance schedules depend somewhat on how the engine is used.  Top end failure occurs without warning which is why the bearing and wrist pin should be replaced at Miniplane's suggested interval (see below).  Once the wrist pin starts to wear out, failure will occur very quickly. C. SUDDEN FAILURE  Abused engines and those that experience fuel starvation can experience failure (cylinder and piston seizure) very quickly – in just minutes.  Engines that run lean (hot) may burn up the lower connecting rod bearing and that means a complete overhaul.

D. IGNITION FAILURE  The weakest link in the Top 80 is the ignition which must be checked the moment a pilot senses a degradation in performance.  Miniplane has improved the quality of some of the components but they are still, overall, delicate. D. REED VALVE  It should be tested and, if necessary, rebuilt if you find performance down a bit after a carb rebuild, a spark plug change, and find the ignition system all in order.  That is, the big maintenance items are the usual but if there are still issues, then we look at compression and things like the reed valve.  A leak in the reed valve body will cause the fuel pump to fail after the engine warms up or pump fuel poorly.  Use BLUE threadlock on these screws.  Once you check that the body is correctly torqued down, you will not have to check it again.  Technicians at the Miniplane factory sometimes do not properly torque down fasteners on new engines and why pilots must check these things themselves. E. COMPRESSION TEST  Do a compression test on the engine every 50 hours or so and record and compare the values to be sure the cylinder and piston ring are in good shape.  If it's 150 psi plus/minus 10% (at sea level) then it's a waste to replace the piston and cylinder.  However, the wrist pin, bearing, and circlips must still be replaced at the specified intervals!

E. WHAT FAILS FIRST  The ignition, carburetor (the worst), and the wrist pin and bearing, in that order, are usually the first things which fail on the Top 80.  They must be regularly checked.  Compression tests of engines with decompression ports can be done but the pressures observed will be substantially less than engines without decompression ports.  Engines with flash starters cannot have their compression measured easily except by removing the starter completely and turning the crankshaft with a powerful electric drill.

F. TYPE OF USE  This maintenance schedule here is for average use.  If you run at full power most of the time, fly near the ocean, or launch from sandy areas, you may have to check and replace things more often.

Maintenance intervals

If you are storing your paramotor for more than a few weeks, PURGE THE FUEL SYSTEM  Ethanol WRECKS all carburetors over time.  Walbro SPECIFICALLY warns about the damage done to carburetors that are stored with any fuel in them.

Changing the spark plug and changing the redrive oil are the (2) most frequent maintenance items on most paramotors.  Use a Sharpie to write reminders on the top of the redrive (or other semi-flat area).  Any other method will not be as effective.  They are easily removed/changed with mineral spirits.  This way, you won't forget.  You have an hour meter/tachometer installed right?  Note: go to this page if you are wondering why the yellow plug is in the redrive.

writing reminders on the Top 80 redrive

NEW engines – Miniplane QC is poor or non existent and factory technicians routinely make serious errors assembling the Top 80.  Here are the most common that I have seen:

After the first 10 hours

Every year (minimum)

Every 25 hours

Every 50 hours

Every 100 hours

Every 150 hours

Every 200 hours

Every 400 hours


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