Top 80 specifications

by Had Robinson & others
updated March 23, 2021

General   Torque values   Maintenance info & intervals

General

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

Carburetor – Note: the WG is out of general production and all production may end soon.  It is still available from some paramotor shops but is more than double the cost a year ago.  The WB may be used in place of the WG and is still available on the open market.

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

Carburetor main jet – size 116 (sea level), size 112 if FSM is installed (sea level).  We custom machine jets of all sizes.

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.  Typically, old springs will be 0.5 mm shorter.

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

Carburetor tubing – 6mm ID x 55cm (fuel tank to inline filter) and 4mm ID x 20cm (inline filter to carburetor

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 - 145°C.  Temperatures above 150°C should be for less than 1/2 minute or so.  If the engine runs hot, use only 100% synthetic oil e.g. Amsoil Dominator.

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

Dimensions of the Top 80 (courtesy of www.tonyfly.com)

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.  Newly rebuilt engines that have not been broken in will show 120 psi or more.

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.

Flywheel diameter  – see "Ignition flywheel diameter" below

Fuel – 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) 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.  Be absolutely certain the fuel lines are NOT leaking.  A leaking fuel line, especially at the carburetor inlet, will leak air and cause fuel starvation.

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 = 1.1 Ohms or less (but not zero)

Ignition coil secondary resistance = 8K Ohms ±10% (measure with a needle stuck into the secondary wire right where it comes out of the coil.)  This value can vary but should never be below 8K Ohms, depending on the production run.

Ignition coil + secondary wire resistance = 8K or 17.5K Ohms ±10% (one or the other depending, on the secondary wire, not the coil).  With our secondary kit installed, the value will be 8.8K Ohms ±10%.  Our secondary wire is not the resistor type.  IDM, apparently, makes some secondary wires with resistance and then some without.  IDM production runs are not consistent.

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 flywheel diameter – 90mm  circumference =  282.74mm

Ignition timing – Official value is 14.5° BTDC or 0.90mm-0.95mm/0.0354"-0.0374" piston distance from TDC or 11.38mm flywheel mark TDC.  Check timing  Change timing  The factory method used to initially set the timing gives a mechanical advance of 14.5° BTDC +/- 0.5°. Pilots who have set the timing to 17° BTDC measured with a timing light have not reported any problems. Even with the timing set correctly, the actual timing will vary, depending on the rotation speed of the flywheel, the condition of the coil and what the coil gap is.  Measured values between 14° and 17° degrees should not cause any issues. For every 1° of timing change, the piston moves 0.1mm (.004") and the flywheel 0.8mm (.032"). The timing specification has a tolerance of 0.05mm (.002") which is 1/2° +/- range in the timing or 14°-15° BTDC.

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 9,500 RPM at sea level

Overheating – see "Cylinder head temperature" above

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 ratios – There are five gearbox ratios: 18:74 (1/4.11)  19:73 (1/3.842)  20:72 (1/3.6)  21:71 (1/3.38)  22:70 (1/3.18)

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) – 500 or 8K Ohms ±10%  The 8K Ohms 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).  In 2020, Miniplane changed the wire back to 8K Ohms resistance.  Not sure why the changes...

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 – OLD model cylinder head (14mm thread)  Cold flying conditions use the NGK B9ES (2611) or B9EG (3530).  Hot flying conditions use the NGK B10ES (7928) or B10EG (3630).  The "G" type plugs will help the engine start easier and reduce oil fouling but cost more.  Use resistor type plugs e.g. BR9ES if interference is noticed using a 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 if it is a removable terminal.  It will loosen if threadlock is not used, even if it is tightened with a pair of pliers.  Some terminals are welded on (flush top surface) and do not need threadlock.  The removable terminal is threaded and the screw from the plug is visible in the center of the terminal.  For more information, see "Spark plug installation and information" above.

Spark plug type – NEW model cylinder head (10mm thread): NGK CR9EB (6955)  This is a resistor-type plug (less radio noise) with a resistance of 4.5K± Ohms

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

If you don't think you need to learn how to use a torque wrench, check this photo of a cylinder head stud that was pulled right out of the aluminum crankcase by applying too much torque to the cylinder head nut.  The threaded hole in the crankcase was ruined.  It was an expensive mistake for the owner of this engine that we had to fix.  For help, take a look at this video on torque.

over-tightening a cylinder head nut

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, if possible.

A. Torque conversion chart of Nm to inch-pounds and a conversion chart of Nm to ft-lbs.  Generally, rid your tool box of all SAE tools.  All paramotors are spec'd and manufactured using the metric standard, an unbelievably smarter and easier way to measure things and used by the entire world other than the U.S.

B. Torque Tips

C. Threadlock – read this important page on threadlock and how to use it and when NOT to use it.

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

E. Torque values of common fasteners.  If you do not see what you need in the below, use the general values in this table which are from Miniplane IT.  Fasteners must be perfectly dry and clean for these values.  I recommend reducing the torque by 20% if the fasteners have threadlock or any sort of lubricant or sealant applied.

Top 80 torque values for various parts

Miniplane back plate to 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.  Heating the screw with a torch is the only way to remove them if this happens.

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 ever need to be removed.  If you break them, we have replacements (cheaper than buying a completely new reed valve body).

Carburetor/air box 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 (5 in-lb/0.5 Nm).  Put RTV between the bottom washer and shroud.  The top metal washer should have a rubber washer between it and the shroud.  The vibrations from the engine are intense and direct metal to metal contact must be avoided.

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 (80 in-lb)  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!

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 ordinary 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 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 threadlock on drain/fill plugs.

Redrive nuts (the nuts that go on the studs that hold the redrive to the engine) – 20-24 Nm  When assembling be certain to check the clutch for drag before torqueing the nuts down.

Redrive screws – 4 Nm.  Do NOT use threadlock on these screws!

Redrive studs (the two that hold it to the engine) – these studs should be removed and reinstalled with red threadlock.  If the studs cannot be removed with moderate force, you can leave them alone.  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 – 14mm plug: 25 Nm (18 ft. lb.)  10mm plug: 10 Nm (9 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 that screws on to the top of the spark plug (if it has a removalable terminal).  It will loosen, even if it is tightened with a pair of pliers, if threadlock is not used.  I have found out that they, too, will loosen if the terminal is not unscrewed and red threadlock applied.  Most newer plugs have the terminals permanently attached.  These terminals cannot loosen.  You can tell the difference by looking at the top of the terminal.  The threaded terminal is not flush and the male threads are visible.  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

If you are storing your paramotor for more than a few weeks, purge the fuel system.  Ethanol fuels wrecks the soft parts in all carburetors over time.  Walbro warns about the damage done to carburetors that are stored with any fuel left 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 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

Every 25 hours

Every 50 hours

Every 100 hours - THIS IS A VERY IMPORTANT MAINTENANCE INTERVAL

Every 150 hours

Every 200 hours

Every 400 hours


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