Miniplane Top 80 – engine, prop, and frame technical information

by Had Robinson
updated August 7, 2019

A. Troubleshooting your engine – Here are the steps and information to solve any problem with your paramotor.

B. Top 80 parts diagrams engine  redrive  redrive before 2004  exhaust  starter assy  WG-8 carb (go to Mecafly for parts identification)

C. If you need us to repair your engine, please see these important instructions.

Gear and wheel pullers should never be used when working with aluminum engine parts or housings!

Before putting any paramotor in service, new or used, CHECK THE TORQUE of the head nuts!

Owners manual – It is not easy navigating any Miniplane website.

SPECIFICATIONS – Gaps, torque values, dimensions, timing value, and maintenance intervals for the Top 80.

AVGAS – see "Fuel & oil specifications" below

Bearing condition – What condition are the bearings in my engine?  Which one is the most likely to fail first?

Bearing replacement and case disassembly and assembly – Here is how to replace the main crankshaft bearings and seals

Breaking in the Top 80 – A new motor will last longer if properly broken in.

Carburetor – Walbro WG-8 information, adjustment, & repair

Case assembly – see "Bearing replacement and case assembly" above

CHT – see "Cylinder head temperature gauge" below

Clutch – This page also includes how to properly mount the redrive so that clutch does not drag.

Clutch bearing replacement – It is done in the same manner as for the main bearings (see Bearing replacement... above).  Steel does not expand as much as aluminum so a press MUST be used to install the clutch bearings.  They will not just "clink" into place.

Cold weather operations – Unfortunately, the WG-8 and, to a lessor extent, the WB-37 are very sensitive to both high altitude and/or cold weather operations.

Cooling box fin breakage – see "Metal fatigue" below

Cooling box – removal and assembly – see cooling box removal in "setting the timing on paramotors" page

Cooling fan – it is integral to the cooling box and is removed with it.  See cooling box removal

Cooling shroud – When replacing the cooling shroud, put copious amounts of RTV between the large washers on the cylinder head studs and shroud.  This will help cut down the wear of the shroud at these points due to severe engine vibration.  Order of hardware: large washer, shroud, plastic washer, nut

Compression check – One of the best ways to quickly check the overall health of an engine.

Crankcase external pulse port – see "External pulse port installation" below

Crankcase leaks – see "Redrive, carb, and exhaust leaks" below

Crankcase pressure test – The only way to be sure the main seals and various gaskets are not leaking.

Crankcase replacement – see "Rebuilding a paramotor" below.  The paramotor must be completely disassembled.

Cruise control – Not a good idea and here is why.

Cylinder gasket installation – see "Squish" below

Cylinder head & piston notes – when doing the 100 hour required top end maintenance

Cylinder head "O" ring gasket installation – NEVER REUSE A CYLINDER HEAD "O" RING

Cylinder head temperature gauge – Not having a CHT is like driving a car without any gauges or warning lights. Most of the time you don't need them....

Cylinder honing – Cylinders that are lightly worn can be honed and the piston ring replaced.

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

Cylinder replacement, new – See "Determining the correct size of gasket to use" and follow the directions.  If a compression check gives a value less than 90% of specifications, replace the cylinder including the piston and ring.  Also, see "rebuilding 2-cycle engines" below for more general info.  Instead of replacement, pilots may have their cylinders bored and honed at this shop (RB Designs).  You will have to measure the cylinder diameter with a micrometer, determine the correct oversized piston needed, get it from Miniplane-USA, and send it all in to RB Designs.

Cylinder squish – See "Squish" below

De-carbonizing a two stroke engine – It must be done often enough to prevent overheating.

Detonation – This is a serious problem caused by cheap gasoline while running engines near sea level.  Use AVGAS  or premium ethanol-free fuel whenever possible in order to prevent this problem.  Incorrect ignition timing and too little cylinder squish can also cause detonation.

Disassembly of the Top 80 – see "Engine overhaul" below

Engine mounts – see "Mounts, engine" below

Electrical troubleshooting – How to check the electrical system in the Top 80 and other paramotors

Engine oil leaks – see "Redrive, carb, crankcase, and exhaust leaks" below

Engine rebuild – See "Rebuilding 2-cycle engines" below

Engine stall – Sudden engine stall when full throttle is applied can have various causes.  Study the 2nd paragraph in the throttle shaft play page.

Exhaust – also see the "Muffler" section below

Exhaust port gasket, nuts, and springs – How to install the gasket correctly and then properly tighten the nuts and springs.

Exhaust port leaks – see "Redrive, carb, crankcase, and exhaust leaks" below

Exhaust port repair tool – If the cylinder exhaust port is damaged, this tool can repair it.  Here is how to do it.

Exhaust springs – How to remove and install them correctly.  Note: for a while Miniplane supplied defective springs which constantly broke.

Exhaust system O-ring leaks

External pulse port installation – needed for some accessories including an auxiliary fuel pum

Fading – see "Performance Issues" below

Finger screw and starter pawl installation and removal

Finger screw modification – Every time the cooling fan is removed, the finger screws should be replaced ($$$).  Here is how to re-use them.

Flywheel removal and installation

Frame cracking – see "Metal fatigue" below

Fuel & oil specifications – 2% (50:1) full synthetic oil with premium MOGAS or AVGAS

Fuel filter – What kind/type to use?  If you choose poorly, the engine will also run poorly, if at all.  Removal and installation tips.  The fuel system MUST be purged of old fuel and air when changing out the fuel filter!

Fuel line size/installation – Pure silicone grease is needed to aid installation otherwise the lines may split.  For sizes and type, see Specifications

Fuel mixed? – Is there oil in the gasoline?

Fuel system leaks – If air finds its way into the fuel system piping/filters, the engine can be damaged from fuel starvation.  These leaks must be fixed!

Fuel system quick test – See the "Quick fuel system test"

Fuel system test – A more thorough test of the fuel system.

Fuel tank cap leaks – How to find and fix the factory defects which make it hard to prime the fuel system.

Gearbox – see "redrive" below

Gudgeon pin circlips – see "Piston wrist pin circlips" below

Harness adjustment

Harness strap repair – Thinner pilots routinely have the buckles break.  Here is how to easily fix the problem.

High altitude use – How to tune your Top 80 for use at high altitudes (part of the WG-8 carburetor page).

Hub – see "Propeller hub info, removal & installation" below

Ignition coil check – see "Electrical troubleshooting" below

Ignition coil, flywheel gap adjustment

Ignition coil, loose inner coil – when it becomes loose/detached from the iron core and how to repair it

Ignition coil replacement

Ignition coil, secondary wire replacement – This is the most common point of failure in the ignition system in all but the newest models

Ignition coil secondary wire troubleshooting – see "Electrical troubleshooting" below

Ignition timing – How to accurately set the timing on most paramotors

Ignition timing check – This method will give a precise timing value that other methods are unable to do.

Ignition troubleshooting – see "Electrical troubleshooting" above

Kill switch problems

Knocking – See "Detonation" above

Leaks, fuel – see "Fuel tank leaks" or "Fuel system leaks" above.

Leaks, oil – see "Redrive, carb, and exhaust leaks" below

Main bearing seals – If they leak slightly after 100's of hours of use, it only causes a little mess and is to be expected.  Leave them alone.

Maintenance info & intervals

Manual, owners – see "Owners manual" below

Metal fatigue – Pilots who put 100's of hours on any paramotor must keep an eye out for this hazardous and hard to see problem.

Miniplane frame information – options, sizes, side stick lengths, etc.

Mounts, rubber (engine) – Here is a way to quickly check them.  These are normal consumable parts that fail with use.

Muffler oil leaks – see "Exhaust system O-ring leaks" above

Muffler problems – Rarely, the muffler can get clogged (from Bill Stoll)

Net stringing – see "Safety net stringing" below

Net repair – see "Safety net repair" below

Net wear – see "Safety net wear" below

Oil leaks – see "Redrive, carb, crankcase, and exhaust leaks" below

Oil specifications for the Top 80 – see "Fuel & oil specifications" above

Overhaul – see "Rebuilding a paramotor" below

Overheating – This will destroy an engine.  What causes it?  How is it prevented?

Owners manual – It is not easy navigating any website authored by Miniplane.  If you dig around you can find some helpful information that is already somewhere on this site.

Packing the Top 80 for shipment  (If you wish to just ship an engine, follow these instructions)

Performance issues – Does your engine run poorly, if at all?  This page can help.  Also, see the WG-8 carburetor page.

Performance tuning – Most paramotors run poorly in the midrange, the range that we spend most of our time flying in.

Piston wrist pin circlips (springs) – Never reuse them.  See this video for how to remove or install them.  Stuff a rag in the crankcase so in case you drop one, it does not disappear in the guts of the crankshaft.  Be certain that the circlip is completely seated and installed with the circlip opening facing down.  This helps insure that the clips do not come out.

Piston replacement – It is not advisable to attempt this without intermediate mechanical skills.  See "Rebuilding a paramotor" below.

Piston Ring – How to remove and install it and tell if it needs replacement.

Piston sizes – see "Cylinder piston sizes" above

Power loss – see "Performance issues" above

Priming the fuel system on a paramotor – see "Starting your paramotor" below

Propeller hub info, removal & installation – Note: A propeller strike that damages the propeller will likely bend the hub and cause vibration!

Propeller info – General information including how to correctly attach and repair it.  A propeller strike can also deform the hub – it must be checked.

Propeller bolt shear problems – Read the info above (Propeller Info).  Also, see "T-Nut Milling Tool" below.

Propeller shaft seal replacement – Here is how to quickly and easily replace the seal without taking the redrive apart.

Pulley, starter – see "Starter pulley" below

Purging the system of fuel – It must be done if a paramotor is to be stored for more than a few weeks, especially if you are using ethanol fuels.

Pulse port, external – see "External pulse port installation" above

Rebuilding a paramotor – includes disassembly and assembly of the major parts of the engine e.g. flywheel, cooling fan, carburetor, etc.

Redrive alignment – see the clutch page.

Redrive clutch – see "clutch" above.  The redrive contains a clutch and a set of reduction gears.

Redrive hub removal and installation – see "Propeller hub and removal installation" above

Redrive removal and installation – see the clutch page.

Redrive fill plug – see "Redrive leaks" below.  The plug can become clogged and cause leaks in the redrive

Redrive, carb, crankcase, and exhaust leaks – is it a leak from the carburetor, the redrive, the exhaust port, or from an engine crankshaft seal?

Redrive lubricant – Info on the correct type, quantity, and how to change.

Redrive mounting and alignment – see the clutch page.

Redrive mounting stud failure – Stainless steel is inferior to class 12.9 steel hardware.  The former will fail on engines with many hours.

Redrive overhaul

Redrive seal replacement – see "Propeller shaft seal replacement" above

Reed valve – Note: A loose reed valve body or clogged ports will affect the fuel pump.  The mounting screws must be torqued to the correct value.

RTV – e.g. Permatex Blue or Ultra Grey.  Used to seal case halves, some gaskets, and surfaces.  Apply with clean fingers.  Forget the spout that comes with the tube.  It is useless.  Use Ultra Grey for sealing surfaces that may become hot, like the exhaust flange gasket.  MORE SEALANT IS NOT BETTER!

Rubber mounts – see "Mounts, rubber" above

Safety net new installation or replacement

Safety net wear – How to minimize wear and tear on the safety net

Sand damage – It is fun to fly at the beach but taking off in the sand one time is worse than 100 hours of normal running time because sand gets into the engine.  The fine grit can also cause the piston ring to stick, causing more damage.  Always launch from grass.  If it is wet, all the better.

Secondary wire replacement – see "Coil secondary wire replacement" above.

Secondary wire troubleshooting – see "Electrical troubleshooting" above

Sidestick mount protection – The sidebars and sidestick mounts will grind away on each other.  Here is a fix.

Smoke systems – Pilots must be extremely cautious when installing smoke systems on any 2 stroke engine with a tuned exhaust and here is why.

Spark plug cap replacement – It is not that simple if you want it to last and work well.

Spark plug info – Meaning of the NGK part numbers

Spark plug installation

Spark plug reading – How to do it.  A cylinder head temperature gauge (CHT) is essential and will confirm what the observed condition of the spark plug.  Also see "Electrical troubleshooting" above.

Spark plug specifications – go to "SPECIFICATIONS" below

SPECIFICATIONS – Dimensions, torque values, maintenance intervals, and other useful information

Springs, muffler – see "Exhaust system springs" above

Squish – Pilots must get the correct size cylinder gasket to prevent overheating, detonation (knock), and engine damage.

Stall – see "Engine stall" above

Starter cord – How to replace it.  See Mark Kubisch's notes below

Starter pawl and finger screw installation – see "Finger screw and starter pawl installation and removal" above

Starter pulley – The OEM Viadana pulley quickly wears out and fails.  Here is the solution...

Starter replacement cord – This cord is 100% Dyneema line and is superior to the OEM cord.

Starter – How to properly disassemble and lubricate the starter and help it last longer.

Starter kick – when stopping the engine, the pawls engage the starter and kick the starter assembly hard.  Here is how to prevent this.

Starting your paramotor – Start your engine the first pull, every time.  Here is the secret on how to correctly prime the carburetor.

Storage – If you are storing your paramotor for more than a few weeks, PURGE THE FUEL SYSTEM!

Stress cracking of the engine frame and other components – see "Mounts, rubber" above

Tachometer – Is your engine due for routine maintenance?  Has power output changed?  You won't know without a tachometer/hour meter.

T-Nut milling tool – Installing T-Nuts will beef-up the propeller-hub mounting system.  It is Miniplane's response to the rumor-mills on the PPG blogs.

Threadlock – An important item in a pilot's toolbox

Throttle support breakage – see "Metal fatigue" above

Throttle cable – Cleaning, lubrication, important modifications, and cruise control info.  For kill switch issues, see "kill switch problems" above.

Throttle return spring replacement – Improve throttle response, lessen hand fatigue with this modification/replacement.

Timing, checking the value – see "Ignition timing check" above

Timing the Top 80 – See "Ignition timing" above

Tools – Paramotor essential tool kit

Torque values

Troubleshooting the engine – see "Performance issues" above

Tune-up – Here is how to tune up the Walbro carburetor

Vapor lock – This is a serious problem with all paramotors that have the tank mounted below the engine.  See our page on fuel and oil specs for more information on this issue.

Vibration – Vibration is most often caused by an unbalanced propeller (especially wooden ones), misaligned redrive, or, most often, a damaged hub from a propeller strike.

Walbro WG-8 carburetor – see "carburetor" above

Water in fuel

Weight – 20.7 kg (45.5 lb) all up weight minus fuel

Wrist pin circlips –see "Piston wrist pin circlips" above

From Miniplane-USA

Parts – Miniplane-USA has excellent stock of everything and the best service.  This site (in French) has detailed diagrams and information on every part in the Top 80 engine so that you can order the parts you need accurately.  It is also handy when repairing the Top 80.  "Where does this part go?" WARNING: Some of the part diagrams have errors in parts placement so caution is advised.

From Miniplane Italy

WARNING: For some reason, Miniplane is unable, often enough, to create a useable website in any language.  If you get a headache trying to comb information from them, you are not alone.  Here is an example.  Maybe the web guy fell asleep working on it?  Or just wanted to go drinking and chase women?  In the Italian Socialist Paradise, you cannot get fired.

Disassembly of the Top 80 – Part 1  Part 2  Somewhat detailed video on how to take apart the Top 80 properly.  It does not include disassembly of the motor itself (cylinder, head, reed valves, clutch, redrive).  If the motor needs additional disassembly, see the respective notes on this page.

Features of the Miniplane (from Miniplane)

Official website for operation & maintenance – it is now in English and kept mostly current by Miniplane.  Note: the English version of this site may not be online at times.  Go here for Miniplane's professional service information.  These sites are quirky, have poor English, and are often out of date.

From Mark Kubisch

Service Notes – Redrive overhaul for older grease filled units (including lubricant replacement) & pull start cord replacement.  When reassembling the cases, use grey type RTV sealantMark's technique for removing the propeller hub will damage it.  Remove the hub with heat, as shown on this page.  Also, bearings will simply drop out of case halves if proper heat is used.  There is never any need to pry/pull on anything if the proper techniques and tools are used.

Pullers should never be used when working with aluminum.  They can be used to gently remove things that are snug but only tightened with the fingers.

When removing the main gear, do not let anything metal (steel) come in contact with the case half.  Thin pieces of wood can be used to protect things.  The small pinion should easy slide off the shaft and does not need to be pulled.  Removing the bearings is easy.

From Alex Varv

De-carbonizing a two stroke engine

Turkey Vulture

USHPA
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