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Miniplane Top 80 – Engine, Prop, and Frame Technical Information

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.

From Had Robinson

AVGAS – see "Fuel & oil specifications" below

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

Bearing condition

Bearing replacement

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

Carburetor – Walbro carburetor information, adjustment, & repair, especially for the WG-8

Clutch – Maintenance issues, problems, and how to properly mount the redrive so that clutch does not drag.

Coil check – see "Electrical troubleshooting" below

Coil-flywheel gap adjustment

Coil replacement

Coil secondary wire replacement – This is the most common point of failure in the ignition system.

Coil secondary wire troubleshooting – see "Electrical troubleshooting" below

Cooling box fins – They eventually will break off from intense engine vibration.  Here is the fix.

Cooling box – removal and assembly – see #2 in the "Steps" section of Timing the Top 80 & other engines

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

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

Cruise control – Not a good idea and here is why (page down to the end of the article).

Note: In previous editions of these pages, I sometimes mistook "cylinder head" for "cylinder".  It has been corrected.  I apologize for any
inconvenience or confusion it may have caused.  It was a result of my many years in the 4 cycle world. – Had

Cylinder gasket installation – see "Squish" below

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

Cylinder replacement – See "Squish" below and page down the article to the last section "Determining the correct size of gasket to use" and follow the directions.  If a compression check gives a value less 90% specs, replace the cylinder including the piston and ring.  Also, see "rebuilding 2-cycle engines" below.  Pilots can also have their cylinders re-bored at this shop for a modest price and get an oversized piston from Miniplane-USA.

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 whenever possible
    in order to prevent this problem.  Incorrect ignition timing and too little cylinder squish can 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 leaks" below

Engine overhaul and rebuild – (I am working on this project with photos and the tools necessary to do it as of January 21, 2017)

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

Exhaust port leaks – see "Redrive leaks" below

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

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

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.

Frame cracking – see "Mounts, rubber" below

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

Fuel filter – A high quality filter is essential for long engine life and performance

Fuel lines – Pure silicone grease is needed to aid installation otherwise the lines may split.

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 test – A quick and easy way to tell if the fuel pump and its related parts are functioning properly.

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

Gearbox – see "redrive" below

gudgeon pin circlips – see "Piston gudgeon or 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 – see "Coil" above

Ignition troubleshooting – see "Electrical troubleshooting" above

Kill switch problems

Knocking – See "Detonation" above

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

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.

Metal fatigue – Pilots who put many hours on their Miniplane MUST keep an eye out for this hazardous and hard to see problem.

Mounts, engine – Here is a way to quickly check them.  These are normal consumable parts that fail with use.  Pilots must keep an eye on them and replace them regularly.

Muffler springs – see "Exhaust system springs" above.

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 leaks" below

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

Overhaul – see "Engine overhaul" above

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

Packing the Top 80 for shipment  (If you wish to ship your engine to us, also follow these instructions)

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

Piston gudgeon (UK)/wrist (US) 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.

Piston replacement – It is not advisable to attempt this without intermediate mechanical skills.  See "Rebuilding 2-cycle engines" below.

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

Power loss – see "Performance issues" above

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

Propeller hub info, removal & installation – Note: Damaged hubs will cause severe 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

Rebuilding 2-cycle engines – When is it time?  This general and helpful article from Utah Motor Trails can help you decide and gives the basics on how
     to do it.  The wrist/gudgeon pin in a well-taken care of Top 80 may be the first part to fail.  It would save cost if just the pin was available and
     it could be replaced along with the bearing and circlips, but this is not possible.  The complete piston assembly must be purchased.  Here are some
     good tips from MCB Performance on rebuilding two-stroke engines.

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 fill plug – see "Redrive leaks" below, go to paragraph "C".  The plug can become clogged and cause leaks in the redrive

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

Redrive mounting and alignment – see section B.1 on 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 lubricant – Info on the correct type, quantity, and how to change.

Redrive overhaul and disassembly – see Mark Kubisch's notes below

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

Reed valves – Info on how to check and replace them.  They can also leak air.

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 stringing

Safety net repair

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 cycle engine with a tuned exhaust and here is why.

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 superior to spark plug reading which is why every pilot should have one.

Spark plug troubleshooting – see "Electrical troubleshooting" above

Spark plug specifications – go to "SPECIFICATIONS" below

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

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 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 – tips on how to help it last longer and where to get quality pulleys that will last the life of the engine.

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

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 cable – Cleaning, lubrication, 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 – This method will give a precise timing value that 100% mechanical methods are unable to do.

Timing the Top 80 – This is the factory method (and the best way) with some tips.

Tools – Paramotor essential tool kit

Torque values – go to "SPECIFICATIONS" above

Troubleshooting the engine – see "Performance issues" above

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

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

Walbro WG-8 carburetor – see "carburetor" above

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

Wrist pin circlips –see "Piston gudgeon or 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

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 disassembly, see the notes by Had Robinson at the top of 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 (including lubricant replacement) & pull start cord replacement.  The service note on the redrive is for the older models (that use grease) but the method for overhauling them is the same.  When reassembling the cases, use grey type RTV sealant.  If you do not feel comfortable splitting open the redrive, send it to us and we can do it for you.  Note: Mark's technique for removing the propeller hub can damage it.  Remove the hub with heat, as shown on this page.  Bearings will simply drop out of case halves if proper heat is used.  Pullers should never be used when working with aluminum.  When removing the main gear, do not let anything metal 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 not need to be pulled.  Removing the bearings FIRST is easy.

From Alex Varv

De-carbonizing a two stroke engine