paragliding training center
A. Troubleshooting your engine – Here are the steps and information to solve any problem with your paramotor.
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!
AVGAS – see "Fuel & oil specifications" below
SPECIFICATIONS – Gaps, torque values, dimensions, timing value, and maintenance intervals for the Top 80.
Bearing condition – What condition are the bearings in my engine? Which one is the most likely to fail first?
Breaking in the Top 80 – A new motor will last longer if properly broken in.
Carburetor – Walbro carburetor information, adjustment, & repair
Case assembly – see "Bearing replacement and case assembly" above
Clutch – This page also includes how to properly mount the redrive so that clutch does not drag.
Coil check – see "Electrical troubleshooting" below
Coil secondary wire replacement – This is the most common point of failure in the ignition system.
Coil secondary wire troubleshooting – see "Electrical troubleshooting" below
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 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 honing – Cylinders that are lightly worn can be honed and the piston ring replaced. Contact RB Designs for more information.
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 "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 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. Alternately, pilots may send the cylinder to us and we can do it all. Contact us for more information.
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 remove and 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 modification – Every time the cooling fan is removed, the finger screws should be replaced ($$$). Here is how to re-use them.
Frame cracking – see "Metal fatigue" 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 quick test – See the "Quick fuel system test" in section A of the link
Fuel system test – A more thorough test of the fuel system.
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 strap repair – Thinner pilots routinely have the buckles break. Here is how to easily fix the problem.
Hub – see "Propeller hub info, removal & installation" below
Ignition coil – see "Coil" above
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
Knocking – See "Detonation" above
Leaks, fuel – see "Fuel tank leaks" or "Fuel system leaks" above.
Leaks, oil – see "Redrive 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.
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.
Mounts, rubber (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?
Performance tuning – Most paramotors run poorly in the midrange, the range that we spend most of our time flying in.
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.
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: Damaged hubs will cause severe vibration!
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 upper connecting rod bearing in a well-taken care of Top 80 will be the first part to fail. Here are some good tips from MCB
Performance on rebuilding two-stroke engines. Splitting open the engine case is a very technical job and requires special tools that will not
destroy the case halves. Go to this page for information on how to remove and re-install bearings and the correct way to seal the case halves.
Redrive alignment – see section B.1 on 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 section B.1 on the clutch page.
Redrive fill plug – see "Redrive leaks" below, go to paragraph "C". The plug can become clogged and cause leaks in the redrive
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 valve – Note: A loose reed valve body 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 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 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 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 pawl and finer 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 tips on how to help it last longer.
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, 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 – 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), misaligned redrive, 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
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.
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.
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.
Service Notes – These include redrive overhaul (including lubricant replacement) & pull start cord replacement.
IMPORTANT: 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. Mark'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.
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 does not need to be pulled. Removing the bearings FIRST is easy.