Polini Thor information for most models
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It is a good idea to check Polini's website to get the latest (or additional) information. If you find errors here or things that will help other pilots, please contact us. We try to be as accurate as possible but the marketing departments make this task difficult and sometimes impossible. Please note that the factory manuals sometimes are missing critical information for the repair and maintenance of these engines. We do our best to fill in these gaps.
The Thor models share a common design and many parts. If you cannot find the info you need below or on the individual Thor model pages, check the Top 80 section for a wealth of info that is common to all Italian paramotors.
Before putting any paramotor in service, new or used, CHECK THE TORQUE of the head nuts!
General assembly instructions - It is CRITICAL when assembling the Thor engines that the manifold mounting nuts be properly torqued with blue threadlock if you do not want any leaks.
Airbox support problems – The airbox tends to slip crossways onto the carburetor and leak after the engine is run for some hours. Here's the fix.
Assembly video – This is for the Thor 130, other models similar.
Bearing condition – What condition are the bearings in my engine? Which one is the most likely to fail first?
Carburetor – The Thor 100 and 130 use the WG-8. The Thor 190 and 200 use the WB-37. If your engine is not purring like a kitten in the mid-range, you need to perform the midrange modification on your carburetor. The Thor 250 has a custom Polini carburetor (we do not stock this one). It is more like the Bing which has a fuel bowl.
Case assembly – see "Bearing replacement and case assembly" above
Choke control – This is needed for safety and convenience.
Clutch – Information and servicing procedures.
Clutch Oil – Here is a list of the oils that can be safely used in the Thor redrive.
Cold weather operations – Unfortunately, the WG-8 and the WB-37 are very sensitive to both high altitude and/or cold weather operations.
Coil secondary wire replacement – This is one of the most common points of failure in ignition systems.
Crankcase replacement – see "Rebuilding a paramotor" below. The paramotor must be completely disassembled.
Cylinder head & piston notes – when doing the 100 hour required maintenance
Cylinder head, temperature, maximum – 230°C and 250°C maximum running temperature, never exceed 265°C/280°C but only for a few seconds.
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....
Decompression port cleaning – It must be clear. Failure to keep it free of combustion deposits will greatly shorten the life of the starter.
Electrical wiring schematic – includes some troubleshooting info
Electrical troubleshooting – How to check the electrical system
Exhaust flange springs – Use paraglider line to stretch the springs for replacement/removal. Do not use Vise-Grips or 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. A defective exhaust flange gasket cannot be fixed with RTV – replace the gasket. Use PG line (best) or aircraft wire to secure the springs if they break.
Exhaust gasket installation – The side of the gasket with the greater metal-faced area goes away from the cylinder head. Thoroughly clean and degrease all surfaces, apply a thin coat of gray RTV to both sides of the gasket, and install the exhaust port. Apply RED threadlock to the studs and torque to 10 Nm. Wait (10) minutes and re-torque. Things compress slowly and the joint will be better if re-torqued after a bit.
Exhaust system installation – 1. Install springs first per above. 2. Install the buttonhead screw underneath the carburetor first THEN 3. Install the buttonhead screw underneath the exhaust port. Use blue threadlock on screws and tighten 3-4 Nm (just snug, let the threadlock do its job).
Flash starter – The Polini Thor manual starter is an expensive, annoying disaster. Here are some permanent fixes.
Flash starter cord length – see "Starter replacement cord" below
Flywheel removal and installation – this information is from the relevant section of the timing page
Frame cracks – see "Metal fatigue" below
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 tubing size – ID 4.8mm (3/16") x OD 8mm (5/16") 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 system test – A more thorough test of the fuel system.
Ignition coil – the black wire goes to ground, the blue wire goes to the kill switch
Ignition timing check – This method will give the precise timing value that 100% mechanical methods are unable to do. The Thor engines have a fixed ignition timing contrary to the the Minari and Top 80 paramotors.
Kill system, alternate – The Italians have demonstrated poor quality control over the years, including faulty cabling and connectors in the kill switch system installed on paramotors. This could be exceedingly dangerous with any engine, especially the Minari 180/200.
Kill switch problems – A low bidder made the wire used in the kill switch circuit.
Manuals – see the links for each particular model on the main paramotor page
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* – Here is a way to quickly check them. If you replace them with the heavy duty Viking mounts, do not make the mistake noted here.
Overhaul – see "Rebuilding a paramotor" below
Performance Issues, general – This is what to do if the engine will not start or, for example, dies at full throttle
Performance tuning – Most paramotors run poorly in the midrange, the range that we spend most of our time flying in.
Pulleys – see "Starter pulleys" 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.
Rebuilding a paramotor – includes disassembly and assembly of the major parts of the engine e.g. flywheel, cooling fan, carburetor, etc.
Redrive fill plug gasket – this flimsy gasket fails after no time. An 11mm ID "O" ring will work better than the gasket ever did. Do NOT over-tighten.
Safety net installation – on NEW Miniplanes the safety net comes already assembled and ready to install
Safety net replacement – replacement safety netting from Miniplane must be assembled. Here is help to prepare the net for installation (above).
Safety net wear – How to minimize wear and tear on the safety net
Spark plug installation – this is the "how to". For type of spark plug see 'SPECIFICATIONS" below
SPECIFICATIONS – Dimensions, torque values, maintenance intervals, and other useful information
Springs, exhaust – see "Exhaust springs" above
Squish – Pilots must get the correct size cylinder gasket to prevent overheating, detonation (knock), and engine damage.
Starter – see "Flash Starter" above
Starter cord length – see "Starter replacement cord" below
Starter pulleys – The OEM Viadana pulleys will quickly wear out and fail. Here is the solution...
Starter replacement cord – The strongest and longest lasting you can install on your engine.
Starting – Start your engine the first pull, every time.
Stress cracking of engine components – see "Mounts, rubber" above
Temperature – see "Cylinder head, temperature, maximum" above
Throttle cable – Cleaning, lubrication, modifications, and cruise control info.
Torque Values – See "SPECIFICATIONS" above. The specific Thor manuals on this website also have torque values. If you cannot find the correct value, check the the Top 80 specification page.
Warming up – when is a paramotor warmed up sufficiently and ready to fly? When the cylinder head temperature reaches 70ºC, the fuel/air mixture is sufficiently hot enough to ensure that it is 100% vaporized and that the engine will not be fuel starved and potentially overheat. Overheating can happen very quickly!