Trickyh Posted July 17, 2013 Share Posted July 17, 2013 (edited) Great post Pete! Can I ask what make of EGT sender and guage you are using? We've been dabbling with these 200's for a while and every now and again one goes pop! for no reason... EGT readings make sense, but we have also been checking for airleaks. A pressure test on a freshly blown motor can reveal a crankcase seal leak which obviously causes a lean burn. I love these engines but god they have their problems... Rich Edited July 17, 2013 by Guest 1 Quote Link to comment Share on other sites More sharing options...
pete_b Posted July 17, 2013 Share Posted July 17, 2013 Great post Pete!Can I ask what make of CHT sender and guage you are using? We've been dabbling with these 200's for a while and every now and again one goes pop! for no reason... CHT readings make sense, but we have also been checking for airleaks. A pressure test on a freshly blown motor can reveal a crankcase seal leak which obviously causes a lean burn. I love these engines but god they have their problems... Rich You want EGT readings as CHT readings can be too slow. Quote Link to comment Share on other sites More sharing options...
Trickyh Posted July 17, 2013 Share Posted July 17, 2013 Thanks Peteb! Forever on the ball! Quote Link to comment Share on other sites More sharing options...
petefinlay Posted July 17, 2013 Share Posted July 17, 2013 Hi Trickyh, I use an MGL gauge & sender. They are made in South Africa but easily bought here. My model has an EGT, CHT, Hobbs & RPM all on the one gauge. When I did my mod to lift the barrel, I put gasket compound between the alloy spacer & the case/barrel. Metal to metal is got to give an air leak! Pete Quote Link to comment Share on other sites More sharing options...
Trickyh Posted July 18, 2013 Share Posted July 18, 2013 Cheers Pete I'm guessing thats the MGL Velocity E1. How deep is it and where do you mount it? Nice bit of kit tho I'm with you on the metal on metal.. I was one of the first uptakers of the squish mod when it was first advised by Stef... I've had the 'official' gasket and reed mod sent, but haven't bothered to fit them, as so far my motor seems fine (fingers crossed) Rich Quote Link to comment Share on other sites More sharing options...
notch Posted July 18, 2013 Share Posted July 18, 2013 (edited) Pete, glad you have your issues solved. Another option would have been to order a set of PWK needles, and use the jetting spreadsheet to figure which one would be best, but it probably would have taken much longer and cost much more $$. Regarding measuring the mixture, the only issue with EGT is that the temperatures measured can decrease when detonation starts. So you can be tricked into thinking that the mixture is ok, when in fact the engine is detonating. I'm sure that's not the case with your mods though, as you have made the mixture richer. But others may be tricked in by this "feature" of EGT? Detonation happens when you are running too lean or have too much compression for the octane of the fuel. And detonation appears to be what is giving issues with the thor? An alternative is mounting a non heated denso O2 sensor & bung off ebay, connected to a high impedance digital multimeter, shouldn't cost more than 50 quid. Only negative is that if the O2 sensor is run in a rich environment for any length of time it will fail. But hopefully you have the mixture sorted by then! Edited July 18, 2013 by Guest Quote Link to comment Share on other sites More sharing options...
Trickyh Posted July 18, 2013 Share Posted July 18, 2013 I run a Keihin HKK needle, cos Polini in 'their' wisdom will not give out the needle dims.. Gives us a starting point to start playing with different needle sizes. Only problem is trying to find the more obscure needle sizes from the tuning vendors without having to pay a fortune. Friend of mine with a Supa-Tuna fitted has also re-profiled his needle after some experimentation and got his running great Quote Link to comment Share on other sites More sharing options...
notch Posted July 18, 2013 Share Posted July 18, 2013 Pollini won't give their needle dimensions? That's really not helpful!!! Perhaps it is custom needle? The cheapest place I found was Sudco in the states. Postage took awhile but each needle was like $5. May be able to reverse engineer them off this: Quote Link to comment Share on other sites More sharing options...
Trickyh Posted July 18, 2013 Share Posted July 18, 2013 Tell me about it m8... They say its custom and confidential, so will not give it out to anyone (even to PJ!) I've got a guy in Nottingham who could measure the needle for us as he is setting up his own needle manufacturing jig for racing, but I haven't sent it yet as the HKK works so well as a direct replacement. Quote Link to comment Share on other sites More sharing options...
petefinlay Posted August 9, 2013 Share Posted August 9, 2013 Hi Guys, I thought I had my PKW sorted after a lot of work but it is now started running hot & the engine “hunts” up & down by 600 rpm+ when set at a constant setting. My mate Pat, who also has a Thor 200 in his Dragonfly microlight also thought he had his set-up perfectly but it has decided to run rich, 10 lts/hr! We spent two days swapping bits & adjusting all sorts but have finally came to the conclusion that the carbs are just crap. So it looks like it will be a Freshbreeze Bing conversion. Pricey, but what else can you do? I spend more time trying to get the engine to run right than I do flying, so something has to be done. The engine is not quite a year old, but I know Polini will not help so I’ll just have to bite the bullet! Has anyone had experience with this mod & are the supplied jets correct? Pete 1 Quote Link to comment Share on other sites More sharing options...
notch Posted August 10, 2013 Share Posted August 10, 2013 The PWK carbs are hard to tune as there are so many things you can change. And one change often has more that one effect. Have you seen the jetting spreadsheet for the PWK? THe PWK carbs are used on almost all two stroke dirtbikes. If you are not getting the results you want, a Walbro may be a better option? Quote Link to comment Share on other sites More sharing options...
stuartasutherland Posted August 10, 2013 Share Posted August 10, 2013 Hi Pete, the joys of the Polini! I live just up the road near Perth and have the 200. I chose the Walbro carb to stop leaks in the car and minimise the risk of carb icing. I've finally got it running well with some overheating issues in the start. I've been getting about 3.75-4 litres an hour and between 180 to 250 degrees CHT. Sent from my iPad using PMC Forum mobile app Quote Link to comment Share on other sites More sharing options...
petefinlay Posted August 11, 2013 Share Posted August 11, 2013 Thanks for the info guys, but when you have two PKW carbs that appear to be running perfectly then, for no apparent reason, go so far out of adjustment, they must be rubbish. I have heard a few paramotor pilots saying that all was well for hours of flying then the carb leaned out & holed a piston! So I think the Thor 200 (I love the engine, it is a beautiful piece of engineering) with a good carb will be a winner. I have just lost all faith in the PKW. I had a Walbro on my Radne Racket powered hang glider, not easy to set-up, I much prefer a conventional carb, and I understand them (apart from the PKW!) The Walbro did work well on my Radne, they are good once you get the set-up right. So I think I will still go for the Bing, I don’t want to waste any more time on the PKW. I’m off-shore for the next three – four weeks but the carb is ordered & I’ll let you know how it goes when I get back & get it fitted. Fly safe, Pete Quote Link to comment Share on other sites More sharing options...
notch Posted August 12, 2013 Share Posted August 12, 2013 Bit strange the carb going lean? Could there be a fuel supply issue? Reeds? Carb icing? But perhaps not in summer! An air leak? Could try pressure testing the crankcase? Not that hard - block off the exhaust and intake, use the air pulse port to pressurize, check than you have less than 1psi loss in 2 minutes. Fuel quality? If you are using an EGT, temps go down when you have detonation - which can confuse the crap out of anyone. Float valve setting? Fuel vaporising in high vibration fuel line? Let us know how you get on with the Bing. Quote Link to comment Share on other sites More sharing options...
AndyB Posted July 6, 2017 Share Posted July 6, 2017 My 190 won't run at high rpm after 20 mins. It will go to 5800 rpm, then just bogs down. Plug looks fine. High speed needle is 1 1/8 turns out, and max CHT I have ever seen is 220 DegC. Humph. Any ideas? Quote Link to comment Share on other sites More sharing options...
AndyB Posted July 6, 2017 Share Posted July 6, 2017 Also, does anyone know what the numbers listed against the carb settings are in the Polini guide? Page 2 in English. http://polinithor.com/dep/taratura_PWK.pdf Quote Link to comment Share on other sites More sharing options...
Steve Posted July 6, 2017 Share Posted July 6, 2017 It took me more than a year of fiddling to get my PWK usable, had loads of bogging issues during flight, but it was brilliant when finally done. It was a daft way of doing it but normal tuning didn't seem to work much. In desperation I leaned the needle right out and put an oversized main jet in it and a stock pilot and it was awesome. The plug colour and temp gauge were perfect but I dropped the needle by one notch to be on the safe side (although this meant it wasn't as good, but still very usable). One of the first flights after that was over The Alps so was on full throttle for 50 minutes without any heating issues. It just seemed that unless the PWK needle is on the extreme it won't run properly (on mine, at least). Quote Link to comment Share on other sites More sharing options...
notch Posted July 6, 2017 Share Posted July 6, 2017 Dropping the needle down will result in a leaner mix - is that what you intended? Safer would be raising it one notch. Or did you mean the needle clip Quote Link to comment Share on other sites More sharing options...
Steve Posted July 6, 2017 Share Posted July 6, 2017 7 hours ago, notch said: Dropping the needle down will result in a leaner mix - is that what you intended? Safer would be raising it one notch. Or did you mean the needle clip The clip. Quote Link to comment Share on other sites More sharing options...
Mentor Posted July 30, 2017 Share Posted July 30, 2017 On 1/13/2013 at 20:21, poz said: At the moment the engine is running (PWK )with jets: slow 38 and 140 main. It seems to be ok with this setting. One of the guys here has been to 5000 metres on this setting. Testing with Walbro also seems to be OK, although it runs hotter (290 at one point). The engine is also harder to start with a Walbro. If it's switched of during flight for more than 10 minutes it's difficult to restart. Vapour lock suspected due to heat transfer from engine to carb. Flash starter takes some getting used to as you don't get the same 'feel' as a normal pull starter. Still not actually purchased my Thor yet. All this is from tests at the PAP factory. More than a little disappointed with Polini at this stage. All of this stuff should all have been sorted out pre-production. Also, they aren't helping out at all with sorting their carb issues. I'm still 50/50 on which carb to have fitted to my unit. I'm definitely going to struggle selling my PA125. Its been so reliable. No issues in 150hrs, although I do have it serviced every 25hrs. Dan Quote Link to comment Share on other sites More sharing options...
Mentor Posted July 30, 2017 Share Posted July 30, 2017 Hello Can you please specify what slo 38 and main 140 mean?Is that the number of turns on the adjustment screws or smth else? Im having problem with starting the engine and maintaining a good work at idle and accelerating.If posible sent some pic or video on mentorsaiti@yahoo.com Thank you very much Quote Link to comment Share on other sites More sharing options...
Pablo Azorin Posted August 4, 2017 Share Posted August 4, 2017 I'm having some troubles to keep the rpms stable between 5200 and 6200 rpms in my Polini Thor 200 Evo. I tried replacing the Walbro carb for a FreshBreeze Bing carb, but nothing changed. With the the engine running at 5000 rpms, when I add a slightly more throttle nothing happens. Rpms still in 5000. I add more throttle and nothing, it does still in 5000. And then I add a bit more, and it suddenly goes up to 6200-6300 rpms. The same on the opposite way. After take-off, I climb at around 6500 rpms. When I want to cruise, I reduce the throttle just a little and rpms drop to 5000. It's almost impossible to keep it somewhere in between 5200 and 6200 rpms, and I need that rpms range to cruise. Is this a common problem on this engine? What can I do to resolve this issue? I was changing about replacing the reed valve for the new version that Polini launched by Sept 2014. Not sure if any of you already did it. Quote Link to comment Share on other sites More sharing options...
Glynn Posted August 23, 2020 Share Posted August 23, 2020 I have a Bing84 carb on my Polini Thor 200. Does anyone know the correct jets and have any advice on the best way to set it up. Quote Link to comment Share on other sites More sharing options...
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