Yamaha RX1 Engines

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Posted (edited)

Never mind...  I just found all my answers.

Edited by Av8r3400

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Posted

All of this new-fangled unproven stuff makes me want to go find a C-75.  I flew one for hundreds of hours with no problems. 

Old EDMO

I have been flying a 2-stroke for hundreds of hours with no problems.

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Posted

Teal - just finished (and subscribed) watching your video.  What a great looking product you have there.  Do you have or can link to any videos of these flying?  All I can find are the 3-cylinders.

Being our new resident expert on these engines, is there any type of provision to run dual ignition sources on these?  It almost looks to be a coil-on-plug system.  Is it?

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Posted (edited)

There's no room in the head for a second plug on the yamaha. 

Edited by LORENZ

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Posted

i understand that there isn't room for a second plug, but a second source to trigger that plug (coil/plug) is what I'm talking about.

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Posted (edited)

Im not so versed on the exact reason aviation engines were designed in the turn of the century with a second plug, but, my best guess is they would foul pretty easily. Weather it be from a rich mixture or lead fouling the plugs, they became a weak link. The mags and cap and rotors of the day would fail as well. I can't tell you how many ignition problems Inhave with my 1976 Baja Bug VW motors it's incessant and POS design from Porshe. My sand car with a 2180 VW had the same ignition issues. From the coul pack laying over when it would heatnup to the cap and rotor not holding the timing internally, there just not reliable. I dont know how guys can fly behind a VW with good conscience.  2 plugs and 2 ignition systems is a band aid, not the answer in older tech aviation motors.

 

In todays world of digital ignition and individual coils that fire individual plugs, the ignition system is no longer the week link. Old habits and thinking dies hard. A second plug on a system that doesnt foul plugs, is fixing a problem that doesnt exist. 

Edited by LORENZ

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Posted (edited)

All of this new-fangled unproven stuff makes me want to go find a C-75.  I flew one for hundreds of hours with no problems. 

Old EDMO

I have been flying a 2-stroke for hundreds of hours with no problems.

I bought a Kitfox that had an engine out damage before 40 hours and at 75 hours another engine out damage.  After repairing the plane and having an expert check out the engine I flew it for about 20 hours and had 2 dead-stick landings and decided never to fly or ride in one again with a 2-stroke engine.  "Different strokes for different folks." 

Please don't even offer me a ride in one, even if you fly it a long ways to get here.   EDMO

Edited by EDMO

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Posted (edited)

In todays world of digital ignition and individual coils that fire individual plugs, the ignition system is no longer the week link. Old habits and thinking dies hard. A second plug on a system that doesnt foul plugs, is fixing a problem that doesnt exist. 

I currently have a CDI unit out on my 912.  Ignition failures are less likely now than the antique magnetos, but they do still happen.  In an airplane, a backup is really needed.  A second plug does not necessarily become a requirement (for the reasons you give), but a second source to fire that plug is.

Ignition systems are the Achilles Heel on gas engines.  (Now I'm daydreaming of a 100 hp light diesel for airplanes…)

Edited by Av8r3400

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Posted

All of this new-fangled unproven stuff makes me want to go find a C-75.  I flew one for hundreds of hours with no problems. 

Old EDMO

I have been flying a 2-stroke for hundreds of hours with no problems.

I bought a Kitfox that had an engine out damage before 40 hours and at 75 hours another engine out damage.  After repairing the plane and having an expert check out the engine I flew it for about 20 hours and had 2 dead-stick landings and decided never to fly or ride in one again with a 2-stroke engine.  "Different strokes for different folks." 

Please don't even offer me a ride in one, even if you fly it a long ways to get here.   EDMO

Sorry to hear that. Bandit is well over 1000 hrs and I am approaching 400 with over 1000 off airport landings. It's that mentality that has kept GA stuck in the 40s. 

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Posted

Teal, I've been watching the development of these engines, looked at gero Ron,s yrs ago,

onething he had to do was case harden the clutch. Me concern is length of engine, 3 cyl,verses 4 ? 

And weight different 

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Posted

The 4 cyl. Is a bit longer but it is practically the same weight. I'm not a resident expert on the 3 cyl. But I'm told it has a heavier crank shaft aND it runs a balance shaft along beside the crank. The 4 cyl. Is really smooth without a balance shaft. The rx1 or 4 cyl. Weighs 128 lbs. With no carbs or exhaust. Steve Henry's engine in the above video was only firing 3 cyl. I spoke with him and he said #2 cylinder carb. Had a plugged idle jet. So it will sound much smoother when he is done. And I don't know of a easy way to add a second ignition but I do agree that these ignition are super reliable. 

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Posted

image.thumb.jpeg.f9e8a260dbded75f92d3251

 

Can you weigh a Rotax C Gear box for us. I have the weights of my 582 and 670 that I just had rebuilt. She came back from Rotax Rick last night. 

 

It would be a great side by side comparison of weight. I'd much rather have the Yamaha in my bird for the reliability.  The 2 stroke 670 was the easy and quick answer. It may have been more expensive as well, all said and done.  I just simply didnt have the time to commit for the labor on an engine swap or you would have had my money for that pretty RX1 adapter. 

 

My next bird will have a Yamaha or Kawasaki conversion.  They're amazing motors  

 

 

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Posted

Rotax c gearbox should be about 11 lbs and my adapter is less than 2lbs

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Posted

LEAF catalog lists a C box at 17.6 lbs.  E box is 24.7, and a B is 9.9  Jim Chuk

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Posted (edited)

All of this new-fangled unproven stuff makes me want to go find a C-75.  I flew one for hundreds of hours with no problems. 

Old EDMO

I have been flying a 2-stroke for hundreds of hours with no problems.

I bought a Kitfox that had an engine out damage before 40 hours and at 75 hours another engine out damage.  After repairing the plane and having an expert check out the engine I flew it for about 20 hours and had 2 dead-stick landings and decided never to fly or ride in one again with a 2-stroke engine.  "Different strokes for different folks." 

Please don't even offer me a ride in one, even if you fly it a long ways to get here.   EDMO

Sorry to hear that. Bandit is well over 1000 hrs and I am approaching 400 with over 1000 off airport landings. It's that mentality that has kept GA stuck in the 40s. 

I'm glad that some of you have the knowledge (maybe some luck too) to fly with these engines.  My experience was bad.  It's like touching a hot stove and getting burned twice - You don't want to touch it again!  I have to stay with the engines I know something about.   I agree with Larry - a light diesel would be good insurance, but maybe after I am gone, there will be some new type of powerplant to keep birds in the air.   Meanwhile, I have a C-90 and an O-200 to get me into the air occasionally, and so far, they have kept the fans turning for lots of hours.   EDMO

Edited by EDMO

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Posted

-What did your warm ups regiment look like while running your 2 strokes?

 

-That synthetic Amsoil stuff mixed 100:1 is good stuff, how did you like it?

 

- When it cold siezed on you the 2nd time what was the scenario. Flat and level for 45 minutes, practicing touch and goes, full power and just getting into the air after your run up?

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Posted (edited)

-What did your warm ups regiment look like while running your 2 strokes?

 

-That synthetic Amsoil stuff mixed 100:1 is good stuff, how did you like it?

 

- When it cold siezed on you the 2nd time what was the scenario. Flat and level for 45 minutes, practicing touch and goes, full power and just getting into the air after your run up?

I followed the advice of Mike Jacober  at his Rotax shop at Birchwood Airport, Alaska, on the runnups - that was a lot of years ago.  I was about a minute from TO and still in the pattern when the 2nd stoppage happened - After the first stoppage while cruising, the engine started again and seemed to run normally - I flew it back to the airport - I had it checked before taking off again and every thing looked normal.  I didn't bother checking it after the 2nd stoppage.  I just stored it for a boat anchor! ??? 

I have forgotten what year Mike died, but it was sometime about 2001, after I came back to Missouri, killed in a crash while he was  instructing in a trike powered by a Rotax 2-stroke engine.   BTW:  Mike Jacober owned Arctic Sparrow, a Rotax distributer and service center - He set altitude records with his mixture control.  He showed me one of the first Rotax 912 engines produced.   EDMO

Edited by EDMO

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Posted

You cold seized the motor, scored the sleeve and piston, and then felt it was OK to fly her again?...  You have some chutzpa to blame the motor. 

The motor has to be run up to full operating temp at 4500rpm for 4-5 minutes AFTER taxing to the runway, before applying full power for TO.  The steel sleeves have to be heated and expanded or it will cold seize just like you described. The piston litterally will not move in the sleeve until the they both cool down. Running that motor again without honing the cylinder and replacing the piston is your own fault and probably the cause of the second outage. 

Im sorry to be harsh, but telling half the story while bad mouthing a 2 stroke motor that Rotax has sold more than 50,000 units of, over 3 decades, based on your experience that you just described, isn't completely fair. 

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Posted (edited)

You cold seized the motor, scored the sleeve and piston, and then felt it was OK to fly her again?...  You have some chutzpa to blame the motor. 

The motor has to be run up to full operating temp at 4500rpm for 4-5 minutes AFTER taxing to the runway, before applying full power for TO.  The steel sleeves have to be heated and expanded or it will cold seize just like you described. The piston litterally will not move in the sleeve until the they both cool down. Running that motor again without honing the cylinder and replacing the piston is your own fault and probably the cause of the second outage. 

Im sorry to be harsh, but telling half the story while bad mouthing a 2 stroke motor that Rotax has sold more than 50,000 units of, over 3 decades, based on your experience that you just described, isn't completely fair. 

I think I said, back about 2011, that I didn't have enough education on the 2-strokes to keep my chainsaw running!  I had depended on a Rotax expert to check out what I thought was a questionable engine that had quit 3 times before.   I don't trust an engine this finicky.  They may have sold 50,000 of them,. but every time I hear about a Kitfox or Avid crashing, (and I have owned 3 of them), it is usually from failure of the 2-stroke engine, and I don't care to be part of those statistics.

I wish the best for everyone who flies the Rotax engines, but I will not be one of them.   "To each his own."  End of story.     EDMO

Edited by EDMO
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Posted

I really think the Yamaha is a good engine, But the availability of it scares me, There cant be that many around anymore. When Yamaha introduced it in the sled the whole package totally sucked, way to heavy, So there wasn't that many made, Now if they get the 3 cylinder figured out I do believe they will have a hell of an engine.

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Posted

What is your source of information on the number of yamaha sleds sleds made? 

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Posted

What is your source of information on the number of yamaha sleds sleds made? 

Ok Maybe I should re say  that, I cant imagine there was that many made, What I was meaning is yes most parts will always be available but if you find a broken crank case, well good luck finding some one to cast you a new one. Now dont get me wrong I love Yamaha engines, Worked on them for years and have always thought they were miles ahead of the rest and glad to see them finally getting to the aviation market.

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Posted (edited)

There's about 15 of them on Craigslist in my neighborhood right now.  (I had to look)  Great motor, terrible heavy pig of a sled...

Edited by Av8r3400
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Posted

Steve Henry posted a video of his running yesterday. 

Hi Teal,I have purchased a couple 2003 rx1 with low mileage so going put the fat avid on a diet and will be needing one of your adapter plates , I sent you a PM on here but not sure if you got it, heres my email if you have any left marshawk@shaw.ca

 

 

 

 

 

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Posted

Teal what is the model of sled I should look for, make and model and yr? thanks

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