Anything new on Yamaha conversions?

NoWingsAttached

Unobtainium Member
Joined
May 21, 2006
Messages
4,871
Location
Columbia, SC
Aircraft
Air Command Tandem w/ Arrow 100hp; GyroBee w/ Hirth 65hp; Air Command Tandem w/ Yamaha 150hp
Total Flight Time
>350
Has anything new developed since Todd and Ron did their 2 Yamaha projects? Anyone else out there done a Yamaha 3 or 4 cyl engine gyro conversion? I see plenty of 4 cyl sleds for sale, but the 3 cyl motors are very rare. Any ideas on a redrive for the 4-cyl? I think they turn 12,000 redline, whereas the triples redline at 10,000, correct? I called Ernie today and he is close to flying a 4 cyl, but he reports the redrive he had made is as about as pricey as a whole used sled will cost.
 
Mine is still flying. There is one flying in a helicopter now. There is one on a Kolb ultralight airplane. And Todd has delivered at least one or two more to customers, but I haven't seen anything posted from those guys.
 
One guy has one on a gyrobee but hasn't flown it yet as far as I know.
 
Well, now I've really gone and done it...I bought a sled on Ebay just now, gotit for $3100. I'm goin to take it up to my house in Michigan and run it around in the snow before I eviscerate it.

This will be a 4-cyl, 150hp Yamaha conversion, like Ernie is doing to his Dominator. Hope he brings his flying "sled" to Bensen Days so I can figure out a few things...I think his is about ready to take to the air, eh? Cheers, hope to see your project there.

I am really thinking long and hard and serious like about keeping the snowmobile clutch as a redrive. It will mean the engine will be several inches lower on the mast, but I can't see how that will make all that much difference in a CLT machine. Maybe a bit, but....hey, they are "Experimental" aircraft, right? Jeez...100hp at 4000rpm, and 150 peak. All this for 120 lbs? Glad I have the Blue Bee to keep me in my flyin jollies n happy while this project is underway. No chance this is the quick motor swap like I was hopin for last summer.....
 
I don't think the snowmobile clutch will do you any good, since it is essentially a torque converter you will have a variable rpm prop, could prove to be difficult to get dialed in correctly.
 
Greg, It was nice talking to you today and congradulations on your buy.
I do not have any 4 cylinders here but I will help you if I can.
Post your progress, I would like to keep up on your build.
Racer
 
Mine is still flying. There is one flying in a helicopter now. There is one on a Kolb ultralight airplane. And Todd has delivered at least one or two more to customers, but I haven't seen anything posted from those guys.

Which guys would those be?
 
You would have to ask Racer, I don't know their names. They have had their engines for months though
 
What about the redrive for this engine where do u get it and will the same one work on the 2 or 4 cyl?
 
What about the redrive for this engine where do u get it and will the same one work on the 2 or 4 cyl?

You need a beefy 160 hp redrive for the 4 cyl. THe 2 cyl puts out 1/2 that HP, so no you can't use the same redrive suitable for the smaller motor on the larger one. Sure, you could go the other way if you had to.

Ernie's been working with his redrive builder for the 4-cyl, you could probably talk to him about getting an AutoFlight redrive built for a 2 cyl Yamma. Todd (Racer) already has a very well-priced redrive package for the 3-cyl.
 
The autoflight gearbox Ernie is going to use has no clutch in it. just a rubber damper.

The first 2 Yamaha's ( Racer's and mine ) were put together with just a rubber damper and somehow Racer was able to get his engine to start and run with it, but I couldn't. The engine just shook itself silly and give it more gas and it got worse. It was my idea to use a clutch to disengage the prop from the engine for start up and since then all the 3 cylinder yamahas have used a clutch.

I will be very interested in seeing if Ernie has issues with the autoflight box or not. I guess I will see him in a month, but I might just call him up in a few days to see how his progress has been.

Personally, the 3 cylinder 120 HP engine makes so much power and weights so little, there is no reason at all to use the larger 4 cylinder engines. My engine weights the same as the Rotax 912 100 HP engine used in the Xenon, yet has more power than their turbocharged optional engines. And I am burning less gas.
 
Personally, the 3 cylinder 120 HP engine makes so much power and weights so little, there is no reason at all to use the larger 4 cylinder engines. My engine weights the same as the Rotax 912 100 HP engine used in the Xenon, yet has more power than their turbocharged optional engines. And I am burning less gas.

I absolutely would have gone with the triple Ron, but they are hard to find and when you do find one they are expensive. You guys got lucky, it will be a few years before the next generation triples are plentiful and cheap on the used sled market. THe 4-cyl, on the other hand are plentiful and it is very easy to grab one for $3500 or less. 3 sold on Ebay this week alone, the one I got for $3100, another went for $3250, and the 3rd sold for $3550.

The cheapest 3-cyl (RS and FX series) on Ebay? Ha, they didn't even meet their reserve, and guys were bidding $4000 and up.

I've been watching and bidding on and off since November. This is the best deal I've seen that I had a chance to grab. I am driving up to PA to pick it up, so throw in another $300 for the trip. I am still under $3500 all-in. If I buy a sled in the Rockies, or way up in New England, it will cost about $600 to ship, so I figure I saved a few bucks there as well.

There is a dealer that will sell an FX I found, for about $3500. But he is charging $190 for "paperwork", PLUS sales tax, so there goes another $600, plus I'd still have to spend $300 to pick it up. Now I would be out $4600.

Got to take what you can get sometimes. I was getting to the point where I really needed a project to perk me back up and put the twinkle back in me eye. Looking at a blown motor sitting in a gyro sitting in a hangar that costs $100 / mo....since August....well, that don't add up neither. Time to git'er done!
 
Apparently RFD has worked with Autoflight to build a redrive that is integrated into the existing gear reduction drive space inside the Yamaha 4-cyl 1000 cc, 5-valve, 150-hp monster motor. Imagine this. It has been reported that when you look at the package, it looks like it came straight out of the Yamaha factory in Japan. Can't wait to see this at Bensen Days.

I myself am going a different route entirely, and will pursue a CVT integrated redrive to try to demolish the fuel economy and performance ceiling on this thing.

Jeez. I'd always envisioned a 4-cyl turbo Porsche power plant back there...this is a bit sad for me, actually. A rice burner? <sigh> I guess even old farts like me gotta go with the ebb and flow. But who can argue with the same hp at less weight and no turbo lag? not me.

The Durango needed a leaky exhaust manifold repair, a transmission repair to get ready to tow the sled down from PA. I thought the tranny alone was going to cost $2k. The dealer called and said, "Hey, it was a corroded electrical connection. We fixed it fro $120. And the manifold ain't cracked, it had a broken stud. "

Earlier today my boss called and said, "Sorry, I forgot to tell you last week that you got a raise and a nice bonus". It's like I got the sled, the repair, the trip to pick this up, all for free and plenty of cash left over. And to think I was agonizing over the costs involved for this project, and suffering SERIOUS buyer's remorse after bidding ended on Ebay last Sunday. Strange how God reacts to good decisions, ya know what I mean?

I love this sport. I love this community. I guess this is where I belong after all.

Onwards and UPWARDS!!!!! YEEEEEEEEEEEEEEEE-HA!
 
Last edited:
Dang boy! Good luck with autos, and a bonus! (What is a bonus?) :D
I think you should buy a lottery ticket! Perhaps the rest of the gyro will be "free"!
:) :)
 
nowings- Its inspirational reading your posts. It looks like to me what goes around comes around. The influence you helped cause on that charitable giver at church is coming back around as it should.


Stan
 
Hey Greg, where you been ? Sorry you missed on those blades.

Where did you hear about the RFD engine ?

Where in PA did you get the sled ? Do you have the ebay link ?

Glad to hear someone is having some good luck.....good for you , man !
 
Greg been following with interest... just love to hear the happy bits.:)

Hope you get this conversion sorted out and that it works for you, rice burner or not.
 
Top