If I were building or wanting to repower a two seat gyro... I think the engine I would want is the 4 cylinder yamaha sled engine with one of Teal's rotax gearbox adapters.
I would be afraid of the Viking engine. Given Jan's history, he could at literally any moment just up and file bankruptcy and leave you with a highly modified engine with no parts support.
The yamaha would also likely run you half as much money, easily 10 grand less, and be more powerful and weight the same if not less, with plenty of parts availability, and really no major modifications needed.
I have no experience with the Yamaha engine like you do.
I do, however, have a lot with the Viking. Lord knows Jan had his early issues with the Subaru engine business and his history is checkered but that is not my point.
The Viking is a Honda block engine (literally millions made) and parts, regardless of modification, are readily available almost anywhere, just like the Yamaha. Both engines would be a good choice. As to after purchase service, well.....like anything else, it seems you get the best responses as long as you are financially advantageous to someone.
You're right Eddie...I simply was trying to tactfully avoid being an 'egg basher' by talking only about the engine comparison. There's enough of that crap on this forum all the time & I don't want to be a contributor. I try to keep it civil and 'informational' only.
Mark, if you look at the viking engine, yes it uses a Honda block... likely also uses a honda crank and pistons and possibly also a honda cylinder head along with likely many other stock parts. But there is also many modifications to the engine to make it a viking... The list of Mods I am not fully aware of, but just by looking at a photo of the engine you can tell there is stuff done to allow the engine to run on its side, there is also a custom gearbox of course and whatever other mods are done to it.
The yamaha on the other hand needs zero mods other than Teals gearbox adapter ( which is a part that should never need replacement or be subjected to any wear and tear, meaning even if Teal never produces another one you should never need a replacement ) And a Rotax C type gearbox. The engine externally and internally is all stock Yamaha, and it is intended for high RPM, high load continued use, and is well proven.
For sure the yamaha will be a little more work in finding a sled, and pulling the engine and doing the conversion yourself, verses sending 22 grand to Viking for a bolt on engine package. But here lately there has been a few people advertising on here that seem to be in the sled parting out business and they have been selling low hour used engines on here at great prices.
The appeal to me for the yamaha is the only part you can't go to either Rotax or your local yamaha dealer to get, is the gearbox adapter. And that is something that should never need replacement. If the gearbox has a issue, you call Lockwood and order whatever you need. If you need a new water pump you order that from the yamaha dealer in town or over the internet. You have no one off special anything with the yamaha. The other appeal is price. You can pick up a good low mile engine for 2500-3500$, Teals adapter for 1500$, and a good low hour C box for 1000$ or less. Meaning a investment of 5 to 6 thousand dollars, with potentially no more than 8 grand all in including shipping, prop and misc items you would need such as a rejet for the carbs and new airfilters etc.... This is about 15 grand less than the viking with prop and shipping would cost. FIFTEEN THOUSAND DOLLARS!!!! Im sorry, there is absolutely no logical reason to justify spending 15 grand more on the viking.
I understand your position and reasoning with this engine.
However, you need to recheck you pricing information.
The Viking engine sells for $12K complete. Plumbing, prop, etc. are extra.
I don't see where you spend an 'extra' $15K??
That would put it in the ballpark of the Rotax 912iS.
I have not had one single issue with this engine; I change the oil every 25 hrs. & the gear box (my initial concern) has proven rock solid for 100+ hrs.
I grant you, it's not for everyone but it works, and it's worked very well so far. I expect it will continue to do so for some time to come.
Ask Ernie about his units and why he is using them on numerous builds now (aside for initial costs).
Why did he sell his 2 place Yamaha unit & opt for the Viking?
Chevy or Ford?? Apples & Oranges...all about preference.
And as I said before, this isn't about Jan.
In addition, if I was a man who had a lot of disposable cash, I would have opted for a 914 up front but unfortunately, I was never 'that blessed'.
Like most here, I had to compromise and that was the best fit at the time I built my unit.
I just looked at the viking web site they now offer the engine upright not on its side using most of the car parts. but it has a taller gear box to put the prop higher above the crank. It looks like you can flip it putting it below the prop. I like this set up better for a gyro.
I like your engine. Nicolas likes the lower weight of the 912's and 914's over all of them.
He really does not like PRA 31's Lycoming O320 and want us to put a used 912 or 914 that he can buy in Europe for much less money than a new one or a used one in the USA as there are more of used ones for sale in Europe.
How much does it weight Joe.. The Lyc o320 weighs 248 lbs.
There is another customer building a two place and he's using the Yamaha so once both are build we should be able to compare the fuel burn and performance to help others decide with is best for them.
I also forget what the Yamaha weighs does anyone else remember?