80 hp yamaha 4 stroke.

[robsat61]

have been impressed with the 120 hp 4 cycle yamaha snomobile engine installs and hope they knock rotax off their high horse;good engines,but expensive beyond belief.is any one working on the 80 hp yammie,my single place really does not need 120 hp at my experience level(21 solo hrs).my 503 is old and i really want a somewhat lightweight 4 stroke,for longevity and better fuel economy.912's cost too much,subaru's and other automotive engines are too heavy.:noidea:

[pilotescort]

The yam 80hp engine will cost you the same as a 120, as all of the motor mounts and conversion plates have to be machined. The 80 is also a super high revver (13,200) w/ a built-in redrive that needs to be further reduced. It isn't proven yet. You might want to consider the 1.0 Suzuki/Geo triple. It puts out about 60-65 hp, though it could be turbo charged.

I'm installing the 120 on my single place as Racer did. Frame modifications are required, and max hp is to be avoided, but a good engine for a 2 place down the road. The 120 is only $4k or $5k to replace compared to a 912 being $8k to rebuild. It also will last 4 times as long as the 912. Expensive? Not in the long run, however the original install will set you back a pretty penny including all necessary mods. Weight may require bigger rotor blades, and power may strongly suggest a tall tail. You may want to PM Ron Awad, or Scott Essex, or just buy a new 503 or pick up a used 582.....I have a complete PPC w/ a 582 bluehead (120 hrs) up for sale ($5k by itself, $7k w/ enclosed trailor).

[Racer]

I have to get some 120hp's out the door first but Yes I will be doing the 80hp version in the semi near future, I have already started but not done or proven them yet.
If you want a Geo 1.0ltr I have one for sale that I will sell for a song.
Todd

[Lspav8r]

What song would you like to hear?:)

[Rehan K.Janjua]

Lets hear the song. Please.

Replacing the 582 with Geo 1.0L on A/C single 25ft SW.

Pics would be nice.

[robsat61]

i try not to be ignorant,but thought the 80 hp yamaha was a twin cylinder engine.

[Racer]

i try not to be ignorant,but thought the 80 hp yamaha was a twin cylinder engine.

Yes the 80hp is a twin cylinder 4 stroke motor

[robsat61]

racer,you seem to be the gitter done guy with the yamahas.i had yamaha bikes and snomos up till i escaped frostbite almost 10 years ago and am out of the loop now. preferred their quality over everything else.(honda does not make snomobiles yet).is the 4 stroke twin worth the weight advantage for its power output?...meaning my ultralight 3drv is already a little fat now(306),just want it not much fatter with the same or better performance as my 503 which is quite old.(provision 4/a-box).

[Racer]

racer,you seem to be the gitter done guy with the yamahas.i had yamaha bikes and snomos up till i escaped frostbite almost 10 years ago and am out of the loop now. preferred their quality over everything else.(honda does not make snomobiles yet).is the 4 stroke twin worth the weight advantage for its power output?...meaning my ultralight 3drv is already a little fat now(306),just want it not much fatter with the same or better performance as my 503 which is quite old.(provision 4/a-box).

The Yamaha 80hp 4 stroke weighs 76lbs (Just the motor)
You would also need a reduction box, Radiator, airbox, oil tank, wiring and plumbing.
My guess is probably another 30 to 35 pounds

[robsat61]

i could easily recoup the extra weight by not using super heavy rotor dynes,getting a set of dragon wings;if i replace the old engine,it would either be 582 or a yamaha,unless i find a healthy 503 w/dual ignition.i refuse to feed the new rotax beast.

[pilotescort]

i could easily recoup the extra weight by not using super heavy rotor dynes,getting a set of dragon wings;

I have a set of damage-free 23' DW's for sale (maybe 20 hrs flight time) for $1200. They cost $1750 from Ernie @ RFD. I need to buy a 25' set.

[WHY]

Pilotescort, you mentioned that the 80hp Yamaha is a high rev engine with a "internal reduction" that will need even more reduction with a re-drive. Has anyone given any thought to what torsional reasonace might do to this internal reduction???????????

I doubt that it is set up for any kind of reasonace like a prop will produce.

Tony

[robsat61]

pilotescort.i see you area florida resident,i would like a set of dragonwings;23's are what i need formy single place.this would be short notice for me.bills and all.in the very near future i could make a deal...rob

[scottessex]

Pilotescort, you mentioned that the 80hp Yamaha is a high rev engine with a "internal reduction" that will need even more reduction with a re-drive. Has anyone given any thought to what torsional reasonace might do to this internal reduction???????????

I doubt that it is set up for any kind of reasonace like a prop will produce.

Tony

Can you explain that in more detail? would a clutch or rubber donut help out? I am interested in this engine, that is why I am asking, thanks.

[WHY]

Hi Scott

Torsional resonance, or the "fight " that takes place between the power stroke putting power into the propellor and the propellor inertia putting energy back into the engine on the compression stroke, is the problem that exist with all reduction design,(belt or gear).

You are "slapping" the teeth of the gears one way on the power stroke and then "slapping " them in reverse on the inertia stroke (compression) and this takes place in every complete cycle of the engine whether 2 stroke or 4 stroke. This reasonance or "fight" ALWAYS finds it's way back to the crankshaft. This is why the idea of using the transmission on a motorcycle engine as a reduction drive doesn't work. No way to internally install a cushion (like a centrifugal clutch or rubber donuts). My concern on the 80 hp engine is the internal reduction set up will get "beat up" llike the transmission gears in a motorcycle engine since there is no way to cushion it like the external drive.

The external reduction drive "cushion" will "help" the internal reduction some but I don't think it will be enuogh and the engine will shell out the internal reduction in a relative short time.

Tony

[scottessex]

Thanks Tony, That is what I thought. I know some engines are worse than others from what I have heard. So I guess the internal reduction would take the beating before the crankshaft. I thought a belt reduction absorbs more of the resonance than a gearbox.

[WHY]

Hi Scott

It does but the crank still gets it in the end, or anything in between.

Tony