91 engine choices - os / ys

[rcmarty]

I'm not one to start a chevy vs ford pissing match.
My 700 is on the way :)!! , i'd like to select a motor that fits what i want.

Wanting to hear about the various different power plants for the trex 700.

Looking for a objective thread here. I'm sure there are many os fans and many ys fan out there. I'd like to day your both right.

My question is why you like your chosen brand.

I have a hyper 50 in my 600n , been a great engine. I thought it was toast due to a rear bearing , but i figured i'd run it and see , that was 5 gallong ago :)

I've done lot of reading on the forums and there's not a major amount of info out there. So far i have a few things :

- os with 'klein' regulator works well (similar system to the ys)
- os pumped works well but can be unreliable at times.
- something about os carb being a little lean at center , not much time during a flight in the mid range though.
- ys takes more effort to tune

My personal preference is to run phanolic (plastic) cages in my motors. I know os does them but my ys 50 had a metal caged bearing. I assume the 91 has a metal caged bearing also. If i go ys i will be changing the rear main to plastic cage.

Are the os engines hard on rear bearings like the 50's ? How about the ys's ?

Does anyone have any more experiences with these engines ? or better yet have run both ?

So far i'm considering the os (not sure if it a hz or yz) non pumped with a kein regulator and the hatori 18 muffler or the YS SR engine with the hatori 19 muffler.

I'm leaning towards the YS SR right now , lots of nice things said about the regulator/tank pressure system they use for fuel delivery. Similar to the os with klein. I'd assume the clunk line should last longer with no exhaust fumes present.

Plan :

700 kit
91 engine
ar7100r
8717
770 / 9254

Martin :)

I bought a toyota if that means anything.

[HELINHAWAII]

Here's one for the YS SR. I bought the engine based on some good feedback I got here at the freak and couldn't be happier with my choice. I'm still dialing in the engine but I find myself more impressed the more I tune it. This being my first nitro anything, I went to the YS as I was told by more than a few that the fuel delivery system was top notch. No pumps to go out, no additional regulators or carbs to buy. I though, why not make this easy on myself and remove all the potential problems I'd have to troubleshoot all while learning how nitro helis work. I fly 15% CP in my 700 with the SB19 and Kasama header and have been surprised by all the compliments I've gotten on the power overall. And...they're not hard to tune at all either.

I've not flown or personally seen a 700 with the OS so I can't give you a good comparison.

I'd consider the YS like a Toyota...you just fly(drive) it and don't worry about what's wrong with it now like most Fords I've been around.

BTW- I'm pretty sure the rear bearings on the SR are plastic caged. I've hydro locked it enough (my own stupidity) to know exactly what the inside of the engine looks like with the backplate removed.

[rcmarty]

thanks for the input :)

Is there a reason for the kasma header ? Does the pipe come with a header ? I assumed so.


Martin :)

[HELINHAWAII]

The SB19 comes with a header. The Kasama is an upgrade. I'm just trying to pull every last bit of power out of the 15% until the 30% comes back to the island. I wish the Olympics would get over with already!