Nickolas

Hi,

What is your actual peak rpm with the ΥS 170DZ with ΑPC 17x12 and 18.1x10/11 on CP 30%? My current rpm is around 8000 to 8100 with the 17x12 but it drops slightly when engine becomes warmer.

I just received my old DZ from service (overhauling etc.) and after this needs to be run on the rich side otherwise it detonates. Now my mix needle is around 2 1/4 to 2 1/2 turns out and also I have richened the regulator 1.5 turns from factory setting. Engine at this setting runs ok but my rpm I think is low compared to my newwe engine.

When I try to lean it it dotonates and creates black spots on the ground...Yamada states that the engine was tested before sent to me...I trust him of course but can not explain this engine behaviour. Any opinions?

Thanks in advance,
Nikos

rcpattern

My Feedback: (45)

Nikos,

Your numbers do sound a bit low. I did have an engine that I had to richen up the regulator quite a bit, and discovered there was some "crap" in the nipple. You might try flushing that whole assembly and see if there is something that is stuck in there, and the same for the needle valve area.

Arch

cchariandy

I'm about to send an Engine to Richard for service...will it need to be run-in again after? I'm guessing bearing and seals will be changed and expected to run a little rich for fist couple flights. Is more needed?

Colin.

rcpattern

My Feedback: (45)

Colin,

Yes, after it is rebuilt you will need to treat it just like a new engine. Run a little smaller prop and run it rich for a while, then after 20 flights or so you can start leaning on it.

Arch

apereira

Mine used to ran at 8350 with the 17x13

shepga

My 170DZ is turning an 18.1X10 at 8200 rpm out of the box with only 80 oz of coolpower heli 30%. Needdle valve is 2 1/4 turns out. I never had to touch the regulator. It idles all day long at 2200 rpm and with excellent transition when the stick is advanced. I'll be maidening my new plane tomorrow with the 170DZ in it tomorrow. Looks like I'll finaly get to see what this YS can do. (Still don't beleive it'll be stronger than my trusty OS160)

Glen

Jon Wold

I've transitioned from OS 160 to YS 170 and trust me - there's a difference. A piped 160 can rev like a 170 on the ground, but in the air you need to fly fast in order for the setup to produce any power and the throttle transitions take a very long time (compared to YS!).

A YS will accellerate vertically from very low speed and brake on downlines. You can fly at half the speed with confidence and use half-throttle most of the time. It's a totally different kind of flying, altogether. (Wow that's a quote from Airplane II movie, isn't it!)

Nickolas

Hi,

I think I wll have to disassemble the the pump and carburator and look for any particles tha block normal fuel flow.

The engine comes from service, we changed everything before sent to Yamada for final inspection , piston, cylinder, piston ring, gaskets, o'rings, rear ball bearing. In terms of power I can fly with it the P11 under normal conditions, I struggle on the 8 point loop on strong wind but I don't think I take full advantage of the engine potential and also I am not sure about the long term operation of this engine with these needle settings.

Any other input before disassembly is more than wellcome. Tried to find some info on the YS doctor web site but was not easy.

Thanks,
Nikos

Thinn

I think I had approx 7800rpm from a 170 w/Hattori short pipe and 30% fuel on an APC 18.1x11.
It has been a long time since I fired it up, but hopefully I remember correctly..

rcpattern

My Feedback: (45)

Glen,

You are in for a treat. There truly is no comparison between the two. The torque of the YS is amazing. Try an 18.1X11 and you will be very happy or even one of the other large props. That is when it comes into its own.

Arch

shepga

Hey Arch,
I was just joking with the OS160 comment. I do have high expectations for this motor. Only 3 hours to go, before my maiden, I'm excited. I'm using the 18.1X10 for breakin. I plan on moving to the 18.1X11 shortly.

Glen

rcpattern

My Feedback: (45)

Glen,

Glad to hear it. As you get some time, also play around with the 19X11, it seems to be a very popular choice and I really like it on mine.

Arch

tuny

17x12 is a very little prop for a 1.70DZ

Nickolas

I know but I break in the new piston cylinder set...

Thinn

I've heard the 19x11 is a bit on the heavy side for the standard 170..? But a good choice for the 170CDi? For me, the 18.1x11 works amazing... Almost too much power for my Oxalys (I'm actually thinking of changing back to the 160 turning a 18.1x10....!).
Tried the 18x10 Sport (too "light"..), 18.1x10 (good) on the 170 also, but found more Ooompf on the verticals from the higher pitch.

Dave Harmon

Thinn.....
I used the APC 19x11 on the YS170 glo version and it works just as well as on the 170CDI.
It will take away that 'too much' power feel and give a better pace to the airplane.
It also slows the downline and improves the feel of the airplane.
A better prop by far....you should see about 7300 rpm.

DH

rcpattern

My Feedback: (45)

I agree with Dave on this one. The engine doesnt care whether it is CDI or not for prop selection. The idle is a little slower and better fuel economy, but the engine will still turn the same props.

Arch

Thinn

That's really good news! I'll give it a try.

Andy P.

Slightly off topic but I totally agree, I am using the same combo on my YS160 and can state it's an awesome combo, no real need for a 170.......................

Apologies for butting in here Nikos......................

Tikanis?

Regards,

Andy.

Nickolas

Hi,

Last night I injected pure alcohol in the carb main needle nipple, today I tested the model. I had about 100 rpm increase, however the engine still does not provide its full potential. Engine is reliable (did not hesitate to perform some low KEs) but does not provide the power.

When I returned I disassembled the engine and I will install soon a new pump. I also cleaned the carb very well again. Engine internals seem to be in a very good condition as new.

I will test soon again and will let you know...thanks to all!

Best regards,
Nikos

Thinn

Looks like you have an air filter on it.. Try without...
I had some issues with an "old" Os 140RX not getting the top revs. Tossed the air filter and fuel filter - VoiÃ*!
Just a thought
(Another "stupid" question - How is your carb throttle valve looking at full throttle...? This has fooled me once!)
(I am no YS Guru, not by far.., just having used these engines for a few seasons. I'm learning from this thread as well!)

riot3d

Nikolas,

With 30% heli & a 9 mm venturi funnel, my regular 170 top at about 7,600 to 7,700 on 18.5x12 wpn. More than enough for the sequence even on windy days, and makes noise. I never use more than 3/4 throttle, even for long vertical maneuvers.

As for the cdi with same fuel & prop, I can dial it down to about 7,400 to 7,500 top, about 1,500 on idle. The cdi transit better on mid range, just set up your throttle curve to take advantage of the torque curve. Use the torque, not the speed for the maneuvers.

Adrian

PeterP

Nicholas,

I would check your disc valve. The condition, fit and tolerance of this assembly is critical to producing peak power. A worn or scored disc will rob you of top end power. The easyist way to determine if this is the cause simply swap out the whole assembly including the carb from an engine which is performing. If the suspect engine produces the power you have been missing you have found your problem.