OS 105 HZ R needles

[Sirolf]

I have the check valve an inch from the backplate..
if there is to much pressure in the tank i see how it could be running rich all the time.

Gonna go over the regulator completely and reposition the check valve and hope for
the best.

[CyprusFlyer]

Good luck with the check valve tube, doesn't make all that much sense to me, pressure is pressure that will equalize inside a closed system and should not make the length of tube that critical, could be wrong be great if I was.
Some photos, cannot measure the hole size of the needle valve seats but can clear see the HZ v HZ-R versions, larger being the regulated version of course, drill is 1mm diameter.
Also how I easily check the regulators using a pen barrel cut off with my finger over the bottom part of the ring to form a seal, easy to suck test for correct operation and blow to ensure full cut off.
Also try and blow through a clean piece of fuel tube on the nipple, should also cut off for a full check.

[Sirolf]

As i see it now the amount of fuel entering the engine will increase when the tank pressure increases. If the reg just reacts on the vacuum created by the downstroke of the piston. The higher the tankpressure the more fuel will enter regardless of much the reg is opened.
Just like a fuelinjector on a car.. the more fuel pressure the more fuel will be injected within the same time the injector is opened by an electrical signal..

Might be a bad check valve. If it closes just fine but lets air through too easily in the right direction tank pressure will also be higher.

So that raises the question how much pressure in the tank is normal?

[CyprusFlyer]

Originally Posted by Sirolf

As i see it now the amount of fuel entering the engine will increase when the tank pressure increases. If the reg just reacts on the vacuum created by the downstroke of the piston. The higher the tankpressure the more fuel will enter regardless of much the reg is opened.
Just like a fuelinjector on a car.. the more fuel pressure the more fuel will be injected within the same time the injector is opened by an electrical signal..

Yes agree, the point where the tank pressure peaks out is a mystery to me but there must be a point where the crank case and tank pressure reaches equilibrium other wise the tank would go pop! That must be a constant that the designer tuned the regulator with! (Sidenote, see YS version is adjustable but factory set).
The regulator should also be calibrated by the strength of the spring and diaphragm surface area to vary fuel according to the vacuum caused by the piston going up, but more importantly of course its airflow through the venturi, more airflow, greater vacuum etc.
So, you are correct, too much pressure, or too little resistance to fuel flow on the otherside of the regulator, I am assuming now with 3 regs that I have ruled it out in my case. Cannot see that the pressure can be made to vary a great deal, except lack of pressure with broken check valve.
Lets keep the ideas coming, solve it sooner or later.

[Sirolf]

Next up reposition the check valve and test..after that use a new check valve.

After that going back to HZ carb and muffler pressure

[CyprusFlyer]

Originally Posted by Sirolf

Next up reposition the check valve and test..after that use a new check valve.

After that going back to HZ carb and muffler pressure

Yes but not beaten just yet, I have the parts to scrap the regulator and use muffler pressure so another option, should know in a week or so when some parts arrive.

[Sirolf]

I'll get a new check valve and change the distance to it from the back plate.. if that doesn't cure anything it's back to a method that works.

[Rodney Kirstine]

Originally Posted by dchekas

Can you guys measure the diameter of the hole through the middle of the main needle seat?

It's the first picture in post #5 from this thread: https://www.helifreak.com/showthread.php?t=515164

If I get some time this week, I'll pull mine and measure it. I have access to a set of pin gauges.

[Sirolf]

Different check valve at a nice 10cm from backplate... cleaned the regulator thouroughly and noticed no chance today what so ever.. so it's back to a non-reg carb for me.
Anybody know if HZ-R carb can be used as a non reg carb?

[CyprusFlyer]

Still no joy here, should not be difficult to go to a HZ, the carb is slightly different but mine ran better with the HZ needle seat. Need to blank off the crankcase or swap it out and get the ring fuel inlet. I have all these and will probably join you soon. Had enough of this nonsense, prefer to go flying.

[Steve Graham]

Really sad that Hobico support can't be bothered to help out here.

[Sirolf]

I also have spare HZ carb and most of it's engine parts and it would be easier to swap parts on the carb to make it non-reg

[CyprusFlyer]

Originally Posted by Steve Graham

Really sad that Hobico support can't be bothered to help out here.

Yes agree, they really need to come into the 21st century, take responsibility and provide some customer service, not holding my breath

[Rodney Kirstine]

Originally Posted by dchekas

Can you guys measure the diameter of the hole through the middle of the main needle seat?

It's the first picture in post #5 from this thread: https://www.helifreak.com/showthread.php?t=515164

Darrick,

I finally tore mine apart and measured that hole with a pin gauge this morning. I measure the high-speed at 1.7mm. The medium-speed measured at 4.11mm.

Hope that's of some help.

[CyprusFlyer]

This thread has gone a bit quiet, any progress from anyone?
Put a YS91 Tareq in my Synergy and took out the OS105 for now, cleaned in alcohol and oiled up with some 3 in 1 light machine oil and put away for now.
So whilst tuning the YS, nearly had the same issue until I read that the Mid or Hover needle should be tuned first. Yes the YS has a different carb that has major differences from OS but went back to factory recommended settings and just about tuned, working very nicely so not going back for now!

[Sirolf]

I pulled all the HZ-R stuff and went back to muffler pressure.
Haven't flown yet since over a week but i know now it will run right..

[jeffsg61]

I'm not claiming to know everything about these regulated motors, but I've been running a 91 3d speed for one season and have changed the length of the backplate to check valve pressure line a few times to get it right. I started with the 10mm length the manual suggested, but it was getting so much pressure that the tank was swelling. It did not seem to change the way the motor was running but I was concerned that it would pop lines off in flight. So I cut some new line, 1cm longer each time until I was happy with the results. If I remember right, it's at about 13-14cm now and running perfect. The point is the length of that line most defiantly will affect how much pressure your pushing to the tank.
With the 105 I believe that if your pushing so much pressure to the tank (increasing the fuel pressure) mix that with the high needle that won't fully close, I would say that's the problem with the rich running. Everything else is operating properly, the diagram in the reg is doing its job just fine. Add the higher fuel pressure, now more fuel can pass through at the same amount of time causing the rich conditions even when the needle is closed. So like what was said in an earlier post, yes changing the needle to one that will fully close May work but you are only masking the real issue.
Of course this is only my opinion, but I believe it's the only logical answer

[jeffsg61]

I think your 100% correct! I think the tuning issue is all about the placement of that check valve and how much tank pressure your running.

[jeffsg61]

I forgot to mention that I was breaking in the 91 3d while adjusting the length of the line, that would have been why I didn't really notice it running to rich because it was already running crazy rich with factory settings. And my last post there was agreeing with Sirolf from an earlier post about tank pressure

[CyprusFlyer]

Well that does not initially make sense in my mind but you may be on to something. Just tuning in a new 55HZ-R yesterday and already down to 1.25 High 0.5 mid and thought oh no here we go again!
Just checked my tube and 9 cm for some reason, extended to 13 and will try again tomorrow. It could be that the piston needs to travel further pushing a longer column of air before the valve opens, then it shuts off at the end of the down stroke, less air being pushed out, now that makes sense. Just another b**** variable in the system, hopefully its not that critical after a certain point and the regulator does what it should.
Kudos for experimenting with that variable