this is getting old

[dodgeboy]

ok i have to vent here cause im tired of dealing with this. i have 3 other 700n's and ive never had this issue in the 3 years of owning any of them. the problem im having is the OWB failing in the clutch. i mean completely failing, like the cage comes out and needle bearings fall out. this first happened at a fun fly earlier this year. thankfully there was 2 GREAT team synergy team guys there that took it upon themselves to help me install a new OWB at their own cost for me.(i did offer to pay) since then, this has happened 2 other times. i notice while walking to the flight line the clutch is real grabby and then it finally let go and would not longer lock up to spin the motor over. other than the first time, i have always just installed a new clutch that came with the OWB installed in it. i have only ever added a drop or 2 of ATF to the owb and made VERY sure that the clutch stack is running straight on the clutch. im on the edge of taking all the electronics out of it and selling it. anyone have any insight or am i just that unlucky?

[Chris Sexton]

Man I am sorry to hear of your troubles. I have seen a couple cases where the owb was greased improperly and had to be cleaned out but that was only preventing starting. The cage wasn't coming out.

I am still running the original bearing from my preproduction kit with over 150 flights on it. I have several of these birds locally and I have only seen one bearing actually fail. That guy was using an older aligh starter and literally jack hammered the bearing while his motor was hydro locked.

It does seem odd to me that you have had so many failures.

What is your setup and starting setup?

Sent from my SM-N900V using Tapatalk

[dodgeboy]

im using a 4s hobbico starter. works just fine on every model i own. i have never had a OWB fail in any of my clutches.

[Chris Sexton]

What are you using to lube the clutch owb if anything?

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[dodgeboy]

A drop or 2 of ATF.

[Chris Sexton]

When these fail are you changing the clutch or just pressing in a new bearing?

Here is what I am thinking. I am going to send you a brand new clutch, free of charge. Don't oil it, just put it in the way I send it. Lets see how long this one lasts.

If this one fails fast then we must have something else causing issues. I can see having one or even two bad parts, it happens. They are made by people after-all. But 3 and 4 is statistically improbable considering how many people are flying these models and NOT having this issue.

Shoot me a PM with your address. I will get the new clutch on the way today.

[dodgeboy]

Ive always just installed a new clutch. i appreciate the offer chris, but i have already ordered another clutch last night. if this one fails, then it goes up forsale.

[Kinger]

I've had a bearing go bad in my clutch with a YS91SRX installed in the model. I tend to think it failed for two reasons. 1.) I could never get the YS91 to line up in the stack as well as my 105 (didn't try shimming it though which it really could have used) 2.) I had a couple hydrolocks on the motor when it was first installed.

As for ordering a cluch with a bearing installed vs. ordering just the bearing, if you have a vice you can get the bearing out relatively easily with some sockets. Will save you a little cash in the long run. However, with 4 going bad, I think you might have something else going on as there do seem to be many owners not seeing similar problems to you that I know of.

[dodgeboy]

I have a ys91srx but i had to make my own shims to get it lined up correctly.
this is only the 3rd time, not 4, but at this point i guess it doesnt matter. ive gone to great extremes to make sure the clutch was straight on the clutch also. i have a new rcbearings OWB im going to install in the clutch and give it a go.

[Frequency]

how does the clutch fit inside the clutch bell? you should be able to wrap a piece of electrical tape around the clutch (without over lapping) and the clutch should fit snug inside the housing with the liner installed. also do you notice any vibes when you spool up? is it possible anything in that clutch stack might be ever so slightly bent or even the cam in the engine? i spose you would be blowing through engine bearings as well if that were the case. Im just throwing out ideas. I'm kinda at a loss. Not trying to kick ya while you're down but the only other variable is you. Is there a possibility that you are doing something in the install or even in transport that could cause this? Next time you are moving your heli around see if you can notice anything that could cause this to happen. Just to be clear I'm not blaming you at all and just want to see you get back in the air, looking at everything is part of troubleshooting.

[dodgeboy]

I understand what your saying, but i have 3 other 700N without this issue. the clutch gap is perfect(2 pieces of tape of a gap) the starting shaft is new and so are the bearings. ive gone as far as starting the motor and then loosing the clutch stack bolts so it can center on its own. everything is super free and moves perfect without binding or anything. i just installed a new OWB in my old clutch till the new ones gets here. i cleaned it very well and just added a few drops of oil to it. i guess i'll see how long this last.

[mdu6]

everything is super free and moves perfect without binding

In checking for this - do you turn the hex adapter CCW to feel the shaft shaft turning free in the one-way bearing AND then turn the fan 90D - turn the hex adapter again and so forth until you have confirm the start shaft to be free at all fan/engine positions ?

This and a good starter should normally make for a long lasting start shaft/One-way.


As for others that have alignment problems with the 91SRX - I can confirm I have absolutely NONE (no shim needed) - so either there is some small variations in part geometry - or the bolt down pattern you are following is incorrect (for example bolting down the bottom plate/engine mount early in the sequence).

[dodgeboy]

There is obviously a difference in motors either ys or os. I know people with os and ys, some need shims some dont.

[mdu6]

Yes if the engine make is different (maybe) - but since I am using a YS91-SRX and others that are using the same engine YS91-SRX are reporting that they are using shims while I am not ...
- So either some parts geometry on the N7 varies or the bolting sequence used

[ChapaWolf]

I didn't read all the replies, however I read most. I am really sorry for the problem. I had a similar issue I have put 2 OWB in mine I figured out my problem was over lubing the bearing. Which was hard for me to believe because I only put a tiny bit of oil in it. What happened was when the bearing goes into free spin mode the lube would push the cage out to make room for the rollers causing the separators to separate, which ultimately caused the OWB to fail. I stop lubing the last one and thank god I have not had the problem in about 8 gallons.