I have a DZ160 which gave me a dead stick for the first time today. When investigating I found that the Check Valve (P/N 87) had come out of the Cylinder Head but I think that it took a part of the head with it when it came out. Specifically attached to the plastic Check Valve is a brass looking fitting with a silver colored metal tube protruding from the centre of the brass fitting (see attached picture). I can push it back in (seems to be a interference fit) but I'm pretty sure that it will just pop out again when it shakes around when running.

Has anyone had this happen before? Is it a "return for service to manufacturer" problem or do I just put some high temp Loctite on it and push it back in?

I'm sure Troy Newman will chime in here, but I believe you may need a new head. That metal piece is pressed into the head and shouldn't come out. I think someone had reported that once before in the YS Support forum, and I believe what happened was the engine overheated, allowing that insert to loosen enough to fall out from vibration.

Hi Twoturnspin

Me and friends of mine had this problem.
Very easy to solve ourself. Dont "return for service to manufacturer". Before putting loctite I cleaned and scratched the surface to make it harsh.

Regards

Thanks mjfrederick, I couldn't find the thread you referred to. I don't think the engine was hot, I run it quite rich and I could hold a finger on the motor comfortably when it landed.

Papaone, what type of Loctite did you use and how did you ensure the brass fitting seated correctly when you reinserted it?

I have used the cylindrical fit loctites in power transmission assemblies for press on gears, its very strong, but check the temperatures. I wonder if YS would send you a replacement head? This has been a common problem.

http://www.loctite.com/int_henkel/loctite_us/index.cfm?verityspider=0&layout=4&productline=OEM5 010&path=Assembly%20Products|Cylindrical%20Assembl ies%20%28Retaining%29|General%20Purpose

Just an update on this issue, I wrote to Central Hobbies and they said they hadn't heard of the issue before and referred me to YS parts and Servie so I have written to them. Will post the results when I receive any. A guy I now who is very experienced with engines suggested Loctite 680 which apparently has the highest bond strength going for high temperature applications.

Central Hobbies doesn't deal with Service issues.

You need a new head. This is not a common problem but it has happened before.

I personally have not had it happen but I have seen it more than once.

The problem you have is Australia vs the USA. To get service if purchased via Central Hobbies you need to contact YS Parts and Service here in the USA. That means the warranty issues are handled here in the USA. Which really is unfortunate for you as the shipping charges will be high both directions and also the turnaround time will be much longer.

YS Parts and Service is not the Yamada factory. In fact they are the distributor that makes these engines available in North America. They handle the warranty issues on the engines they sell in that market. Thats part fo the deal with Yamada. In the end I'm sure there is some business consideration between Japan and YS Parts and Service to handle the warranty issues caused from defects in manufacture.

I think you may end up getting much quicker service from a local YS distributor or perhaps Yamada Japan directly.


I would not expect too much from an email to YS parts and Service. Richard is always pretty busy and doesn't spend much time on the internet. That is why I handle the YS forum on RCU on his behalf.

The best way to contact YS Parts and Service is by telephone. And you being an ocean away this I understand is difficult.

I'm not trying to dash your plans just letting you know the reality of the situations. YS Parts and Service provides extremely excellent service and warranty repair services for Yamada Japan with the engines that come to North America, however the simple logistics of your situation can be difficult for both parties involved.

Troy Newman
Team YS

Thanks Troy, much appreciated. I called YS Parts and Service but there was no answer and subsequently emailed him this morning (Australian time), I will call Rich again in the morning to try to get resolved should I not receive an answer by then.

As you say it is difficult/expensive to handle because of the distance involved. It's a shame that YS warranties are not international given the propensity for people to purchase this way. (ie. my Toshiba notebook was purchased in the US and was repaired locally when I had a problem).

I understand that in Australia this problem is resolved locally by the importer/agent glueing the unit back in. If YS is going to do this rather than replace I think I would rather just do that myself using loctite. Anyway hopefully I will get a better understanding when I get onto Rich.

Thanks again for taking the time to write Troy.

All the best, Simon

Simon,

we had one do this down in Wollongong. Tates tried to glue it back in (twice I think) but it just popped out. I took it up to Japan and sent it over to Yamada they replaced it no charge (in fact they supplied the whole head assembly with all the valve gear) Eventually Tates also replaced it so we had a spare head in the club. If you have no joy with YS Performance I would just put the head in bag and send it to YS. If you have any questions PM me.

Brian

I had the same problem!

The engine hade about 80 flights when it happened.
The Israeli dealer gave me a new head under warranty.

Ram

I called YS Parts and Service this morning and Rich advised that the problem was rare and that he had fixed those returned to him by using JB Weld (after roughening both surfaces). He felt that JB Weld would be stronger than the simple press fit used by the factory. Given the distance he suggested I do this myself rather than return to him because that's what he would do anyway. He also said that the problem had been caused in the past by the motor banging around and hitting the cowl or something.

I just spoke to Richard about this issue. He told me he has seen a few of these about 4-5 engines total. He said that the JB weld is a very secure fix and that you should be setup.

As I said YS Parts and Service are very good about the service, and warranty issues. I did not know that they were using the JB weld as a fix. I just assumed the injector was pressed into the head.

One thing to make sure is that the engine doesn't hit the side of the model when its on the soft mount. I have seen this damage the black plastic check valve assembly and I guess this is the thinking regarding the injector coming out as well. That does make sense. So make sure you have good clearance and it is not hitting the airframe. You should be right back in the game.

Richard always manages to get things taken care of. Thats why I love running the YS engines and helping to support him in his business. Its really easy to be associated with a company that takes care of their customers.

Let me know if there is anything more you need. I was not aware so many of the engines sold via Central Hobbies are going out of the country. I guess this really makes a statement about the great product and service from both Central and YS Parts and Service. I always say that but its good to hear it from other folks too.

Troy Newman
Team YS

I've had a bunch of very kind people give me advice on this and I think the best way forward is to roughen and clean both surfaces, heat up the head, freeze the injector and use JB Weld. Thanks to all for the thoughts and advice.

See picture for head reassembled. I pushed the injector in as hard as I could but there is still a gap as you can see, I think it should have seated deeper. Too late now, it seems to be in very firmly, hopefully it will hold up ok in flight.

Flew the DZ160 over the weekend and the injector held up just fine. It wasn't hot mind you but I ran the engine hard for the first flight (harder than I would normally run the engine) and it didn't miss a beat. In fact when I put the head back together I checked and adjusted the tappets and felt I had more power than previously so all is well.

Thanks again to all for your thoughtful advice.