Yes, Synthetic is fine for breakin. For some time now I have been using Stihl HP Ultra synthetic for everything. On my test bench it's mixed at 32:1, on my flying planes it's mixed at 50:1. Have had great results with it.

Does anyone have the factory carb settings for this engine? The engine just about shakes the plane to bits. Can't get it to idle properly. I did tinker a bit to much with the carb I believe.
I have read that the proper idle speed is 1600 - 1800 correct? The engine also does not start right up after it is warm which is a real sign something is wrong. This is my first gas engine so any help is appreciated.

Thanks

1-3/4 on the high, 1-1/3 on the low will get you started. You will need to tune from there. It should idle all day long at 1600.

Thanks for the settings. I also read a few other threads about soldering fuel barbs on the brass line feeds in the tank, I do not have them on, would this cause the engine to not run correctly due to air in the lines?
I also noticed that the black Pressure nipple from the crank case (I believe acts as the pump) moves, is it suppose to or mayby that is the leaky problem? As you can see I am new to gas and have alot of trouble shooting questions. I appreciate all the help.

If you don't use small zip ties or some other type of clamp it will eventually be a problem as the fuel line will harden and can come loose on the fittings. I just use solder to form a small bead around the very end of the tubes, then use a small zip tie as a clamp. If it's leaking you will see a bunch of small air bubbles in the fuel line going to the carb.

The pulse fitting in the crankcase is a plastic nipple pressed onto a brass fitting that is pressed into the case. If the brass is turning, that is a problem. The plastic nipple will turn and you should feel light clicks as it seats in detents around the brass fitting, just make sure it is in one of the detented positions and it should be fine.

I now own two of these Low cost Chinese motors, A SPE 26cc from Valley View models and now the CRRC KIT 40cc (not sure where my wife purchased it for me for Christmas). These engines are both great. My 26 is running on a CM Hellcat F6F that has been seen at Bomber Feild and several other scale fly-ins in the south. I use a 16 x 8 Master Airscrew and it powers the 9lb model just fine. The 40CC engine went together in about an hour and has replaced ZDZ40 on my old Dave Patrick Edge 540T. What a difference!! I run a XOAR 20x8 and it seems to hit the sweet spot. I have been flying this model for about 5 years with the ZDZ but it never quite had enough umph!! Now it has almost unlimited vertical. I purchased the CRRC pitts style muffler that actually broke in half on the second flight but the vendor is replacing it next week.

Jody, I did not know about the bearing issue I used sealer on the joints as instructed. How do you know if the bearings are spinning and what do you use to fix it?

I recommend either of these motors and there is something really cool about actually building the motor too....

I like what I hear. I ordered the 40cc from Valley last week.
Edwin

Gunner,
I'm not sure what you mean by "bearing issue" on the GF40I. I have not experienced anything that could be construed as any kind of trend. I've done over 50 of them now and had one problem with a bearing that spun in the crankcase, I replaced the engine and the customer is very happy. If the bearings spin in the crankcase you will notice about 1/16" - 1/8" of end play (in and out) in the crankshaft along with noticeable looseness side to side, it's really kind of hard to miss.

Edwin,
Your engine is on it's way, it purred beautifully!

If there isnt too much clearance in bearing seat, you can fix it in place by red (nut-locking) high temp loc-tite.
If a bearing change is needed, you can dismantle it easily by heating the crankcase over 300-350 *C.

Once I even used a blue loc-tite (medium strength) and it still holds nicely after 20 liters of gas in a 26cc..

I received one of the first kits that were advertised on this site.The first time I ran it I noticed bearing slop in the case as soon as it warmed up and after cooling down it would tighten back up. I removed .002 off the bottom cover and that resolved the problem. The aluminum case expanded more then the bearing after warming up causing the problem. It is probably just a very few engines that have the bearing saddle machined too loose. The engine was NOT overheating! I have over 30 flights on it now and it is a good engine! Hamman

WooHoo!! Good times a comin. Just in time Jody. My big bipe failed the depth perception test yesterday. I nailed a power pole with my Sig SunDancer. At least the G62 appears to be in good shape. Your engine will get my Yak back in the air. Thanks
Edwin

The comparison made between ZDZ 40 and CRRC 40, is ridicules, I own both and the zdz is at least 1000rpm stronger then crrc, if not more then that, if i put 20*8 on my zdz it will spin above 8k rpm, both are good, about the same weight, the crrc is a lot easier to start, they are different, nothing bad to say bad on either.

Jody, Thanks for the bearing info. My prop shaft is still as tight as when i assembled it. side to side and front to back after about an hours running time. I will check it regularly. You were a great help with my SPE 26 that now has over 50 flights on it sipping about 10 cents worth of fuel per flight!!!!


SRimer

Which version of the ZDZ 40 do you have? Mine is one of the first side exhaust, and has never really been very powerful. I used it because it was small and light by comparison to other motors of the day. I know they are generally very strong engines, mine isn't. Maybe it was a lemon to begin with! I did wieght the two motors with their respective ignition and muffler systems. The CRRC is almost a full pound lighter. That too helped a great deal on the Edge 540T performance. i agree with starting comment the CRRC is a breeze to start.

You must not be familiar with this engine, the crankcase splits in half on the crankshaft center line. No heat is needed for anything.

Jody,

Im sorry I didnt put it all well in my post; my comment was directed as a generic method, not particularly for this engine.

No sweat TR, for many engines that is the correct method. One of the nice things about the CRRC 40 is that it is so easy to work on and you don't have to burn your fingers to work on them.

Hi Guys: I just completed assembling my GF40I kit and am busy making a test stand for it. I notice the carb on mine has a choke set up that once set, releases if you give it any throttle. So, unless the throttle is completely closed, the choke will not stay on. I've never seen one of those before and am wondering if all the GF40i's come with that same carb set up. Also, on mine, the throttle arm is very short and also has very little clearance between it and the intake manifold. A clevis is the only way I'm going to be able to hook up the throttle linkage to mine the way it is. A more secure, bolt-on connection would hit the manifold and jam. The question is: Is yours the same way or did I just get and odd one?
Thanks! [8D]

I've got the engine and it's mounted on a 13#2oz Katana waiting for the weather to break for it's maiden......and was trying to get some input as to the performance on a plane weighing it at this weight..I love the little 40cc...like everyone states,,easy starting and very reliable in transition...and it runs forever it seems on 12oz of fuel...broke it in with a 20 x 6 which is too small for the engine (7700rpms) and now have a Xoar 20 x 8 which brings the rpms down where they should be..around 7150..any info you could send my way would be appreciated...

I don't even have an airplane for my engine yet and in fact am looking for suggestions as to what would be a good model to use it on. Who sells the Katana you have for yours? [8D]

Your intake is installed upside down.

As for the carb, when you buy the kit, that is the way the choke comes on the carb. If the velocity stack is accessible in the installation you won't need the choke valve in the carb, I just use my thumb.

I'm embarrassed if I got that manifold on incorrectly. I thought I made it look like the photo that came with the engine instructions!
If it wouldn't be too much trouble, Jody, could you post a photo similar to mine so I can copy your installation and be sure to get it right? I'll bet I'm not the only guy who did it this way. As for the "use your thumb" to choke it routine, I agree that works fine. I do it all the time on my Q-42 powered Extra and it works great.
Thanks for the help!!!! [8D]
Rocky

I encountered some quality control issues when assembling my engine this weekend.

First, the lock washer that goes at the base of the prop shaft was not supplied.

Next, the rare-earth magnet in the prop hub (for the ignition trigger pickup) was not there. Just the hole for it!

And finally, on one of the 4mm screw holes for the ignition sensor mounting, about half way down, the threads were buggered. The screw would go in about three turns then stop.

Bought an 8mm lock washer at Home Depot , the engine supplier is sending me a magnet which I will need to install, and I have a 4Mx.7 bottoming tap on the way from MSC ($6 + $12 frt.).

Just wanted to pass this along for others building the motors.

For the price, that's kind of what I expected to find with my engine too but mine had all the parts, they were finished nicely and went together with good quality fit. Hopefully, next week when it stops raining and snowing here, I'll be able to bench run it. Sorry you got a "bad" one.
Rocky

I'm not discouraged by any stretch. I still expect to have a nice running engine that will last a long time.
I will also be ordering another one shortly.