Hatori 821 or 725
 

Is there anyone using, or have any experience with the Hatori 821 or 725 short pipes with the rigid headers? If so, how are the working and are the headers staying snug. I'd like to try one on a YS160 but have heard they headers come loose.

Thanks,

Todd Schmidt

RE: Hatori 821 or 725
 

Todd,

I have just finished installing the 821 on my Astral XX (one piece wing) with a 160 DZ, but have not had the chance to run it yet. However, I will suggest using the Asano header instead of the Hatori one. The Asano has a metal tap on the side of the header so you can fasten the header onto the head of the engine, therefore, no worry about header coming loose. Also, be sure to have a slight clearance between the header and the pipe (10 mm) for expansion.

In addition, you should use a Nishioka soft pipe mount. I understand this set up works really well with the one piece wing configuration. However, I have had no experiene on a two piece wing design.

Good luck,

Adrian

RE: Hatori 821 or 725
 

Riot 3D any pics of what you are talking about?

RE: Hatori 821 or 725
 

Here are the pix

Adrian

RE: Hatori 821 or 725
 

Here is a pix of the pipe and soft mount

Adrian

RE: Hatori 821 or 725
 

Hello tschmidt
I have 2 Asano header.
The collet of the Asano header tighten by the nut on the cylinder head broke on every pipe after about 50 flights. I'm going to install Hatori because friend did a lot of flights without problem and Hatori is cheaper as Asano.
Regards

RE: Hatori 821 or 725
 

Thanks for the info Papaone, that's interesting to hear.

Robert, Adrian told me the Asano header is about $110 US. [X(]

RE: Hatori 821 or 725
 

that sounds cheap Tod?!?@?@?@

RE: Hatori 821 or 725
 

Papaone,

Which part of the pipe broke? The metal tap, or the flange?

I have friends using the Asano for hundreds of flights without any problem. Again, the key is to use the Nishioka soft pipe mount, and leave a gap between the header and the pipe for expansion.

Rgreen24,

The Hatori is 5,355 Yen, and the Asano is 12,600 Yen, which comes out to about US$47.00 and US$110.00 respectively. The difference is the Hatori doesn't have the side metal tap, and they only have 10 or 25 mm rise. The Asano comes in 10, 20, or 30 mm which fits my Astral XX.

Adrian

RE: Hatori 821 or 725
 

Hello
It's the flange of the header which broke. Others friends using Asano header had same problems.
So ZNLINE did'nt sell this header and replace it by Hatori header.
Yes there was a gap between header and reso for expansion.
Hatori don't need metal tape if correctly mounted.
Regards

RE: Hatori 821 or 725
 

Hello tschmidt
Here a picture of Header Hatori.

RE: Hatori 821 or 725
 

Look at the funky red valve cover... must have.
How is the coupling between the header and the pipe neck holding up?
I presume there are a couple of silicon O rings inside the neck of the pipe to produce the seal... are they breaking down... easy to replace etc etc?
Or is it to early to tell?

RE: Hatori 821 or 725
 

The only problem I had with my Hatori short pipe was the spring pipe mounts on
the rear of the pipe constantly breaking, and yes, there was adequate clearance
between the header and the pipe. Check out this web site about building a Twister
and there are a couple of pictures of a new mounting method for the short Hatori
pipe that looks like a better way of doing it to me.

http://perso.wanadoo.fr/cmdieppe/Actualites%202005.htm

tommy s

RE: Hatori 821 or 725
 

I ordered the 821 and Hatori header, well see what happens!:)

Thanks Papaone for the pics, nice looking set up.

Todd

RE: Hatori 821 or 725
 

I see many people are using the short type (821) also on plug in wing airframes where there is no real space concerns to have a short pipe. What are the pros and cons of this?
I guess some weight could be saved, and that it could be nice to have a shorter pipe tunnel, but I imagine that having the exhaust further to the front require a lot of extra wiping to clean the of the oil after flight?
What is the conclusion regarding noise between the long and short hatoris?

RE: Hatori 821 or 725
 

Very quiet.

As for oil residue, almost non-existence, just use a rubber extension on the stinger

Adrian

RE: Hatori 821 or 725
 

Seems then that the 821 is the better option.

Is there anyone who know some “numerical” facts about the sound level of these pipes? I mean sound measurements with both pipes done by the same person in the same environment. All the volume of the longer pipe should make some difference, either on sound or on power, but maybe it doesn’t.

/David

RE: Hatori 821 or 725
 

I don't know if this will help, it might be like comparing apples and oranges, but:
I ran a YS 1.10 powered pattern ship with the short Hatori #725 muffler and my current
YS 1.40 powered pattern ship with the long Hatori #699 muffler and the long muffler is
definitely quieter than the short one. I just changed to an ES Composites muffler in my
new plane as it's quieter than either of the Hatori mufflers although all three of them are
quiet enough for pattern competition.

tommy s