OS91 HZ tuning help

[aww]

Does anyone fly the following combination :- 700LE, OS91HZ, Align pipe and Optifuel 20%

I’m looking for the needle settings for this setup. I know there will be slight difference to what mine should be but it will just let me know if I’m some where near with mine. I’ve got it some where close to what I think it should be but at 1950 head speed there is a resonating sound and I’m not sure what it is. There is no visible vibration and the head temp yesterday was about 185F. Can anyone please help!

Anthony

[rachel]

hi Anthony,
I start at 1 & 3/4 turns out on the main needle and 1 & 1/4 turns out on the mid range needle.
If you engine sounds harsh its most likley lean so its best to ritchen it up and work back in.

There is a very good set up video on engine settings at Smack Talk here Download Center - SmackTalk RC

hope this helps
x Rachel

[aww]

Hi, thanks for that. I’ve downloaded the smacktalk vid some time ago ( as well as the Tim Jones one on Helifreak) and found it very interesting. Unfortunately I'm not up to the "tic toc" stage in my flying as Bert shows so I'm doing big loops with full collective instead. I think I may have my main needle to lean as it is under 1 & ½ at the moment.

Anthony

[Nick B]

as rach says,get the main to 1 3/4,optifuel is smokey fuel even if your on the lean side,my needles are 1 3/4 on main and 1 1/2 on medium with hatori pipe,my head is about 85c normal running and spikes at 105 during tic tocs.

[sacko]

Factory settings are 2 turns out on this engine.

1.25 turns out sounds very lean IMO, but 1.5 on both is about right, richen it up and see.

Is on page 25 of the manual.

[Eckchaz]

Mine was really hard to get right.. at first it was either hot or cold (within 2 clicks) with Outrage pipe and 20SLV.. after changing shim to just the 2mm, ive settled on 1 3/4 high and 1 2/3 med.. I can go leaner as the plates just barely luke warm but it still produces enough power for me at the mo.. what shimming have you got in your head 1,2 or 3... the thicker it is the easier to tune

[aww]

I'm running with the shim that it came assembled with. The engine was running ok with good power and I only started to re-tune it after I'd stripped down my 50 hyper and found that the bore was glazed due to running it in too rich. I think I’m concentrating too much on engine temp rather than engine noise and power.

Anthony

[aww]

Well today was the first time I’ve been able to get out and fly in 3 weeks! Set the main to 1¾ and the mid to 1½ and flew much better, eventually got the mid down a couple of clicks but because I’m no 3D’r the head temp didn’t get above 160 deg.
Anthony