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Old 04-03-2008, 01:02 PM   #1
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Default Sirio engine can't get to tune?

I bought this new sirio c7b .21 engine to go in my new buggy and put the turbo head on and I fired it up for the first time last nite and was really hard to get any kind of tune. It's mostly on the low end and the engine came with a extra idle screw am I suppose to change that with the turbo head?that's the plan for tonight. The high needle came 6 turns out and I started it 3 out and then ran up to 190 then started turning out to cool it and didnt bog down till 7 or so out then once it cooled turned in turn or 2 and ran up 200 did this for 2 tanks then nite time and plan on running some fuel though tonight, the problem is with the low end and plan on switching the needle and try that is that it?
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Old 04-03-2008, 02:54 PM   #2
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I bought this new sirio c7b .21 engine to go in my new buggy and put the turbo head on and I fired it up for the first time last nite and was really hard to get any kind of tune. It's mostly on the low end and the engine came with a extra idle screw am I suppose to change that with the turbo head?that's the plan for tonight. The high needle came 6 turns out and I started it 3 out and then ran up to 190 then started turning out to cool it and didnt bog down till 7 or so out then once it cooled turned in turn or 2 and ran up 200 did this for 2 tanks then nite time and plan on running some fuel though tonight, the problem is with the low end and plan on switching the needle and try that is that it?
I think this is the most confusing paragraph of what the problem is.
What is the problem with the tune? Won't idle, runs then cuts off, etc.
You shut it down at 190 and richened the mixture to cool it down. You need to get it over 200 when breaking it in.
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Old 04-03-2008, 02:55 PM   #3
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sounds like your trying to break this engine in like an airplane engine( i've flown for last 7 years) and you don't want to do that. put the needles back to factory setting and start engine.use a heat gun to get the temp of the head about 200* to make it turn over easier plus put less stress on con rod.use the throttle,not the high speed needle,to get the engine up to about 200*. then let engine totally cool down. then do the same process 4-5 times then start to lean the high end SLOWLY until you get the performance you desire. once broken in you can use temp gun for a "ballpark" setting but ALWAYS tune to performance. i.e. if you have good smoke and engine has good power, but runs at 240* or so, then that is where that engine is "happy". some engines like 200-225*,others like it a little hotter.hope this sheds some light on it for you....
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Old 04-03-2008, 05:08 PM   #4
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what I am doing is called temp cycle and I put the pointed low needle in and just ran 3 more tanks though and it ran alot better, I have never seen a flat needle like what was in there but the idle was just all over the place, I think I need higher gearing though has way to much power( the rear just squats on take off) and the last tank I wound it out a little and top speed is like 40'
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Old 04-03-2008, 05:41 PM   #5
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You mean heat cycle the engine!?
Anyway, if you got a few tanks through it, you should try and not to full speed the engine so soon. Try to keep the HSN needle a little rich so it won't take off so much on the top end.
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Old 04-04-2008, 08:44 PM   #6
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Thanks for all the input on breaking in engines but the questions was about the two different needles and a high speed out 6 turns and running good, I called Kyosho today and found out my answers< just thought I could get the answer from somebody with this engine and save the call and hold time
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Old 04-11-2008, 08:27 PM   #7
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the engine should be easier to tune with the short needle, the long low/mid needle is for mileage
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Old 01-08-2009, 01:01 AM   #8
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the engine should be easier to tune with the short needle, the long low/mid needle is for mileage
ok i got a sirio .21 and it will not start unless you pul throttle and as soon as you let go it stals and we have done the turbo and the right plug and nothing got new carb still nothing we have tried HSN, LSN and idle everything and 25% nitro 6 and 6 syn and caster please help im stuck
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Old 01-08-2009, 03:17 AM   #9
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I have a Sirio CL7B and I had exactly the same problem. First I changed the head to the turbo head. This did help the problem slightly. I then opened the bottom end right up, so that the needle sits outside the needle casing, (really rich). I then adjusted the high needle accordingly.

Also the motor is factory shimmed for 15% nitro, so that may also be a thing to look at.
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Old 01-08-2009, 02:56 PM   #10
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I have a Sirio CL7B and I had exactly the same problem. First I changed the head to the turbo head. This did help the problem slightly. I then opened the bottom end right up, so that the needle sits outside the needle casing, (really rich). I then adjusted the high needle accordingly.

Also the motor is factory shimmed for 15% nitro, so that may also be a thing to look at.
my Sirio is S21 BK EVO4 "STI KANAI EVO4 STI" 5+2 PORTS-ABC-SG SHAFT
and i was told to run it the the book says to and the hobbie shop says to so i ran the right racing
fuel
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Old 01-19-2009, 02:10 AM   #11
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ok its fine it works it was the piston liner and i was runing it around my back yard which is 15meters long and 10 meters wide and it is funning rich and i can't see the thing half the time
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Old 01-19-2009, 05:41 AM   #12
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i have heard of guys putting novarossi carb on the sirio motors to make them easier to tune.. i have an evo 3 and it was always a pain in the butt to tune
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