Don't run it thru the gears in the air, you could damage the engine from over revving.
Find factory settings for that engine, reset to those, then tune from there.

To get it tuned, First get the engine fully warmed up!
Never tune a cold engine.
Start from factory settings on all needles. (Maybe 1/8 to 1/4 in on the HSN from factory if already broken in.)

Be sure to set the idle gap as well as needles to factory settings before retuning from scratch.


Get your HSN set first.
Keep leaning the HSN 1/8 turn in at a time and watch the performance increase.
Making a couple top speed passes each time to let the engine get used to the new setting.
When you see a decrease in performance turn the HSN back out 1/8 to 1/4 turn to richen it back into the safe zone. Keep an eye on temps as well.
Good top speed and good trail of smoke at all speeds is what you want.

Then set the LSN.
You can do the pinch or punch test, or both.

PUNCH TEST-
Once you have the HSN set, engine warmed up.
Make a couple top speed passes and bring it in and let idle for 10- 15 seconds.
Then give it 3/4 to full throttle.
If is slow to take off and smokes alot you are too rich and need to start leaning the LSN.
If it takes off fast, rev's and dies, etc... it is too lean and you need to richen the LSN.

If it smokes and is slow taking off, start turning the LSN in 1/12 to 1/8 turn and again make a few passes to get it used to the new setting in between adjustments.

PINCH TEST-
Make a couple top speed passes, bring it in and pinch off the fuel line near the carb.
Start counting 1...2...3...
It should run for about 3 seconds before it revs and dies.
If it runs longer you need to lean the LSN.
If less than 3 seconds you need to richen the LSN.


Once you have good acceleration and still have smoke at all speeds you are done.
You may need to reset the idle on the carb once you are done tuning.

Weather always plays into your tuning and you will need to adjust the HSN for day to day conditions.
I.E.- colder weather requires more rich settings and vice versa.

I am just a basher and no expert so use this info at your own risk!

SLAYER
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Supplied by Robin from Extreme RC Mods.

This is the way that I tune engines, there are many other ways to tune but I figured this is the most simple way to do it so I will share my info. This technique is for a fully broken in engine that is ready for a full performance tune. This tuning procedure will set your needles where they need to be for optimum performance, a temp gun is not required (other then high temp safety check) because there is no guessing, the engine will tell you.

For this to work the engine has to be at running temps (or as close to it as possible) as well as having the standard 1mm gap for the carb opening.

#1) High Speed Needle.
Pull a wot pass a couple times and listen what the engine does when you let off the throttle. As long as the rpm drops right to idle, the HSN is either good or on the rich side. At this point you can lean the HSN in 1/12 increments until the idle seems to hang a little after a wot pass, when it starts to idle high after a pass it is just on the lean side of a perfect tune. Back the HSN out 1/12 turn at a time after a wot pass until the engine drops right to idle after a pass. Now your HSN is set.

To give an explanation to what is happening is simple. If your HSN is too lean, after a wot pass when you let off the throttle the engine is still lean causing the idle to hang and idle high until the LSN has a chance to take over and meter the right amount of fuel to bring the idle down to normal running speed (given the LSN is set correctly)

Now if the opposite happens, after a wot pass when you let off the throttle, if it drops to a good idle right away and then starts to idle back up too high, this is a sign that the LSN is too lean. If it comes off wot with a good tune and will drop rpm nicely then the HSN is metering the fuel properly but once it hits idle the LSN being too lean will quickly take over causing the rpm to go back up.

#2) Low Speed Needle
Most of this setting was explained above but there are a few little tricks you can use to make sure the LSN is adjusted perfectly. We all know that you don't tune for temps but a temp gun is very handy for this part. After some wot passes with the engine good and warm, bring it in and let it sit for about 10 seconds. At this point take your temp gauge and hold it as steady as possible on the head, what you want to see is the temp dropping a degree every 4-5 seconds. You want the temp to drop very slightly at idle because when your off throttle the engine should be cooling, if not, the temps will keep pushing higher with on and off throttle running and will cause temp issues.

This is how I do it and I have tuned a lot of engines for people whether bashing or racing. I have seen across the board from beginners to veterans that when they hear the high idle after a pull, the first thing they go for is the LSN when in fact it is the HSN causing the issue. The veterans are surprised when we richen the HSN an hour or two and the problem goes away. I hope it's not too hard to understand as typing it out is much harder then explaining it to someone first hand, if you have any questions feel free to ask.

Robin