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tuning help

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Old 02-26-2006, 11:26 PM
  #1
tricked03
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Default tuning help

I have a Lightning VX and am new to the nitro world. I'm not sure what all the adjusting screws are or what they do. I was stupid and thought I could tune my engine but failed. Now my car runs like crap. I have alot of fuel coming out the exhaust and when I hit reverse on the controller trigger, my car just dies. Can someone help me get my car back to factory settings or just set the right way. The screws I already messed with are: Directly below air filter, Right above fuel line on engine and the screw that is part of that rubber bushing...I think at the end of the throttle linkage. Any help will be greatly appreciated!!
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Old 02-27-2006, 10:50 AM
  #2
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Default RE: tuning help

It sounds like you have the high speed needle valve to rich.Mine was blowing fuel out too.
So I adjusted the high speed needle valve about an 1/8 of a turn down.It leaned it out.
It seems to be working just fine for mine.

A little fuel out of the exhaust is not a problem as long as it is not TOO much to where you are going through a tank of fuel in 5 minutes or less
The most important thing you need to remember is PATIENCE when tuning these things..(1/16-1/8 turns on any of the needles)...very minor adjustments can make a HUGE difference in how they perform...plus...you need to give them time to adjust to new settings...the effects WON'T be immediate.

That is the BIGGEST problem most people have when trying to tune these things...(especially newbies)...they make an adjustment..(usually a BIG one like a 1/4-1/2 half turn or better)...then nothing happens immediately so they keep turning screws and get frustrated... you need to change a little at a time...run it and see what happens....also...do you have a temp gun or anything??.....temperature is key to proper tuning also....these should run anywhere from about 210-240...that is about the best and safest temp range..
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Old 02-27-2006, 11:36 AM
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Default RE: tuning help

LOL....hey...the majority of that post looks VERY familiar..

I really don't mind being plagerized in this instance...I'm glad I could help and it's actually kind of nice to see my advice being quoted...VERBATIM...lol!]

Tricked03...the needles go like this...the one under the air cleaner is the idle speed screw...the one next to the air flilter that the fuel line attaches too is the high speed mixture screw (it controls the fuel/air mixture from about 50%-W/O throttle)....the screw inside the end of the throttle arm is the low speed mixture screw (it controls the air/fuel mixture from idle-50% throttle)....

Try this....lets start all over from scratch and tune from there....screw in the LSN (low speed needle) all the way in so it seats...DO NOT CRANK IT DOWN TIGHT...just screw it in GENTLY until it stops then back it out about 2-2 1/2 turns....set the HSN (high speed needle) so the head of the screw sits flush with the outer edge of the collar it sits in....take off the air cleaner and see what kind of gap is in the carb....with all your controls ON and the throttle servo centered in it's "neutral" position there should only be about a 1/16th gap showing....you shouldn't have to mess with the factory idle setting...unless and until you get the rest of the tuning right...then you may or may not have to adjust your idle speed screw slightly...

This should get you started and running decent then you can fine tune from there...

My biggest question is...have you finished break-in yet?...and if so did you do it correctly??
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Old 02-28-2006, 12:01 AM
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tricked03
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Default RE: tuning help

Ok...I'll have to do those adjustments. As for the break in, I didnt mess with any of the screws untill I went through about 4 tanks of fuel. After that was finished, it just didnt seem like my car had the speed it should. Thats why I started messin around with the screws. Also, I am very bad with measurements...the opening in the carb right now is set at about 1/4. So Im thinkin it needs to be closed alot more or a little more...lol?? Are these real scale measurements also? So if I looked at my tape measure to get an idea how much 1/16th is and adjust to that size, it will be right or at least close? Thank you so much and I will post again and let you know the outcome.
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Old 02-28-2006, 12:04 AM
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tricked03
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Default RE: tuning help

One more thing... I already messed with the idle speed screw. How should I adjust this?
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Old 02-28-2006, 12:13 AM
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Default RE: tuning help

1/4 of an inch??......WHOA!!!..NO WAY!...LOL!!....that thing should be zinging off the charts if it is set at that...yes...that is WAY too much!

Look at a tape measure and set the idle speed (gap in your carb) to about a 1/16th of an inch....turn the controls on and see where it sits then back the idle speed screw (the one under the air cleaner) out (counterclockwise) until the gap closes down to 1/16 or even just a little less....then set the LSN and HSN to the settings I gave you above...then see if she will start and run....then you can tune from there.
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Old 02-28-2006, 12:21 AM
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tricked03
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Default RE: tuning help

LOL LOL...Exactly...my car goes berzerk!! No wonder its so hard to pull the starter!
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Old 02-28-2006, 12:29 AM
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Default RE: tuning help

Well DUUUUUUH!....LMAO!!!!

You should have stopped right there the first time it happened and got some help...not run 4 tanks like that...

To be honest...I'm worried you may have ruined the motor if you were trying to break it in that way!

So...start over from scratch using what I told you above and see what happens and I'll keep my fingers crossed for you.
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Old 02-28-2006, 04:50 PM
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tricked03
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Default RE: tuning help

Ok my friend, seems my car is headed in the right track now. I still have quite a bit of fuel coming out of the exhaust which could be some of the left over fuel when I had it set wrong. It still wants to die though when I hit the brake on my controller.
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Old 02-28-2006, 06:12 PM
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Default RE: tuning help

Good...I'm glad you are getting there!

Start leaning it out a bit if you are dumping a lot of fuel out the exhaust...lean out your low speed needle a little bit first and see what happens...remember...small adjustmets at a time and give it a chance to get use to the changes...the changes won't be immediate.
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Old 03-05-2006, 10:12 PM
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Default RE: tuning help

If you have the lsn to rich will it make it die when you break..... if you have it to lean will it make it idle high????
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Old 03-05-2006, 10:29 PM
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Default RE: tuning help

If it dies when you brake the idle speed screw could be set too low and you have the trim on your controller to set the idle higher...DO NOT rely on the trim setting to set the idle....make sure you have everything (servo and controller to their centered/neutral position with all electronics ON)...check the opening in the carb...it should be about 1/16 (when fully closed)...maybe a little more or a little less..every engine varies a bit...and yes the LSN will affect the idle speed...I would suggest resetting everything back to zero (see above) then start over from there....

Remember...adjust one setting at a time while tuning (small adjustments 1/16-1/8 turns at a time) and give it chance to get use to the new settings...they won't take affect immediately...the biggest thing is PATIENCE...I can't stress that enough...


Start over from scratch and see what happens.[8D]
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Old 03-05-2006, 10:36 PM
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Default RE: tuning help

well i got my carb set to about 1/16 hole and the car finally dont die when i apply the break but the idle is rev'd pretty high .... so I'm hoping that if i make the lsn richer it will drop the idle down some rpm's.... am i headed in the right direction????
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Old 03-05-2006, 10:50 PM
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Default RE: tuning help

Yes sir I believe you are...is the gap staying where it should when you hit the brake and the car is idling?....is so then richen your LSN about a 1/16th to an 1/8 of a turn...blip the throttle a bit and let her come back down to idle and see what happens.

If the car doesn't take off while it is idling where it is right now then I wouldn't worry about it...these little motors and 2 strokes in general idle kind of high anyways.
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Old 03-06-2006, 10:01 AM
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Default RE: tuning help

I was having the same problem. so when i adjust the idle screw. i should be able to look in the carb and see the opening get larger or smaller correct? cause it didnt look like it was moving when i adjusted the screw. maybe im wrong...ill have to check again. so mr rpms at idle are way high. do i turn the idle screw clockwise to slow the idle rpms?
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Old 03-06-2006, 05:16 PM
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Default RE: tuning help

Couterclockwise to slow it down...and it doesn't take much of a turn to affect it....try about an 1/8th of a turn...blip the throttle a couple of times and give it chance to get use to the change.
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Old 03-15-2006, 11:10 AM
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Bumping this to the top for the newbies coming in.[8D]
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Old 03-15-2006, 03:55 PM
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Thank's for that
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