Hmm - maybe a few long needles slipped through with the last distributor.
I am pretty sure all the new GX motors Trey is bringing in are short needle. Maybe he can confirm that for us. Still won't explain why A-Main are showing a short needle with the long needle part number.
All I can suggest is you order it, cross your fingers and toes, and see what you get. Guess the cost isn't too much if it's wrong.
For a long needle tuning guide visit the Tech Tips page on our web site www.go-racing.co.nz

hi guys,

how long is the short needle? i have an old 7 port (gen5) where the needle never fully leaves its housing, not even at WOT. this is the long needle of course.
but i have another brand new gx series 7 port where the needle leaves its housing, but only at WOT. i'm not sure if this is a short needle or some sort of intermediate lengths needle. i know of some novarossi needles which are significantly shorter and leave their housing at app. 3/4 throttle.
who can help?

thanks!

Hi all

I was recommended this engine from my local RC shop

I have a Caster Racing ZX1 (just getting into Nitro cars so a n00b) and this was a good basis to start with

unfortunately I did not realise that in the UK at competition level, the largest engine you can run is a .21, and my Caster has a .25! doh!

I read through the first couple of pages, and what everyone has said simply confirms what my model shop has advised me

This is the package I am looking at. Would that exhaust be ok, or can anyone advise on a better exhaust?

GX-3R-PI2072 - ENGINE with EFRA 2072 TOUGH pipe

Thanks for the help

Thats probably the best all round combo for a beginner..Nice smooth powerband with enough power everywhere but neither too much grunt at the bottom nor too insane a top end to get you into trouble.At the same time a perfectly capable competition engine.Should easily see 10-11 min runtime with a 7mm insert as well..

thanks chief

to be honest, (track dependant) having as you say an all round engine is key, but only a small percentage to the overall package as the rest is down to handling, braking and mostly driver skill

I too am a petrol head (drive a tuned 1.8T Seat Leon) and I always say, power is nothing without control

I am on a UK RC forum, and its good for local meets, but so far this forum has simply excelled itself in terms of general and technical knowldge

Funnily enough, I ignored the old skool break in advice on my nitro, and kinda used my own, which reading the "break in bible" on this forum is exactly the same as to what I did so things are running sweet. I am not too concerned about my first engine, its there to be wrecked as I will run many more, so understanding this engine and the bible method of break in will be strongly adhered to for my next engine, which will be this Go 21. engine

Hey, right tried this..........set both needles to flush, fires up right from the go after a little pre-heating but it just wont idle for more that 10 secs if that, normally just stalls as soon as I take the glowstarter off.....

Doing my head right in now........as I really want to get this thing run in but cant even get it to idle

Does it idle long with glow igniter on ?
And only plays up once you remove it ?

It could be a bad plug !

You also said you set both needles to flush after Mark advised tuning and setting your bottom end using the pinch test, so wich way did you do it ? Flush or pinch test way ?

Yep keep the glow on and it will run happily enough

There both flush, thats how Marks link states to start then idle for 30sec and do the pich test, I cant get it to idle to do the pinch test

[QUOTE=Tony20VTurbo;7094166]thanks chief

to be honest, (track dependant) having as you say an all round engine is key, but only a small percentage to the overall package as the rest is down to handling, braking and mostly driver skill

I too am a petrol head (drive a tuned 1.8T Seat Leon) and I always say, power is nothing without control

I am on a UK RC forum, and its good for local meets, but so far this forum has simply excelled itself in terms of general and technical knowldge

QUOTE]

Obviously the engine is only a small part of the overall performance of your buggy , what I meant was if you are looking for a GO engine to start with as a nitro noob then the 3 portR is probably the best choice.The 5 port is an animal low down and needs taming with careful choice of carb insert and probably throttle limiting too..the 7 port has insane top end which is fine but needs perhaps a little more experience.The 3 port is a nice balance between the two but is still a "race" engine..I ran a MM5 3 port a couple of seasons ago and was very happy with it..used it for very loose low grip tracks when my MM5 7 port was just spinning out the wheels everywhere...

swop the plug and if that doesn't cure it then you are drowning the plug.Lean the LSN 1/8 of a turn at a time..despite the flush/flush factory settings I'm on my 6th GO engine and I've never had one yet that will idle without the glow starter until I lean the bottom end at least 1/2 a turn..DO NOT lean the HSN!! This might cure the idling problem as it will lean the bottom end as well but will cause you all sorts of problems the moment you start to rev it some!

Oh and I forgot ..for god's sake take off the air filter and set the idle gap to .7mm-1.0mm before you do anything.Then if it still won't idle follow the above.

Hey guys. sorry for the silence. Been a busy week with tax season. Anyways, the GX motors are shipping with the short LSN. I do have the longer one in stock, however.

O.k. I am in the process of breaking in a new gx5r and had downloaded the tuning procedure for a long low speed needle, but after reading above I went and checked and my low speed needle does come out of the spraybar at full throttle. Does this mean I need to tune it like any other two needle carb? Thanks.

Yes, with the short LSN it will tune similar to an OS engine but the GO carb is much more touchy. Use small increments. I usually set the top to where it is just clearing out then set the bottom to my liking then go back and make final adjustments with the HSN. With the short needle I rarely touch the bottom from race to race once I have it set.

If the needle in your carb does come out of the receiver jet at WOT, and has a stubby bull nosed tip - then you have the "short" needle (1.42" long)
The "long" needle (1.6") is much more tapered to a fine point, and will stay in the receiver jet at WOT.

Short needle as stated by matrixmike28, will tune like OS or most other carbs.
The long needle requires more care with the HSN setting. You must not go too lean on the HSN or things start going wrong (read the afore mentioned tuning guide which explains everything regarding the long needle).
On the GX motors (and MG66) the HSN is very sensitive, and only requires a 1/16 of a turn to make a noticable difference, so don't be too heavy handed.

The long needle is pretty much as Mike described too. Once you have it set, you just need to tweak the top end from day to day depending on conditions.
If you have to change the top end quite a bit for any reason, then revisit the LSN as well, as changing the HSN noticably will have a direct effect on the LSN tune, ie If you lean the HSN - you effectivly lean the LSN.

+1 on the 3 Port Gizz.
The GX-3R is a little sleeper I run one as a club day motor and it's a little ripper. Plenty of power and very smooth to drive (especially on our dusty loose summer tracks here at present). Plenty of bottom, and a surprising amount of top end too (more than I expected to be honest). It's a very competitive little motor. I run alloy shoes with 1.1 springs on a std clutch or the JVD (Ascenency clutch) with 4 x 1.0 mm springs.
It's just about to receive a set of Answer ceramics and a Massive Mods tweaked head button as well

Hang on .. What type of plug are you using ? what sort of fuel are you using ? what pipe are you using ? Is the engien rich ? is there a bit of fuel coming out the pipe un burned ?

If the engine is fluffly and rich then just lean the LSN about 1/4 turn , chances are you wont get it to run till it gets a chance to burn the fuel properly , the other problem is with new engine you are fighting a war on 2 fronts.IF The engine is tight and its rich .. This is a shitty combo to keep running , rich settings will constrict the sleeve ie it wont expand through heat.

SO

recommendation is

Run a med to hot plug

about 20 % nitro