Ok thanks for that, will leave needles as fitted and learn to tune as your info.
1 question though, when removing the shim on about 30 tanks, will this through out the tune? do i need to set both needles back to flush and retune.

You will need to tweak things a little bit - not much. You are effectivley upping the compression ratio when you remove the break in shim, so this will effect the tune a little. An 1/8 to a 1/4 of a turn should do the job. You will most likely need to lean things a little. Just follow the tuning guide and retune the LSN first for a smooth take off and good idle, then tweak the HSN if needed for a good clean top end. If you needed up to a 1/4 turn in the HSN to get things right on the top end, then revisit the LSN and check that again too. The HSN needle has a direct effect on the LSN - ie when you lean or richen the HSN to any significant amount, you effectively lean or richen the LSN at the same time (as the HSN regulates the amount of fuel the LSN receives overall). So the order of events for a full tune would be - check and set idle gap / adjust LSN / adjust HSN / recheck LSN and tweak if needed / set final idle speed if required (be aware that adjusting the idle will also change the LSN setting, as the LSN needle is fixed to the spray bar, so you have to balance any changes here out as well . No one said it was that simple
With the newer GX Series motors you will probably be able to take the break in shim out earlier, say 20 tanks, as these new motors are not as tight as the previous models. You can break them in without the extra shim fitted, but it does alleviate some stress and strain on the internals during the first 10 or so tanks by dropping the compression using this shim. It is recommended.

Hey Grizz1, do i have a break-in shim in my GX-5R??? I have a thick chrome shim and two thin cooper shim, and another one is supply as a spare in the box.
Is i have to remove one after break-in or add the spare one for break in

OK. The thick alloy shim (.3 mm) and the two thin copper (.1 mm each) are standard in the motor.
The "break in shim" we are talkiing about is the other shim provided in the box. It will be on a white card inside a plastic bag. It is a .2 mm copper shim.

Add this to the existing shims for the first 15 or so tanks when running your motor in. It will lower the compression, make your motor easier to start and idle during this period.
At tank 15 take it out and re-tune slightly. You will notice an increase in performance when you remove the shim also.

Some people use this shim when running 30% nitro, but the motors are shimmed for up to 30% from the factory, providing you use a medium - medium cold plug with the higher % fuel, which is standard practice anyway.
You can fiddle with the shimming for increased performance and tank times, but only after the motor is fully run in.

OK thank you! But i've not install this .2mm shim and i have 6 tank of break-in now in the engine. Is this could hurt something??
But i'll put it on right now

does anyone have a case from a 3 port sport they could sell me, i just broke a mounting tab on mine LMK what you have

I have a brand new one.

Rex

how much shipped to 60411 Rex?

If you already have 6 tanks through dakamat I wouldn't bother fitting it now. You will be fine. The newer motors have reduced pinch, so if you already have some fuel through and it's starting easy enough, just carry on. Just be sure to change the rod at 7 - 9 litres as recommended

Right!
Thank you

what kind of run time,temps are the new motors getting?

Depends really on the set up and driver but between 9 and 12 mins in buggy and between 10 and 15 mins in truggy

I will be buying an MG66 in February 2010. I plan to build a buggy for racing next season. I'm sticking with Go Tech for all of my engines. I like what I'm seeing so far in support, power, and tunability. Great value and I hope it stays that way. I'm all in with Go Tech...


Mark M.

Hey, that's great news Mark. With the new GX Series and MMods MG66 engines, the GO product range is going from strength to strength. This coming season with these new motors on the track will be very exciting.
Response to both the GX series and the MG66's has been fantastic down here in New Zealand. GO is on a roll

I am very impressed with the Go engines so far...the 7 port I am currently testing is performing awesome..... very smooth power, broad powerband and wonderful track manners... It is also as fast as hell if you want it to be...... I am now a Go dealer and will be carrying stock of both engines and parts.. As well I will do extensive dyno testing of different pipes and setups on these engines over the winter..... expect to see alot of Clockwork Go engines running around over the next year !