OK lets see if we can help.

In comparison to the older Gen 5 or 5.5 silver head Pro Series - chalk and cheese.
There has been a lot of refinement and R&D gone under the bridge since the older Gen 5.5. The GX Series was a big leap, but the new GXII is streets ahead IMO from the GX Series again.

The GXII makes more power, but it is delivered in a smooth linear fashion.
One of the most common things I hear from new customers is how smooth the motor is to drive. It is a very powerful motor, but because of the smooth response it IS very easy to drive.

Fuel economy once bedded in is great.
We have done lots of timing etc, and running with the 2072 pipe, stock shimming, OD 97T med plug, 25% fuel and 6.5mm restrictor in buggy we can get 9.30 to 10.15 without running on the ragged edge of tune. In truggy running the same set up but with 7mm restrictor we have customers easily getting 11.5 to 12 min. One customer is getting between 12.5 to 13 min at race pace in his new Serpent Truggy.
These are straight up times, some done in my own buggy, some I have timed or witnessed at the track on race days when fueling etc.

Makes it's power ? - I guess through evolution in crank and sleeve design.
The GXII crank has been modded over the previous GX crank quite signifigantly, lightened and epoxy ramped. The crank is very lightweight, as is the entire motor - some 34 grams lighter in total than the GX.
The sleeve has been modified, piston cooling ports added under the exhaust ports and the crankcase (totally new) interior and exhaust area has been modified from the GX Series too I believe. I don't have any inside knowledge from the factory, so I am not able to be more specific I'm sorry. Needless to say, make power it does

Hope this has been of some assistance.

Thank's for the detailed reply, exactly the info i was looking for.

I'm just on the hunt for something new motor wise to try. I've been running the speed's for the past 12months and then before that the alpha's and go's. The speed's were a big jump, mainly in the smoothness of their power delivery. I've just retired my latest speed as it broke the rod on the weekend (result of a run-away which happened at femca 2 weeks ago) so to get me by i've got an argus coming, because it was cheap, and i'm thinking of giving the "$200 engine's" another go.

Speaking of femca, if my memory serve's me correct, was Craig Underwood running the GXII? If so what runtime's was he seeing do you know? That would give me a good comparison fuel economy wise to the xz-b speed i was running.

I'm still having bad tuning issue with my mg66. I'm getting a hi idle no matter what I do. It always ran great then during my main noticed the idle was very high. I checked the linkage, new fuel tank , fuel line loose motor screws, glow plug, set needles back to stock and re tuned.....etc, I did notice I'm getting air bubbles in the fuel line but can't remember if I had a few before or not. I would think if it was the front bearing I would see some oil leaking. Im about done with this motor.

Hey Shane,
was doing the 10 minute heats and having about 3-4 mm of fuel left, enough for 1 and a bit more laps...i'd say on that track 11 - 11.30 tanks depending how hard you drive.

I was over there with Craig on the weekend, so probably bumped into you somewhere
Craig was doing the 10 min heats easy I am told, and on the weekend in the practice session and the semi we were doing 10 min stops.
Craig will most likely pop up on here and give you more detail then I can.
Hey - looks like Craig popped up while I was writing this post

Is it a steady high idle, or a ramped up "machine gunning" high idle ?
Could be a faulty front bearing. I have seen them leak air without much seepage of oil and fuel at all.
Other thing to check is a blockage in the HSN body. This can cause all sorts of funky tuning issues. Remove the needle and back flush with fuel, or remove entirely, clean and blow out with compressed air.
Without actually seeing and hearing the motor it's hard to be more specific on what it might be.
Steady high idle that eventually falls is normally too wide and idle gap and rich bottom end.
Ramping up and down "machine gunning" idle is usually and air leak somewhere, or a very lean bottom end (like .5 to 1 turn too lean).

Thanks for the reply. It's more of a machine gun type idle. But I think I found the problems. 1. The hsn/lsn o rings were trashed and 2. I found a small crack in the crankcase where the motor mounts it had some fuel seepage . Now it makes since that the car would run great for the first few laps then start the high idling. But all is a waste now I just got off the phone with go-USA and he tells me they don't do business with massive mods any longer. But he says a lot of the parts are the same so send an email off from the go-USA site( mind you this is after sending emails and calling several times someone finally answered the phone) and the contact email doesn't work on the site so I'm done. I'm getting a different brand motor. Anyone have any good recommendations for 1/8th scale buggy? Thanks

excellent motor for the price!!

http://www.rctech.net/forum/r-c-item...tras-nice.html

Ok and you're still standing behind the motor with a money back if you're not satisfied? If so I'm in.

sent you pm

Pretty much the same as i was getting out of my xz-b speed then, that's pretty good. I'm pretty smooth on the throttle and have found i can run a leaner bottom compared to other guy's i race with.

We probably did, i know i spoke with big paul a bit as he was in the same qualy as me, and tim was pitting for me aswell. I was surrounded by kiwi's

Is Mark/MassiveMods still the australian distributor for go tech?

From what shane's told me he is not the distrubtor any longer and has parted from GO...his next line of motors will be made by a european company.

From what we saw at the femca race GO engine sales in OZ would account for a fraction of the market in .21 race motors, quite a different story in NZ.
The GX 5R /7R and the MG66 had a very good year in 2010 taking many titles and podiums, that created quite an interest in the new GXII HO for the 2011 season...add to that Shanes service and support for the brand it all makes sense.

Last I heard Mark was still the importer, but the people that bought the Massive Mods business off Mark are the distributors, if that makes sense.
I would approach Massive Mods in Sydney (or the website) for more info on the availability of the GXII in Aus.

Rc Hobies you say flanno, thank's mate

HI all,
Massive Mods are still suppling GO Motors in Australia. I have purchased 4x new GX 11- 5RHO series motors from them in the last 2 months, Along with "o" rings for carby needles, and crankcase rear seals, no problems. Mark still visits the shop, I spoke personally to him while he was in the shop less than a fortntight ago to inquire about the new fuel he has developed,NEO+:, He returned my phone call as requested: i was calling from Cairns, North Queensland. Massive Mods have extended there range of products and I have always had good service from them.