Originally Posted by
bigmatt
I have been breaking in my gxr-3port.I have almost 1/2 gallon through it and I swear it dropped it's nuts. isn't this a little soon? I did the idle-1/4 throttle 3 tanks,1/4-1/2 blips next 3 tanks. was out running it again this afternoon and after 2 more tanks of up to 1/2 throttle blips it just started hauling ass. I cannot turn engine over by hand, trying to turn flywheel with finger. so should I leave the break in shim in? or take out? I also needed to lean the lsn,and hsn. so it would run. it was getting way to much fuel. my tank times went from 22-24 min down to 12-14 min. I,m use to the gen5/5.5 engines where at 1 gallon you were praying you didn't fry the starter box. One last bit,I kept foil around the head/heated with heat gun temps 240/260, dropped to 220/230ish range.then dropped down to 200/210. So I need some one with alot of knowledge on the gxr series to let me know. grizz/gizmatron/racer22/ruune.
Hi Matt. The GX motors are a lot more user friendly than the older Pro Series ones. They start to come to life around tank number 8 on the run in.
We have found if you can turn the motor over by the flywheel straight after a run (in the buggy from underneath), they are ready for a reasonable tune and some track time. This is normally happening around tank 15. When you get to this stage, take out the break in shim, tune just a little bit rich and go do some laps. After another 5 tanks, tune for racing and let her rip. It will still be tight, but will perform admirably. Just don't lean the top end too much expecting full on performance until the remaining pinch goes (around 1 - 1.5 gallons - rod change time). At this point remove 1 x .1mm copper shim, so you will now be running .4mm shim total. Much easier than the older motors
Originally Posted by
buglite62
I do get my parts from racer 22 but I can't justify spending money on the mod. Where having a hard time keeping nitro going in West MI so there's not alot of races or mutiple tracks on the same day and nothing the next weekend.
The 7p runs great exept on 30 min main where it leans it's self out to much. I might try the 5p this time and see how it compares since 75% of the tracks are fairly large. Not sure the 3p stock would have enough grunt down the long stretches. Wish I had money to get one of each.
The 7p has been my first true race eng and I love the GO.
On the larger tracks the 7 Port would be more suitable due to the extra top end it has over the 5 port. You are right with the 3 port. In stock form the 3 port lacks a little top end on a larger track with longer straights.
Ideal solution - get an MG66and have the best of both worlds.