Originally Posted by
defcon13
well,
just to give some feedback about my go pro 5port. i'm now at the 1.5 gal on this engine and so far, its a dream to drive and tune. i was a bit sceptical about the tuning with a long lsn, but i found it very easy. the powerband is exactly what i was looking for, good bottom (not too much like a .28) and very good top end with the 086 pipe. only thing i didn't checked yet is runtimes. they seem good but i dont think that the 086 pipe is the best pipe for this.
i have changed the conrod at the 1 gal mark like some have suggested. i was a bit surprised to see that there was some slope of the conrod on the crank pin. i just hope it was caused by the breakin and that it wont be an issue during the rest of the life of the engine.
last thing to see is the lifespan of the engine. if it lives as long as some say (8-10 gal) i will be definitely sold to these engines!
If it's a Gen 5 model the slop in the big end of the rod will have been caused by the super tight pinch during run in. This really hammers the rod. That's why it's recommended to change the rod after the first gallon or two.
The new rod will be sweet, now that you have it loosened up.
The 086 is pretty good on the 5 Port, and economy is not bad. The best pipe for economy and performance on the 5 Port IMO is the GO 0801. The new 2072 goes really well, but I don't know how it compares economy wise yet to the 0801 on a stock motor.
Replace the bearings when necessary (or just before it's necessary) to keep everyrhing lined up inside correctly and the 5 Port will last very well. With regular maintainence you should see up to 10 gal or more.
Originally Posted by
bigmatt
Is this the new gx 5 port? did the new con rod have the slop? Also did you put in the run in shim? Do the new gx line need a run in shim? 22 racer you seem up on the gx line chime in and let us know.
Hi Matt. I spoke with Massive regarding the break in shim in the MG66, and he said not to bother with it. The new range of motors (MG66 and GX Series) are designed with less initial pinch, so the strain on the rod etc is greatly reduced. The 66 turned over on the starter box no problems without the break in shim, so the GX should be the same.