will the rod part #28-0600 fit that silver top ? or dosent any one here really know what parts fit what in this thred :rolleyes:

The GRP rod is a 29.5 mm x 4.20 mm top yoke x .0499 bottom yoke with a 5 mm Crank pin . The Go rod wont work as the top yoke on it is 3.99 mm.

and im glad you asked the question ! cos i dug out my engine Cemetary Box .. ( where all the ones that didnt make it live ) And found a GRP, and in its box i found an original new 28-0600 ROD ! in the pics below im using a CNC machine setting pole to measure its dia. The pole set i have was given to me from a huge CNC machining / engineering company here in AUS back a few years ago when i was designing and making custom rods for Drag Racing and Off road applications .. , the poles are used to calibrate their CNC machines and are extremely accurate. The 5 mm pole will fit snugly in the new 28-0600 and the new 21-0600 but not in the original 28-0600 as pictured below.

Hoep this finally puts this one to rest


Cheers MM

Im trying to find the right replacement rod for my go 5 port that i have pictured and also im looking to find a rod that will work in the GRPs...cant find them anywere...wanna sell yours? I think the part number for my go 5 port rod is 28-0600 ?

i snaped my rod in my older 7 port after about 3 gals. messed my case up badly....like to replace the rod in that 5 port before the samething happens, it has about 4 gals. on it .

Captain Crash

the Silver top you got is between a gen 4 and gen 4.5 .. you will need the new crank 21-0907T-03 and Rod 21-0600 to rebuild that engine properly , there is no rod that will fit hat engine unless you can get an Original 28-0600 which is pretty rare now, not many places will have these in stock.

The GX you can get a 21-0600 rod as replacement.


Cheers MM

Thanks guy, thats the info i was looking for.:D

I will go to the studio in the morning, but I do believe I have 2 of those con rods. 25.00 each shipped.

;) Good enough for me my friend :D

I also think some of the confusion came about because of the long history, and easy parts availablity of GO motors in this part of the world. We have worked with the older rods etc from Gen 3 (or earlier in some cases), so we do know the older generation motors, and the subtle changes that occured from phase to phase of the different generations better than most in other parts of the world. It would appear that outside of Australasia, nobody else knew that the 28-0600 rods changed (late Gen 5) before the introduction of the newer 21-0600 rods. Hence they were comparing apples with apples instead of apples with oranges and not seeing the difference in sizes we were trying to explain to others.
Anyway, all sorted now - if you have an early Gen5 or older motor and you want to replace the rod, get the new GX coated crank (21-0907T-03), coated wrist pin (P-0414-03), and new Pro rod (21-0600) - or just upgrade to a new GX motor and be done with it. You won't regret it :)

i to would suggest the new gx series :D

I have a 3 port race and i have gotten pretty good at tuning motors but am having some trouble with mine. Its broken in good I have 2 gallons on it now. I put a good tune on it and will start running around the track and sometimes running up to the base of a jump it will bog or coming out of a turn and going back into the gas it willb og on me..any ideas?

Sounds rich on the top. make sure your putting the tune on it after it's warmed up good. How's your temps after running it around for a few laps?

Don't know if you have the long or short low speed needle version, but what you describe is a classic symtom of the long needle carb being tuned TOO LEAN ON THE TOP END. If you are running a long needle carb, richen the top end 1/2 hour at a time until the bogging goes away.
For full long needle carb tuning instructions visit the Tech Tips section on my web site - www.go-racing.co.nz.
If the low speed needle stays in the receiver jet even at full throttle, then you have a long needle carb. If it pulls out at aroound 3/4 throttle, then you have the short needle carb.

If you have the short needle carb, then you may be too lean on the bottoom end, or you may have an air leak in your fuel or pressure line somewhere perhaps. If it was running good before and you haven't touched anything on the motor siince, chances are it is something external from the motor. :cool:

Hey Shane ! Nice read man ! very good article !

Changed rod,pin,clips and bearings on my MG66 last night after breakin.
Felt like a waste as there was NO wear on the rod and the bearings felt mint.
Best to heed the advice of the experts I suppose,shouldn`t need to replace them for a long time.:)
Be interesting to see how the ceramics perform:sneaky:
The coating on the crank is protecting the clutch bearing area nicely as well.

You will notice it spool up quicker with the ceramics in there Ben. It's instant power now !!
Yes, every MG66 I have looked inside after quite a bit of fuel has been through, have been just like new. Crank, bearings, rod all like they just came out of the box. I guess it depends on the fuel you use, but with the A-Main and our local brew here in NZ, everything is a nice clean shiny honey brown colour. No black carbon on the piston crown or around the ports (unlike the motors I look at that run a certain "top" fuel). They are so caked up with carbon, you can actually scrape it off the piston !! But that's another story which we won't get into here :cool:
Sounds like your all ready for that long back straight at Wellington now :nod:
We will have a big number of 66's running there (in proportion the size of the feild). See you Friday :)