Ok Im gonna try it to see how it runs and are the parts the same as the new one meaning interchangeble

Hmm - I have only had experiance with GO's back as far as Gen 4. I am not 100% certain what would be interchangable going back any further than that. The new GX coated crank would be OK, plus I am pretty sure a new GX piston / rod / sleeve set would slip in too. The carb I am not sure. But once again - if you are going to buy a new crank, PRS etc, you may as well just get a new motor with the much improved GX carby, plus the spare rod etc that comes with it. Keep the motor you have a spare practice motor etc.
If it where a Gen 5 or 5.5, then it would probably be worth while, but if it is a Gen 3 or 2 we are talking pretty old technology there.

Yeah im gonna try it I run os speeds and ninja motors but for the price i want to try the new GO motor and the parts are really cheap to replace on amain

Yes the black case dose have the all black composite carb. The other silver case motor has a black carb also, but the fuel intake nipple and camber are silver. What is the difference.
Thanks Jim

Run the new GX-7R or MG66 in your buggy and you won't look back. Just as powerful and probably smoother than what you have tried before - and much more affordable.

The later model (black case) motor will be a Gen 5.5. The 5.5 motors came out with a modified crank that had better balance and tolerances, plus a larger crank pin. Also comes with the newer 21-0600 Pro con rod to match the crank pin. Gen 5.5 carbs were also improved over previous models.

Ruune, Gizmatron, Massivemods & Grizz1, a big thank you guys, got the GX5R running today and put a couple of tanks through it...........

Just like you guys said, used a drill bank to check the idle gap, both needles flush, leaned out the LSN to just achieve a decent idle, wrapped the head in foil.........so its getting there slowly but surely

Just have to check my EPA on the throttle servo as its not quite shutting off when returning to neutral

Wow thats between a gen 3 and 4 , early 2007 id say. Yes you need to change the carb , the new one is real nice. The gen 3 carb runs fine , it just had a weird idle .. this problem was sorted in mid 2007 .

Cheers MM

The All black carb is a Gen 5 , The gen 5 carb was just a tad nicer than the gen 4.5 on the silver case.

Hey grizz1 just to hark back to the earlier dispute about the change in conrod internal diameters but with the same part numbers...Ripped down my old MM5 7 port today and threw in a new TiNi coated gen 5.5 crank to replace the gen 5 that was in there and the con rod wouldn't fit..Now I had a spare of the new lightened knife edge rods so no problem there but I also had a slightly older but still nip of the older shape rods..And it fitted perfect.So there was a definte size change in the rods..I wasn't aware till today I had one of each ..Just as well I changed the wrist pin at the same time..then I dropped the bloody circlip...god I hate those things..There must be an easier way to hold the pin in ..argh

You guys can make my head hurt. My stock gx-7 is dialed and anybody and everybody that drives my car loves the motor. couple guys have purchased the motor and love them. The new carb and motors are awesome.

+1 on that one. these guys know alot about these motors. I have learned alot just by reading there posts.

Alright thank you Im just gonna buy a new one motor and do you guys just use the GO PIPES with these motors and what kind of runtime

Ha ha - yeah those clips are a bugger sometimes

With the rods - it seems there was a few months at the end of the Gen 5 production were the factory made a few batches of the older shaped rods with the bigger big end bushings - either to fit the last of the old Gen 5's with a 5.5 crank fitted in the change over period, or to fit the new 5.5 motors until the newer 21-0600 Pro rod came into production (correct me if I'm off beam here Massive). These were the rods that the other boys had, and were measuring, thinkiing they had the standard old shaped Gen 4 - 5 rod (as you would), which is what caused all the confusion. But in short - yep, the "original" older style 28-0600 rods were just that little big smaller than the new 21-0600 ones in order to fit the smaller diameter crank pins on the older Gen motors.

Hey Gizzy, that JDV clutch with the 1.0 mm springs on the MG66 is the bee's knees man. Nice progressive engagement, real easy to drive. Worked awesome on the weekend



Yeah Puddin - the GX-7R is a strong motor for sure


Other pipes will work OK, but the GO EFRA 2072 is the pipe you really want on the GX and MG66 motors.
Run time is a tricky one, but fully run in with 6.5 restrictor and a nice tune should see 9 - 10 minutes no problem depending on trigger finger. Shim reduction and a real sweet tune will see more run time if you want to push the envelope

I need to correct myself here.
The Gen 5.5 (std) and GX Series (coated) cranks came out with a tolerance change only. No extra balance work.
The MG66 is the only motor with both the tolerance change and the balance work done on the coated crank, which explains why it rev's it's little head off and won't stop winding out

The JVD clutch is real nice eh grizz1..I only ran mine for a few meetings at the end of last season but the shoes show no wear at all..Having put the coated crank and wrist pin in my 7 port I think I'm going to buy a spare set of the xray upper motor mounts so I can swop it in if I need to do a motor change.I'm gonna buy a second JVD to fit that one too and pick up a spare set of shoes/springs at the same time..