Hi Daryl, According to the Massive Mods "Shimmimg 101" article, you should be running .5 to .7 mm of shims under the head button and using a Med/Cold plug on 30%

.5 mm would be the alloy shim (.3mm) and 2 x thin copper shims (.1mm each)
Which is how the motor comes in the box as standard.

or

add the included run in shim to the above for .7 mm total.

For best performance, cooler pipe temps and better run time, use the .5 mm, just make sure you don't use a plug that is too hot. Stick with a medium, or medium cold plug and you will be sweet.

1. Completely remove the pinch bolt IE at the bottom of the carb in the block there is a small screw totaly remove it and the 2 retainers

2. pull the carb straight up (this may be a little hard)DO NOT WIGGLE SIDE TO SIDE as you could damage your carb.

3. Then all you have to do is reinstall the carb in the required direction and replace the pinch bolt make sure you don't over tighten it

hope this helps

Adrian

Heys guys I am trying to find bearings and a con rod for a Go .21 3 port race. I am in the US, I look at amain and only saw a bearing for a .28.

Thanks

mate go to massive mods web site you will get a great geal on bearings and conrod mate

or contact 22 racer he a dealer in th US he should have the parts your after

Thanks will do!

no probs

O.K. Grizz, that is probably were i'm having problems. I used the extra shim for break in and never took it out. Also i was using a ultra hot plug in it. Strike two. I run it in my truggy and use a dynimite 086 pipe. Was having trouble with the tune but this will probably help. Thanks for the info.
Daryl

I lost the carb restrictor for my 3 port race. I bought a new one on Amain and its plastic... Is that ok? I can't remember if the original one was plastic or not. Also it didn't come with any o-rings on it to hold itself into the carb. What size o-rings do I need?

Not my month engine wise...3 port has now followed the 7 port..happily ..well maybe happily isn't quite the word..the loss of compression seems to due to a sudden wearing of the crankpin following the rod change..measures 4.98mm at the base but only 4.82 at the tip..needless to say this has produced some very bad slop in the crank/rod interface department..Bugger! But I was thinking of replacing the crank with a 5.5 especially as closer inspection reveals it to be a gen 4 crank anyway..As I only ran it for a short time the rod/piston/sleeve seem unaffected..Oh and to cap it all the GO factory have apparently delayed the MG66 till august sometime..

So I am sad and motorless

Connecting Rod: http://www.amainhobbies.com/product_...Connecting-Rod

Front Bearing: http://www.amainhobbies.com/product_...ng-5-Port-Race

The stock one installed is plastic and is 8mm.

i agree the p4 med hot plug may be better but i have been using p3 plugs in the old go motors and in the new ones with no problems at all while using the 30 % fuel ....

if your having trouble with your tune are your carby seals all okey ? this will catch people out

I have tried both and I like the OS better..

BUMMER Giz !!!! My old Gen 4 crank went the same way. The pin ovalled out. Get the new 5.5 crank from Massive. That's what I replaced mine with, and their a nice piece of engineering. Changed the specs slightly for better performance and fit, giving longer engine life. Bummer on the MG66 mate. But like they say, all good things take time - I think it will be worth the wait

I hear ya Matt. The GO's do seem to like the P3 plugs - despite all the theories about plug temps etc. I am running mediums now, but the old P3 goes just as well, if not better on very cold and damp mornings. Only down side is the P3's cost more than double what I'm paying for the mediums here, so that sort of makes it a no brainer for me right now

really p3 plugs must be going up in price or something .. i bough a whole sheet i think they worked out to be aroun $8 each what are you paying for them ?