Those dimensions are quoting wrist pin length.
21= 4x14mm
25= 4x14.75mm
28= 4x15.55mm

21GX engines = P-0414-3
21GXII engine = PS-0414
25Pro = P-0415
28Pro = P-0416

at A Main = a "GOT" prefix is added to the GO part#

Very cool. Thank you, and I edited because its a 5 port , not seven, but still, the pin remains the same. I want to pick up a pin and rod to put in within the next half gallon or so.

I have 4 tanks on the new Go engine and it seems like a typical Go so I am really excited! On top of that, the idle seems stronger than before already.
However, the tune seems to be pretty much the short LSN procedure. Anyone have a different experience with the brand new Mk2 carbs? The LSN only seemed to affect the mixture near the idle, and immediately after that point, it seemed like the HSN was in full effect. This is not a complaint, tons of motors tune this way, but when you're expecting a long LSN it can throw you off during breakin procedures. After I got the idle mixture set, it seemed that all I did was adjust the HSN.
Am I crazy?

Well, my little Go 5 port ran like a champ all day of the mo rc pro series yesterday and gave me more than I needed all day without needing the needles set all day. low 90's and it purred all day coming off at about 212 to 226 all day without touching it. Could have leaned it out for more power but traction was more of an issue than power. Front diff went out in the beginning of the main, so it got a rest. I know another guy running a 7 port Go in his Truggy (Serpent 811T) took 3rd in intermediate truggy and was screamin!
Hey and by the way, I flamed out twice earlier in the week during practice with a 97T plug in it, grabbed a 77T by mistake (found out after looking at the package later) it purrs now and seems much happier with it in there. FYI

thats normal with the new GXII engines Travis, the GX1 was more of a lsn tuning motor, with the GXII once the lsn and idle are set leave them till the temps change a lot or the engine feels like they need changing.

77T thats good to know, i here Odonnel are no longer making plugs, I guess most of us will revert back to the OS P4 and P3, would be nice to have a reliable alternative, OS plugs can be very expensive.

Oh don't sat that

I don't have any on hand ATM as all my stuff is on it's way to QLD, so remind me /check if I'm correct
77T Cold, 87T medium-cold, 97T Medium and 99T Hot ?

first 10 tanks I run Hot99, next 10 litres I run Medium97, then MG race tune with a medium - cold87 and the GODZILLA race tuned I run Cold77 Pugs on 25% fuel

Hey Flanno - 97T is medium, and 77T is hot (actually an on-road plug for .12 motors I believe). Both work fine.
The 99T is a cold plug - never tried one (and not that readily available it seems).

Oh I had the numbers backwards oops

So it's 77T Hot, 87T Medium/hot, 97T Medium, and 99T Cold.
OS ex P3 hot, P4 Medium/hot, P5 medium, and P7 Cold.

Any hoo, I'v got all 4 types OD, a pretty good supply of medium and colds

I bought up big when they were on sale, way back when

Ive ran all the odonnell plugs from 100t-77t and never found one that my gxII didn't like....just depends on your willingness to play with the needles lol...a colder plug will give you a much narrower tuning window than a warmmer plug...but will yield slightly better run times and power....a warmer plug will be easier to tune with, give you a much broader "sweet spot"....but at a slight loss of mileage and power...then you get into the fuel game....then the head shim game....and let's not forget the pipe/header game...then if your bored the mass air flow game...and then..... And then.... Lmao!!!! Just remember....if your running a GO your gonna have more power than you truly need no matter wich plug you choose.... So just kick the tires and light the fires

OOops...forgot the 102t :-D

Well, I dusted it. The air filter popped off (don't ask), motor stalled, and I can see a tiny scratch down the length of the piston. It happened a few weeks back, right after my last post, but just now finally had time to tear it apart. Not sure how long I ran with it like that, possibly 1 to 7 laps. I spent an hour disassembling, flushing and reassembling the carb alone. Lots of little spots for dirt to hide, but it's super smooth and clean now. The bearings are removed, flushed, and seem smooth and tight still, not wobbly. The crank has no marks on it, the rod and wrist pin look good.
So... I've decided to throw in a replacement PSR and see what I end up with. Reliability is paramount so if it doesn't seem right I'll make myself a few keychains from parts and order a new motor. The plan is to run break-in with the current bearings if they are good, then order new ones after it loosens up a bit before I really push it.

From those that have gone through this, are there areas I'm going to overlook in cleaning and ruin the new parts? I've done a pretty thorough job but I would love to hear any "gotcha's" you might have for me.

Thanks guys
T

+1

no Trav youre not going crazy this is how all nitro engines should be tuned regardless of short or long LSN needle carbs


cheers m

I have 2 gxII's with maybe two gallons on each. I cant get them to idle at all. I have ran nitro for five ye ars now and know alittle about tuneing. I have tried everything fromd gas tank to fuel, , i am stumpted. Im ready to send theese out hopeing someone can help me out. Anyone who would like to help please contact me.

If your in Aus, try the guy above your post.

Google "Nitro Addicts Australia"