I have been wating on a wrist pin from A-main for 3 months now. Just hit 2 gal on my 5 port and got the rod and C-clips. just no pin. Dont want to order from massave for a 3 dollor part. will another brand wrist pin work?

Some other brand pins will work, most Nova ones will but you need to make sure the length is right or grind it the same.

Rex

Sorry guys i meant the crankshaft would not turn properly not the con rod :D:D

I assemble everything in correct order, its just that it will turn to some degree but will not turn over (I have to force it to make it turn over. It was difficult to take the crank shaft out when I took the engine apart. I told my LHS that it seems that the bearing does not align properly, it looks offset a little bit however I put it back in :confused::confused: But when they replace the crank shaft every thing is ok but still a little bit tight when turning at some angle :confused::confused:
Wat do the engine factory use to lub the O rings, I thought rubber grease :smile: , is it same as automotive rubber grease ???

What is happening is normal - it is called "pinch".
The sleeve is slightly tapered at the top, to provide a good piston to sleeve seal. When the motor is new the piston is very tight in the sleeve at, or around TDC. As the motor wears in this "pinch" slowly wears away to where the piston is a nice snug fit, not as tight. This is what gives you your compression.
When turning the crank over without a flywheel on, it will be very hard to get the piston past TDC and back again because of the pinch. This means your motor is in good condition, and will have good compression and performance.
Re-assemble the motor and run it. It is fine by the sounds of it. Make sure you have the piston facing the right way - lower skirt to the rear, and the con rod in the right way - oil feed notch running the length of the rod should be facing the front (crank shaft), otherwise you will not get sufficient oil to the rod bushes.
Hope this makes sense. :cool:
You should only need to lube the carb needle O ring seals. Guys use all different things. Rubber grease should be OK. Get yourself some of the newer Nitrile O ring seals. These won't go hard and flakey, and they last forever.

But I tried to turn it witout the piston/liner and con rod and it still gets stuck (before changing crankshaft) Now that the crank is new it still fells a little bit tight at some point :confused::confused:, My LHS says its ok :confused: My other engines does not do that :D

By the way thanx for the tips on greasing o rings :D:D

Oops sorry :blush: I just assumed you had it all assembled.

OK - sounds like you have a bearing problem, can't be much else. Either one of the bearings is faulty, or one of them is not sitting fully or squarley in the crankcase. I would lean toward the later. Normally bearings only get rough or "notchy". It would have to be partially seized to stop the crankshaft turning, and I am sure you would have picked that up straight away.
Do you have access to a bearing removal / installation tool. If so, heat up the crankcase real hot, and try to ensure the bearings are seated properly with the tool. If not heat up and gently tap the bearings all around the circumference with a soft wooden dowell or something similar to make sure thay are seated properly. You mentioned you thought one of the bearings was a little off line - could well be they were not fitted correctly, especially if they were seated in without heating the crankcase first.
Let us know what happens :)

Could it be the crankcase is not machine properly, from the way I see it, the rear bearing is off set a bit, if I look from the front (without the front bearing ) the rear bearing seems off set a little bit, By the way I do have access to a bearing removal tool but I never had to heat the crank case before to fit the bearings. Ill try ur suggestion and I will let u know wat happens

Heat the motor up, and re-do the bearings. I think it will solve your problem. I doubt very much that the crankacase has been machines incorrectly. More likely the main bearing is not seated properly. Have a look directly down on the main bearing with the sleeve removed. You should be able to see if it is flush with the seat on both sides from this angle.
Some of the top line removal tools will pull and replace bearings without heating, but I believe it is always a good policy to heat the crankcase to expand it and make removal and re-fitting easier on you, the crankcase and the bearing.
The bearings are a press fit and are designed not to move. When you pull them out and hammer or force them back in cold it's very hard on both surfaces. If they were put in cold and one of them didn't fully seat, this may well be your problem.
I use a simple OFNA tool. Nothing fancy, and with some gentle heating with a hot air paint stripping gun, the bearings come out and go back in with very little effort.

Update,

Managed to get 9 tanks through the motor now (neighbours must hate me:lol:)

done 1 tank on idle with a sock over the head
done the next 4 tanks with a sock over the head driving around garden

then removed sock added shell leaned the top out to get temps in the 200 range i done 3 tanks like this bottom end was sluggish

then i leaned the bottom end out to make it a little crisper on take off this done a nice job of that highest temp was 235 and that was when the tank was nearly empty

Its going to get raced this sunday so far really really impressed with this motor, no cuts during run in and it idles like a champ:D

i have to replace one of the blocks on my old 7 port the front bearing wouldnt sit square when looking at you could see a fant line gap and the crank felt awful to rotate but it still ran but chewed bearings , got another seconhand block problem solved .. have you removed the bearings at all ?

another 15 sec on the rest of the field with the 7port

Hi all after reading a couple hundred pages I still have a few questions on my new GO .28 6p that was brought to life yesterday on my Hyper ST PRO basher truggy!:nod: I got the .28 for big power bashing and want to run it to it's true potential.

Setup: GO .28 6p Race/JP-3/OS p3 #8/30%/stock shimmed/no restrictor. HSN 1 hour out from flush and LSN 1 turn in. Idle 1mm open. Any comments? (was planning on running GO #6 cold plug)

After reading the 50 different break in methods on this thread I still need some direction. Without hesitation the engine fired up and idled soundly and with foil around head I so far have two tanks through it keeping it from 220f to 240f. Throttle limit is set at 50% and I've been blipping 25% throttle bursts around on the tarmac, allowed it to cool to ambient at BDC before second tank.

The guide ive been using (on p.78 originally) says do this tanks 1-6 then tanks 7-12 smoothly go to 100 throttle pulls. Anyone have anything to add?

After 12 tanks can I start to bash it normally? (understanding true power won't be unlocked until around 1.5 gallons)

Thanks for the help! And PS: When I showed it to the local hobby shop, the guy said there is something wrong with that engine when he couldn't turn it over with his hand!:sweat: I laughed and said go read the 1000 page thread!

Did it come with a break in shim? If you have it add it. It is way to early to be shimming for 30%. You will do that after the first gallon. I usually add the shim, idle 1 tank through, then let cool to about 120 degree's fire back up,throw on ground start doing what your doing with the throttle. DO NOT do long wide open runs until you have at least a gallon through it. After I have 2 gallons through my engines I will change the con rod,wrist pin,bearings. Then I change con rods every 3 gallons just cuz. The other thing is I use a dynamite 086 pipe,but again I am running 3/5/7 port go's. I tried my jammin 3 and 4 pipes and neither one really did any good. Just sucked fuel like crazy. Switched pipes and my rb modded 3 port will spank my stock 5 and 7 ports. One last thing ,we all usually heat the engines up with a heat gun for the first gallon for break in.

Hi OG Ryder, sounds like your pretty onto it with the break in :nod:
That method on page 78 (originally) is a very sound way to break in the GO engines. The newer Gen 5.5 and GX Series motors are a lot easier to break in. If you buy one of those at some stage in the future, use the same method, but you can start to run it harder after half a gal or so.
Definitely heat the motor like Matt suggests, even after it's broken in if you can. Makes for a longer lasting engine. Make sure you always return the engine to BDC everytime you stop it too, always.

you wouldnt beleive it i have completly destroyed mu new GO-tech gx5r blew it up , put in the wrong receiver pack went flat , truggy went mental snapped the conrod and made a real mess :cry: got a good spare carby now but :D