Yes id say its happening because its tight provided the sound is coming from the engine. One thing that people MUST understand is that engines do not like being run in on a bench. Its what will shorten the life of an engine every time. I know people will tell you differently based on their experience, but on a law of averages an engine will last longer when you run it nice and hot, i run in about 6 to 12 engines a week and the method i use is to put load on the engine IMMEDIATELY !
Why ?
because this creates heat and heat expands the engine. if the engine dosent expand you are restricting the operation of the engine at its most critical point in its life. What happens is the piston will slam into a tight sleeve at an avearge of 12,000 times a minute ! Thats like taking a jack hammer to the rod and bearing.
The best way to create heat in an engine is to put load onto it .. Start it , idle it for 30 seconds , give it a quick tune to make sure its not too lean or rich , then put it on the ground on high traction surface and drive it. Dont baby it and dont abuse it. Gradually increase the rpm with every tank.
By the time you hit the litre mark ( quart for the imperially impared ) you should be giving the engine some stick !
Running an engine cold on a bench will give you no end to grief later in its life.
Cheers MM
Good explanation!! Me too.
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22racer or anyone for that matter, I need a couple of those shims that go behind the collet I know they are 7mm ID but the OD I have no idea. I had to use them on my 5 port to get proper mesh and now need some for my new 3 port. Without them on there I have to use like 50 shims in my clutch set up and do not want to be doing that. That leads to killing bearings and just is a pain.
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The machine gunning is probably coming from having the top end too lean, which is being masked by the bottom end being too rich.
You will have a Gen 5 long LSN carb. Re-check the idle gap is .7 - 1mm wide. This is really important, otherwise you will be chasing a tune forever.
Set the HSN at flush, and the LSN at 1 turn in from flush and give it a run.
Depending on what happens go either in or out on the LSN until you have a good idle and take off, then tweak the HSN for a good top end. Half a turn in on the HSN is about max for a long LSN motor (which is what you will have). Any leaner on the top than this and you will start getting lean bog etc.
Let us know how you get on.
Still a bitch to tune and to hold a tune when it's close. Guess I have to tear it down and seal it up. I don't understand why I have to do this when it's new. Never had to seal up a Traxxas or Losi engine and they tuned up just fine with no extra shit to do to them. WTF GO? Should change their name to WAIT. Why can't one just just drop a new engine in, break it in, tune it up and GO? NO NO NO got to go to the hardware store and buy a drill bit to set idle, buy sensor safe sealant, tear it down, seal it up, teflon tape the needles, do the hokey pokey and pray it will tune. My fuel tank and and lines are new and pressure tested so I know it's the damed carb. Can't wait for the Novarossi carb to come in the mail.
I'm sure it's me and I don't know what I'm doing but I've never had to put this much effort into getting an engine to run right. I had better luck with the older gen GO carbs.
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Still a bitch to tune and to hold a tune when it's close. Guess I have to tear it down and seal it up. I don't understand why I have to do this when it's new. Never had to seal up a Traxxas or Losi engine and they tuned up just fine with no extra shit to do to them. WTF GO? Should change their name to WAIT. Why can't one just just drop a new engine in, break it in, tune it up and GO? NO NO NO got to go to the hardware store and buy a drill bit to set idle, buy sensor safe sealant, tear it down, seal it up, teflon tape the needles, do the hokey pokey and pray it will tune. My fuel tank and and lines are new and pressure tested so I know it's the damed carb. Can't wait for the Novarossi carb to come in the mail.
I'm sure it's me and I don't know what I'm doing but I've never had to put this much effort into getting an engine to run right. I had better luck with the older gen GO carbs.
I donīt hear too many others complaining
I have never had to seal anything, lube anything or fiddle with anything. Start it up (yes they are tight), heat cycle it, tune it, race it hard and maintain it regularly. No problems with four .21īs up to this point.
Teflon tape the needles Whats with that ? I would check that a bit of the teflon tape hasnīt been ground off and found itīs way into the high speed jet. Could be the cause of the problems your having.
I am sure the new carb will do the trick, but honstly there is nothing wrong with the GO carbs. Take that teflon tape out, blow out the HS jet and give it anothr go.
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Still a bitch to tune and to hold a tune when it's close. Guess I have to tear it down and seal it up. I don't understand why I have to do this when it's new. Never had to seal up a Traxxas or Losi engine and they tuned up just fine with no extra shit to do to them. WTF GO? Should change their name to WAIT. Why can't one just just drop a new engine in, break it in, tune it up and GO? NO NO NO got to go to the hardware store and buy a drill bit to set idle, buy sensor safe sealant, tear it down, seal it up, teflon tape the needles, do the hokey pokey and pray it will tune. My fuel tank and and lines are new and pressure tested so I know it's the damed carb. Can't wait for the Novarossi carb to come in the mail.
I'm sure it's me and I don't know what I'm doing but I've never had to put this much effort into getting an engine to run right. I had better luck with the older gen GO carbs.
My go 5 port did something similar on sat at the race. I had a very tiny air leak where the bottom of the carb go's into the block. I only noticed because there was a very tiny wet spot on the top of carb. and if it hadn't been for the dust I would not have found it. If you take the carb out and look down the bore of the block shaft you will see it. I don't know why it's there but when I put silicon on the seal-top and bottom, seals, It went back to running almost perfect and I was able to finish my main.
I haven't done anything to it yet except bolt it up and break it in. It's brand new with a little over 1/2 gal in it so far. The sponsored guy from the old Racefactor web site said that one should teflon tape the needles right off the bat. I think it's silly too but I guess he was dealing with the older gen carbs.
I can you tell right now there is fuel build up around the carb neck. I'm going to loosen it up and squish it in a little tighter. Maybe have to use some RTV, I don't know. I hopping to get it in shape in time for a race this weekend.
Update: Got the carb off, and noticed the bottom carb seal was somehow chewed up on installation. A piece of it as cut off by the pinch bolt opening. Luckily, I have a new one. Gonna air it out and seal the bitch up a see how it does tomorrow.
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Last edited by ConciliumDesign; 05-12-2009 at 10:47 PM.
sealing the carb, pinch bolt and back plate is something i do on all my engines, it should be an automatic thing to do with any engine.
it is better to not need to do it and have it done than to need it done and havent done it
Good point. I have just never found the need to do it on my GO's. The back plate has a very good O ring seal in it, and the Gen 5 Carbs have little O rings on both pinch bolt sections to eliminate any air leaks there. Carb neck is sealed top and bottom with O rings. But your quite right - better safe than sorry
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Hey Fellahs,
Great to see that there are experts that are familiar with the GO engines here on these forums. I have a couple of questions about my GO.21 5 PORT TURBO:
I have 3/4 gallon of Trinity 30% through it. That includes the initial break in tanks.
I am running the stock carb venturi and the extra head shim I added as directed pre-break in.
Upon purchasing the engine I sealed the backplate, carb, pinch bolt and the needles. Firmly believe in this move.
I am just waking this engine up after the winter and it seems to be SCREAMING in the pavement shakedown runs so far. I have had it out for 3 or 4 tanks. Still fairly rich and smokey. Temps just at or under 200 deg. HERE ARE MY ?'s:
VENTURI: Keep it or no? What is this really doing for me? Run time? At what power cost?
HEAD SHIM: Does this have to come out at some point to continue making good power? OR do i just leave it in and run it. I cant believe the power this thing seems to want to make right now with the Venturi and the head shim and its only at 3/4 of a gallon. As I understand it this thing will really wake up in another 1/2 a gallon... Any input for me from the experts?! Thanks in advance.
Hey Fellahs,
Great to see that there are experts that are familiar with the GO engines here on these forums. I have a couple of questions about my GO.21 5 PORT TURBO:
I have 3/4 gallon of Trinity 30% through it. That includes the initial break in tanks.
I am running the stock carb venturi and the extra head shim I added as directed pre-break in.
Upon purchasing the engine I sealed the backplate, carb, pinch bolt and the needles. Firmly believe in this move.
I am just waking this engine up after the winter and it seems to be SCREAMING in the pavement shakedown runs so far. I have had it out for 3 or 4 tanks. Still fairly rich and smokey. Temps just at or under 200 deg. HERE ARE MY ?'s:
VENTURI: Keep it or no? What is this really doing for me? Run time? At what power cost?
HEAD SHIM: Does this have to come out at some point to continue making good power? OR do i just leave it in and run it. I cant believe the power this thing seems to want to make right now with the Venturi and the head shim and its only at 3/4 of a gallon. As I understand it this thing will really wake up in another 1/2 a gallon... Any input for me from the experts?! Thanks in advance.
Leave the venturi in, maybe even get some smaller ones. I run either a 6.5 or 7 in my buggy depending on the track. It'll help with mileage and help to smooth out the nasty bottom end of that 5 port. Keep the shim in if you continue to run 30%, only take it out if you run a lower (20-25%) nitro content. I've found from my 5 and 7 port GO's like to run between 230-280 so you've got some more leaning to do and yes it wil really wake up for you soon. I'd say you're pretty safe to put a race tune on it now.
+1 to all that...I run a 7mm venturi in both my MM5 3 and 7 ports.The power loss isn't noticeable really just smooths it out a bit but the longer run times are cool..The shim can stay in for 30% nitro but I only ever run 20 or 25% and after 2 gallons I remove the xtra shim and change the rod and wrist pin and clips all at the same time..I don't see the need for 30%..I found the power increase to be negligible but the engine & plug life are shortened and I found the engine to be much less tolerant of being a bit lean on the mixtures..I killed one engine real quick with a can of 33%..
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The boys have pretty well covered it
I agree with Giz on the fuel. 25% is all you need and it is more friendly on the motor.
If you have nearly a gallon on it, I would switch to 25% and remove the break in shim. Run a hot or super hot plug (OS P4 or P3). Lean it out some and when you hit the 1.5 gallon mark put a full race tune on it and stand back
Change the rod, pin and clips at 2 gal as suggested (just as a one time precaution).
Run the 7 mm restrictor, and if you are looking for 10+ min run times go to the 6.5 mm restrictor and maybe look at reducing the head shimming a little. Go to Massive Mods web site and check out his "Head shimming 101" article - http://www.massivemods.com.au/produc...roducts_id=192
I run 25% with a total of .6mm shiming (as opposed to .8mm standard). Makes the engine run a little warmer and the pipe run a little cooler, plus better run times.
You will love your 5 port, they are a beast. All you have to do is work out how to tame it down via the clutch etc if you are running it in a buggy. If it's in a truggy just go hard
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Whats with that ? I would check that a bit of the teflon tape hasnīt been ground off and found itīs way into the high speed jet. Could be the cause of the problems your having.
and yes it wil really wake up for you soon. I'd say you're pretty safe to put a race tune on it now.
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