hammerhead gy6 problems

[chris]

I just installed a stage 1 stator on gy6 hammerhead go kart and now it starts ,run at an idle but at faster throttle engine starts shaking and missing and eventually die, any Ideas

[bige]

pull the flywheel back off and check the keyway, sounds like its sheared off

[chris]

do you think since i upgraded my stator that i should upgrade my cdi unit or do you think this wouldn't have anything to do with this, Also I checked the key on the stator it was fine,and also the carberator is running rich.

[bige]

what size jet do you have in now? if the plug shows black after a wot run then its to rich and need to down a size on the main jet. what is a stage1 stator? did you install an 8 pole stator

[chris]

yes its an 8 pole stator

[chris]

how do you know what size jet is in the carb?

[joshstep1]

It kinda depends on where. I live in TN and a 130 works good for me. Where do you live?

[chris]

indiana

[chris]

another question could a bad ignition switch cause a weak spark?

[joshstep1]

In Indiana a 130 -135 should work well. By ignition switch, do you mean ignition coil?

[chris]

no the switch

[chris]

by the way what is a spark arrester and what does it do?

[joshstep1]

Are you talking about the 2 way button on the dash?

[joshstep1]

The spark arrestor is the screen mesh at the very end of the exhaust. It prevents any fire or flame from coming out of it. Removing it helps the engine breathe easier.

[joshstep1]

However it is illegal to ride at public place without one.

[chris]

No its a key ignition, I guess what I'm asking is, how do I check for weak spark?

[joshstep1]

I'm not real sure what a good spark looks like, but I would take the spark plug out. Then put the ignition coil on and ground the other end of the plug. I guess just make sure it looks good, not a dull spark. I would not expect it to be a weak spark though because it runs a good idol and runs good up to a certain speed.

[chris]

My buggy Is a hammerhead 150 cc it starts, idles fine but if you go to throttle it up it misses and wants to die if I slowly move the trottle I can get about have throttle before it start missing ,but if I do get it to run have throttle it only runs ok for short while.

[joshstep1]

For a second I thought it might be bad fuel, but bad fuel wouldn't run a good idol. Have you cleaned out your jets recently?

[chris]

yes, I don't what size it is but its running rich

[joshstep1]

Did you check the pilot jet as well?

[chris]

do you think if the buggy start and Idles well I could eliminate the ignition part and narrow it down to a carb problem?

[chris]

I went through the whole carb.

[joshstep1]

Yes, I would rule out the whole ignition part and focus on something else. So, it's not the carb, it's not the ignition system... I'm pretty sure it's not bad fuel.

[chris]

just put a new plug in it, i'm stumped, may be it has to big of jet in it.

[joshstep1]

has the buggy always done this?

[chris]

no, before the stator went bad it ran pretty good , I replaced the stator and it went down hill from there, but at least it starts now , right

[chris]

there is no adjustment on the stator or pick up coil, so it can't be a timing issue . I don't know if a valve problem might cause this or not ,maybe my choke is sticking.

[joshstep1]

I'm going to post a pic in a minute and you tell me if it looks like this.

[joshstep1]

Here it is. Tell me if your carbs air intake looks like this.

[joshstep1]

Or if the black plunger is stuck half way or something.

[chris]

i can see the black plunger half way

[joshstep1]

so it is about half way down?

[chris]

yes I can see it, is this good or bad

[chris]

yes, I can see it

[joshstep1]

I'll post a pic of what it should look like. The one in the pic above is a bad one.

[chris]

If I can see the plunger ,what is it doing and how do I fix it?

[joshstep1]

Here's what it should look like.

[joshstep1]

You want to be able to see it like in the latest pic I've posted.

[chris]

why is the plunger down there?

[joshstep1]

It is what helps regulate how much air gets to the engine. In the first pic where it is stuck all the way at the top, it let in too much air. It would run a perfect idol, but as soon as you open that metal plate, massive amounts of air would get in the engine. Thus, it dies. If its stuck half way, I would assume it would run a good idol and you would be able to get some good rpms out of it. But open it too much and too much air gets in the engine. Exactly where is the plunger on yours? Is it like the second pic (where it should be) or somewhere in between the first pic and the top?

[chris]

it is about exactly in half of the opening

[joshstep1]

Can you post a pic?

[chris]

it would take me a while, I have the air filter box back on it , but I do remember looking in the back of the carb today and seeing the plunger hanging half way down. you say it should not be down that far, if not how do I fix it?

[joshstep1]

You have to take the carb off and take the bowl off the top and clean/lube it.

[chris]

lube what , the black plunger, and lube it with what?

[chris]

do you mean the lid or top is sucking air in?

[joshstep1]

The plunger and gold needle is what I lubed with carb cleaner. And neither is sucking air in. With the plunger up too far, too much air is getting in the engine.

[chris]

so if the plunger is down to far it is starving the engine of air and that is the reason its running rich, by the way what will lubing these parts do?

[24evanwilson]

holy crap O_o

[chris]

I cleaned them with carb cleaner the other day when I took it apart.

[joshstep1]

make sure they move freely

[joshstep1]

holy crap O_o

What's holy crap?

[chris]

I'll take it apart tommorow and clean and lube it and see if it helps,I'll let you know how it goes, Thanks for the help

[joshstep1]

Not a prob.

[bige]

the black plastic part has a needle in it that goes into the main jet, its called a slide, it should sit all the way down, when there is enough vacumn the slide moves up and pulls the needle out of the main jet some to let more fuel in to go along with the extra air thats coming in.

if you have a vacumn leak it will not get enough vacumn to operate properly or if its sticking. remove the top plate on the carb, remove the black diaphram, be careful not to damage it, clean the slide and check for scratches on the side

[BuggyMaster]

I doubt your ignition is causing your problem. You are describing a carb problem. How did you clean the jets? Or..what did you use to clean the jets?

[joshstep1]

Pretty much what Bige said.

[chris]

I think I might be on to something , this morning I checked the needle valve in the carb and it was fine so I started moving some wires around and found that if I touch the power wire going into the cdi box the buggy dies , maybe a low rpms or Idle there is not enough vibration to lose connection but at higher rpms it starts cutting out, if I'm losing connection on the plug, can I get a replacement plug that I can slice into my harness, if not how could I fix this problem?

[joshstep1]

Can you post a pic of the wire so I can see which wire you are talking about?

[bige]

you can remove the wire from the plug with a very small screw driver, it has a locking tab on it, bend the tab back up some and reinstall the wire in the plug.

[chris]

after looking at the plug, it looks pretty bad, I'm going to see if the local buggy dealer has some old wire harnesses they can cut that plug off of. by the way do you think that my cdi could be failing at higher rpms ?

[joshstep1]

I wouldn't think a cdi would work at low rpms and not at higher rpms, but you will probably want to ask that to someone who knows a little more about those.

[chris]

I went ahead and messed around with the cdi plug and got it to hold and that wasn't the problem. still will not run half to full throttle, I also noticed when I hold it about 1/4 throttle it surges.

[chris]

when I try to rev it up by feathering the throttle its blowing black smoke out exaust

[chris]

I'm about ready to call it quits

[joshstep1]

Black smoke out of an engine? Huh... I'm stumped... I don't know what could burn black in an engine.

[bige]

black smoke is a sign of being way to rich, either the choke is bad, the slide is sticking, or the jet is to big.

with the engine cold, remove the choke, measure the brass section, turn the key to the on position for 10 minutes, remeasure the brass section. if it moved then the choke is working, if not then the choke is bad

[joshstep1]

Oh yeah... It's rich.

[bige]

have you tested the choke?

[chris]

I think my prob is diaphragm in the top of carb, if I raise it up with a screw driver when it is running and give full throttle at the same time it runs like it suppose to, but I don't know why the diaphragm isn't working right?

[BuggyMaster]

I had a problem similar to that and the problem was that the hose that goes to the diaphram actuator (sits behind the throttle mechanism on carb and shares a T with the line the works the fuel petcock) was pinched. Damn thing drove me nuts trying to find it. The way I did find it was I took the air intake off to where I could look down the throat of the carb and actually SEE what it was trying to do. In that case, the slide wasn't going up like it should. The fix was I took that hose out of the round metal clip that it runs through. It was causing the line to pinch and not giving it what it needed vaccuum wise. Try that but your description fits too large of a pilot jet. Happened to me when I tried to use a small drill bit to clean the jet.

[chris]

if its not the hoses or the jets what else could it be?

[BuggyMaster]

My vote is that it is still in your fuel delivery system somewnere. I need to see it via a vid or something to advise further.

[BuggyMaster]

There is one other thing that you could do though but you need a timing light. If it is in fact an ignition problem, you can see it in how the timing light blinks.

[chris]

tell me if I'm right on this , the black plunger or choke you can see when you look up in the carb on the breather side controls the amount of air that enters the carb, so if I lift that plunger up with a screw driver and give it gas and runs good, then you would think that I'm not getting enough fuel, right, I mean if I was getting to much fuel then the plunger would stay up on its own, I 've checked the vaccume hoses and diaphram,spring, what does the diaphram on the side of carb control?

[chris]

also, do you think I should just buy a new carb?

[BuggyMaster]

That black slide has a needle attached to it on the bottom. When you give it gas, vaccuum will cause that slide to raise up. As it raises up, it lets more fuel come through your main jet. The diaphram on the side regulates how that slide will raise.

Take a look at this vid that shows a GY6 carb in action:

CJV4IqDpJTk

[chris]

so if the diaphram on the side is not functioning right the diaphram in the top of carb will not work properly

[chris]

Its sad to say but I'm on dial up so it's take for ever to watch video's but from what I've seen , my buggies black needle plunger is not raising like the one in the video, what would cause that? mine only move a little bit on full throttle

[chris]

so do you think the diaphram on the side is not working right?

[BuggyMaster]

When mine was not working correctly, the effect was that it would only rev so high. Like you could floor it and it would only get to half of its rpm at best. Personally, I don't think this is your problem but I can't say for sure. When I had a problem with that on mine, I actually stuck my finger in the end of the carb and assisted that slide to see what my probem is. If you decide to do that, do so at your own risk. A backfire through the carb could hurt.

[chris]

I already did assist the carb but I don't know what is causing that, sounds like we had the same problem, what was the cause of yours not getting full rev?

[chris]

If I assist the slide I can get full throttle or rev and it run great but if I don't assisit it I can't even get half throttle, the only thing I can think of is the diaphram on the side.

[BuggyMaster]

maybe the diaphram however, not likely just from sitting. Would take some outside help to be bad generally speaking. Check your vaccuum lines REAL good and be sure there are no kinks in the line.

[chris]

there are only two vaccuum lines that go to carb, they are fine , is that what was wrong with your, kinked vaccuum lines?

[chris]

after inspecting the the diaphram on the side of carb I noticed rubber missing on both sides which would explain lack of vaccum to needle slide, I guess Its probably time for new carb, any Ideas on the price of one and where I should get one?

[BuggyMaster]

For mine, the reason it had a problem was there is a little retainer ring that the line goes through that is attached to the screws that holds the top of the carburetor on. Because of the angle that the hose was at going through there and attaching to the tip that the line goes on, it had actually pinched the line to where not enough vaccuum could do the job. The cure was simply to take it out of that ring.

BigE or ****Mike should be able to hook you up on a new carb. Note that though carbs can come with different size jets in it. I've got one that came with a 114 and another that came with a 105. If you get a new carb, make sure the jets in it are the same as yours sizewise and if not, move the ones from yours over to the new carb.

[roysheepdog]

is there a way that you could have put the diphram in upsidedown?just a thought i havent inside one like that.or does it have a small hole in it?if you could find one it should be cheep.

[roysheepdog]

if you need a gasket make one out of a cereal box.it works good i put one on my truck 3 years ago and never had a problem.trace out what you need and cut it out,do a good job and you will have good luck with it.

[chris]

is the carb in the video a stock 24mm carb because my needle slide will not go up as high as that one does not even if I assist it, if I take the top off of the carb remove the spring, in the center , there is a needle hold down with a handle on top, the handle on top hits the top before it can fully open, is this suppose to happen or is something wrong?

[BuggyMaster]

That is a stock carb. Sounds like something is going on with that slide. It should move freely all the way up and back down.

[chris]

what size jets come in a gy6 carb, and what size jets would you think I would need for indiana climate, I just bought a new carb and was checking the jets in it and they were smaller than the ones that came out of the old carb, there were no numbers on the jets that came on the new one but I did find the number 135 on the main jet out of old carb so I just switch them out. I assume this is the right move?

[BuggyMaster]

typically that is ok. Bige may be able to comment better but I am thinking a 135 is big for an otherwise stock machine and actually, that may have been what your problem was.

As to the jet that came in the new carb, it should have had a number somewhere on it. Some are on the face of the jet, some on the side. I've seen a wide range of jet sizes in new carbs.

[chris]

I looked them over and there is not a number anywhere, but I could tell a difference in size, the new carb jets looked smaller I'll just install it and if it doesn't run I'll switch them out

[bige]

a 135 is way to big for a stock motor. the strock jet could be any where from a 105 to a 110.

[SYCARMS]

If you are running the stock exhaust not moded and the stock airbox leave the jet which come with the new carb in.If you were to open the exhaust up along with a UNI filter than you would need a 123-125 jet. The 135 jet if run long enough will wash out your rings. TOM

[chris]

Hey Tom, The hammerhead lives, It seems to be running fine, but will that big of jet really hurt the rings, everything on it is stock except for that jet and its the one that was in the old carb, you can check the buggy running on youtube, just search under Parker City Hammerhead , there are five clips, and let me know if it looks like its running the way it should. By the way thanks to everyone thats helped along this journey.

[SYCARMS]

If you are running too rich all the fuel will not burn and than the left over fuel will wash the cylinder walls down causing the rings and cylinder to prematurely wear. I would check to see if your running rich. To do this find a long flat surface 1000ft or more, the longer the better. Bring your plug wrench with. Accelerate to full throttle never letting up, at the end of your run turn engine off but do not let off the throttle until engine quits. Immediatly pull your plug and read. It should be light to dark brown. If black you are too rich, which I believe you will be, and if not you probably have a vacume leak some where. TOM

[chris]

so what your saying is that if the buggy is running well with the 135 jet then when I put the stock jets in there it will not run well because the reason its running well now is because it has a vaccume leak, if the jet is to big wouldn't I notice it while I was riding it?

[BuggyMaster]

Looking at your vid, it looks like it is running fine. Roll with it. I would pull the plug on it and see how it looks. If it is really dark, like almost black, you are running rich.

There is a point in which the buggy will start running like crap from being too rich. Your's is not there per your vids. If you do find that your running too rich via reading the plug, what you have to gain is a little power. Running richer has the advantage of giving you a little extra engine protection at the cost of losing a little power. If you get just the right air fuel mixture, you will be running at ultimate power. Can't really say where you are at until you see what the plug looks like.

I don't think you are running so rich that you'll wash the rings out. It looks to be running pretty good.

[SYCARMS]

Your buggy come with a 110 to 114 jet installed in the stock engine. this jet tends to run on the lean side of the spectrum, so with everything being stock it should run fine. Being that the factory sets the air fuel mix to the lean side of the spectrum, lets just say your carb has a 110 jet. You can increase 1 to 2 sizes up to bring it a bit richer and still be in the spectrum. By spectrum I mean the areas of acceptable lean or rich. so being your at the lean side you would replace your stock 110 jet with a 112 or 114 and still be within the acceptable spectrum. With the 135 jet on the stock engine you should be way above the acceptable spectrum which means you are running rich. If I were to take a stock GY6 motor and gut the exhaust and add a UNI filter I would rejet to a 123 jet at the most. What I said in the last post is this. Your buggy being totally stock the jet supplied with the new carburetor should be sufficient, and if you do not run good than you have another problem and it is likely to be a vacume leak.If the engine runs fine with the stock jet , than you would check the plug as described in the last post and if the plug is light tan you can increase the jet size 1-2 sizes to bring the plug into the brown color. This will give you the optimum performance providing all else is right. There is no way I can know all the specifics with your buggy since I do not have it in front of me. All I can tell you is what is known as far as specs go as to what is and is not correct. The 135 jet is deffinately to big for your application and if the engine runs fine its likely that whom ever owned it last had a vacume leak and compansated with a larger jet. If I had the buggy in my posession I would put the carburetor on with the supplied jet and if it did not run correctly I would find the cause and repair it. TOM