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Post by galileo2 on Jun 18, 2010 16:32:08 GMT -5
I got the valve keepers in today and installed them. I tested the valve for leaks and there werent any. I Put everything back together and tested the compression, getting a consistant 120psi. I tried spraying some oil into the chamber but there was no change in pressure, and it still doesn't start. Where else could I be losing compression?
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Post by unorthodoxneon on Jun 18, 2010 22:22:28 GMT -5
If you think valves are good and your pistons rings are good your loosing through the headgasket or a crack in the block/head. Also if you overheated your scoot did you check the cylinder head and block to make sure there wasnt any warpage which could give you the issues you are having now?
Also how did you test the valve for leaks?
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Post by WildMan on Jun 18, 2010 23:26:55 GMT -5
galileo2 A Guy's, I said it once, now I'll say it 1 more time... If you didn't buy a good quality compression tester, or you're using one w/ quick disconnect air fittings, that's your compression loss... If you have a cheap tester, the 120 lb. is probably more like 175 lb. +-... I have 4 compression testers & only 1 gives & accurate compression reading... I would suggest you either spend the money for a good tester, or start looking elsewhere for your problem... Don't take this the wrong way, I'm just trying to help you from my past experience... I've been wrenching for over 30 years, & I know for a fact that, even though 120 lb. compression isn't the greatest reading even if accurate, the engine will run, & probably not to awfully bad either, unless there is something else wrong... I've seen engines run w/ 75 lb. compression.. Even w/ bad compression the engine should, fire, fire up & run like crap, or just fire up & quit... If you have 120 lb. compression & won't at least do 1 of the 4 things in bold, your problem is something other than compression...
David Sr.
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Post by galileo2 on Jun 19, 2010 14:15:35 GMT -5
David Sr. I used they type of compression tester that you suggested. It is the type with the rubber cone adapter that does not come off, and it certainly wasn't cheap. I do think that my cylinder head is warped. I think this because even after using the copper sealent I am still finding gas on the gasket and stud on the cam chain side of the engine. I think that I should raplace the cylinder head. Money is tight now though, so it will have to wait untill I can afford it. In the meantime, I will use the old gasket with plunty of sealent (it atleast sputtered before I installed the new one) and see how it goes.
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Post by WildMan on Jun 19, 2010 15:22:37 GMT -5
galileo2 Here's another thing w/ compression tests, the internal volume of the hose or the stem of the tester will also play a part in the final results of a tester.. But, that's why I'm saying, w/ 120 lb compression it still should at least fire up, even if it doesn't stay running, or not run good, it still should do something w/ 120 lb. Does it at least fire?? That's why I say something else is probably wrong..
You can take head off & check for warp-age w/ a steel ruler from a good combination square & feeler gauges... Check once, w/ 1 edge of the ruler, measure any gap w/ feeler gauge, then flip the ruler & check w/ opposite edge of ruler, measure any gaps w/ feeler gauge, then subtract the 2 #'s the sum is the amount of war-page.. .001" is usable, .002" is questionable but still may be usable, anything over .002" is not good..
For checking valve seats, w/ spark plug in & tight, place head level & w/ combustion chamber upward, fill combustion chamber w/ gas or lacquer thinner watch for 5 minutes, if the intake & exhaust ports stay dry valves are seated properly, if the intake & exhaust ports are wet then the valves are not seated properly.. I use gas or Lacquer thinner for this test because these 2 fluids are difficult to seal out because of their wicking abilities, if you can seal out these fluids you've got a really good seal..
David Sr.
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Post by unorthodoxneon on Jun 19, 2010 19:56:11 GMT -5
dwild62 is 120% correct i even gave him a dog bone for it.
I still wouldnt rule out a spark/fuel issues. She should still be putting along even if weak compression.
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Post by galileo2 on Jun 20, 2010 13:54:34 GMT -5
Well, I tested the valves using engine degreaser, and no leaks. The head gasket does seem to be leaking, though it should still start. After all, it would start with a bent valve, a beat up piston and cylinder. I have two theories. 1. I am loosing too much of the vacuum pressure to opperate the carb. 2. The timing is still wrong. My flywheel doesn't just have the T mark. It looks like this.. <____________|TF|______| Does any one know what to make of this? 3. I screwed something up, which is probable, but I don't know what.
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Post by WildMan on Jun 20, 2010 15:49:55 GMT -5
galileo2 Ya those timing marks are right... I do believe you said how you set the timing.. But let me ask you, when you lined up the 2 small holes on the cam sprocket w/ the top of the head, was the larger hole (3rd hole) pointed away from the head at 90 deg. (perpendicular) The "T" mark should line up w/ the little cast gusset at around 11 O'clock position, piston at the vary top of it's compression stroke, & intake & exhaust valves 100% closed & free play at the rocker arms... David Sr.
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Post by galileo2 on Jun 20, 2010 19:16:24 GMT -5
That is exactly how I set it. So the timing is good. I took the cylinder head off today to look at the gasket, which looks fine, but there wasn't any gas in there, just barely a residue and I had just cranked it a few times trying to start it. It is definitely not getting fuel. The carb is getting fuel though. I don't think that the intake stroke creates a vacuum strong enough to bypass a seal that holds back 120psi. Do you know if there are any common problems that would lead to loosing vacuum at the carb? I don't fully understand how the vacuum system works; there is nothing in the manual about it.
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Post by als01seville on Jun 20, 2010 19:25:22 GMT -5
Hi Galile02, Have you made sure that the Vacuum Line coming from your INTAKE which is connected to the Head in front of the Carb goes to most Likely a Plastic "T" or "Y" connector and there is most likly a hose from the Diagprham pump on the Right side of your carb connected to the "T" or "Y" connector as well as the Vacumm Line from your Fuel Pump. Make sure that hose coming from your INTAKE which is the one that creates sucken for your fuel pump and carb is not cracked or ripped or bent. Alleyoop
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Post by galileo2 on Jun 20, 2010 19:26:11 GMT -5
Would a leak in the airbox prevent it from starting?
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Post by WildMan on Jun 20, 2010 22:39:19 GMT -5
galileo2 No, a leak at the air box won't keep it from running... Do like Alley said, check all your vacuum hoses, make sure they are all clear (no obstructions) & no cracks, & hooked up like he described, accept fuel pump if you have gravity feed, but if you have fuel pump then 1 hose will go to the vacuum port of the fuel pump, if you have one... Have you had carburetor apart yet & cleaned it?? Carburetor may be all gummed up... If your cylinder & plug is dry (not wet w/ gas from trying to start engine) the Carburetor may be all gummed up, you could have a bad float, or a stuck float valve (float valve might be stuck in the closed position)... It's starting to sound like you may have a stuck float valve & or carb is varnished up from sitting... I think you said you had spark, it sound like you have cam timed right, so at the moment that pretty much just leaves carburation, & that where I'd be focused... Oh, almost forgot, it's not a priority, but at some point down the road I'd recommend going to your local hardware or plumbing store & buy a 1/4" brass or nylon barbed "T" to replace your existing vacuum "T"...
Don't fret, keep plugging at it, & w/ some help from the Dawg's, I'm sure we'll get you scoot'n... Just don't give up, cause if you give up, you won't learn, & scoot will never run.. & believe me, some times that's difficult, I know there's been times I just wanted to give up & just throw it away, & walk away & never look back, but that doesn't accomplish anything, beside a challenge is good brain exercise..
David Sr.
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Post by galileo2 on Jun 21, 2010 16:24:33 GMT -5
All of the vacuum lines look good. I know that doesn't mean that they are good, but I don't see any gashes, cracks or anything like that. I am having trouble figuring out what a couple of things are and what they do. Here are some pics of what I'm talking about. I can't seem to find any literature about the vacuum system or any replacement parts online. Attachments:
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Post by galileo2 on Jun 21, 2010 16:25:46 GMT -5
I can only upload one at a time. Attachments:
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Post by galileo2 on Jun 21, 2010 16:27:14 GMT -5
2 Attachments:
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Post by galileo2 on Jun 21, 2010 16:28:07 GMT -5
Last one. This one is on the vacuum line going to the fuel tank. Attachments:
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Post by WildMan on Jun 21, 2010 22:36:23 GMT -5
galileo2 1st pic is looks like the charcoal canister - function = absorbs & filter out fumes from the gas tank...
2nd & 3rd pics, the one on the left is a vacuum operated air valve, the on on the right is an air intake filter - function = (I'm taking a stab at it here because I can't see where the 1 hose leads to) the vacuum valve controls air flow in through the air intake filter & I'm guessing here, into to possibly the charcoal canister, another dawg may be able to help us w/ that...
4th pic, well I don't have a clue on this one, another vacuum valve, Possibly a check valve??? Something for another Dawg, or more pics..
Your scoot has lots of gigits on it... But from the pics you have here, I don't see any problems w/ the vacuum system that sticks out, but of coarse that's kind'a hard to tell for sure from the pics, but nothing that catches my eye...
David Sr.
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Post by philr54 on Jun 21, 2010 23:03:16 GMT -5
Yeah, 2 & 3 use the air pulse to operate a one way valve to put fresh air back into the manifold at low speeds - for what I don't know. The one way valve body was leaking so I removed it during the PDI. #4 looks like the check valve for the fuel tank vent hose to the charcoal canister.
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Post by als01seville on Jun 21, 2010 23:20:27 GMT -5
What I don't see, is the Hose that should come from the PUMP into the Gas Filter and INTO THE CARB. I have never seen so many hoses on a scoot in my life:) Man talk about possible troubles.
So check and make sure there is a HOSE coming from the Fuel Pump Into the Filter and from the FIlter to the Carb Fuel Bowl.
Did you do any tearing apart or putting on a New Pump or something. Now the Vacuum line on the PUMP is that connected to the Plastic "Y".
Also make sure the VACUUM Hose coming from the FUEL PUMP is really the VACUMM on the PUMP. The pump should have TWO Nipples one is for the Gas to come out of the other is the Vacuum Nipple and of Course the one from the Tank to the PUMP. Alleyoop
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Post by philr54 on Jun 21, 2010 23:30:46 GMT -5
That looks the same as my Carino, fuel filter is between the tank and the fuel pump, not the pump and the carb. You can see it in the 3rd pic.
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Post by als01seville on Jun 21, 2010 23:37:30 GMT -5
philr54, Does that pump also look like yours, he could have the hoses backward. In otherwords the Vacumm line is connected to the Gas outlet and the Gas outlet is connected to the Vacumm nipple.Normally the hose near the Top of the Pump is your Vacuum nipple and the lower one is where the gas comes out. Just throwing staws out here because I am sure he had to disconnect quite a bit of stuff to do what he had to do. My Guess he has something connected wrong. Alleyoop Here is what my pump looks like and the Top one is the Vacumm line and the bottom is the Gas outlet going to the Filter.
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Post by philr54 on Jun 22, 2010 0:07:33 GMT -5
Had to check the old pump, I have a Mikuni now. Single nipple is fuel in, top (front) nipple is fuel out, bottom (rear) nipple is vacuum, opposite of yours so galileo2 will need to verify the fuel outlet.
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Post by unorthodoxneon on Jun 22, 2010 9:06:21 GMT -5
Could there be an issue with the pump itself. Are these kinda known for going out over time?
Is it also possible to take the fuel line hose off and the vacuum line hose off. Suck in the vacuum line and see if fuel comes out of the fuel line? Dont know much about the scoots as i dont have one but i believe i heard you can do this on these to check to make sure its working properly...
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Post by WildMan on Jun 22, 2010 10:52:42 GMT -5
A Guys I believe galileo2 said he was getting gas into the carburetor, though I'm not sure how he came to that conclusion...
The only real way to test the integrity of a vacuum operated fuel pump it's self, would be to hook up a vacuum brake breeder that has a vacuum gauge, & manually create a low pressure vacuum, if you can create a low pressure vacuum then the fuel pump has some integrity, then the next step is to hold that low pressure vacuum, & check for leak down, if you can hold a low pressure vacuum, then the integrity of the fuel pump is good... A vacuum tester would tell how much vacuum the system is creating..
But, if he's getting gas to the carb, then the vacuum & the fuel pump is at least functioning to some extent, & won't cause the engine to not fire & at least try to start... If the cam timing is right (which I believe it is), it's getting spark (which I believe it is), it's getting gas to the carburetor (he claims it is), then it should fire & at least try to run, meaning vacuum system & fuel pump has some integrity... This means you need to investigate farther into the basic engine mechanics of operation... So if all the basic stages required for engine operation are right & functioning, & if you have gas in the carburetor & have a dry spark plug, & have a dry combustion chamber, then the gas isn't getting from carburetor to the cylinder, which means gas isn't getting through the carburetor, this means the failure is in the carburetor, varnished, gummy, dirt, bad float, stuck float valve... If the float has sunk, or the float valve is stuck in the closed position, you won't get gas into the cylinder & this may be the failure..
I do respect every ones opinions because they are all possibilities for failure.. But I also believe you're all making this more complicated than it really is... You first start w/ the 4 basic principals for an engine to operate, meaning if these 4 basic principals of operation are correct & functioning the engine will at minimum fire, & or fire up & run to some degree... Then & only then do you investigate into the complexity of the engines system of operation... In other words you have to start w/ the 4 basic principals first, & in this case 1 of the 4 basic principals is not functioning, dry combustion chamber - NO EXPLOSION..
I apologize if anyone thinks I come off like a KNOW IT ALL, which I defiantly don't know everything & don't mean to imply such, which is why we have to trouble shoot, but we have to start from the bottom up, which is the 4 basic principals of operation... INTAKE, COMPRESSION, COMBUSTION, EXHAUST, for anyone who may not know the 4 basic principals for 4 STROKE ENGINE OPERATION...
David Sr.
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Post by philr54 on Jun 22, 2010 19:04:48 GMT -5
I apologize if anyone thinks I come off like a KNOW IT ALL, which I defiantly don't know everything & don't mean to imply such, which is why we have to trouble shoot, but we have to start from the bottom up, which is the 4 basic principals of operation... INTAKE, COMPRESSION, COMBUSTION, EXHAUST, for anyone who may not know the 4 basic principals for 4 STROKE ENGINE OPERATION...David Sr. Not at all dwild, I was just clarifying what the pics showed because that setup is the same as mine was. And I agree with you on going to the basics. It's the best way to isolate the problem.
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Post by unorthodoxneon on Jun 22, 2010 20:08:28 GMT -5
One question is would it be advised to try alittle bit of starting fluid to see if that help to atleast get it started.
Also since it seems to be that fuel is getting to the carb and not to the head another once over on the carb is probably in order.
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Post by WildMan on Jun 22, 2010 22:53:57 GMT -5
philr54 Ya, it's quite an experience just to try & trouble shoot a machine 1,000 mile away, or even half way around the world, by a picture, some text, & then create a vision, all while not being able see & touch it... Hay that sounds like a new software game for the computer or Xbox.. Oh, Hold it, I think American Choppers already took that idea, oh well, it was a good idea while it lasted!!!
unorthodoxneon I personally don't like recommending ether (starting fluid) to anyone, for the simple reason, ether can burn rings & valves, & if to much is used it can cause scoring & ceasing.. I'm not totally against ether though, ether isn't as hard on big engines, such as diesel engine, automotive engines, but I try to stay away from using ether in small engines.. What I've done, & do recommend is a clean oil gun filled w/ gas & squirt a couple of shot of gas into the carburetor, & see if it'll fire up that way, or suck a little gas up into like a piece of fish tank air tubing & plug the ends w/ your fingers, then stick the end of the gas filled tubing into the carb & release the gas into it, or pull the spark plug & squirt some gas into the spark plug port, put the spark plug back in & see if it fires up that way... In my opinion never use ether if you can use gas in it's place... Here another thing, galileo2 engine has been sitting idle since last year, so it's going to be a bit dry as far as oil in the cylinder & bearing surfaces, + it been getting cranked over trying to start it, so by using even a small amount of ether could cause damage ever easier... So that's my ether theory... This theory was drummed into my head as I grew up around mechanics, machinists, & farmers, & I now agree w/ this theory as I've seen the damage it can cause especially if used improperly...
David Sr.
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Post by als01seville on Jun 22, 2010 23:18:37 GMT -5
Another way to squirt some gas in there without taking the Air Filter off or Spark Plug which can be a pain. Is use a little tubing like David Sr. mentions and just pull out one of the Vacumm Hoses on your Intake . Push the tube with the gas on and release it or get a small baster at your grocery store and put on a piece of tubing that will fit the intake nipple and squeeze some gas in, put the Vacumm hose back on and see if fires up. Alleyoop
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Post by WildMan on Jun 22, 2010 23:37:03 GMT -5
Hay chalk 1 up for Alley!!! You know, I hadn't thought of that, but I'd bet that would be easier on these GY6 scoot setups, they don't give much room if the body skin is still in place!! I like that one, good idea Alley... Have a bone on me!!!
David Sr.
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Post by als01seville on Jun 23, 2010 22:09:38 GMT -5
Thanks for the bone David Sr., I was tired on chewing on the last one, all the juice was out of it Alleyoop
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