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Scooters - 50cc => Super 8 => Topic started by: love2ride2222 on February 01, 2020, 09:24:19 PM
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What is the reason for this ? I am having big problems to just start normally. I have checked for air leaks , I have the carb adjusted almost all the way rich , I've tried adjusting the rich /lean jet to no avail fixing the problem. I checked the auto choke , not sure if it is bad or not. I pull it all the way off and sometimes it does then idles ( but that I don't think gives an answer because it is letting both air and fuel when its off ) and I let it warm up and put it back in. I purchased a new one and just stuck it in the hole( which would allow it be rich as should be upon starting ) incase the old one has the needle broken down causing a lean mix. I installed it but nothing changed.
Something to add , maybe help with this mystery is that when the weather is back being hot or warmer ( I live in Florida ) it starts and idles fine. I have a pod air filter so nothing would be blocking the air I don't think .
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Any chance this machine sat unused for a long time before this problem? Long time = months/years.
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I ride it every day or several times a week . I talked to a scooter mechanic today. I told him a few things that are apparent and going on, such as the plug has been showing hot even with the Arriche carb tuned/turned all the way in rich , exhaust is loud even with new pipe , some reason pipe wont seal , bolts constantly loosen . He said to change the plug , as he says he changes them every few months. I don't see the need I owned this for 14 years and have gone years with out changing it , but Ill put another in. I changed the fuel filter the other day , nothing changed . He said the reeds could be bad but I don't think so . I checked them a few months back looked strong , no light came through ,etc etc. Ill check again . It idles sometimes for 30 secs and then makes this POOOOOOF sound out the exhaust and dies.
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The plug tells the story that you have an intake leak somewhere between the carb and the reeds.
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Just thought of another possibility: have you checked the vacuum operated fuel valve?
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Howdy.
No I don't think so what is vacuum operated fuel valve ? But I had a dream while sleeping about something I remembered someone saying about a valve in gas tank lid . If I remember correctly the lids have some small simple one way valve for air and if it somehow gets blocked it can mess things up ?
I've checked a variety of ways for air leaks , none seem apparent , except the exhaust . Though I have not pulled the carb intake to look at the reeds any time recently, guess Im gonna go an check. The mechanic ( different answer then others ) says the exhaust leak doesn't do anything bad , he says they race these with no exhaust . Idk , I always was under the impression the exhaust we put on these have particular tuning and give our bikes extra power.
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There are two vacuum valves on most bikes, one for fuel tank vent and one for fuel feed to carb. Either one sticking can cause the engine to run poorly or not at all. The fact that it runs for 10 seconds means the run/stop switch on the handlebar is RUN!
Two-strokes may or may not have Reed valves. I do not know if yours has them or not but you have one or more of the three causes: 1. Stuck vent valve, 2. Stuck fuel valve or 3. Air/ vacuum leak. That's why your plug color is white and why it quits quickly.
The "tuned" two-stroke exhaust pipe can produce amazing engine outputs over just a muffler. Running any engine without either a muffler or exhaust pipe of some kind is terrible practice. Especially 2t engines have an exceedingly irritating sound with nothing on the exhaust port.
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Howdy.
so what is vacuum operated fuel valve ? But I had a dream while sleeping about something I remembered someone saying about a valve in gas tank lid . If I remember correctly the lids have some small simple one way valve for air and if it somehow gets blocked it can mess things up ?
Vacuum operated fuel valve uses vacuum (sometimes via a hose from the intake) to open the fuel valve allowing fuel to flow to the carburetor. You can check this by first,disconnecting the fuel hose at the carburetor and directing this hose into a container; then, disconnect the vacuum hose from the intake. Now, draw in air on the disconnected vacuum hose like you're sucking a soda straw, hold that vacuum with your tongue, and watch to see if fuel begins to run into the container. If it runs, the fuel valve is working.
As for the valve in the gas tank lid, just loosen the gas tank lid and ride. If the problem persists, the lid is not the problem.
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Sorry for late reply, just did that today. So there are 2 lines to the carb as you said . I pulled them off drew in air like you explained and the fuel flooded out the other. I got a propane the other day because I am so fed up with this . I was trying to use it to detect leaks , but something happened to the propane tank , it was not full or something and that was then the end of my test. I held it around the intake connection and the flange where the reed is and nothing changed. If I held directly at the carb opening the engine would die. I put a new plug it last week to see if that did anything different , I pulled it after riding it and it is very white.
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Too white spark plug = too lean = air/vacuum leak, jet too small, starve for fuel, etc.
Too black spark plug = too rich = choke/ auto rich too much, clogged air filter, jet too large, etc.
Tan spark plug = everything perfect!
All this is with engine under normal load for about 15 minutes after warm-up....
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You seem to have determined that the vacuum operated fuel valve is working properly. I re-read the posts and it does not appear that the jets have been removed for inspection. Make sure they are clear (i.e. you can see light through them). By the way, what is an Arriche carb?
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Also, I have no idea of your exhaust set-up or your jet sizes. But...a pod type filter will allow a lot more air to enter the carb than the factory filter and can cause a lean issue.
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Yes its lean , it has been for a little while now . I cant figure it out that is one reason why I am here.
Yes pulled a few weeks ago , jet is clear , and its large , not stock and scooter was showing gray plug for years with same size carb and jet. Im just so confused , its not that much to these engines . The exhaust is still leaking at the exhaust port( or its loud coming from somewhere ) , something is wrong down there . Ive been advised to redrill the exhaust port threads but am afraid to do that . The power is still with this kitted scoot. It launches like a rocket.
I had a Tecnagas r - next or what its called now I have a reverse made by GIANNELLI. Neither exhaust changed the leak or the plug color. it has a pod filter.
arreche 19mm Carb
Actually this is more accurate https://www.ebay.com/itm/Arreche-19mm-Kymco-Carburetor-/232559475481 (https://www.ebay.com/itm/Arreche-19mm-Kymco-Carburetor-/232559475481)
I just changed the link.
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I'm not familiar with this carb. Aren't there 2 jets?
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The problem can be caused by a faulty CDI, or insufficient Voltage supplied to the CDI.
Make sure the battery is fully charged, and the battery terminals are clean. Specially if your scooter has a DC CDI, the engine will not run properly if power supply to the CDI is not correct.
If the battery is fully charged, passed a proper load test at a specialist, all terminals are clean, and you still experience a problem - maybe you should try another CDI. Specially if your scooter has a DC CDI.
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@Scooterfan.
This is the first time I have ever heard this , how do I check if the cdi is working properly ??? I will tell the story here. About a year a go I was washing my scoot and splashed the suds off with a bucket of water the floor plate was temporarily off and the water got down thru the the battery cover to battery area and cdi . I took it for a ride and about 2 miles away my scooter died , I had to push it home . I pulled the battery cover and saw the cdi melted. I ordered ( CDI DC Kymco 50 50cc 2 stroke, Grand Dink People Super 9 LC Top Boy Yager etc ) from parts-galore on ebay . The seller told me this is the one I needed , im not even sure if mine is dc or the other. Anyway I put it in and it ran. I never checked the plug right away so I didn't know if it was hot. About 6 months ago I started having problems with the starter turning the engine . I ordered a few batteries , it was weird they didn't work but were brand new . Also Im not sure if it was the batteries , lots of confusion , but one time a new battery worked and I said I not touching it and returned the others . Then early winter I have been having hard time to start and idle , basically it woudnt at all for just a seconds and then make a poof sound and die. But I recently noticed ( maybe its complete coincidence ) but I would take the gas cap off and it would start , idk could be my imagination , but this has gone onto long.
So the battery is new and strong, terminals clean , the cdi is new didn't seem to be any problems but how would I know ? So plug shows hot , runs good when I ride it.
What do you think ?
Thank you .
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Hi love2ride222,
To start with - no new battery bought off the shelf will be fully charged. Our local new batteries (South Africa) are usually between 80 to 90 percent charged when it comes off the shelf. When only battery acid gets poured into a new battery it will never be fully charged - therefore a brand new battery actually needs to be hooked to battery charger if you expect it to be fully charged before installation.
On a normal car, truck, etc this hardly ever cause any problems, but in case of a scooter with DC CDI I am quite convinced that a new battery should actually be hooked to a battery charger before installation. The reason being - the voltage reading at a DC CDI itself must at least be about 9.6 Volts, otherwise the engine will not start.
Regarding your experience with batteries which didn’t work - I think there is a possibility that the batteries were not faulty, the batteries were perfectly normal. It probably came off the shelf without being fully charged with a battery charger before installation, therefore the voltage reading at the CDI was probably lower than 9.6 Volts when you tried to start the scooter. (If your scooter has a DC CDI)
To see if you have more than 9.6 volts at your scooter’s CDI , you can just remove the plug at the CDI, let somebody pull a brake lever, switch the ignition on, and press the engine “start” button. Then you need to do a Voltage test at the loose CDI terminal while e engine is swinging . One of the wires on that terminal is the power feed to the CDI, and if you get a reading of more than 9,6 Volts while the engine is swinging it means there is no need to worry about he battery - the problem could be at th CDI. ( This is in case your scooter has a DC. CDI).
If I remember correctly there are videos on Youtube about how to test a CDI, but I haven’t bothered to test one yet. I actually bought an extra CDI, just in case the CDI on my scoot start giving problems.
I have no experience about AC CDI’s - so in case your scooter has an AC CDI somebody else might be able to give advice.
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You wrote : I am quite convinced that a new battery should actually be hooked to a battery charger before installation.
Yes I charged all of them . Before all the problems , I tried a jumper box and it turned it over real good , but then later didn't . I came to the conclusion it might have been how I put the starter gear back in . Anyway I should test the cdi if it is getting 9,6 volts is that correct ?
Also this wont address the hot plug , but the * MODIFIED my message * start up and idle issue seems to go away when its hot out ( I live in South Florida , US). So that got me thinking about pressure and with in lines and stuff. Recently as I think I mentioned it wasn't starting well at all and when someone mentioned fuel valve and to pop the gas lid off , that possibly it wasn't venting allowing the fuel to circulate. I did that and it seemed to work.
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Yes, if you get a Voltage reading of 9.6 Volts or more while the engine is swinging the engine should start when you connect the plug to the CDI again.
That Voltage drop is normal while the engine is swinging.
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Another thought - just make sure the fuse connections are not corroded, and make sure the fuses are not sitting loose at the fuse terminals.
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Sorry for late reply.
Im certain the battery/fuses are good and pretty certain the cdi is fine. I could not find any youtube or advice on where to stick multimeter probes to test cdi and with my luck if I do it wrong Id ruin it , and don't have that option at the moment as its my transportation . Id say if it takes off like a rocket ship , its getting ok spark, and that's never changed unless I messed with the air fuel screw .
I still can't make sense of why its so loud even when its bolted up tight now.
No air leaks can be found except I guess somehow from the exhaust but I can't seem to figure it out. The idle revs high at stop light and sometimes comes down in a bit or not at all. Another thing ( why I initially started this thread was scooter would not idle ) , but now it does but for a while it wouldn't .Recently I popped the gas lid off and that seemed to make the difference. I checked fuel flow like instructed and it showed it was working fine. Its like this scooter has Gremlins . There are no respectable scooter shops near me and it seems everything has gone to crappy 4 stroke also.
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So my scoot was vandalized yesterday. My seat razor bladed , and paint .
Can some one advise me where to get a new seat ?
I tried to post a photo of damage but it keeps saying error .