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Post by astray on Sept 30, 2015 19:15:59 GMT -5
Hi there, I recently received a scooter from a friend and I've run into my first mechanical problem. As a preface the first thing I did when I got it was install a new 20mm carb and aftermarket exahust and redid all of the gas lines. The gas tank was also cleaned out to remove any debris in it since it had been sitting around for quite awhile before I used it. It was running very well after that often hitting 45 top speed without many issues. It's a 1P39QMB on a 2011 Taotao CY50-T3
Anyways I noticed the scooter was having a slightly tougher time during the beginning of acceleration where it kind of hopped a bit before continuing to move forward sometimes. It was also having a tougher and tougher time getting started until recently it suddenly started dying while in idle and had a reduced power output at max throttle so I pulled it off to the side of the road. After letting it be off for a bit it would settle down and ride again pretty well. Today it started cutting out right in the middle of the street and I had to start it by using the ignition and throttling it a decent bit to get it going again from rest. After I left it off for awhile it just straight up would not start until I maxed the throttle and held the ignition for quite awhile and I had to keep it from idling or it would die on my way home. It was working fine at max throttle right until a was a block or two away from home and it died even with max throttle after it lossed a significant amount of power. It now no longer even turns on. From what I've read there are two things that could be causing the issue. One is the valves need adjustment after all this time or the piston/rings are shot and I'm no longer getting any compression in the engine and need to have it replaced. What are your thought on this?
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Post by katastroff on Sept 30, 2015 19:21:14 GMT -5
What does your spark plug look like?
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Post by astray on Sept 30, 2015 19:52:51 GMT -5
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Post by katastroff on Sept 30, 2015 19:59:52 GMT -5
Finding a solution to a problem is like digging for treasure. You never start 20 feet under. I would start with checking the compression, then see from there. But i does sounds like a valve issue.
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Post by astray on Sept 30, 2015 20:05:04 GMT -5
What's the best way to check the compression? I don't really have any specialize tools for that unfortunately.
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Post by katastroff on Sept 30, 2015 20:17:18 GMT -5
Remove the spark plug and stick your finger over the hole. Press hard on the hole and try to start it with your electric starter. If you cant keep the hole sealed, you got good/decent compression. You could try to buy a compression tester if you have the budget. Its like a finger but with a gauge on it. www.harborfreight.com/catalogsearch/result?q=compression+tester
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Post by astray on Sept 30, 2015 20:50:57 GMT -5
Won't that get gas all over my finger? =(
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Post by katastroff on Sept 30, 2015 20:52:10 GMT -5
Not really.
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Post by Fox on Sept 30, 2015 20:55:07 GMT -5
Since a valve check/adjust is free, why not start there? A valve that is slowly getting tighter and tighter shows up as an engine that starts stalling/hard starting and then gets worse and worse as that valve gets tighter and tighter just as you describe. A tight valve = low compression.
I would also verify spark because it's also free and to eliminate that as a suspect. Inspect the plug for cracks or any other anomalies while you are at it. How old is that plug?
Another way to check for low compression is to work the kick starter really SLOW with your hand. If it moves past the compression stroke easily with little or no effort at all then it's low. If it fights you hard then it's got some decent compression.
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Post by astray on Sept 30, 2015 21:02:00 GMT -5
The spark plug is brand new, I replaced it along with the carb with an iridium his or whatever it is. Definitely gonna try the compression tests and adjust the valves. The scooter broke down my way from harbor freight to buy a feeler gauge to do it lol
Which part is the compression stroke of the kick start?
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Post by Fox on Sept 30, 2015 21:14:52 GMT -5
Just keep working the kicker slowly a few times with the spark plug installed and if it has good solid compression then you'll feel it. It will get pretty hard to push the lever and then it will get easy and repeat as you keep working the kicker. The compression is stroke #2 of the 4 strokes. one the intake valve opens and it sucks in fuel and air (intake stroke) two compresses that stuff (compression stroke) three the spark plug ignites that stuff driving the piston downward (power stroke) four the exhaust valve opens and the gasses are expelled (exhaust stroke) The valves kind of control everything. If one has no play in the rocker that opens it, then it won't close all the way and compression is partially lost.
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Post by ams417 on Sept 30, 2015 22:14:19 GMT -5
Go to you local auto parts store and rent a compression tester. Most auto parts store will "loan" you one for a deposit and you get the deposit back when you return it. It's the only way you will know for sure. Start there, work your way through the free stuff first. Check the valves as other have mentioned to make sure they have the proper clearance. Make sure you have the correct spark plug. Then move on the the fuel system. Are you running a stock airbox and filter?
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Post by astray on Sept 30, 2015 22:21:23 GMT -5
No, I've got one of those chrome filters and I removed all limiters between the carb and and air filter. I've got the valve cover relief line going into the connecting plastic tube between the filter and carb too.
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Deleted Member
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Post by Deleted on Sept 30, 2015 22:22:40 GMT -5
I am surprised you said it was running well when it is a stock 4T and you are running a 20mm carb (the stock carbs are 19) and an 88 jet. What size is the pilot jet?
I am running a 19mm carb with an 85 jet and I have modified exhaust and a cone filter. I am still running a bit on the rich side, but not bad. Did you tune the new carb when you installed it? It just turned a lot colder here and maybe the tuning was close when you put it on but if your weather is now colder, you may need to re-tune it a bit?
I agree with the others about checking the valves first and also compression but, I think you are way too rich for a stock 49 cc from your description of your set up. Maybe you fouled out your plug?
Bill
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Post by astray on Sept 30, 2015 22:30:04 GMT -5
There are pictures in the thread of the spark plug, I have a modified exhaust and air filter and there's a decent chance this scooter is a secret 64 given the date if its manufacturing (2011) and engine code 1P39QMB on a taotao magic 50 which were some what well known for it. With an 88 jet it is definitely running rich but not too bad looking at the spark plug.
Not a clue on the idle jet though, I just used what was I the carb.
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