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Post by skuhskewterz on May 21, 2015 1:48:03 GMT -5
I have a 49cc 2009 pronto/ sun50 gy6, I just opened up the engine to make sure everything was okay, put the t-mark back, set the valves, I changed the valve pin from another 4 stroke scooter(an ice bear 50) and I cleaned the carb. I started it up after a few minutes (kicked it to start it, giving it a small amount of throttle) it ran but puttered and if I turned the idle down to what would be a normal idle it would die. I tried to ride it to test it but it bogged out after a few minutes, I could start it again but if I opened the throttle to fast or too much it would die, it also went really slow when this happened. After taking the seat off I noticed smoke coming out of the breather hose on the top of the cylinder head. Thinking it might be piston rings I took a look the piston and it's rings but they seemed fine. Is there a position they actually need to be in? Or do they just need to be closed? Parts that could be causing these problems?If anyone has any ideas definitely open to suggestions >.<
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Post by Silar on May 21, 2015 7:09:18 GMT -5
Many questions have do I! (Yoda)
Why did you do all that in the first place?
Is this a new scooter? New to you but old scooter? Scooter you've had for a while?
Are you sure you set the valves correctly at TDC? Better double check that. Almost sounds like an exhaust or intake valve isn't closing.
What is a valve pin? Why did you change it?
What's your valve's set at?
Is the carb good and working properly?
The piston rings should have their gaps not overlapping. When the rings are compressed in the cylinder bore, there should be a ever so slight gap and that gap should be set appropriately. There's a write up on this forum of what the space should be for each ring.
I've had a bad CDI cause not running/sputtering/smoke come out of intake, but from the sounds of it and without having any other information to go on, it's probably something you did. I wouldn't run it anymore until I was sure everything was correct.
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Post by skuhskewterz on May 21, 2015 17:54:12 GMT -5
Well it was used until I got it a year ago, it had a battery on it that died a month ago, the kicker was broken so I waited till had some money's, got the battery and couldn't get it started. Figured cleaning the carb would've gotten it running. The carb was fine though after i cleaned and I've made sure it has gas running through it, it seems like it's functioning right. And yes the valves are set correctly, the pin I was talking about is literally the pin that pushes the valve open, the old one was stripped. But I got a feeler gauge and checked online for the right measurements to set the valves, which was .05mm
And I understand that about the rings I guess the question I'm asking is if they have to be facing any certain direction for example do the gaps need to be facing the intake side of the engine or the exauhst side of the engine or does it matter?
And I did put a different used cdi on there so that is definitely something I'm going to try switching out again.
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Post by Fox on May 21, 2015 19:32:39 GMT -5
That valve "pin" is actually the "rocker arm adjuster screw" or the "valve adjustment screw"
Doesn't matter where the piston ring gaps are per-se but I always make sure that one is on the opposite side from the other.
The "smoke" coming out of the vent tube. Does it get worse or smoke less when the engine warms up?
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Post by skuhskewterz on May 22, 2015 17:39:46 GMT -5
Sadly it gets worse, I was hoping it was burning off some excess oil, but after a minute or two the smoke gets pretty thick. Whenever I start the bike, I have to kick it while running the electric starter. Also, as the smoke gets worse, the bike bogs down more, and after a few minutes will die completely. I can start it up again, but same process as before. Except only difference now is wheneve I kick it smoke poofs out of the breather hose. Again it will run for a few minutes, but even if I give it throttle continues to bog down and die. If I open the throttle too much and/or too fast it will die unless I instantly let off it and barely give it any throttle. Either way eventually after a few minutes it dies again.
Also thx for the piston ring suggestion I've been facing them the same way.
I wish I could describe the sound the bike makes in writing, the best way to describe it's to say that It revs up thens puts/bogs, then revs up and puts/bogs, id say it does this rev up then put sequence every couple seconds as it's running.
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Post by Fox on May 22, 2015 19:36:09 GMT -5
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Post by Silar on May 22, 2015 22:18:02 GMT -5
Sadly it gets worse, I was hoping it was burning off some excess oil, but after a minute or two the smoke gets pretty thick. Whenever I start the bike, I have to kick it while running the electric starter. Also, as the smoke gets worse, the bike bogs down more, and after a few minutes will die completely. I can start it up again, but same process as before. Except only difference now is wheneve I kick it smoke poofs out of the breather hose. Again it will run for a few minutes, but even if I give it throttle continues to bog down and die. If I open the throttle too much and/or too fast it will die unless I instantly let off it and barely give it any throttle. Either way eventually after a few minutes it dies again. Also thx for the piston ring suggestion I've been facing them the same way. I wish I could describe the sound the bike makes in writing, the best way to describe it's to say that It revs up thens puts/bogs, then revs up and puts/bogs, id say it does this rev up then put sequence every couple seconds as it's running. Like I said before, I would check everything before running it again. Is there any way you can post a video? Videos and pictures help greatly to understand what you are experiencing. Does it rev up and putts/bogs by itself, or when you twist the throttle? You are definitely getting oil in your combustion chamber somehow. Is there a chance you may have overfilled the crankcase with oil? Dumb question, but are you checking your oil level while on the center stand and not the kick stand? That will make a huge difference. The bike should be level when checking the oil. If you hold your hand over (not blocking it) the valve cover breather tube, is there a lot of pressure coming out? There should be a tiny bit of air coming out pulsing. Almost like an aquarium air pump if you've ever felt the air coming out of those.. |
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Post by skuhskewterz on May 25, 2015 21:19:50 GMT -5
Well, I checked the valves, but with water instead of WD-40(I wasnt sure if it made a difference) But, when i did put water on the combustion side, it did look like there was liquid coming out of the other side, and this was after i let it sit out overnight in case it needed to dry anything out of it i.e. the oil that got past the piston if the rings were shot. so i presume the valves are shot so yeah i ordered the new head and piston, the stock ones. i just wanna get it running, like you said im not to worried about modifying it. buty eah your right. if you think about it what your saying fox makes sense. because if oil was JUSt getting past the rings would'nt it only come out of the exhaust? instead of the breather on top of the valve cover?(also when I've been saying the smoke has been coming out of the breather, I've been meaning the one on top of the valve cover.)
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Post by skuhskewterz on May 25, 2015 21:20:46 GMT -5
so yeah just waiting for those parts to get here. thanks again for all the help guys! soon as i install the parts ill letcha guys know whatsup!
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Post by skuhskewterz on May 29, 2015 19:53:55 GMT -5
okay so ended up getting the new head and piston with the rings, now before i did this, when the old piston and head was on there, the kicker did this weird thing where about every third kick, it feels like it kicks back at me. I don't think its in the engine i think its in the kicker assembly itself. but yeah just seeing if anyone knows what it is >.<
but yeah the electric starter is kindo funky, the place where it sits(like the housing on the engine, is all stripped out, so the starter sits in there funny, and unless the battery is fully charged it cant catch. anyone know how bad of an idea it is to maybe jumpstart it? iunno supercharge it with the car so it like a x10 electric start lol? this should be cool to do yeah? or is the battery gona like, explode on me? heh...
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Post by katastroff on May 29, 2015 20:55:11 GMT -5
okay so ended up getting the new head and piston with the rings, now before i did this, when the old piston and head was on there, the kicker did this weird thing where about every third kick, it feels like it kicks back at me. I don't think its in the engine i think its in the kicker assembly itself. but yeah just seeing if anyone knows what it is >.< but yeah the electric starter is kindo funky, the place where it sits(like the housing on the engine, is all stripped out, so the starter sits in there funny, and unless the battery is fully charged it cant catch. anyone know how bad of an idea it is to maybe jumpstart it? iunno supercharge it with the car so it like a x10 electric start lol? this should be cool to do yeah? or is the battery gona like, explode on me? heh... You can jump start it with a Mack truck battery if you want, no problem. I used to have a lawn tractor battery in my scooter. |
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Post by Fox on May 29, 2015 21:00:45 GMT -5
I don't recommend a super jump. You can hook a car battery up and jump it but you don't start rthe car.
On the smoke: What happens is that the oil gets past the rings, gets burned in the combustion chamber and then the smoky combustion gasses get past the rings and into the crankcase which gets pressurized more than normal since the rings are bad, then the smoky gasses have to go somewhere so out the crankcase vent they come cause that's the vent's job. Even on a near-new engine you get some gasses/oil that get by the rings. That's why the vent is there, and that's why the oil turns black over time.
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Post by scooterpimp on May 29, 2015 22:09:57 GMT -5
Blow-By
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Post by Silar on Jun 5, 2015 14:15:24 GMT -5
okay so ended up getting the new head and piston with the rings, now before i did this, when the old piston and head was on there, the kicker did this weird thing where about every third kick, it feels like it kicks back at me. I don't think its in the engine i think its in the kicker assembly itself. but yeah just seeing if anyone knows what it is >.< but yeah the electric starter is kindo funky, the place where it sits(like the housing on the engine, is all stripped out, so the starter sits in there funny, and unless the battery is fully charged it cant catch. anyone know how bad of an idea it is to maybe jumpstart it? iunno supercharge it with the car so it like a x10 electric start lol? this should be cool to do yeah? or is the battery gona like, explode on me? heh... If I understand what you are saying about the starter gears and the case being stripped out, I'm guessing you are talking about the CVT cover and starter bushing that goes into it. You can buy both of those items pretty darn cheap. I ended up getting a new CVT cover for mine for around $20.. The new CVT cover does not come with the starter bushing, so you'll have to buy one of those also.. To verify though, can you snap a pic of what you are talking about? |
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