Got this scoot for $400 and the previous owner said it was having motor problems. Hoping its not the compression, but I tried using my hand on the kickstarter and it didn't go down super easy. Just a quick test, still need to get a compression checker. Will it start up without the valve cover on? Good - -1000miles on engine. -Has Spark -Good CDI - Checked from another gy6 -Turns over I have confirmed all these things so far. There is oil on the valves as seen in the photo below, is this how it should look? Never opened that part up before. I poured gas in the spark hole, reassembled and still won't fire up. I then tried starter fluid in the carb and that didn't work. Tried a gas tank with a gravity feed and fuel flowed to carb but wouldn't fire still.
Since you said it has spark, try starting the scooter with the gas cap off. The venting on these scooter's gas tank suck. But after looking at your cylinder head, I can't help but notice that the camshaft sprocket is rusted and I see a bit of rust under the rocker arms. Is that rust or is it something else? Another thing is that oil on the rocker arm looks burnt.
Adding to what he said it appears from the photo that there is grass, dust bunnies or cob webs all over the valve assembly. Why is this? Did you acquire this with the valve cover removed already? I'm a little concerned that the metal surfaces all seem to be extensively corroded- is that normal in Hawaii due to the salt air? If so, you can expect that a lot of the electrical connections are corroded as well, so don't discount the possibility that you may have a problem in that area as well. I sure hope it hasn't rained on that engine with the valve cover off- no telling what the inside of that engine could look like.... The only way to go about finding the cause of something that a prior owner has been messing with is to start with the basics and work from there. First verify that it has compression and not a burnt valve or something worse. Change the oil (to ensure no parts fall out or that there is water in the oil). Empty the fuel and put fresh in, clean carburator and if it still won't start, then you'll have to start digging deeper....Also, be sure the battery is plenty good (in case it's giving you a weak spark).
Yep, it's a mess in there. Looks like the cover was left off for some time, with nothing to cover it. That stuff will grind up the engine, if it hasn't already. I wouldn't try to run it until after removing the head and cleaning it up real good. Don't know what this involves on a GY6. The cam chain will have to come off the sprocket. Assuming it has a tensioner, loosening or removing that should allow enough slack to get the chain off the sprocket.
Theres a chain tensioner you could loosen to get the chain off the sprocket but you need to split the case to get the chain totally off.
We did a kind of ghetto compression test and it read 30psi. Could of been a bad seal but we can easily hold our fingers over the hole. My new question. Even with gas going into the carb, the spark plug is perfectly clean. No gas or oil on it. Looks like nothing is getting there even when we flood the carb with gas. Could a valve be stuck? I'm getting ready to dive into the engine head. Just trying to cover all bases first. And yes. I think the valve had was left off for a few months and just sat in there garage.
If your test results were anywhere near accurate, the engine is toast. You will need at least 130 psi for it to run, and 150-170 psi for it to run good. I'd look for another engine.
So I have attached some photos of my progress and teardown today of the motor. Please give me any feedback that you can on the condition of all the things shown in the images. I am not a piston guru so I don't know if this looks normal or not. All pieces looked good, nothing had holes in it and all the gaskets have a great seal. Like I said, the engine is just at 1000miles so everything looks pretty good. Hopefully the pictures help shed some light on what I should do next. Also if anyone could tell me what Kind of piston and cylinder kit i should buy for this that would be awesome, I see on the cylinder head its marked. Mahalo for your help!
Thanks for the info. Good to know where I stand this far. How do I go about checking the crank journals and bearings? I didn't seee anything fall out during the oil change. The previous owner did say that when it died the oil was extremely low. He ran it a few hundred more feet till it bit the dust till I got it a year later.
So I just ordered a new piston and cylinder. Only cost $50 so hopefully that will be a cure all. Haha. I'll check out the crank rod when I take it apart and see how tight it is. First time getting this deep into an engine so I don't mind spending the time I get it running.
That piston is one of the worst I've ever seen that was still in one piece. Definitely run without oil. If it were a 2 stroke, there would be a remote chance that the lower end might still be usable, but not likely with a 4 stroke. The crank main bearings and con rod big end bearings are probably completely shot. Can you turn the crank over with the piston, and if so, is it easy or hard? Regardless, I would not put any money into that engine. A 4 stroke engine that has been run without oil to that point is rarely worth trying to rebuild, and this one is Chinese one top of that. I would look for a crashed Chinese GY6 scooter that still has a running engine. I believe there are 2 types, a long case and a short case.
I wouldn't sink another dime into it. Cancel the order for the piston and head and find a running gy6 to put in it. I'm sure the lower end is fragged or it will soon be.
A new GY6 motor on ebay costs under $400 shipped. I would definitely buy a new motor since this would save a lot of time. The only caveat is that you might have to pull the stator off your old motor and stick it on the new motor because the electrical system might be different between the 2 motors and this would require the purchase of a flywheel puller.
Well I know there were some nay sayers. But I got her purring like a kitten. New piston and cylinder did the trick! Only problem now is that I'm leaking some oil after every ride. I think its coming out of the starter which just needs a new o ring if so. Really love the power this scoot has and the ruckus body. Question - I put synthetic in on my first change, but then took it out cause online said to break in the new piston with normal oil. Could this be where the leak started from because of its consistency? Thanks!
Got the leak fixed. Turns out I didn't tighten the valve head and the cam chain tensioner down enough. Its running great now. Thanks for all the help guys.
