Piaggio Fly 50 won't start! Was performing badly « Thread Started on Jan 27, 2011, 11:27am »
I have a vexing problem with my Piaggio Fly 50. I bought it the day after Christmas and it has just about never run well. Here's what it does:
Upon starting up, it needs to warm up for at least 15 minutes to even run passably on the road. When first riding, it will often run more slowly than even a bicycle - opening the throttle makes just about no difference. Once it's thoroughly warmed up, it can accelerate up to 15 mph just fine, then it plateaus and starts "chugging" cyclicly. In other words, it will accelerate, then back off, then accelerate, start putting, over and over. Even while cruising it will do this. In this fashion it will SLOWLY accelerate to about 25 mph with difficulty if always operating under WOT.
Lately, this problem has been getting worse, and along with it, it has become more difficult to start it. I have to try to turn it over about 4-12 times before it will stay running. Lately it won't even start at all.
There was one sunny Sunday when it was around 35F when I started it up and it ran beautifully. I was easily able to cruise down roads at 30-35 mph, climb up hills (although it slowed down the way a 50cc scooter would expect to), and it ran consistently and smoothly. On my way home after the engine had cooled off about 3 hours later, it went back to running the crappy way it usually has. It was a fluke, but I KNOW it can run well if whatever is preventing it from doing so is fixed.
The battery is fine, trust me. I have cleaned the carburetor THREE TIMES - once by the dealer and twice by me. I am convinced that the main jet and idle jet are clear, as brake cleaner will spray through each of them consistently. I am not POSITIVE that the carburetor is absolutely clean, but I am pretty sure at this point. In any event, the carburetor would not be the source of difficulty starting, would it?
I have also replaced the spark plug, which looked normal when I replaced it. The air filter was supposedly replaced at about 5,000 miles - in now has 5,800 - but I haven't looked at that. Again, would a clogged air filter be the source of starting difficulties?
I have been told these scooters frequently have an ignition coil unit that frequently fails. I have bought a new one but haven't installed it. I did take out the old unit and have a voltmeter and have tested both the old and new units. The only meaningful resistances I was able to get from each of them were about "350 ohms" between the first and second wires. But the resistances on both units registered the same. I have not yet installed the new unit on my scooter, but if I do, I can't return it if it's not the problem. The damn thing cost $72. But my other choice at this point is renting a U-Haul AGAIN and delivering it to a scooter garage. The garage says the problem I am describing is probably not electrical because, if the igntion coil is failing, it's an either/or proposition they say: either the bike runs or it does not. I am not sure I believe that.
I would also like to add that the idle is now too low when standing and it will frequently stall if I do not open the throttle when idling. I did NOT mess with the idle adjustment on the carburetor.
What the hell is the problem with my bike? I would especially like to know from any other Fly owners out there, if anyone reading this is one. Thank you for reading this detailed post.
Re: Piaggio Fly 50 won't start! Was performing ba « Reply #1 on Jan 27, 2011, 11:48am »
A failing ignition coil will certainly produce the symptoms you describe, but as it has run fine before it's best to check for an intermittent short before installing the new coil.
Re: Piaggio Fly 50 won't start! Was performing ba « Reply #2 on Jan 27, 2011, 1:30pm »
I haven't looked at the spark yet. I'll do that when I get home. Just look for a consistent, rhythmic spark right? I'm starting to read some stuff online about this and it's possible I could have a "vacuum leak"? I'm not really sure quite what that means though, so when i see instructions about spraying carb cleaner or WD-40 to find a vacuum leak, I'm not sure what they mean - spray it at the throttle valve? Or where?
I haven't looked at the spark yet. I'll do that when I get home. Just look for a consistent, rhythmic spark right? I'm starting to read some stuff online about this and it's possible I could have a "vacuum leak"? I'm not really sure quite what that means though, so when i see instructions about spraying carb cleaner or WD-40 to find a vacuum leak, I'm not sure what they mean - spray it at the throttle valve? Or where?
It's a two stroke, right?
The crank case and intake system is sealed, any leaks will cause strange running issued. You spray WD-40 around the carb and intake, on the outside whilst the scoot is idling. If you have a leak, the idle will change noticeably.
Re: Piaggio Fly 50 won't start! Was performing ba « Reply #4 on Jan 27, 2011, 2:02pm »
No it's a four-stroke. "Piaggio Fly 50 4T" in full. When properly running, it actually runs pretty good for a small four-stroke engine. So just spray the fluids in the vicinity of the body of the carburetor itself, in various places around it, with nothing detached? That will detect a vacuum leak?
Re: Piaggio Fly 50 won't start! Was performing ba « Reply #5 on Jan 27, 2011, 2:18pm »
In that case, it think it's unlikely to be a vaccum leak. Worth a try, though.
Basically, you spray the outside of anything carrying air into the engine, from the carb onwards. If there's a leak you'll know about it, the idle of your engine should change noticeably.
Joined: Jun 2008 Gender: Male Posts: 783 Location: Maryland Eastern Shore
Re: Piaggio Fly 50 won't start! Was performing ba « Reply #6 on Jan 27, 2011, 3:40pm »
You have over 5000 miles on this engine...I almost hate to suggest it but valves may need to be adjusted though your problem could be electrical or gas related as well. I know that's not much help but if you do a valve adjustment at least you can eliminate that as a possible source of your problems and move on to troubleshoot fuel and electrical.
ANYONE SEE SCARFACE TELL HIM LEFTY IS BACK IN TOWN
Joined: Dec 2010 Gender: Male Posts: 5,411
Re: Piaggio Fly 50 won't start! Was performing ba « Reply #7 on Jan 27, 2011, 11:23pm »
I agree with Jimh, you have a lot of miles on that engine and I would first adjust the valves. Tight valves will cause hard starting and no power, and it gets worse the hotter the engine gets. Then you can move on to fuel delivery and or leaks if part of the problem still is there. But at least you will know that the valves are opeing as they should and not cause restrictions and or loss of compression. Lefty
Re: Piaggio Fly 50 won't start! Was performing ba « Reply #8 on Jan 28, 2011, 12:42am »
The previous owner said the valves were adjusted at the first check-up with the dealer. The Piaggio "service menu" doesn't recommend checking the valve clearance again until 48,000 miles? Anyway I don't know anything about valves so that would be new for me. There WAS a vacuum leak, because there was a third rubber hose that connects into the carburetor, on the bottom, that I was not aware of before. I reconnected that and now it starts up fine. I also replaced the ignition coil and it made no difference. It still bogs down, and it's worse when it's not thoroughly warmed up. It did ride well enough to drop it off at an independent Scooter dealer (NOT the local Vespa dealer - they suck). Hopefully they can figure it out.
And since when is 5,000 miles "a lot of miles" on a scooter engine? I should hope they would last to 50,000 miles and beyond.
Re: Piaggio Fly 50 won't start! Was performing ba « Reply #9 on Jan 28, 2011, 1:27am »
Scooter engines live a hard life. Pretty much always running full throttle is hard on any engine. Very few scooters can make it to 50,000 without a couple overhauls because most owners keep modding them to the point where they die early. Before then other things can go wrong. People are lucky to get 50,000 miles out of a Honda Rebel engine and those are among the most durable of small engine designs. I can almost guarantee you that you personally will not own your scooter to 50,000 miles. You'll either tire and get rid of it, crash it, or power-mod it til it breaks.
Even worse is the Piaggio's Hi-Per4 engine. This is a 4 valve higher compression engine. This means very tiny delicate valves and the higher compression wears your cylinder and rings faster. So compared to a stock gy6 that has no manufacturing problems I would bet that your Piaggio engine would fail earlier simply because it's a much more highly tuned engine. Think about it this way, the Piaggio is like a Ferrari or a better example, a Porshe and the GY6 is a tried and true Honda (Honda design anyways). The Honda will generally outlast the Porshe because it isn't tuned for maximum output.
And yes 5,000 miles is a lot of miles to go in between valve adjustments. Oh and dealers are notorious for not actually adjusting valves on the first checkup. You're lucky if they even crack open the valve cover to check the valve clearance. So I'm betting a lot of problems can be solved with a valve adjustment. People come here every week and say they did this, that, and the other thing. Replacing parts left and right, all to avoid adjusting the valves. I don't know how difficult it is for the Piaggio Hi-Per4 engine but it's pretty easy to adjust the valves on most scooters. And it tends to be that the valve adjustment is all they needed, they end up kicking themselves for all the parts and labor invested for the sake of avoiding a valve adjustment. So to sum up, adjust your valves.
The previous owner said the valves were adjusted at the first check-up with the dealer. The Piaggio "service menu" doesn't recommend checking the valve clearance again until 48,000 miles? Anyway I don't know anything about valves so that would be new for me. There WAS a vacuum leak, because there was a third rubber hose that connects into the carburetor, on the bottom, that I was not aware of before. I reconnected that and now it starts up fine. I also replaced the ignition coil and it made no difference. It still bogs down, and it's worse when it's not thoroughly warmed up. It did ride well enough to drop it off at an independent Scooter dealer (NOT the local Vespa dealer - they suck). Hopefully they can figure it out.
And since when is 5,000 miles "a lot of miles" on a scooter engine? I should hope they would last to 50,000 miles and beyond.
There are a lot of Chinese scooters on this forum, for one of them 5000mi is a lot. My Piaggio has done 3000mi, so I consider it barely broken in.
Joined: Jun 2010 Gender: Male Posts: 826 Location: Lower Cape Cod
Re: Piaggio Fly 50 won't start! Was performing ba « Reply #11 on Jan 28, 2011, 2:13pm »
Like it or not 5K on a scooter is a lot of work for a 50cc engine, I have to say though that your troubles seem like the same as I'm running into with my 80cc. My issue is a bit worse though and while I agree with the valve adjustment as a possible solution, I've also been told it might be a float needle issue with the carb. The question is: After you try to start the bike, have you checked the plug to see if it's wet/flooded? You did mention an air filter cleaning or lack thereof. A plugged filter can cause the carb to flood out and running rich can cause the symptoms you're describing. Hope that might help.
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