I wonder if anyone can help me out with this problem. I’ve been lent a 50cc Yamaha scooter which is quite old (say 10 years) by my school. It works OK generally. Aside from a broken fuel gauge (which runs to zero when the tank is still full and has trouble starting (I was warned about these), usually requiring a few goes over what feels like several minutes to get the thing going. This would be OK, I guess but it also stalls when I’m going along on it. By stalling I mean the engine stops and I have to pull over pretty sharpish. I don’t know if the problems are related.
I’m not any kind of motor mechanic, but I’m guessing maybe the carberetta’s aren’t getting enough fresh air at times, or that it’s running to rich (with too much oil in the mix, mb). Maybe I ride it too hard.
I’ve no money to take it for a service just at this time. Was hoping I might be able to solve the prob myself.
Anyone know how I can work out what the problem really is? Any similar experiences or advice?
[quote=“trubadour”]I wonder if anyone can help me out with this problem. I’ve been lent a 50cc Yamaha scooter which is quite old (say 10 years) by my school. It works OK generally. Aside from a broken fuel gauge (which runs to zero when the tank is still full and has trouble starting (I was warned about these), usually requiring a few goes over what feels like several minutes to get the thing going. This would be OK, I guess but it also stalls when I’m going along on it. By stalling I mean the engine stops and I have to pull over pretty sharpish. I don’t know if the problems are related.
I’m not any kind of motor mechanic, but I’m guessing maybe the carberetta’s aren’t getting enough fresh air at times, or that it’s running to rich (with too much oil in the mix, mb). Maybe I ride it too hard.
I’ve no money to take it for a service just at this time. Was hoping I might be able to solve the prob myself.
Anyone know how I can work out what the problem really is? Any similar experiences or advice?[/quote]
I’ll bet the carb is totally dirty and your jets are clogged. It is easy to clean it yourself, or get a mechanic to do it. I’ll just bet that will fix your problem. Same thing happened to me with my 50cc
Yeah, it is pretty easy. The easiest way is to buy a can or two of carb cleaner. You’re going to have to take your seat off, the side panels around your seat, and your actual seat bucket (the bolts for the bucket are under the bucket inside liner). It is easy, just get a bowl to put all the screws and bolts in so you don’t lose them.
Once you do this you will easily be able to take off the carb. You will need to disconnect the air box, the accelerator cable (this is attached by two small screws on the carb itself, just unscrew them and it will come right out with a spring), also disconnect the gas line, and choke cable. It sounds a lot harder than it is. Once you have the carb out, just take it apart and clean it with tons of cleaner. Make sure all the jets are not clogged. If this is your first time, it might take you a while to do all this. It might be easier with a friend too. If you don’t want to get your hands dirty, any shop will do that for probably around $500nt. Maybe less, but I don’t know.
DO NOT poke anything hard, like steel wire, into the jets in the carburetor. any small holes there are carefully calibrated sizes. air pressure aqnd solvent are the way to go for hat.
a new plug, air filter, fuel filter will be a best first place to start, even before pulling anything else apart on the bike. then try cleaning the carb if that is not enough help.
also replace the drive belt on such an old bike if you don’t know when it was last replaced. cheap insurance.
Its not necessarily difficult to clean a carb but there are tiny parts that are very easy to loose.
I recommend using a digital camera and / or sketches to record how the (choke and accelerator pump) linkages go together because (on a Kymco motorcycle anyway, dunno about scooters) it may not be completely obvious on re-assembly.
Parts and castings are fragile and its important to use tools that fit the slots (screwdriver) and nuts (spanner) well.
I found carb cleaner inneffective on a well-clogged carb but got good results with heat and water based cleaning (see recent “carb cleaner” post). This is probably unconventional though so emulate at your own risk.
On re-assembly you’ll need to know how to tune it to run again, though you could push it to a scooter shop for this bit.
Apparently “black hands” don’t like cleaning carbs because its time consuming and they can’t charge enough for it, so if you are careful and take your time you may do a better job than they would.
Apparently “black hands” don’t like cleaning carbs because its time consuming and they can’t charge enough for it, so if you are careful and take your time you may do a better job than they would.[/quote]
This doesn’t mean they won’t do it. I was on a ride one time, and my NSR just wouldn’t stay running, it was because my small jet was clogged. I found a shop and he cleaned the carb for me no problem, but he charged me $500nt. Also a new carb for a 50cc is relatively cheap; I think they cost around $2,000nt. You can always just buy a brand new one if you don’t want to get your hands dirty, carbs can wear out over time.
Apparently “black hands” don’t like cleaning carbs because its time consuming and they can’t charge enough for it, so if you are careful and take your time you may do a better job than they would.[/quote]
This doesn’t mean they won’t do it. I was on a ride one time, and my NSR just wouldn’t stay running, it was because my small jet was clogged. I found a shop and he cleaned the carb for me no problem, but he charged me $500nt. Also a new carb for a 50cc is relatively cheap; I think they cost around $2,000nt. You can always just buy a brand new one if you don’t want to get your hands dirty, carbs can wear out over time.[/quote]
Sure, no argument with that.
My point, 4WIW, was that if they don’t want to do it, then maybe they won’t do it very well/thoroughly, but I guess they still have to do it well enough for it to work.
Time/money wise, as you imply, its hardly worth it. It took me ages, but I quite enjoyed it, but then (as a girl pointed out at the time) “Maybe you are quite a boring person, then”
Should have mentioned that if you use the “wet method” you should flush with a little alcohol or acetone (cheap at the chemist here). Get the screw-on needle type hypodermic (ditto), otherwise it’ll blow off under pressure and spray your eyes.
By the time you have read Tommy 525’s reply you could have already taken off your side panels. I wish I had a “competent” Taiwanese mechanic. I don’t think they know how to do too many things “right.” Anyway, doing it yourself is half the fun, then you can spend that hours teaching wage on something else. Maybe it is just me, but I love fixing things on my vehicles.
I had just about the most competent local bike mechanic that I know bleed the brakes on my scooter and take an age just cause he wanted to use as little brake fluid as possible. Really this takes about 15 minutes, but he still took an hour. Tip Tapping and trying to get the bubbles to reverse course and come back up the pipe instead of just blowing them all straight out the bottom with more fluid. Edit: I should mention that this was after I took the bike back after the service left air in the system and the brake wouldn’t work properly. I have witnessed Taiwan garages completely remove the old fluid from the system by draining it entirely and leaving it full of air before replacing the new fluid.
I despair sometimes. I can’t wait to get my own work shop set up and just do things myself.
My advice is have a go at your carb yourself. You will only do as good a job if not better than many blackhands as you will take more care with your own vehicle.
Oh, don’t forget a can of compressed air and a clean soft rag as well as screwdriver is a great way to start preparing. It’s all I ever needed to clean carbs in the past. I did use an airline though with a little more compression. I also had a tube of Threebond (A recommended must have.)
If working on similar looking components and screws, it is wise to colour code them as you take them apart by dabbing touch up brush paint onto small areas and locations.
Touch up paint is a must in Taiwan when having things serviced as well. You can dab paint onto seals, bolt heads, cam cases, plug heads and all sorts of places that should be disturbed during proper service. Paint spots that remain in place are a sign that the job hasn’t been done properly in many cases, and you then have evidence to take up with the garage.
By the time you have read Tommy 525’s reply you could have already taken off your side panels. I wish I had a “competent” Taiwanese mechanic. I don’t think they know how to do too many things “right.” Anyway, doing it yourself is half the fun, then you can spend that hours teaching wage on something else. Maybe it is just me, but I love fixing things on my vehicles.[/quote]
Case in point: My carb (see recent “carb cleaner” post), which was leaking, was held together with contact adhesive instead of gasket, and was initially (until soaked with cleaner for a couple of days) impossible to dismantle. This was almost certainly done by a motorcycle shop.
When I was applying liquid gasket (not the 3Bond stuff recommended above, but still proper, designed-for-the-job, 100 or so NT a big tube stuff. Sorry, dont know the brand offhand) some mechanics came over from the local building site to see the funny foreigner bugger up his bike, and give incomprehensible advice which included repitition of “Nan Pao”, which I think is a commonly available brand of contact adhesive (10NT for a small green,white and red tube. Chlorinated rubber base. I use it for fixing bicycle tyre flats)
So “glue it together” is probably part of the local mechanic culture. Much cheaper and more available, and it works…sort of…for a while. And then its probably someone else’s problem.
Threebond I recommend because it has certain advantages over other brands that I have used. Some sealants don’t dry efficiently and can leak immediately, especially when they come in contact with oil. Threebond mates surfaces together well as the consistency is more like silicon and less like glue, so it offers a slightly more elasticity which is great if the two faces move around a little during installation as the bonding tends to retain most of its alignment. Threebond is also not that difficult to separate once it needs to be dismantled again. Granted for some smaller mating surfaces that are more easily damaged it is best done with a razor blade and a small thin screwdriver, but I have never damaged any surface because Threebond was too strong, as it separates quite nicely. It really is a must, especially when sometimes you pop something open to realize you have just destroyed the original special gasket only to find you can’t readily get a replacement.
The next question I’ll be trying to find an answer to is where the hell can I get Threebond if not online?
Update: I took my bike a local mechanic after having it repeatedly cut out on the way to work (on the first day) I pointed to the carb, he (without taking it apart) said it was fine. He cleaned the spark-plug, bled some fluid and noted that I didn’t really have very much gas in the can. Mutally embarressed, refused to take payment, I filled it up, but have still had the same problems. It still regularly cuts out is very unreliable when starting up.
I guess I should take it to this to the garage and just come to an agreement for a price and watch the guy take it apart. I lack the tools and the space do do it myself - not to mention the experience. I certainly would like to be able to do this kind of thing myself, in the future though.
well, many things can cause this, including a faulty or even worse, an intermittently faulty CDI unit. (controls the timing of the spark). them little black boxes are a pain in the butt, and are unfixable and untraceable by the average back yard mechanic (read:90% of grease monkeys here).
or it could be something as simple as dirty or wet fuel.
