Help me heal my sick scooter.

August 1, 2007 8:11 PM

I have a two-stroke, 50cc scooter. The miles are starting to add up and its idle is sounding rougher and rougher whenever I use it. Can I get a "tune up" for a small scooter like I would a car? What does this involve? Something I can do myself is fine, though I'll probably just take it to a garage.

Don't know if this makes a difference, but it takes 2-stroke oil, but I don't mix it in with the gas; there's a separate oil tank and I suppose it's mixed with the gas automatically.

posted by zardoz to travel & transportation (11 comments total)

Before you do anything, change the spark plug... might make a world of difference..
posted by HuronBob at 8:20 PM on August 1, 2007

2-stroke engines are very dirty because they burn the oil with the gas like you say. The simplest thing to try first is a new spark plug. The old one will be all crusted over with oil.
posted by putril at 8:22 PM on August 1, 2007

darnit.
posted by putril at 8:23 PM on August 1, 2007

I had pretty much the same problem; I was riding a 20+ year old Honda. Can you tell us what kind of scooter you're riding? If there's a [manufacturer] motorcycle dealership they should be able to give it a "tune up". The Honda folks certainly did for me, and it did help, although HuronBob is pretty much right. I bet they changed the oil, checked the battery and changed the spark plugs and that was good enough.

Course, I did end up totaling that scooter, so all that might not've been worth it. ;) but you can't predict that. I am, however, the proud rider of a (almost) brand new Yamaha. It is much more snazzy.
posted by indiebass at 8:25 PM on August 1, 2007

Yes. Spark plug. Hi-test gas only, check the fuel filter, Make sure you are using a fully synthetic oil that is designed for injector type engines. The only thing that could go wrong with a well oiled 50cc two stroke is bent or stiff reed valves. They can be changed, but require some expertise.
posted by Gungho at 8:26 PM on August 1, 2007

Totally spark plug. I used to race two strokes (motocross). Get a V-plug if they make them for your motor. Changing the reeds can also make a difference, but I'll bet you'll be amazed at what a new plug will do.

You can also vary the amount of premix (oil) that mixes with the gas (as well as the type of oil). Adding less oil will give you a cleaner burning motor, albeit with less lubrication. Within reason, however, you shouldn't see any longevity issues. But, to be on the safe side, I wouldn't thin the oil out much without some verification from others with your scooter type.
posted by SciGuy at 8:53 PM on August 1, 2007

Nobody has mentioned changing/servicing your air filter, but a key to keeping a 2 stroke running efficiently is to keep intake pressure losses to an absolute minimum. If you have a paper element filter, buy a few of them, and change them at 80% of the recommended mileage interval, or sooner if when holding them up to the sunlight, you see any significant blockage of light through the paper of the element. If your air filter is a foam type, be sure you can clean it thoroughly in solvent (usually gas), dry it, and if necessary, re-oil the surface to trap dust as intended.

A plugged air filter makes the engine run rich, fouls even good spark plugs, reduces reed valve action, causes excess carbon in the exhaust (leading to fouling of the exhaust and muffler), and cuts the effectiveness of lubricating oil, by getting it dirty much faster, and in extreme cases, diluting it with excess fuel.

And if you typically don't get the vehicle out for speed driving regularly, it would probably benefit from that occasionally. Clearing the exhaust system of built up carbon by running the motor close to full out for at least a half-hour is a tried and true performance strategy.
posted by paulsc at 2:36 AM on August 2, 2007

Yah. New plug, new plug wire, new air filter, new fuel filter, and the scoot should start puttering like new. Also check the local motorcycle shop for carb cleaner feul additive suitable for a 2-stroke, if there is such a thing. After that, you can get fancy with checking the ignition and electrical system.
posted by Slap*Happy at 3:00 AM on August 2, 2007

Mostly what paulsc said.

Spark plugs last a LOT longer than most people think, and they can simply be cleaned by soaking them in ether/starting fluid. Having an air compressor makes blowing the crap out a lot easier. Just make sure it's dry before putting it back or you'll be in for a startling surprise. You can also re-gap the plug with a tool that costs about a dollar.

If your fuel line isn't clear, the oil injector is putting more oil than it should be, which will lead to a clogged exhaust.

You might want to have someone check out the oil injection. That could easily cause what you're seeing. Call your local motorcycle repair centers. If they can't help you and don't know where to send you, call any place that sells or services chainsaws. Lots of them are/used to be two cycle, and are mechanically similar.

V plugs are useless, unless you're spewing enough crap into the engine to foul a spark plug quickly, at which point something else is very wrong and you should look at that instead.
posted by onedarkride at 4:50 AM on August 2, 2007

Mechanic maintenace for scooters is easiers than on motorbikes, which themselves are easier than cars.

There are fewer components to get in the way, so it will be easier to get to the part you want to maintenance. Also, parts are smaller, easier to move around, and easier to screw in place.

2-stroke engine also have way fewer parts overall than 4-strokes.
posted by gmarceau at 6:18 AM on August 2, 2007

Nth the spark plug. If you want to do it yourself, you'll need a socket wrench with a socket that fits your spark plug and you'll need a gapping tool (cheap at an auto parts store) and you'll need to know what the right gap should be. That information should be in the owner's manual for the scooter, and any good book on auto maintenance will teach you how to set the gap on a plug.

Taking out a spark plug is easy. Undo the wire, pop on the socket, turn counter clockwise.

Putting in a plug is easy too, but with one caveat - when you put in the plug, you really, really, really want to make sure that the threads align. If they don't and you cross thread the plug, it's probably cheaper to buy a used replacement scooter than to fix it.

Put the plug in by hand and by hand turn it slowly COUNTER clockwise until you feel/hear the threads click, then turn it clockwise and it should go right in without cross-threading. Then tighten it down with the socket wrench. The phrase I've heard to describe how much is "just tight."

Scared? Try this with the a screw cap on a soda bottle to get an exaggerated feel for it.

If you have the time, doing it yourself is way cheaper if you already have the socket set.
posted by plinth at 6:56 AM on August 2, 2007