In scooterdom PDI is an important concept. Officially it means Post Delivery Inspection. This refers to the inspection a dealer does after he gets a scooter and prepares it for sale, or when an individual receives a crated scooter and assembles it. This is vitally important to make sure everything on the scooter is connected tightly including body panels, electrical connections, vacuum hoses, and fuel lines. This process can be more extensive with modifications to insure a better running and more reliable scooter. In this sense it could be referred to as Preventing Depressing Issues. So we will first touch on the basic set up from a crate and then move on to more involved procedures. First, you should watch a video from the good people at Fx Motorsports and Flyscooters starring the famous Jessica. Here you will see the basic parts of a scooter and how they work. You can also see the basic fuel system, please take note of this in case you want to do some modifications later on. HEEEEEEERRRRREEEEES JESSICA!
Rich or "The Big Guy" is a very nice man who runs a scooter dealership down in New Orleans. He's been very kind to scooterdom by providing free technical advice and tutorials. He also has a discussion forum that he would be glad for you to join in on. Links to his dealership and forum follow:
His famous PDI follows soon. Rich, who has put together a slew a scooters favors torquing the front axle tightly to about 80 lbs. to seat the bearings. As he states, the manuals often say around 40 lbs., so that is your call. Since we are not dealing with 250cc's the water dump will obviously not apply.
Great tutorial huh? I hope you took notes, there's a test at the end. A couple additions could be made here towards Preventing Depressing Issues. Many folks feel that fuel supply problems are an area of particular concern. If you have a gravity feed scoot follow the supply line from the tank, (obviously this should be done when you have the plastics off as the Big Guy instructed), and make sure there are no obvious dips or rises where air can get trapped; it's gravity feed so keep things moving downhill. Obviously, if you have an electric or vacuum fuel pump this is not a concern. "Air sucks" can be a problem also; they are tiny air leaks at hose connections. Some like the Corbin clamps, others wire clamps, and Rich has now changed exclusively to zip ties; all of these will prevent air from sneaking into the lines and causing problems if properly utilized, so it's your choice; I personally like the Corbins.
Also, adhesives can be applied that will help hold the hose on and seal the connection, two products here:
BE CAREFUL! Only use the adhesive behind the bulb of the connection, do NOT let it get into the line it may plug up the carb or fuel valve. If you're not comfortable using these preparations, just make sure the hose is securely clamped behind the bulb.
Those wire spring hose clamps do more than they look, though the Chinese ones aren't that great. The key to spring type hose clamps working right is they only work when you use the right size hose for the fitting you're using. I like the spring flat band hose clamp from Napa Auto Parts, other auto part stores should have them as well. It's not the hose clamp that makes the seal, it's the hose it's self. Most hose fittings are either barbed or have a bulge at the end of fitting; that's what does the sealing to the hose. All the clamp does is sit on the hose to the inside of the ridge (bulge or barb), which in turns keeps the hose from sliding off the fitting. So you have to use to correct size hose w/ the right size fitting. A bigger fitting size (bulb) is better than smaller in size vs. hose size, it's better to expand hose to fit than it is to compress hose size to fit. David Sr.
Thanks David. The nipple sizes on the tank, fuel filter, fuel valve, and carb are almost always different sizes; usually either 1/4" or 3/16". The line to use for vacuum lines is 3/16". You may have to work with getting all the lines to fit tightly and use differently sized lines. Hoses can be temporarily softened and expanded to facilitate installation by soaking them in hot water, carefully using a hair dryer, or as my brother-in-law from Ohio succinctly put it "use a light bulb!". The carb inlet is almost always 3/16"; an appropriately sized line should be attached here to insure a good seal. Lubricants can be SPARINGLY used to help work a hose over a bulb or barb. This has been much debated but the following seem to be safe and won't harm the system: WD-40, gasoline, motor oil, cooking oil, water, and kerosene. I would avoid battery acid, freon, and epoxy glue, (humor folks...just humor). Humble Bashan offers a short video on where the lines are that need to be replaced; (note: the emissions system referred to as an EGR is actually called a PAIR system):
While you're changing the fuel lines, it's a good idea to change to a smaller, more efficient filter to prevent air lock. A good choice is from Visu-filters which you can get at Bike Bandit at the following link. Use the drop down to find the size you want:
Other makers are obviously available on the web if you choose to shop around.
This next item is not as big a concern today as in the past but still bears mentioning. The Chinese sometimes coat the inside of the tank with an oily protectant, it's not good for the system. While you have the scooter apart it would be a good idea to attach a drain line to the fuel tank nipple, (just a 1/4" line with a loose plug in it would do), and pour in a big bottle of rubbing alcohol; it's cheap and a great solvent. Slosh it around by moving the bike back and forth and then drain it out the line into an appropriate container. I wouldn't save this for later use as an antiseptic if I were you. Also, shine a flashlight into the tank, (don't use a match please), and make sure there is no debris in it. If there is, you're going to have to remove the tank and flush it out upside down; I know, bummer, but you'd have to do it.
Dave at Absolutely Scooters (http://absolutelyscooterparts.net) has sold and serviced scooters in the Chicago area for many years. In a lengthy discussion with him he told me that Chinese scooters are often started with leaded gas over in China and then left to sit for extended lengths of time before being shipped over here. He often has to clean the carb on a new scooter to get the jets clear. This is not as daunting as you may think although you do have to unhook the carb and remove it from the bike. First remove the air hose from the back off the carb. Here's a couple pictures to show you where things hook onto the carb, they're easy to remove; you loosen the clamp holding it to the intake manifold and work it off. Then you follow, you guessed it, The Big Guys cleaning video, a link for which is provided.
You may choose to try the scooter without first cleaning the carb and it may work just fine. If it doesn't, you're going to be taking all that plastic off again, so it's your roll of the dice. Newer made and upper tier scooters are not as prone to this problem, and of course a dealer would have already checked for this. Carb cleaning video:
One more thing...I know, I know, it's for your own good, so be quiet! While you have the scoot stripped down, you may want to tackle setting the valves, they are often wrong if it is a crated scooter. The valve gap can seriously affect the performance of the bike and cause problems that will have you scratching your head later wondering what is causing the problem. It may seem intimidating to a new owner but it is not that bad. Dave at Absolutely Scooters gave me some good, succinct advice on setting the valves:
I set the valves to .003 intake and .004 exhaust (inches not mm). I also always use the set one valve while the other is open (depressed) method instead of trying to make sure it is at TDC and doing both.
Also, here is a decent video from our friends at Youtube.com on how to do this:
So a quick summary:
All of this may seem more extensive than a simple go through for setting up your scooter. However, while you have the bike apart you may want to go ahead and do most of these things. Some even opt to get rid of the vacuum fuel valve which eliminates a few vacuum lines and potentials for air leaks. This, and other modifications, will be covered in a later section.