NEW NOTE: The response to this instructable has been really good. I hope to do another one related to slightly more advanced/unusual issues related to saving old 2-wheelers. I've had a lot of good suggestions (Tires, exhaust,points, etc.) that I hope to include next go round. Thanks for your enthusiasm and your continued patience!!!
Step 1: Choosing Your Bike : Better Safe Than Sorry!
1. Is it all there? Many broken parts can be repaired easily and cheaply, but missing parts must (usually) be replaced. Pay special attention to gauges, side covers, carbs, sprockets, and brakes. Lots of these parts "walk away" while a bike is lying around unused.
2. Is the engine seized? A seized engine may or may not be a big deal. If you buy one with a seized engine, only pay scrap prices as the engine MAY (or may not) be ruined. I'll show in a later "Ible" how to deal with a seized engine.
3. Can you shift through the gears? Transmission work is no small undertaking (but not impossible) for the newbie!
4. Does it have compression? If you can kick it over (or crank it), check for compression.
5. Consider buying a semi-classic, as these machines are easiest to deal with when searching for replacement parts.
Step 2: Getting Started : the Basics
1. How's the battery? Put it on a charger, or replace if necessary.
2. Drain the old gas, and check the condition of the tank. If tank is not rusty/dirty, replace with fresh gasoline.
3. Replace (or flush) the fuel filter.
4. Clean the petcock/fuel valve. (I use carb cleaner.) Make sure that gas will flow from the tank, through the petcock, through the filter, to the carb.
5. Clean the carb(s).
6. Check the spark plug(s). Clean or replace if necessary.
7. Change the oil, oil filter, and other fluids. Very often a bike that's been in storage will have such deteriorated fluids, that it will damage your machine very quickly (if you run it that way).
8. Put it all back together.
Don't worry, I'll describe the "How-To" for all of these steps (and a couple more), in the next few pages.
Step 3: The Battery
Note: Some bikes will run without a battery, others will not. Some will run for a while (without a battery), but do serious damage to your charging/ignition.
Step 4: Fuel Delivery System
If you have a rust problem, drop a handfull of washers/BB's/pennies into the tank. Fill it 2/3 full of soapy water (I use dishwashing liquid). Put the lid on and shake vigorously. Drain the liquid. Repeat this process with fresh water (no soap) until the water that drains out, runs clear. You can expedite this process with a pressure washer or even a garden hose with good pressure.
2. Check fuel line to make sure it does not leak. If it leaks, replace with new line. When replacing, make sure hose clamps from petcock to filter, and filter to carb are in place and sufficiently tight.
3. Check the fuel filter. If gas doesn't flow through (or flows slowly), try rinsing it out. You may use carb cleaner (sprayed in the reverse direction of the fuel flow) to clean most filters. Be careful and wear eye protection! If the filter can not be flushed, replace with a new one.
4. Check the petcock/fuel valve. If fuel will not flow through it (with the valve turned "on", "res" or "pri"), remove it from the tank. Clean it, and any filter that might be attached, thoroughly with carb cleaner. Make sure fuel will run through it, and reinstall it on the tank. Note: Be careful not to damage any gaskets during this process. Replace any damaged gaskets/seals.
5. On to the Carb!
Step 5: The Carb(s)
1. Gently remove the carb from the bike. Take care not to damage the rubber intake boot.
2. Remove the bowl. Clean as needed.
3. Remove the float. Clean as needed.
4. Remove the needle/fuel valve. Carefully clean both the opening and the needle itself.
5. Clean any exposed jets (both inside the bowl,on the body of the carb, and in the throat of the carb). Carb spray and a tiny wire/needle will work wonders.
6. Carefully replace these items in reverse order, making sure that the float travels freely and opens and closes the needle/valve properly.
7. Remove the cap.
8. Remove the venturi/slide/piston. Clean all exposed parts (both the venturi and the exposed inner parts of the carb body).
9. Reassemble. (Reverse order of disassembly.)
10. Carefully reinstall carb, one again taking care not to damage the intake boot.
Note: Check out the instructable Star (stasterisk) did on cleaning carbs. She did a great job, and under good circumstances, carbs can be cleaned while still on the bike.
Step 6: The Plugs.
1. You may clean an old plug. A wire brush, carb cleaner, and compressed air do a good job. A lit match held just under the electrode will usually help a fouled plug. If you use a match or lighter on your plug, keep it away from fuel and carb cleaner!
2. If you can't save the old plug, replace it with a new one. Make sure it is the correct one for your machine!
3. Gap your plug to manufacturers specs.
4. Make sure the plug will fire. This is really a test of your entire ignition system. With the plugwire attached to the plug, (But the plug not installed in the head), turn your ignition system on, make sure kill-switch is set on run, and give the bike a kick/crank. If everything is right, you'll see the plug make a fat blue spark. If there's no spark, work backwards(from the plug) through the electrical system, until you find a short, a bad connection, or a non functioning component. Often on old bikes, the points need to be cleaned. I'd try it with a business card first, then spray-on electrical-contact cleaner, then emory (not sand)paper. When your electric problems are solved, it's all downhill from there.
5. While you have the plug out, it's a good time to check for compression. The best way is with a pressure gauge. The other way is to place your thumb or finger tightly over the empty plug hole. Have a friend slowly crank the engine. You'll feel the pressure, and it should forcefully escape around your finger. If you don't have pressure, prepare for a ring-job or valve-job or worse!
6. If you have spark at the plug, and good compression, you're almost there! Install the plug, connect the wire, and you're ready to start the bike.
Step 7: Start It Up!
1. Turn the key to "On".
2. Turn the kill-switch to "Run".
3. Put the bike in neutral. (On some bikes, you'll want to
pull in the clutch as well.)
4. Put the choke in the start/choke/on position.
5. If it's a kickstart bike, there needs to be
pressure/resistance at the top of the kick stroke. You may have
to slowly rotate the kicker till you find pressure, then
release to allow the kickstart arm to come all the way to the
5. Give it a kick, (or on an electric-start) hit the start button.