Getting a Dead Scooter Back on the Road
This article describes how to get a dead scooter back on the road. Barn finds, garbage pickups, free, cheap, and dead scooter. All those non-runners.
There's really nothing in the service manual on how to do this. The official service manuals, available on the forum, will tell you how to do each of these steps in detail. But, first you need to know what steps to follow, and it's frankly not something that the engineers and technical writers that actually write these manuals think much about. There are a few things you can do wrong during the process that can turn a 1 hour, no-cost project into a week-long ordeal where you actually have to spend money, e.g. breaking the kick start, ruining the bearings with old oil, burning up the starter, overheating the motor b/c of missing shrouds all come to mind.
I'll break this up into steps, but I'm not going to spend a lot of time on what, exactly, you need to do. That can be found elsewhere here, and in the factory service manuals. The article's based on my personal experience getting many of these bikes, once dead, back on the road, and typically for no cost.
Make sure that it might actually run
This seems like an obvious step, but depending where you are in life, you may or may not want to spend a lot of time getting the scooter going. First step is to check how far gone the motor is. Usually (90% of the time), they are fine, and if they're not it's obvious.
Remove the fan cover and spin the motor over. It should turn and you should feel compression. If it whirls over easily with no compression bump, put some oil in the spark plug hole; if it now has compression you will need new rings soon but may be able to get it to start... just don't run it long like that, you'll cause much more damage if there's a complete failure.
If it turns but feels gritty, you have bad bearings. This is a fairly serious issue that requires special tools. You may be better off running down another, less challenged engine.
If it's locked, it's either stuck rings or very bad bearings. WD-40 or other break-loose oil down the spark plug hole and try to break it loose over a few days. Once you get it loose it will be obvious which it is.
Wash the bike
I always do this first. Dirty bikes are annoying to work on and fixing this first takes little time.
Drain, clean, refill the gasoline and oil tanks
You've no idea what gas and/or oil was in this thing, so drain all gas and oil. Refill gas with 1/4 tank (pint to a quart) 32:1 premix. Fill oil with Honda GN2 oil or other 2-stroke injection oil! Do not fill with premix oil... this destroys pumps and engines over the long haul. Bleed and fill the oil pump with known good oil, and ensure that it's working before you replace the premix gas with unmixed gas.
The oil tank, by the way, has a filter. It collects a grease-like substance over time. Now is the time to clean it, when it's empty.
Check the gas tank for rust, and take appropriate action.
Check the air filter
Air filters break down over a few years and turn to dust, which gets into the carb and jams up the reeds and jets so that it won't run. Before trying to start it, check to see if it's broken down and replace it. On many Honda scooter (Spree is an example) the bike will not start without the factory filter element in place, so don't even bother trying until it's in place.
Get a 12V power source
If you're optimistic, buy a 12V motorcycle battery. If not, borrow one from a friend / other motorcycle or use jumpers off your car battery. See if the starter works. Getting a dead bike going with only the kick start is a great way to destroy the kick start... you will inevitably get frustrated and break it.
When the bike is a going concern, the "kick start" is more of a "gently push the pedal" start... but you won't know that until you can get the bike running. Most noobs kick and kick and kick until they destroy the gears and/or the side cover. This is an expensive part to replace, and one of the reasons so many bikes are missing these parts.
Get gas into the carb
Suck or otherwise pull vacuum on the vacuum-operated petcock to fill the carb with gas. The petcock are sometimes jammed up; fix/replace/work around, but get gas to the carb... there is no point cranking the motor over with an empty carb; it won't fire until the carb fills, which will take 30 seconds or so of cranking... which is about how long it will take to burn up the windings on your starter, so if you insist on this method, at least do it in 3 second bursts (10 cranks at a time) so that your starter will survive the abuse.
If it starts leaking onto the ground, time to pull the carb and clean it; you have a gummed up float valve.
If you pull vacuum and get a mouthful of fuel, you likely have a blown petcock. You will need to replace it at some point, but for now you can just block it off at the tube and plug off the intake manifold (make sure to plug off the intake manifold if you do this!). Usually in this failure mode, gasoline is flowing freely from both tubes. For getting it running, this is OK. Fix it later. If you pull vacuum and get no fuel, you can try cleaning the petcock, or replace it. These parts often go wrong but are readily available and pretty cheap.
Try to start the bike
See if it will start. Crank it over... never more than ~3 seconds at a time, or 10 cranks over, or you will kill the starter. The starter's another expensive item to replace once you've killed it... typically by cranking over an engine with a dirty carb for 30 seconds and burning up the windings in the process.
If it won't start after a few tries, check spark, and then pull the carb and clean it. If it starts, runs 2 minutes, and dies, pull the carb and clean it, with special attention to the idle jet (which is clogged.) Excessive smoke is normal; the oil pumps leak and fill the bottom end with extra oil. If this is the case, plan on replacing the spark plug.
The bike won't start, now what?
- Clean the carb. 90% of running issues are due to the carb. If it fires with a few drops of gas put down the spark plug hole, you have a carb issue. Start reading up. These are simple carbs, but the passages are tiny... your prior experience with MC / auto carbs will be different in this respect. Those tiny jets need to flow, or it will not run.
- Check spark. Try replacing the plug if in any doubt... they are cheap and sometimes fouled even when they look fine on 2-stroke bikes. Make sure the plug cap is screwed down well (yes, it unscrews from the wire.)
- Do you have compression? If not, try oil in the plug hole and try again... you may need new rings. If there's not enough compression to blow your thumb off the spark plug hole it won't likely start
- Is the air filter in place? Is there an element in it?
- Pull the exhaust and try blowing through it... unusual, but sometimes they are completely plugged up. Clean as required.
- Other, rarer issue is a set of bad reeds... this is uncommon.
Once you've done the above, and it's still not going, it's time to head over to the forum and start asking questions. You either skipped a step or have something unusual going on.
Yay! It runs! Now what?
- First things first. Before test riding it, make sure that the brakes and kill switch work. That tires have air and are in serviceable condition. That the throttle is free and does not stick. That it will run and idle more than 2 minutes (unless you like pushing your bike home.) Nothing is going to kill your new-scooter buzz like crashing into a parked car at 30 MPH b/c your throttle sticks wide-open, your kill switch is inop and your brakes don't work to stop your crumbly, dry-rotted tires from spinning.
- Make sure all fan shrouds are in place... Spree, especially, seem to always be missing the top shroud. If you don't have them you will overheat and eventually kill your bike. People that say you don't need one are out there, and they are typically soft-seizing their bikes over and over again and not realizing it until it blows up 100 miles later, to their total surprize. Get or make one from sheet metal.
- Verify oil pump operation. Once you know it's going, fill the rest of the tank with gasoline... since you didn't fill it all the way up, the remaining oil will be pretty diluted. If the pump does not work, give it more time and check again (proper oil flow at idle is about 1 drop every 5 seconds or so.) Either fix the pump, or plan to run premix only and modify/block off the pump accordingly. Used oil pumps are typically pretty cheap items... they rarely go wrong, but when they do they will kill the engine.
- Check rear gears for oil. Pull the plug and tip bike; some should come out. If not, address issue or you will burn up the gears and in the process, trash the block. Fortunately, most bike have gear oil and this isn't an issue. If not, any 10-30W (or close) will work to top it off.
- Check if the headlight is working... a blown headlamp is usually a symptom of a bad regulator; replace the regulator before you replace the bulb or you'll just kill the new one.
You may find other issues now... that it's slow, won't launch, does weird things on the road... read up and address these as needed. Most will either be more carb issues, or driveline (belt, clutch, etc.) Read up and address issues; if you can't figure it out time to go to the forum.
Longer term things to check and fix
- If everything seems fine, one more test. Pull the belt cover, loosen the belt by grabbing in the center, and push on the crank fore-aft and up-down at the starter ring. There should be zero detectable play. If there is play and/or you hear a "click click," chances are there will also be bearing noise coming up from the engine; it sounds like a skateboard rolling down the road which gets louder/faster as RPMs climb. Unless you know what you're listening for you may not notice it. It means you'll need to replace the bottom end bearings soon before they completely fail. This is a serious issue; consult with the forum and either fix the bottom end or plan to find a replacement engine when it blows.
- Decarbonize the engine and exhaust
- Address low compression as needed
- Buy a real battery if you haven't yet, and make sure the charging system is working while you're at it.
- Everything else (paint, tires, bulbs, etc.)