What do I need to do to get my motorcycle running again after I've left it in my garage for over a year?
I'll take a slightly different stance here - having a vehicle stand for a year or a little longer than that isn't that long, so I'd try to get it running first before I start changing out parts.
Here's what I'd do:
- Drain the carbs if it's not FI. Chances are that the fuel has evaporated and left some residue. If you didn't drain the carbs it might be worth pulling the float bowls and run some carb cleaner through them and the jets. Also make sure the floats and float needles move freely so the engine doesn't get drowned in fuel.
- At least top up the tank with some fresh fuel, better to drain it, pour the old fuel into the wife's car (don't forget to top it up with some fresh juice) and pour some fresh fuel in
- Charge the battery fully. If it doesn't hold charge or not well, get a new battery and remember to buy a trickle charger :)
- Check if there's enough oil in the engine, top off if necessary. Don't change it yet.
- Turn over the engine, if you can spin it on the starter without the ignition being on, do that to get some oil to the bearings
- Hook up the ignition and crank the engine in short bursts (giving the the starter time to cool down in between) until it fires or the battery is dead :). If it doesn't fire then I'd check/service ignition, carbs etc.
Once you've got the engine running OK I'd let it warm up and change the oil if it was not reasonably fresh when you put the bike away.
And yes, checking rubber parts for dry rot and stuff like that is good practise when reawakening any vehicle but I'd save that until I knew it was running OK.
To expand on xpda's answer, and genericise it for any engine that has been standing for some time:
Drain and replace the fuel - modern unleaded goes off after a couple of months so won't be any good if it has been standing for longer than that. Replace/clean the fuel filter.
Drain and refill the oil. If it has been standing for a long time it would be worth doing this again after a few miles. Replace the oil filter.
Check the coolant. If it had been left with little or no antifreeze, drain, flush and replace as there will be corrosion in the system - if it had plenty of antifreeze in that should have prevented this.
Remove the battery and charge it fully. If it has been sitting for a long time the battery will have degraded so you may well find that it won't hold much of a charge and may need to be replaced.
Check all the perishable components - hoses, tyres etc.
Check the brakes - Disks will have at least a coating of surface rust, but make sure the hydraulics work properly and tyhat none of the cylinders have siezed and that the seals are in good condition (check carefully for fluid leaks around all the flexi hoses and cylinder seals - if in doubt, replace)
As Mauro suggests, remove the plugs and turn the engine over manually. If it has been standing a long time, dribble a little oil down the bores a few days beforehand to lubricate the piston rings. If it is reluctant to turn, don't force it, as there is a risk the rings have corroded into the bores and could break - if that happens it's rebuild time!
Replace the plugs, disconnect the king lead and turn the engine on the starter to allow oil pressure to build up and fuel to be drawn through the system.
Refit the king lead and try to start it...
If there were contaminants in the gas, it could gum up the carb, so it might be worthwhile to drain the gas and refill with new gas. At a minimum, drain a little gas from the lowest point you can find in the fuel system.
Check the battery and make sure it is charged.
Check the fluids, brakes, lights, tire pressure, and oil level.