This is an answer to one of the most frequently asked questions from new and potential owners of xs360/400/650/1100
Repair Manual
It is a great place to start and the best money you could spend. You will be able sell it through a Classified Section listing or on E-Bay if you decide not to keep the bike. The Clymer manual is still in print. Haynes, Clymer, and Yamaha manuals can all be found on eBay on a regular basis. Ask the previous owner if he has one, he will probably let you have it for free.
Price: $20 - $40.
Battery
New batteries usually only last 3-5 years in service with proper care. Any battery left sitting for a year or more will be junk if not charged on a regular basis.
Did they leave the old one in? If so, look for corrosion damage to wiring and connectors. If cables are badly corroded get new ones. Short cables, in black or red, are available at most small engine / lawnmower repair shops for relatively low price.
Price: About $35-$100 depending on battery.
Tires
These will need to be replaced for sure. According to Dunlop, if they are 6 years old or more they should be replaced. Check for dry rot and cracks. Your tires are the only thing between you and the road, even if they look good and you know they are more than 6 years old, replace them. A tire will harden over time and lose grip even if it looks good! DO NOT buy replacements until you get the bike to run and idle OK. They are too expensive to buy if you can't get the bike run right.
Price: $200 at least (for 2 quality tires), more if a shop does it.
Engine
Of course change all fluids.
Also check to make sure engine is not seized up. Usually at least one cylinder will be left open to the air (valve open). I bought one stored for only 6 years and the engine was rusted solid. Buy new spark plugs. Take out the old ones and check for rust at the ends. If one or more is seriously rusted, you may be in trouble. Dump some penetrating oil in the cylinders and let it soak before you try to spin the crank (BY HAND). When you have the new battery and oil in, pull the plugs and spin the motor with the starter to distribute fresh oil around the engine. (I usually take the valve cover off and dump oil on the cams, but the whole idea is to get some oil to the top of the engine) for a minute or two. (If you don't mind overheating the starter and recharging your battery, do it until the oil light goes off).
Price: About $25 for new oil, filter and plugs
Air filter
You will need a new air filter. Check the old one for mice before you even think about turning this engine over! The XS can be replaced with stock, K&N, Uni, or pods.
Price: $30
Exhaust
Also a place mice like to hang out. Check for rusted out portions on bottom and back because they rust from the inside out when left sitting.
Also check for cracks, or patches that are hiding cracks. Cracks are very hard to fix and usually mean the exhaust will have to be replaced.
Price: $200 - 400
Tank
If gas was left in it, there will be a nasty mess. But easier to clean than if they left no gas in it and it rusted up badly. A rusty tank can be fixed as long as it is not rusted through. Also clean the petcocks out. Same for fuel lines-also check fuel lines for cracks and replace if needed.
Price: $?
Carbs
If the gas was drained you are all set. If not, you are in for another mess. They will need to be disassembled and cleaned thoroughly before even thinking about running this bike. 10 year old gas in the carbs will not be pretty.
Price: $?
Fuse box
This is a known trouble spot and years of sitting just make it worse. Check clips for tightness and corrosion, replace if needed with an after market one.
Price:$10 -$40
Brakes
Fluid will be turned to sludge after 10 years, it should be changed every two years, so this will need to be done before you drive the bike. Plan on rebuilding them if you have problems or are keeping the bike after you get it running. Check hoses for cracks!
Price: $5 for fluid, (rebuilt kits are about $30 for mc's and calipers X5) or up to $300 or more for a complete rebuild with caliper and MC rebuild kits, new pads, and stainless lines.
Other Stuff
Check your vacuum and fuel lines for cracking or brittleness,replace if needed.
The throttle and clutch cables will need to be lubed or replaced.
This is just a start...you will find more stuff that needs attention. We have been through it all. Join this forum, ask for advice!
I am not trying to scare you with this list. It is just some real world advice from somebody who has resurrected more than one of these great bikes after a long slumber. Most bikes will not have all these problems but some have all these and more! Good Luck with yours