Restoring Vintage Japanese Motorcycles
What to Look for When Buying a Vintage Japanese Bike
Restoring vintage motorcycles can be both rewarding and very frustrating.
I am a motorcycle nut and have been riding for 36 years, in that time owning over 50 motorcycles. Many of my 'vintage' motorcycles were brand new when I first owned them.
Not all vintage Japanese bikes are worth the trouble. Many early Japanese bikes were absolute 'classics' when they were released, and an equal number were absolute dogs, or even worse, death traps. Some bikes had almost 'bullet proof' reliability, and some had inherent mechanical faults. Some bikes seem to stand up to the ravages of time and some definitely do not. Some bikes are relatively easy to get parts for and others are downright impossible.
A really good starting point when considering buying an old bike is to go online and read up about the model and year of the bike. Se if you can find old motorcycle magazine reviews from the days when the bike was released. Look up forums and bike clubs on line and post a few questions about the bike you are looking for. Google the bike and see if you can still purchase any parts for that model bike. Ring up motorcycle wreckers and see how available second hand parts are.
Now that you have done that, let's look at some basics:
Is It Running?
Now this is one of my rules that I stick to. I only buy a bike that is still running, the cosmetics are often far easier than the mechanical issues. If the bike is still running, although it may be worn it can be re-built. If an engine is a non-runner, it could have been sitting in weather for years, the entire internals are probably corroded and sized together. Considering that Japanese bikes use alloys which turn to white powder and steel that rusts, you may find the most of the engine is of no use.
Is the Petrol Tank Leaking?
Have a look in the tank for rust and around the bottom of the outside of the tank for little pinholes. Leaking rusty petrol tanks can be a nightmare to fix; in most cases you can throw them away, unless they are so rare that you are willing to shell out big bucks for an engineer to cut and weld new pieces.
Do You Want to Risk an Old Long-Parked Two-Stroke?
Also remember that a four-stroke engine is full of oil and a little more sealed up than a two-stroke engine which usually only has gearbox oil. So two-strokes often fare poorly when left for a length of time without starting. It's easier to tell the condition of a four-stroke engine, for instance if it has poor compression (easy to kick over) and it rattles, knocks and blows smoke, then it's probably time for a rebuild ... but at least it runs. Two-strokes on the other hand, especially vintage ones, are rattly, noisy and smokey from new, its much harder to pick up a serious mechanical problem, like a big end knock or a broken piston. Two Strokes are very simple engines, especially the old ones but will run amazingly with the most horrible things wrong inside, like a broken piston skirt, broken ring etc. But they are just waiting for that magic moment to self destruct and throw you over the handle bars.
What's the History?
This is where a few intelligent questions arise. Like: How long have you had the bike? How many miles have you done on it? Have you worked on the bike?
Have a look for the tell signs of bodgy mechanics, like silicone gasket goo around engine joins, burred screws, cracked engine cases, wired up bits etc.
If are lucky enough to get an old bike with a good running engine, but that has not been used much for years, then change the oil and spark plugs and clean out the fuel system and carbies and most important DON'T THRASH IT. An old bike needs to be gradually bedded in again, almost like running in a new bike. Run the bike for short periods and then check everything, gradually increasing the duration of each ride. Remember everything is old.
Bikes pre-late 1970s have points and a relatively simple ignition system. Electronic ignition systems came in primarily in the 80's and can be very hard to source and very expensive. $1000,00 for a new one is not uncommon. Be VERY careful working on the electrics on bikes with electronic ignition systems, even the power from a multi-meter can blow them up.
Water cooled two-strokes also came in during the late 70, but mainly 80's. Be wary, the water pumps have seals and bearings, when they wear, they generally leak water into the gearbox. Check the gear box for brown milky oil.
Many two-strokes also introduced power valves for example, Kawasaki KDX. These valves gum up with carbon and used oil, they can seize up and fail, but the bike will still run without them....as long as the disintegrating bits don't fall inside the engine. If the bike is old and has done some miles, count on replacing the power valves and the water pump seals, shaft and bearings...this ain't cheap.
Where You Can Get Parts
Finally there are some really good sites on eBay supplying new parts for old Japanese bikes at very reasonable prices. I have had no trouble getting parts for my 1973 Honda MT250 Elsinore (a very nice simple classic bike that was a revolution when released). Same for my 1973 Honda XL100, another classic, reliable bike. I have very easily rewired the bikes and found flasher cans, indicators, brake switches, mirrors, side plastics, decals, cables, and speedos all cheaply on eBay from all over the world.