by Victor Wanchena
Poor guy. He thought a Full House, queens over 10s, was a sure bet. He was wrong. As the winner of this last hand in a late night card game, I found myself in possession of a 1972 Yamaha DS7. That was the good news. The bad news was I was now the owner of a 34-year old bike that hadn’t run in at least 10 years. Bringing the mighty DS7 back to life was going to take some work. The following are the basic steps I used to resurrect my dead DS7.
A quick safety note; motorcycles contain flammable and hazardous substances. Use the proper caution when working on any motorcycle. If you are accident-prone or have ever lit yourself on fire, stop reading now. If any of the steps outlined here are more involved than you are comfortable with, bring your bike to a qualified mechanic. Inevitably the stuff you break costs more than the mechanic would have charged.
The first step in any project to revive a non-running machine is to give the bike a good visual inspection. Start at the front and work backwards. Look for any obvious signs of damage or major missing parts. This sounds obvious, but it will save time and effort down the line. Make a list of any needed parts. Test as many systems as you can, like brakes, throttle, clutch. If the battery is still serviceable, turn the bike on and test the lights, horn, blinkers but resist the urge to hit the starter. We’re not that far yet. Remember that even in heated storage a bike can deteriorate over time. Rubber parts are always susceptible to cracking. Critical components like tires, brake lines, and carb boots should be carefully inspected. Be sure to remove side covers and the air cleaner checking for damage. Mice love to use a motorcycle as pantry, stuffing seeds and crap all over the place.
Take a trip to your local bike shop and pick any parts needed including fresh oil, oil filter, spark plugs and fork oil. If your bike has separate oil for transmission and final drive, get fresh oil for them as well. If the battery has seen more than one president or was dead when you last checked the bike, do yourself a favor; just replace it.
The first step in reviving the motor is to make sure it turns over. Remove the spark plugs and spray a light oil, like fogging oil, into each cylinder to ensure good lubrication. Verify that the oil level in the crankcase is at proper level. If you have a kick start, gently turn the motor over. It you don’t have the benefit of a kick start, put the bike in first gear and push the bike forward or with it on the center stand and in gear rotate the rear wheel. The motor should rotate without much force. If doesn’t, stop. Something serious is wrong with the motor. On the DS7, which is an oil-injection two stroke, I also verified that the auto lube tank had oil in it and that the oil pump was still connected.
Now we move on to the ignition. If you’re lucky, nothing has become defective while the bike was sitting. Or in my case, I inherited a pile of parts and wires that once were the points ignition. The simplest way to check your ignition is to see if the spark plugs actually produce a spark. Insert a new spark plug in each plug wire. Make sure that they are grounded properly; a wire clipped from the plug body to the cylinder can help. Using a new or fully charged battery, crank the motor for several revolutions. You should see a strong blue spark at the spark plug. If not, you’re in for some wire tracing and an Ohmmeter. Refer to your service manual for specifics. And if you don’t have the benefit of a wiring diagram, check that all knowing oracle, AKA the web. It is amazing the obscure information that can be found trolling on the Internet. At the risk of stating the obvious, look for loose wires, corrosion, or other obvious defects. Sometimes simply unplugging and plugging in a connection with solve a problem. If the bike has points style ignition, verify they are opening and are set to the right gap. Points and the condenser are two items that should be replaced on any bike that’s been sitting.
Next step is to clean up the fuel system. The most important item here is to remove any old gasoline. Drain the tank and the carb bowls if so equipped. If the bike was stored properly there should be no reason to open the carbs. If instead you rolled the bike into a corner of the garage during the Reagan Administration and promptly forgot about it, you will most likely need to open them up. At very least, remove the carb bowls and clean any sediment out from them and spray the jets with carb cleaner. Normally you will need to remove the jets and thoroughly clean every opening. This is a job best left to pros, unless you are up for the challenge. Once the carbs are cleaned, it is time to add fresh fuel to the bike. Usually a gallon is all that is needed. As a safe guard on any oil-injection two-stroke like the DS7, I used a premixed oil and fuel just in case the oil pump was malfunctioning.
Now for the moment of truth; starting your bike. Verify that all hoses, clamps, and bolts loosened while working on the bike are tight. The new spark plugs you purchased should be installed. The battery should be fully charged and a gallon of fresh fuel should be added to the tank. When you hit the starter button, hopefully it starts on the first few cranks. If not, begin to trace down the issue. A motor needs three things to run: air, fuel, and spark. If a motor won’t start, one of these is the culprit.
So if everything has gone well to this point, it’s time to take your newly running machine for a short test ride. Check for proper inflation of the tires and operation of the brakes. If your bike has chain drive, check the tension of the chain and double check all axle nuts. Resist the urge at this point to leave on a multi-day trip with your newly running machine. Your tires are most likely beyond their useful life. Look for cracks on the sidewall. If they are more than 5 years old, do yourself and the bike a favor, replace them. Even cheap, modern tires are superior to the premium tires of 20 years ago.
After taking a short ride around the block a few times; it’s time to drain all those old fluids. Drain and replace the engine oil, the transmission and final drive oil (if so equipped). Once you’ve replaced all the fluids, you can now begin to evaluate how the bike runs and how much tuning and tweaking it will need.
After one good night in my garage I had the DS7 running. Some of the steps outlined above weren’t needed because of its two-stroke simplicity. I did have a little work deciphering the wiring for the ignition, but my patience was rewarded. It runs very well and it is wonderful example of vintage Japanese engineering.