Before you get back on that old bike, learn how to set timing on a motorcycle and how to change a motorcycle tire step by step with pictures.
Well we’re down to the wire on the final installment of our Honda CB175 revival So far we’ve cleaned the fuel system and put the carburetor back on after cleaning. This issue we will take a look at checking and cleaning the ignition points, followed by checking the engine timing and adjusting it if necessary. After that we’ll show you how we removed both wheels in anticipation of having the tires and tubes replaced. Once that’s done, we’ll install a new battery, double check our tire pressures, and reinstall the tank. After hooking up the carburetors and filling the tank with fuel, we should be ready for a road test. Let’s get started.
How to Set Timing on a Motorcycle
We start out by removing the alternator cover on the left side. We’re using our impact driver because the bits fit the cover screws better than the screwdrivers we had on hand. Have a tray underneath to catch any oil that flows out of the crankcase.
Next we remove the points cover, also on the left side of the engine. Paper is abrasive without being too abrasive, so it’s always a good choice to clean up the points without changing the gap. If paper doesn’t do the job, you can always move on to a points file or emery cloth.
Once we have the points clean, it’s time to check the gap. The nominal gap is .016″ and we’re using a spark plug wire gauge here, so our choices are .015″ and .018″. I prefer using a wire gauge as it’s easier to feel the gap. In this case the .015″ slides freely while the .018″ won’t pass at all. So we’re close enough to .016″.
Now we can move to checking and adjusting the timing. I was going to use a Xenon timing light, but this 175 liked to sling oil for distance while running with the cover off, so the old school static timing light was used instead. This one is self powered, so we’re testing with the ignition off. Here you can see that we have arrived at the F mark where the points should be opening but the light is still on, so we have some adjusting to do.
In the last photo, the timing light was still on when the rotor mark F passed the index mark on the crankcase, so we needed to move the timing. Slightly loosening the 2 large phillips head screws in this picture allow you to move the points plate to adjust the timing. The cam rotates counter clockwise, so rotating the plate clockwise advances the timing, which is what we need here.
It’s a trial and error adjustment because tightening the screws can slightly change the timing. Be patient and your result will be as here, where the timing light goes out just as the rotor passes the index mark.
How to Change a Motorcycle Tire
Now we’re on to changing the tires. Since we didn’t have a lift, we had to use the old method of raising the bike with a couple of 2 x 4s under the center stand. If you do this, find a way to lock the stand so the bike won’t roll off if you accidentally push it forward. I have a scar on my left forearm from learning that lesson the hard way when I was 15.
Straighten the bent legs of the cotter pin and remove it to allow you to remove the axle nut. Loosen and remove the axle nut. While not optimum, this adjustable wrench is just fine for the job if you’re careful. As always with an adjustable wrench, the movable jaw should face the direction of travel if possible.
Rotate the rear wheel and remove the master link and clear the chain from the rear sprocket in anticipation of removing the rear wheel. Remember when replacing the master link that the closed end of the locking clip should face the direction of travel.
Remove the cotter pin, nut and bolt that hold the brake stay to the rear wheel. Removal of cobwebs is desirable too.
Loosen and remove the brake adjusting nut. Depressing the foot lever should allow you to disengage the brake rod from the brake lever on the wheel.
Using a screwdriver in the through hole in the axle bolt for leverage, twist and pull the axle out of the wheel. Having a helper makes this much easier, but you can do it alone if needed.
With a little careful maneuvering, you can free the rear wheel from the swingarm and fender.
Moving to the front wheel, again you need to straighten and remove cotter pins, one holding the axle nut and the other keeping the brake cable in place. Not shown, the plate jack we are using to steady the bike so we can remove both wheels at once. Otherwise we’d be forced to take the wheels off one at a time.
Loosen the locknuts holding the brake cable to the brake plate and slacken off the brake cable enough to remove it from the end of the brake lever.
Remove the front brake stay after bending the lock tabs back on the lock washer attached to the stay.
Using a properly sized screwdriver, remove the screw holding the speedometer cable in place. Then pull the speedometer cable out of the hub.
Remove the front axle nut.
Now you can pull the front wheel axle out and remove the front wheel. We took our two wheels to our local independent motorcycle shop and had new tires and tubes mounted and balanced. Once that was finished, we just reversed all the disassembly steps and put the wheels back on the bike.
Our last steps included checking the tire pressure and installing a new battery. Once the gas tank was back on and attached to the carburetors, it was time to start it up and road test it. Jordan has been riding it and reports that it starts easily and handles well with the new tires. Now that it’s roadworthy he can clean and polish it to his liking.
Originally published in the March/April 2023 issue of Motorcycle Classics.
